Investigation of Characteristics of Impinging Jet for 1/5-Scale ECC injection

Energy Technology Data Exchange (ETDEWEB)

Shin, Byung Soo; Ko, Yung Joo; Bae, Hwang; Kwon, Tae Soon [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

2010-05-15

In ECCS of SMART reactor, safety injection pump discharges cooling water into the core to maintain the water level by filling the amount of loss of coolant under emergency situation such as SBLOCA. Once the ECCS starts to operate, the injected water will be impinged to the upper wall of core support barrel (CBS). And the water will fall along the wall forming liquid film or droplets as shown in Fig. 1(b) due to high Reynolds number. The breakup and film flow will be bypassed by high temperature and pressure steam-water mixture cross flow from RCP discharge into the atmosphere through broken injection nozzle. Then, the flow phenomena in the downcomer is very complex situation with including jet impingement, jet breakup, liquid entrainment, steam condensation, counter-current flow and etc. In this study, the hydraulic features of impinging jet were investigated through visualization for full scale test for simulation of SMART ECC jet and SWAT test of 1/5 simulated test for ECCS of SMART reactor and measurement of the film width. And the scaling method for SWAT test was discussed considering jet break up and other phenomena

Plasma jet source parameter optimisation and experiments on injection into Globus-M spherical tokamak

International Nuclear Information System (INIS)

Gusev, V.K.; Petrov, Yu.V.; Sakharov, N.V.; Semenov, A.A.; Voronin, A.V.

2005-01-01

Results of theoretical and experimental research on the plasma sources and injection of plasma and gas jet produced by the modified source into tokamak Globus-M are presented. An experimental test stand was developed for investigation of intense plasma jet generation. Optimisation of pulsed coaxial accelerator parameters by means of analytical calculations is performed with the aim of achieving the highest flow velocity at limited coaxial electrode length and discharge current. The optimal parameters of power supply to generate a plasma jet with minimal impurity contamination and maximum flow velocity were determined. A comparison of experimental and calculation results is made. Plasma jet parameters are measured, such as: impurity species content, pressure distribution across the jet, flow velocity, plasma density, etc. Experiments on the interaction of a higher kinetic energy plasma jet with the magnetic field and plasma of the Globus-M tokamak were performed. Experimental results on plasma and gas jet injection into different Globus-M discharge phases are presented and discussed. Results are presented on the investigation of plasma jet injection as the source for discharge breakdown, plasma current startup and initial density rise. (author)

Ideal magnetohydrodynamic simulations of unmagnetized dense plasma jet injection into a hot strongly magnetized plasma

OpenAIRE

Liu, Wei; Hsu, Scott C.

2010-01-01

We present results from three-dimensional ideal magnetohydrodynamic simulations of unmagnetized dense plasma jet injection into a uniform hot strongly magnetized plasma, with the aim of providing insight into core fueling of a tokamak with parameters relevant for ITER and NSTX (National Spherical Torus Experiment). Unmagnetized dense plasma jet injection is similar to compact toroid injection but with much higher plasma density and total mass, and consequently lower required injection velocit...

Direct injection of high pressure gas : scaling properties of pulsed turbulent jets

NARCIS (Netherlands)

Baert, R.S.G.; Klaassen, A.; Doosje, E.

2010-01-01

Existing gasoline DI injection equipment has been modified to generate single hole pulsed gas jets. Injection experiments have been performed at combinations of 3 different pressure ratios (2 of which supercritical) respectively 3 different hole geometries (i.e. length to diameter ratios). Injection

Simulation of Jetting in Injection Molding Using a Finite Volume Method

Directory of Open Access Journals (Sweden)

Shaozhen Hua

2016-05-01

Full Text Available In order to predict the jetting and the subsequent buckling flow more accurately, a three dimensional melt flow model was established on a viscous, incompressible, and non-isothermal fluid, and a control volume-based finite volume method was employed to discretize the governing equations. A two-fold iterative method was proposed to decouple the dependence among pressure, velocity, and temperature so as to reduce the computation and improve the numerical stability. Based on the proposed theoretical model and numerical method, a program code was developed to simulate melt front progress and flow fields. The numerical simulations for different injection speeds, melt temperatures, and gate locations were carried out to explore the jetting mechanism. The results indicate the filling pattern depends on the competition between inertial and viscous forces. When inertial force exceeds the viscous force jetting occurs, then it changes to a buckling flow as the viscous force competes over the inertial force. Once the melt contacts with the mold wall, the melt filling switches to conventional sequential filling mode. Numerical results also indicate jetting length increases with injection speed but changes little with melt temperature. The reasonable agreements between simulated and experimental jetting length and buckling frequency imply the proposed method is valid for jetting simulation.

Investigation of the motion of diesel injection jets using high-speed cinematography and short time holography

International Nuclear Information System (INIS)

Eisfeld, F.

1987-01-01

The knowledge about the penetration of diesel injection jets, particularly about the flow within the short behind the nozzle, and the arising of droplets from an injection jet is very limited. Experimental investigations are required to describe the process of penetration and spreading of the jet. The research method requires high speed cinematography and short time holography. Problems in the investigation method are described

Pulsed, supersonic fuel jets-A review of their characteristics and potential for fuel injection

International Nuclear Information System (INIS)

Milton, B.E.; Pianthong, K.

2005-01-01

High pressure fuel injection has provided considerable benefits for diesel engines, substantially reducing smoke levels while increasing efficiency. Current maximum pressures provide jets that are at less than the sonic velocity of the compressed air in the cylinders at injection. It has been postulated that a further increase into the supersonic range may benefit the combustion process due to increased aerodynamic atomization and the presence of jet bow shock waves that provide higher temperatures around the fuel. Pulsed, supersonic injection may also be beneficial for scramjet engines. The current program is examining pulsed, supersonic jets from a fundamental viewpoint both experimentally and numerically. Shock wave structures have been viewed for jets ranging from 600 to 2400 m/s, velocity attenuation and penetration distance measured, different nozzle designs examined and autoignition experiments carried out. Inside the nozzle, numerical simulation using the Autodyne code has been used to support an analytic approach while in the spray, the FLUENT code has been used. While benefits have not yet been defined, it appears that some earlier claims regarding autoignition at atmospheric conditions were optimistic but that increased evaporation and mixing are probable. The higher jet velocities are likely to mean that wall interactions are increased and hence matching such injectors to engine size and airflow patterns will be important

Control, data acquisition and analysis for the JET neutral injection test bed

International Nuclear Information System (INIS)

Jones, T.T.C.; Brenan, P.R.; Rodgers, M.E.; Stork, D.; Young, I.D.

1984-01-01

The Neutral Injection Test-Bed (NITB) is a major experimental assembly in support of the Neutral Beam Heating Programme for JET. In addition to its prime function of testing the Neutral Injection hardware, the Test Bed serves as the prototype to test the computer control and data acquisition system, which is described. (author)

High kinetic energy plasma jet generation and its injection into the Globus-M spherical tokamak

International Nuclear Information System (INIS)

Voronin, A.V.; Gusev, V.K.; Petrov, Yu.V.; Sakharov, N.V.; Abramova, K.B.; Sklyarova, E.M.; Tolstyakov, S.Yu.

2005-01-01

Progress in the theoretical and experimental development of the plasma jet source and injection of hydrogen plasma and neutral gas jets into the Globus-M spherical tokamak is discussed. An experimental test bed is described for investigation of intense plasma jets that are generated by a double-stage plasma gun consisting of an intense source for neutral gas production and a conventional pulsed coaxial accelerator. A procedure for optimizing the accelerator parameters so as to achieve the maximum possible flow velocity with a limited discharge current and a reasonable length of the coaxial electrodes is presented. The calculations are compared with experiment. Plasma jet parameters, among them pressure distribution across the jet, flow velocity, plasma density, etc, were measured. Plasma jets with densities of up to 10 22 m -3 , total numbers of accelerated particles (1-5) x 10 19 , and flow velocities of 50-100 km s -1 were successfully injected into the plasma column of the Globus-M tokamak. Interferometric and Thomson scattering measurements confirmed deep jet penetration and a fast density rise ( 19 to 1 x 10 19 ) did not result in plasma degradation

Mixing enhancement in a scramjet combustor using fuel jet injection swirl

Science.gov (United States)

Flesberg, Sonja M.

The scramjet engine has proven to be a viable means of powering a hypersonic vehicle, especially after successful flights of the X-51 WaveRider and various Hy-SHOT test vehicles. The major challenge associated with operating a scramjet engine is the short residence time of the fuel and oxidizer in the combustor. The fuel and oxidizer have only milliseconds to mix, ignite and combust in the combustion chamber. Combustion cannot occur until the fuel and oxidizer are mixed on a molecular level. Therefore the improvement of mixing is of utmost interest since this can increase combustion efficiency. This study investigated mixing enhancement of fuel and oxidizer within the combustion chamber of a scramjet by introducing swirl to the fuel jet. The investigation was accomplished with numerical simulations using STAR-CCM+ computational fluid dynamic software. The geometry of the University of Virginia Supersonic Combustion Facility was used to model the isolator, combustor and nozzle of a scramjet engine for simulation purposes. Experimental data from previous research at the facility was used to verify the simulation model before investigating the effect of fuel jet swirl on mixing. The model used coaxial fuel jet with a swirling annular jet. Single coaxial fuel jet and dual coaxial fuel jet configurations were simulated for the investigation. The coaxial fuel jets were modelled with a swirling annular jet and non-swirling core jet. Numerical analysis showed that fuel jet swirl not only increased mixing and entrainment of the fuel with the oxidizer but the mixing occurred further upstream than without fuel jet swirl. The burning efficiency was calculated for the all the configurations. An increase in burning efficiency indicated an increase in the mixing of H2 with O2. In the case of the single fuel jet models, the maximum burning efficiency increase due to fuel injection jet swirl was 23.3%. The research also investigated the possibility that interaction between two

Jet Injection of 1% buffered lidocaine versus topical ELA-Max for anesthesia before peripheral intravenous catheterization in children: a randomized controlled trial.

Science.gov (United States)

Spanos, Stephanie; Booth, Rebekah; Koenig, Heidi; Sikes, Kendra; Gracely, Edward; Kim, In K

2008-08-01

Peripheral intravenous (PIV) catheter insertion is a frequent, painful procedure that is often performed with little or no anesthesia. Current approaches that minimize pain for PIV catheter insertion have several limitations: significant delay for onset of anesthesia, inadequate anesthesia, infectious disease exposure risk from needlestick injuries, and patients' needle phobia. Comparison of the anesthetic effectiveness of J-Tip needle-free jet injection of 1% buffered lidocaine to the anesthetic effectiveness of topical 4% ELA-Max for PIV catheter insertion. A prospective, block-randomized, controlled trial comparing J-Tip jet injection of 1% buffered lidocaine to a 30-minute application of 4% ELA-Max for topical anesthesia in children 8 to 15 years old presenting to a tertiary care pediatric emergency department for PIV catheter insertion. All subjects recorded self-reported visual analog scale (VAS) scores for pain at time of enrollment and pain felt following PIV catheter insertion. Jet injection subjects also recorded pain of jet injection. Subjects were videotaped during jet injection and PIV catheter insertion. Videotapes were reviewed by a single blinded reviewer for observer-reported VAS pain scores for jet injection and PIV catheter insertion. Of the 70 children enrolled, 35 were randomized to the J-Tip jet injection group and 35 to the ELA-Max group. Patient-recorded enrollment VAS scores for pain were similar between groups (P = 0.74). Patient-recorded VAS scores were significantly different between groups immediately after PIV catheter insertion (17.3 for J-Tip jet injection vs 44.6 for ELA-Max, P ELA-Max, P = 0.23). J-Tip jet injection of 1% buffered lidocaine provided greater anesthesia than a 30-minute application of ELA-Max according to patient self-assessment of pain for children aged 8 to 15 years undergoing PIV catheter insertion.

Uniform and non-uniform inlet temperature of a vertical hot water jet injected into a rectangular tank

KAUST Repository

El-Amin, Mohamed; Sun, Shuyu

2010-01-01

In most of real-world applications, such as the case of heat stores, inlet is not kept at a constant temperature but it may vary with time during charging process. In this paper, a vertical water jet injected into a rectangular storage tank is measured experimentally and simulated numerically. Two cases of study are considered; one is a hot water jet with uniform inlet temperature (UIT) injected into a cold water tank, and the other is a cold water jet with non-uniform inlet temperature (NUIT) injected into a hot water tank. Three different temperature differences and three different flow rates are studied for the hot water jet with UIT which is injected into a cold water tank. Also, three different initial temperatures with constant flow rate as well as three different flow rates with constant initial temperature are considered for the cold jet with NUIT which is injected into a hot water tank. Turbulence intensity at the inlet as well as Reynolds number for the NUIT cases are therefore functions of inlet temperature and time. Both experimental measurements and numerical calculations are carried out for the same measured flow and thermal conditions. The realizable k-ε model is used for modeling the turbulent flow. Numerical solutions are obtained for unsteady flow while pressure, velocity, temperature and turbulence distributions inside the water tank are analyzed. The simulated results are compared to the measured results, and they show a good agreement at low temperatures. © 2010 IEEE.

Uniform and non-uniform inlet temperature of a vertical hot water jet injected into a rectangular tank

KAUST Repository

El-Amin, Mohamed

2010-12-01

In most of real-world applications, such as the case of heat stores, inlet is not kept at a constant temperature but it may vary with time during charging process. In this paper, a vertical water jet injected into a rectangular storage tank is measured experimentally and simulated numerically. Two cases of study are considered; one is a hot water jet with uniform inlet temperature (UIT) injected into a cold water tank, and the other is a cold water jet with non-uniform inlet temperature (NUIT) injected into a hot water tank. Three different temperature differences and three different flow rates are studied for the hot water jet with UIT which is injected into a cold water tank. Also, three different initial temperatures with constant flow rate as well as three different flow rates with constant initial temperature are considered for the cold jet with NUIT which is injected into a hot water tank. Turbulence intensity at the inlet as well as Reynolds number for the NUIT cases are therefore functions of inlet temperature and time. Both experimental measurements and numerical calculations are carried out for the same measured flow and thermal conditions. The realizable k-ε model is used for modeling the turbulent flow. Numerical solutions are obtained for unsteady flow while pressure, velocity, temperature and turbulence distributions inside the water tank are analyzed. The simulated results are compared to the measured results, and they show a good agreement at low temperatures. © 2010 IEEE.

The Jet multipellet launcher and fueling of Jet plasmas by multipellet injection

International Nuclear Information System (INIS)

Kupschus, P.; Cheetham, A.; Denne, B.; Gadeberg, M.; Gowers, C.; Gondhalekar, A.; Tubbing, B.; Schmidt, G.L.; Colestock, P.; Hammett, G.; Zarnstorff, M.

1989-01-01

A multipellet long-pulse plasma fueling system, in operation on JET, is described. Plasma fueling experiments are performed with the 2.7 and 4.0 mm guns operating in the multipellet mode. The penetration of the pellets, which agrees with neutral and plasma shielding models, is shown. Details of particle deposition in ohmic plasmas and the plasma density evolution from far-infrared data, in response to pellet injection, are illustrated. A variety of plasma density profile shapes is produced with peak to average values ranging up to 2.5 and peak plasma density up to 1.2 X 10 20 /m 3

Flow structure of conical distributed multiple gas jets injected into a water chamber

Energy Technology Data Exchange (ETDEWEB)

Zhao, Jiajun; Yu, Yonggang [Nanjing University of Science and Technology, Nanjing (China)

2017-04-15

Based on an underwater gun firing project, a mock bullet with several holes on the head was designed and experimented to observe the combustion gas injected into a cylindrical water chamber through this mock bullet. The combustion gas jets contain one vertical central jet and 4 to 8 slant lateral jets. A high speed camera system was used to record the expansion of gas jets in the experimental study. In numerical simulations, the Euler two-fluid model and volume of fluid method were adopted to describe the gas-liquid flow. The results show the backflow zone in lateral jet is the main factor influencing the gas-liquid turbulent mixing in downstream. On cross sections, the gas volume fraction increased with time but the growth rate decreased. With a change of nozzle structure, the gas fraction was more affected than the shock structure.

Numerical Modeling of a Jet Ignition Direct Injection (JI DI LPG Engine

Directory of Open Access Journals (Sweden)

Albert Boretti

2017-01-01

Full Text Available The paper presents indirectly validated simulations of the operation of a LPG engine fitted with Direct Injection (DI and Jet Ignition (JI. It is demonstrated that the engine may have diesel like efficiencies and load control by quantity of fuel injected.  As the liquid propane quickly evaporates after injection in the main chamber, the main chamber mixture may be much closer to stoichiometry than a diesel for a better specific power at low engine speeds. This design also works at the high engine speeds impossible for the diesel, as combustion within the main chamber is controlled by the turbulent mixing rather than the vaporization and diffusion processes of the injected fuel of the diesel. 

Emergent kink stability of a magnetized plasma jet injected into a transverse background magnetic field

Science.gov (United States)

Zhang, Yue; Gilmore, Mark; Hsu, Scott C.; Fisher, Dustin M.; Lynn, Alan G.

2017-11-01

We report experimental results on the injection of a magnetized plasma jet into a transverse background magnetic field in the HelCat linear plasma device at the University of New Mexico [M. Gilmore et al., J. Plasma Phys. 81(1), 345810104 (2015)]. After the plasma jet leaves the plasma-gun muzzle, a tension force arising from an increasing curvature of the background magnetic field induces in the jet a sheared axial-flow gradient above the theoretical kink-stabilization threshold. We observe that this emergent sheared axial flow stabilizes the n = 1 kink mode in the jet, whereas a kink instability is observed in the jet when there is no background magnetic field present.

Hanford 100-N Area In Situ Apatite and Phosphate Emplacement by Groundwater and Jet Injection: Geochemical and Physical Core Analysis

Energy Technology Data Exchange (ETDEWEB)

Szecsody, James E.; Vermeul, Vincent R.; Fruchter, Jonathan S.; Williams, Mark D.; Rockhold, Mark L.; Qafoku, Nikolla; Phillips, Jerry L.

2010-07-01

The purpose of this study is to evaluate emplacement of phosphate into subsurface sediments in the Hanford Site 100-N Area by two different technologies: groundwater injection of a Ca-citrate-PO4 solution and water-jet injection of sodium phosphate and/or fish-bone apatite. In situ emplacement of phosphate and apatite adsorbs, then incorporates Sr-90 into the apatite structure by substitution for calcium. Overall, both technologies (groundwater injection of Ca-citrate-PO4) and water-jet injection of sodium phosphate/fish-bone apatite) delivered sufficient phosphate to subsur¬face sediments in the 100-N Area. Over years to decades, additional Sr-90 will incorporate into the apatite precipitate. Therefore, high pressure water jetting is a viable technology to emplace phosphate or apatite in shallow subsurface sediments difficult to emplace by Ca-citrate-PO4 groundwater injections, but further analysis is needed to quantify the relevant areal extent of phosphate deposition (in the 5- to 15-ft distance from injection points) and cause of the high deposition in finer grained sediments.

Structure and Dynamics of Fuel Jets Injected into a High-Temperature Subsonic Crossflow: High-Data-Rate Laser Diagnostic Investigation under Steady and Oscillatory Conditions

Energy Technology Data Exchange (ETDEWEB)

Lucht, Robert [Purdue Univ., West Lafayette, IN (United States); Anderson, William [Purdue Univ., West Lafayette, IN (United States)

2015-01-23

An investigation of subsonic transverse jet injection into a subsonic vitiated crossflow is discussed. The reacting jet in crossflow (RJIC) system investigated as a means of secondary injection of fuel in a staged combustion system. The measurements were performed in test rigs featuring (a) a steady, swirling crossflow and (b) a crossflow with low swirl but significant oscillation in the pressure field and in the axial velocity. The rigs are referred to as the steady state rig and the instability rig. Rapid mixing and chemical reaction in the near field of the jet injection is desirable in this application. Temporally resolved velocity measurements within the wake of the reactive jets using 2D-PIV and OH-PLIF at a repetition rate of 5 kHz were performed on the RJIC flow field in a steady state water-cooled test rig. The reactive jets were injected through an extended nozzle into the crossflow which is located in the downstream of a low swirl burner (LSB) that produced the swirled, vitiated crossflow. Both H2/N2 and natural gas (NG)/air jets were investigated. OH-PLIF measurements along the jet trajectory show that the auto-ignition starts on the leeward side within the wake region of the jet flame. The measurements show that jet flame is stabilized in the wake of the jet and wake vortices play a significant role in this process. PIV and OH–PLIF measurements were performed at five measurement planes along the cross- section of the jet. The time resolved measurements provided significant information on the evolution of complex flow structures and highly transient features like, local extinction, re-ignition, vortex-flame interaction prevalent in a turbulent reacting flow. Nanosecond-laser-based, single-laser-shot coherent anti-Stokes Raman scattering (CARS) measurements of temperature and H2 concentraiton were also performed. The structure and dynamics of a reacting transverse jet injected into a vitiated oscillatory crossflow presents a unique opportunity for

Pool scrubbing and hydrodynamic experiments on jet injection regime

International Nuclear Information System (INIS)

Peyres, V.; Espigares, M.M.; Polo, J.; Escudero, M.J.; Herranz, L.E.; Lopez-Jimenez, J.

1995-01-01

Plant analyses have shown that pool scrubbing can play an important role in source term during PWR risk dominant sequences. An examination ofboundary conditions governing fission products and aerosols transport through aqueous beds revealed that most of radioactivity is discharged into the pool under jet injection regime. This fact and the lack of experimental data under such conditions pointed the need of setting out an experimental programme which provided reliable experimental data to validate code models. In this report the major results of a pool scrubbing experimental programme carried out in PECA facility are presented. One of the major findings was that a remarkable fraction of particle absorption was not a function of the residence time of bubbles rising through the pool. Such a contribution was assumed to be associated to aerosol removal mechanisms acting at the pool entrance. As a consequence, a hydrodynamic experimental plan was launched to examine the gas behaviour during the initial stages in the pool. Size and shape of gas nuclei the pool were measured and fitted to a long normal distribution. Particularly, size was found to be quite sensitive to inletgas flow and at minor extent to gas composition and pool temperature. SPARC90 and BUSCA-AUG92 were used to simulate the retention tests. Whereas SPARC90 showed a pretty good agreement with experimental data, BUSCA-AUG92 results were far away from measurements in all the cases. SPARC90consistency apparently pointed out the important role of fission products and aerosols retention at the injection zone; nonetheless, a peer examination of pool scrubbing phenomenology at the pool entrance should be carried out to test both hydrodynamic and removal models. Hence, one of the major highlights drawn from this work was the need of further research under representative severe accident conditions (i.e., saturated pools, jet injection regimes, etc.), as well as separate effect tests to validate, improve and

Pool scrubbing and hydrodynamic experiment on jet injection regime

Energy Technology Data Exchange (ETDEWEB)

Peyres, V.; Espigares, M.M.; Polo, J.; Escudero, M.J.; Herranz, L.E.; Lopez, J.

1995-07-01

Plant analyses nave shown that pool scrubbing can play an important role in source term during PWR risk dominant sequences. An examination of boundary conditions governing fission products and aerosols transport through aqueous beds revealed that most of radioactivity is discharged into the pool under jet injection regime. This fact and the lack of experimental data under such conditions pointed the need of setting out an experimental programme which provided reliable experimental data to validate code models. In this report the major results of a pool scrubbing experimental programme carried out in PECA facility are presented. One of the major findings was that a remarkable fraction of particle absorption was not a function of the residence time of bubbles rising through the pool. Such a contribution was assumed to be associated to aerosol removal mechanism acting at the pool entrance. As a consequence. a hydrodynamic experimental plan was launched to examine the gas behaviour during the initial stages in the pool. Size and shape of gas nuclei in the pool were measured and fitted to a lognormal distribution. Particularly, size was found to be quite sensitive to inlet gas flow and at minor extent to gas composition and pool temperature. SPARC90 and BUSCA-AUG92 were used to simulate the retention tests. Whereas SPARC90 showed a pretty good agreement with experimental data, BUSCA-AUG92 results were far away from measurements in all the cases. SPARC90 consistency apparently pointed out the important role of fission products and aerosols retention at the injection zone; nonetheless, a peer examination of pool scrubbing phenomenology at the pool entrance should be carried out to test both hydrodynamic and removal models. Hence, one of the major high lights drawn from this work was the need of further research under representative severe accident conditions (i.e., saturated pools, jet injection regimes, etc.), as well as separate effect tests to validate, improve and

Pool scrubbing and hydrodynamic experiment on jet injection regime

International Nuclear Information System (INIS)

Peyres, V.; Espigares, M.M.; Polo, J.; Escudero, M.J.; Herranz, L.E.; Lopez, J.

1995-01-01

Plant analyses nave shown that pool scrubbing can play an important role in source term during PWR risk dominant sequences. An examination of boundary conditions governing fission products and aerosols transport through aqueous beds revealed that most of radioactivity is discharged into the pool under jet injection regime. This fact and the lack of experimental data under such conditions pointed the need of setting out an experimental programme which provided reliable experimental data to validate code models. In this report the major results of a pool scrubbing experimental programme carried out in PECA facility are presented. One of the major findings was that a remarkable fraction of particle absorption was not a function of the residence time of bubbles rising through the pool. Such a contribution was assumed to be associated to aerosol removal mechanism acting at the pool entrance. As a consequence. a hydrodynamic experimental plan was launched to examine the gas behaviour during the initial stages in the pool. Size and shape of gas nuclei in the pool were measured and fitted to a lognormal distribution. Particularly, size was found to be quite sensitive to inlet gas flow and at minor extent to gas composition and pool temperature. SPARC90 and BUSCA-AUG92 were used to simulate the retention tests. Whereas SPARC90 showed a pretty good agreement with experimental data, BUSCA-AUG92 results were far away from measurements in all the cases. SPARC90 consistency apparently pointed out the important role of fission products and aerosols retention at the injection zone; nonetheless, a peer examination of pool scrubbing phenomenology at the pool entrance should be carried out to test both hydrodynamic and removal models. Hence, one of the major high lights drawn from this work was the need of further research under representative severe accident conditions (i.e., saturated pools, jet injection regimes, etc.), as well as separate effect tests to validate, improve and

A bio-ballistic micro-jet for drug injection into animal skin using a Nd:YAG laser

Science.gov (United States)

Yoh, J. J.; Jang, H.; Park, M.; Han, T.; Hah, J.

2016-01-01

Imaging of the abdominal skin of a guinea pig after injecting a fluorescent probe and biotin via the laser-induced ballistic technique revealed the epidermal and dermal layers which were stained well below 60 \\upmu m underneath the outer layer of the skin. An extensive network of cells was evident in the deeper layer of the stained dermis as the distributed fluorescein isothiocyanate dose was administered by repeated injection using a laser-based micro-jet. We performed optically controlled release of the drug by breaching the guinea pig's skin tissue targeting the region 10-400 \\upmu m beneath the outermost layer. Tissue damage was minimized by reducing the injection volume to approximately 100 nl per pulse. This was done using a micro-jet diameter equal to half of that of a conventional 200 \\upmu m syringe needle. Thus, the optimally controlled delivery of liquid drugs using an irradiated laser pulse was shown to be possible.

Test for Jet Flow Induced by Steam Jet Condensation Using the GIRLS Facility

International Nuclear Information System (INIS)

Kim, Yeon Sik; Yoon, Y. J.; Song, C. H.

2007-03-01

To investigate the characteristics of the turbulent jet induced by steam jet condensation in a water tank through a single-hole sparger an experimental investigation was performed using the GIRLS facility. The experiments were conducted with respect to two cases, e.g. horizontal and vertical upward injections. For the measurements, pitot tube and thermocouples were used for turbulent flow velocity and temperatures, respectively. Overall flow shapes of the turbulent jet by the steam jet condensation are similar to those of axially symmetric turbulent jet flows. The angular coefficients of turbulent rays are quantitatively comparable between the traditional turbulent jet flows and the turbulent jet flows induced by the steam jet condensation in this work. Although the turbulent flows were induced by the horizontally injected steam jet condensation, general theory of turbulent jets was found to be applicable to the turbulent flows of this work. But for the vertically upward injection case, experimental data were quite deviated from the theoretical ones, which is considered due to the buoyancy effect

CoJet technology for oxygen injection injection in EAFS - industrial gases supply and customers productivity improvements; Tecnologia CoJet para injecao de oxigenio em FEAS - fornecimento de gases e aumento da produtividade dos clientes

Energy Technology Data Exchange (ETDEWEB)

Marques, Izaias Lucas; Zagury, Pedro Athias [White Martins Gases Industriais Ltda., Rio de Janeiro, RJ (Brazil)

2010-07-01

PRAXAIR is one of the largest industrial gases producers of the World, being present in more than 40 countries and strongly connected to the steel industry. PRAXAIR has experience to supply products and services to all kinds of steel mills. Several technologies developed by the Company, such as CoJet (a system to coherent oxygen jet injection in EAF and BOF furnaces), Slag Splashing (splashing slag to cover BOF furnaces walls increasing refractory wear campaign life), AOD (a process for specialty steel production) and others, are currently in commercial operation in different parts of the world. In Brazil, Praxair is the owner of White Martins, the largest industrial gases company in South America, present in nine countries of the continent. Company's portfolio includes atmospheric gases, carbonic gas production, acetylene, hydrogen, specialty and health and care gases, mixtures for welding, gas seamless steel cylinders, applications equipment, and storage and gases transportation. The Company also operates a natural gas liquefaction unit. In addition to technologies and process, Praxair / White Martins can also supply solutions for measurement, control and gases injection, according to strict safety and quality standards. The present work has the objective to show the benefits of the CoJet EAF System, oxygen injectors positioned in the furnace walls. In 2009, two systems have been installed in South American mills and the results achieved will be following discussed. (author)

Potential safe termination by injection of polypropylene pellets in JET

International Nuclear Information System (INIS)

Schmidt, G.L.; Ali-Arshad, S.; Bartlett, D.

1995-01-01

Thermal energy and the magnetic field energy associated with the plasma current must be dissipated safely when a tokamak discharge is terminated in a disruption. Magnetic energy can be dissipated by impurity radiation if position control is maintained. Prior to the dissipation of magnetic energy, thermal energy is usually conducted to the plasma contact points on a 1ms time scale in a thermal quench. A resistive, highly radiating plasma formed prior to the thermal quench, might dissipate both the thermal and magnetic energy by radiation minimizing damage due to local deposition. High speed injection of a low Z material can produce a resistive, highly radiating plasma on a 1ms time scale. Neon has recently been used in such an application on JT60-U. A large carbon pellet producing dilution temperatures < 1 keV is a possible alternative. This paper summarizes the results of an initial experiment performed in JET using carbon injected at high speed, as a 6mm polypropylene pellet, to investigate this potential approach to a safe plasma termination

Numerical simulation of flow characteristics of lean jet to cross-flow in safety injection of reactor cooling system

International Nuclear Information System (INIS)

Wang Haijun; He Huining; Luo Yushan; Wang Weishu

2011-01-01

In the present work, a numerical simulation was performed to study the flow characteristics of lean jet to cross flow in a main tube in the safety injection of reactor cooling system. The influence scope and mixing characteristics of the confined lean jet in cross-flow were studied. It can be concluded that three basic flow regimes are marked, namely the attached lean jet, lift-off lean jet and impinging lean jet. The velocity ratio V R is the key factor in the flow state. The depth and region of jet to main flow are enhanced with the increase of the velocity ratio. The jet flow penetrates through the main flow with the increase of the velocity ratio. At higher velocity ratio, the jet flow strikes the main flow bottom and circumfluence happens in upriver of main flow. The vortex flow characteristics dominate the flow near region of jet to cross-flow and the mixture of jet to cross-flow. At different velocity ratio V R , the vortex grows from the same displacement, but the vortex type and the vortex is different. At higher velocity ratio, the vortex develops fleetly, wears off sharp and dies out sharp. The study is very important to the heat transfer experiments of cross-flow jet and thermal stress analysis in the designs of nuclear engineering. (authors)

Needle-free jet injection of rapid-acting insulin improves early postprandial glucose control in patients with diabetes

NARCIS (Netherlands)

Engwerda, E.E.; Tack, C.J.J.; Galan, B.E. de

2013-01-01

OBJECTIVE: Clamp studies have shown that the absorption and action of rapid-acting insulin are faster with injection by a jet injector than with administration by conventional pen. To determine whether these pharmacokinetic changes also exist in patients with diabetes and benefit postprandial

Analysis of High Speed Jets Produced by a Servo Tube Driven Liquid Jet Injector

Science.gov (United States)

Portaro, Rocco; Ng, Hoi Dick

2017-11-01

In today's healthcare environment many types of medication must be administered through the use of hypodermic needles. Although this practice has been in use for many years, drawbacks such as accidental needle stick injuries, transmission of deadly viruses and bio-hazardous waste are still present. This study focuses on improving a needle free technology known as liquid jet injection, through the implementation of a linear servo tube actuator for the construction of a fully closed loop liquid jet injection system. This device has the ability to deliver both micro- and macro- molecules, high viscosity fluids whilst providing real time control of the jet pressure profile for accurate depth and dispersion control. The experiments are conducted using a prototype that consists of a 3 kW servo tube actuator, coupled to a specially designed injection head allowing nozzle size and injection volume to be varied. The device is controlled via a high speed servo amplifier and FPGA. The high speed jets emanating from the injector are assessed via high speed photography and through the use of a force transducer. Preliminary results indicate that the system allows for accurate shaping of the jet pressure profile, making it possible to target different tissue depths/types accurately.

Contribution to the study of an lpg jet in the combustion chamber of a spark-ignition engine; Contribution a l'etude d'un jet de gpl dans la chambre de combustion d'un moteur a allumage commande, pour differentes strategies d'injection

Energy Technology Data Exchange (ETDEWEB)

Duong Viet, D.

2002-07-01

It appears tempting to combine the less polluting combustion of LPG with the energy performances of a direct injection spark-ignition engine. To this aim the study of high pressure injection of a liquid LPG jet, directly inside the combustion chamber of an engine was performed in two ways: Experimental studies: one with fast cinematography and another with the method of Doppler phases in an one-cylinder 'transparent' engine for various conditions of injection and without combustion. They respectively deliver empirical laws for the jet development and some informations about size and speed of the droplets of LPG. A modeling of the jet could then be made on the basis of a turbulent and deviated jet the parameters of which could be adjusted using results of the preceding experimental study. (author)

Initial instability of round liquid jet at subcritical and supercritical environments

International Nuclear Information System (INIS)

Muthukumaran, C. K.; Vaidyanathan, Aravind

2016-01-01

In the present experimental work, the behavior of laminar liquid jet in its own vapor as well as supercritical fluid environment is conducted. Also the study of liquid jet injection into nitrogen (N_2) environment is carried out at supercritical conditions. It is expected that the injected liquid jet would undergo thermodynamic transition to the chamber condition and this would alter the behavior of the injected jet. Moreover at such conditions there is a strong dependence between thermodynamic and fluid dynamic processes. Thus the thermodynamic transition has its effect on the initial instability as well as the breakup nature of the injected liquid jet. In the present study, the interfacial disturbance wavelength, breakup characteristics, and mixing behavior are analysed for the fluoroketone liquid jet that is injected into N_2 environment as well as into its own vapor at subcritical to supercritical conditions. It is observed that at subcritical chamber conditions, the injected liquid jet exhibits classical liquid jet characteristics with Rayleigh breakup at lower Weber number and Taylor breakup at higher Weber number for both N_2 and its own environment. At supercritical chamber conditions with its own environment, the injected liquid jet undergoes sudden thermodynamic transition to chamber conditions and single phase mixing characteristics is observed. However, the supercritical chamber conditions with N_2 as ambient fluid does not have significant effect on the thermodynamic transition of the injected liquid jet.

Current-Voltage Characteristics of DC Discharge in Micro Gas Jet Injected into Vacuum Environment

International Nuclear Information System (INIS)

Matra, K; Furuta, H; Hatta, A

2013-01-01

A current-voltage characteristic of direct current (DC) gas discharge operated in a micro gas jet injected into a secondary electron microscope (SEM) chamber is presented. Ar gas was injected through a 30 μm orifice gas nozzle (OGN) and was evacuated by an additional pump to keep the high vacuum environment. Gas discharges were ignited between the OGN as anode and a counter electrode of Si wafer. The discharge was self-pulsating in most of the cases while it was stable at lower pressure, larger gap length, and larger time averaged current. The self-pulsating discharge was oscillated by the RC circuit consisting of a stray capacitor and a large ballast resistor. The real time plots of voltage and current during the pulsating was investigated using a discharge model.

Pellet injectors for JET

International Nuclear Information System (INIS)

Andelfinger, C.; Buechl, K.; Lang, R.S.; Schilling, H.B.; Ulrich, M.

1981-09-01

Pellet injection for the purpose of refuelling and diagnostic of fusion experiments is considered for the parameters of JET. The feasibility of injectors for single pellets and for quasistationary refuelling is discussed. Model calculations on pellet ablation with JET parameters show the required pellet velocity ( 3 ). For single pellet injection a light gas gun, for refuelling a centrifuge accelerator is proposed. For the latter the mechanical stress problems are discussed. Control and data acquisition systems are outlined. (orig.)

Transverse jets and their control

Energy Technology Data Exchange (ETDEWEB)

Karagozian, Ann R. [Department of Mechanical and Aerospace Engineering, University of California, 48-121 Engineering IV, Los Angeles, CA 90095 (United States)

2010-10-15

The jet in crossflow or transverse jet has been studied extensively because of its relevance to a wide variety of flows in technological systems, including fuel or dilution air injection in gas turbine engines, thrust vector control for high speed airbreathing and rocket vehicles, and exhaust plumes from power plants. These widespread applications have led over the past 50+ years to experimental, theoretical, and numerical examinations of this fundamental flowfield, with and without a combustion reaction, and with single or multi-phase flow. The complexities in this flowfield, whether the jet is introduced flush with respect to the injection wall or from an elevated pipe or nozzle, present challenges in accurately interrogating, analyzing, and simulating important jet features. This review article provides a background on these studies and applications as well as detailed features of the transverse jet, and mechanisms for its control via active means. Promising future directions for the understanding, interrogation, simulation, and control of transverse jet flows are also identified and discussed. (author)

The effect of water injection on nitric oxide emissions of a gas turbine combustor burning ASTM Jet-A fuel

Science.gov (United States)

Marchionna, N. R.; Diehl, L. A.; Trout, A. M.

1973-01-01

Tests were conducted to determine the effect of water injection on oxides of nitrogen (NOx) emissions of a full annular, ram induction gas turbine combustor burning ASTM Jet-A fuel. The combustor was operated at conditions simulating sea-level takeoff and cruise conditions. Water at ambient temperature was injected into the combustor primary zone at water-fuel ratios up to 2. At an inlet-air temperature of 589 K (600 F) water injection decreased the NOx emission index at a constant exponential rate: NOx = NOx (o) e to the -15 W/F power (where W/F is the water-fuel ratio and NOx(o) indicates the value with no injection). The effect of increasing combustor inlet-air temperature was to decrease the effect of the water injection. Other operating variables such as pressure and reference Mach number did not appear to significantly affect the percent reduction in NOx. Smoke emissions were found to decrease with increasing water injection.

Combined aerodynamic and electrostatic atomization of dielectric liquid jets

Science.gov (United States)

Kourmatzis, Agissilaos; Ergene, Egemen L.; Shrimpton, John S.; Kyritsis, Dimitrios C.; Mashayek, Farzad; Huo, Ming

2012-07-01

The electrical and atomization performance of a plane-plane charge injection atomizer using a dielectric liquid, and operating at pump pressures ranging from 15 to 35 bar corresponding to injection velocities of up to 50 m/s, is explored via low current electrical measurements, spray imaging and phase Doppler anemometry. The work is aimed at understanding the contribution of electrostatic charging relevant to typical higher pressure fuel injection systems such as those employed in the aeronautical, automotive and marine sectors. Results show that mean-specific charge increases with injection velocity significantly. The effect of electrostatic charge is advantageous at the 15-35 bar range, and an arithmetic mean diameter D 10 as low as 0.2 d is achievable in the spray core and lower still in the periphery where d is the orifice diameter. Using the data available from this higher pressure system and from previous high Reynolds number systems (Shrimpton and Yule Exp Fluids 26:460-469, 1999), the promotion of primary atomization has been analysed by examining the effect that charge has on liquid jet surface and liquid jet bulk instability. The results suggest that for the low charge density Q v ~ 2 C/m3 cases under consideration here, a significant increase in primary atomization is observed due to a combination of electrical and aerodynamic forces acting on the jet surface, attributed to the significantly higher jet Weber number ( We j) when compared to low injection pressure cases. Analysis of Sauter mean diameter results shows that for jets with elevated specific charge density of the order Q v ~ 6 C/m3, the jet creates droplets that a conventional turbulent jet would, but with a significantly lower power requirement. This suggests that `turbulent' primary atomization, the turbulence being induced by electrical forces, may be achieved under injection pressures that would produce laminar jets.

Re: Penetration Behavior of Opposed Rows of Staggered Secondary Air Jets Depending on Jet Penetration Coefficient and Momentum Flux Ratio

Science.gov (United States)

Holdeman, James D.

2016-01-01

The purpose of this article is to explain why the extension of the previously published C = (S/Ho)sqrt(J) scaling for opposed rows of staggered jets wasn't directly successful in the study by Choi et al. (2016). It is not surprising that staggered jets from opposite sides do not pass each other at the expected C value, because Ho/D and sqrt(J) are much larger than the maximum in previous studies. These, and large x/D's, tend to suggest development of 2-dimensional flow. Although there are distinct optima for opposed rows of in-line jets, single-side injection, and opposed rows of staggered jets based on C, opposed rows of staggered jets provide as good or better mixing performance, at any C value, than opposed rows of in-line jets or jets from single-side injection.

Effect of gas injection during LH wave coupling at ITER-relevant plasma-wall distances in JET

International Nuclear Information System (INIS)

Ekedahl, A; Goniche, M; Basiuk, V; Delpech, L; Imbeaux, F; Joffrin, E; Loarer, T; Rantamaeki, K; Mailloux, J; Alper, B; Baranov, Y; Beaumont, P; Corrigan, G; Erents, K; Hawkes, N; McDonald, D; Petrzilka, V; Granucci, G; Hobirk, J; Kirov, K

2009-01-01

Good coupling of lower hybrid (LH) waves has been demonstrated in different H-mode scenarios in JET, at high triangularity (δ ∼ 0.4) and at large distance between the last closed flux surface and the LH launcher (up to 15 cm). Local gas injection of D 2 in the region magnetically connected to the LH launcher is used for increasing the local density in the scrape-off layer (SOL). Reciprocating Langmuir probe measurements magnetically connected to the LH launcher indicate that the electron density profile flattens in the far SOL during gas injection and LH power application. Some degradation in normalized H-mode confinement, as given by the H98(y,2)-factor, could be observed at high gas injection rates in these scenarios, but this was rather due to total gas injection and not specifically to the local gas puffing used for LH coupling. Furthermore, experiments carried out in L-mode plasmas in order to evaluate the effect on the LH current drive efficiency, when using local gas injection to improve the coupling, indicate only a small degradation (ΔI LH /I LH ∼ 15%). This effect is largely compensated by the improvement in coupling and thus increase in coupled power when using gas puffing.

Jet Noise Reduction by Microjets - A Parametric Study

Science.gov (United States)

Zaman, K. B. M. Q.

2010-01-01

The effect of injecting tiny secondary jets (microjets ) on the radiated noise from a subsonic primary jet is studied experimentally. The microjets are injected on to the primary jet near the nozzle exit with variable port geometry, working fluid and driving pressure. A clear noise reduction is observed that improves with increasing jet pressure. It is found that smaller diameter ports with higher driving pressure, but involving less thrust and mass fraction, can produce better noise reduction. A collection of data from the present as well as past experiments is examined in an attempt to correlate the noise reduction with the operating parameters. The results indicate that turbulent mixing noise reduction, as monitored by OASPL at a shallow angle, correlates with the ratio of jet to primary jet driving pressures normalized by the ratio of corresponding diameters (p d /pjD). With gaseous injection, the spectral amplitudes decrease at lower frequencies while an increase is noted at higher frequencies. It is apparent that this amplitude crossover is at least partly due to shock-associated noise from the underexpanded jets themselves. Such crossover is not seen with water injection since the flow in that case is incompressible and there is no shock-associated noise. Centerline velocity data show that larger noise reduction is accompanied by faster jet decay as well as significant reduction in turbulence intensities. While a physical understanding of the dependence of noise reduction on p d /pjD remains unclear, given this correlation, an analysis explains the observed dependence of the effect on various other parameters.

Isothermal and Reactive Turbulent Jets in Cross-Flow

Science.gov (United States)

Gutmark, Ephraim; Bush, Scott; Ibrahim, Irene

2004-11-01

Jets in cross flow have numerous applications including vertical/short takeoff/landing (V/STOL) aircraft, cooling jets for gas turbine blades and combustion air supply inlets in gas turbine engine. The properties exhibited by these jets are dictated by complex three dimensional turbulence structures which form due to the interaction of the jet with the freestream. The isothermal tests are conducted in a wind tunnel measuring the characteristics of air jets injected perpendicular into an otherwise undisturbed air stream. Different nozzle exit geometries of the air jets were tested including circular, triangular and elongated configurations. Jets are injected in single and paired combinations with other jets to measure the effect of mutual interaction on the parameters mentioned. Quantitative velocity fields are obtained using PIV. The data obtained allows the extraction of flow parameters such as jet structure, penetration and mixing. The reacting tests include separate and combined jets of fuel/air mixture utilized to explore the stabilization of combustion at various operating conditions. Different geometrical configurations of transverse jets are tested to determine the shape and combination of jets that will optimize the jets ability to successfully stabilize a flame.

Characteristics of compressed natural gas jet and jet-wall impingement using the Schlieren imaging technique

International Nuclear Information System (INIS)

Ismael, M A; Heikal, M R; Baharom, M B

2013-01-01

An experimental study was performed to investigate the compressed natural gas jet characteristics and jet-wall impingement using the Schlieren imaging technique and image processing. An injector driver was used to drive the natural gas injector and synchronized with camera triggering. A constant-volume optical chamber was designed to facilitate maximum optical access for the study of the jet macroscopic characteristics and jet-wall impingement at different injection pressures and injectors-wall distances. Measurement of the jet tip penetration and cone angle at different conditions are presented in this paper together with temporal presentation of the jet radial travel along the wall.

Fundamental study on gene transfer utilizing magnetic force and jet injector

Energy Technology Data Exchange (ETDEWEB)

Hasegawa, T.; Nakagami, H.; Akiyama, Y.; Nishjima, S. [Osaka University, Osaka (Japan)

2017-03-15

Recently, DNA vaccination is attracting attentions as a new therapeutic method for lifestyle diseases and autoimmune diseases. However, its clinical applications are limited because a safe and efficient gene transfer method has not been established yet. In this study, a new method of gene transfer was proposed which utilizes the jet injection and the magnetic transfection. The jet injection is a method to inject medical liquid by momentary high pressure without needle. The injected liquid diffuses in the bio tissue and the endocytosis is considered to be improved by the diffusion. The magnetic transfection is a method to deliver the conjugates of plasmid DNA and magnetic particles to the desired site by external magnetic field. It is expected that jet injection of the conjugates causes slight membrane disruptions and the traction of the conjugates by magnetic field induces the efficient gene transfer. In conclusion, the possibility of improvement of the gene expression by the combination of jet injection and magnetic transfection was confirmed.

Fundamental study on gene transfer utilizing magnetic force and jet injector

International Nuclear Information System (INIS)

Hasegawa, T.; Nakagami, H.; Akiyama, Y.; Nishjima, S.

2017-01-01

Recently, DNA vaccination is attracting attentions as a new therapeutic method for lifestyle diseases and autoimmune diseases. However, its clinical applications are limited because a safe and efficient gene transfer method has not been established yet. In this study, a new method of gene transfer was proposed which utilizes the jet injection and the magnetic transfection. The jet injection is a method to inject medical liquid by momentary high pressure without needle. The injected liquid diffuses in the bio tissue and the endocytosis is considered to be improved by the diffusion. The magnetic transfection is a method to deliver the conjugates of plasmid DNA and magnetic particles to the desired site by external magnetic field. It is expected that jet injection of the conjugates causes slight membrane disruptions and the traction of the conjugates by magnetic field induces the efficient gene transfer. In conclusion, the possibility of improvement of the gene expression by the combination of jet injection and magnetic transfection was confirmed

Numerical analysis of isothermal JET injection into a denser liquid pool using RD-MPS Method

Energy Technology Data Exchange (ETDEWEB)

Park, S. [KEPCO Nuclear Fuel, Daejeon (Korea, Republic of); Park, H. S. [POSTECH, Pohang (Korea, Republic of); Jeun, G. [Hanyang Univ., Seoul (Korea, Republic of)

2012-03-15

In this study, the rigid body dynamics coupled moving particle semi-implicit (RD-MPS) method was used to simulate a plunging liquid jet penetrating into a denser liquid pool. The phenomenon is related to fuel-coolant interactions (FCI) during severe accidents in nuclear power plants when coolant water is forcedly injected into a melt pool. A numerical particle method like MPS enables to simulate the complex multiphase flow in that significant deformation of fluids occurs due to its inherent grid less algorithm. However, the MPS method alone cannot continue the calculation for a long time as shown in the Ikea's work due to the large deformation of fluid surfaces and the difference in both liquid densities. In the RD-MPS method, the rigid body dynamics was coupled with the moving particle semi-implicit method to increase the overall stability of calculations and to calculate the multi-phase behavior of fluids. We performed two and three dimensional calculations to simulate jet penetration behaviors in a denser liquid pool, and the result was in good agreement with that of experiment. The simulation results suggested that the coupled model be useful in simulating dynamic interactions of multi-phase incompressible fluids as well as that the 3-D simulation for the plunging jet in a confined geometry predicted better agreement with experimental results than the 2-D simulation did.

Numerical analysis of isothermal JET injection into a denser liquid pool using RD-MPS Method

International Nuclear Information System (INIS)

Park, S.; Park, H. S.; Jeun, G.

2012-01-01

In this study, the rigid body dynamics coupled moving particle semi-implicit (RD-MPS) method was used to simulate a plunging liquid jet penetrating into a denser liquid pool. The phenomenon is related to fuel-coolant interactions (FCI) during severe accidents in nuclear power plants when coolant water is forcedly injected into a melt pool. A numerical particle method like MPS enables to simulate the complex multiphase flow in that significant deformation of fluids occurs due to its inherent grid less algorithm. However, the MPS method alone cannot continue the calculation for a long time as shown in the Ikea's work due to the large deformation of fluid surfaces and the difference in both liquid densities. In the RD-MPS method, the rigid body dynamics was coupled with the moving particle semi-implicit method to increase the overall stability of calculations and to calculate the multi-phase behavior of fluids. We performed two and three dimensional calculations to simulate jet penetration behaviors in a denser liquid pool, and the result was in good agreement with that of experiment. The simulation results suggested that the coupled model be useful in simulating dynamic interactions of multi-phase incompressible fluids as well as that the 3-D simulation for the plunging jet in a confined geometry predicted better agreement with experimental results than the 2-D simulation did

Multi-pellet injection on Jet

International Nuclear Information System (INIS)

Kupschus, P.; Cheetham, A.; Denne, B.; Gadeberg, M.; Gowers, C.; Gondhalekar, A.; Tubbing, B.; Schissel, D.

1989-01-01

The investigations carried out with the JET multi-pellet injector are presented. The results show that with central deposition, peaked density profiles with central values exceeding 10 20 /m 3 can be reached. These peaked profiles can persist for times of the order of seconds. Auxiliary heating seems to accelerate the slow central density decay; it is also observed that high electron pressure values are generated in a core with a high D-D reaction rate

Combined aerodynamic and electrostatic atomization of dielectric liquid jets

Energy Technology Data Exchange (ETDEWEB)

Kourmatzis, Agissilaos [University of Sydney, Clean Combustion Research Group, Aerospace, Mechanical and Mechatronic Engineering, Sydney, NSW (Australia); Ergene, Egemen L.; Mashayek, Farzad [University of Illinois at Chicago, Department of Mechanical and Industrial Engineering, Chicago, IL (United States); Shrimpton, John S. [University of Southampton, Energy Technology Research Group, School of Engineering Sciences, Southampton (United Kingdom); Kyritsis, Dimitrios C.; Huo, Ming [University of Illinois at Urbana-Champaign, Department of Mechanical Science and Engineering, Urbana, IL (United States)

2012-07-15

The electrical and atomization performance of a plane-plane charge injection atomizer using a dielectric liquid, and operating at pump pressures ranging from 15 to 35 bar corresponding to injection velocities of up to 50 m/s, is explored via low current electrical measurements, spray imaging and phase Doppler anemometry. The work is aimed at understanding the contribution of electrostatic charging relevant to typical higher pressure fuel injection systems such as those employed in the aeronautical, automotive and marine sectors. Results show that mean-specific charge increases with injection velocity significantly. The effect of electrostatic charge is advantageous at the 15-35 bar range, and an arithmetic mean diameter D{sub 10} as low as 0.2d is achievable in the spray core and lower still in the periphery where d is the orifice diameter. Using the data available from this higher pressure system and from previous high Reynolds number systems (Shrimpton and Yule Exp Fluids 26:460-469, 1999), the promotion of primary atomization has been analysed by examining the effect that charge has on liquid jet surface and liquid jet bulk instability. The results suggest that for the low charge density Q{sub v}{proportional_to} 2 C/m{sup 3} cases under consideration here, a significant increase in primary atomization is observed due to a combination of electrical and aerodynamic forces acting on the jet surface, attributed to the significantly higher jet Weber number (We{sub j}) when compared to low injection pressure cases. Analysis of Sauter mean diameter results shows that for jets with elevated specific charge density of the order Q{sub v}{proportional_to} 6 C/m{sup 3}, the jet creates droplets that a conventional turbulent jet would, but with a significantly lower power requirement. This suggests that 'turbulent' primary atomization, the turbulence being induced by electrical forces, may be achieved under injection pressures that would produce laminar jets

Needle-free delivery of macromolecules through the skin using controllable jet injectors.

Science.gov (United States)

Hogan, Nora C; Taberner, Andrew J; Jones, Lynette A; Hunter, Ian W

2015-01-01

Transdermal delivery of drugs has a number of advantages in comparison to other routes of administration. The mechanical properties of skin, however, impose a barrier to administration and so most compounds are administered using hypodermic needles and syringes. In order to overcome some of the issues associated with the use of needles, a variety of non-needle devices based on jet injection technology has been developed. Jet injection has been used primarily for vaccine administration but has also been used to deliver macromolecules such as hormones, monoclonal antibodies and nucleic acids. A critical component in the more recent success of jet injection technology has been the active control of pressure applied to the drug during the time course of injection. Jet injection systems that are electronically controllable and reversible offer significant advantages over conventional injection systems. These devices can consistently create the high pressures and jet speeds necessary to penetrate tissue and then transition smoothly to a lower jet speed for delivery of the remainder of the desired dose. It seems likely that in the future this work will result in smart drug delivery systems incorporated into personal medical devices and medical robots for in-home disease management and healthcare.

The Mochi LabJet Experiment for Measurements of Canonical Helicity Injection in a Laboratory Astrophysical Jet

Science.gov (United States)

You, Setthivoine; von der Linden, Jens; Sander Lavine, Eric; Carroll, Evan Grant; Card, Alexander; Quinley, Morgan; Azuara-Rosales, Manuel

2018-06-01

The Mochi device is a new pulsed power plasma experiment designed to produce long, collimated, stable, magnetized plasma jets when set up in the LabJet configuration. The LabJet configuration aims to simulate an astrophysical jet in the laboratory by mimicking an accretion disk threaded by a poloidal magnetic field with concentric planar electrodes in front of a solenoidal coil. The unique setup consists of three electrodes, each with azimuthally symmetric gas slits. Two of the electrodes are biased independently with respect to the third electrode to control the radial electric field profile across the poloidal bias magnetic field. This design approximates a shear azimuthal rotation profile in an accretion disk. The azimuthally symmetric gas slits provide a continuously symmetric mass source at the footpoint of the plasma jet, so any azimuthal rotation of the plasma jet is not hindered by a discrete number of gas holes. The initial set of diagnostics consists of current Rogowski coils, voltage probes, magnetic field probe arrays, an interferometer and ion Doppler spectroscopy, supplemented by a fast ion gauge and a retarding grid energy analyzer. The measured parameters of the first plasmas are ∼1022 m‑3, ∼0.4 T, and 5–25 eV, with velocities of ∼20–80 km s‑1. The combination of a controllable electric field profile, a flared poloidal magnetic field, and azimuthally symmetric mass sources in the experiment successfully produces short-lived (∼10 μs, ≳5 Alfvén times) collimated magnetic jets with a ∼10:1 aspect ratio and long-lived (∼100 μs, ≳40 Alfvén times) flow-stabilized, collimated, magnetic jets with a ∼30:1 aspect ratio.

Pneumatic pellet injector for JET

International Nuclear Information System (INIS)

Andelfinger, C.; Buechl, K.; Jacobi, D.; Sandmann, W.; Schiedeck, J.; Schilling, H.B.; Weber, G.

1983-07-01

Pellet injection is a useful tool for plasma diagnostics of tokamaks. Pellets can be applied for investigation of particle, energy and impurity transport, fueling efficiency and magnetic surfaces. Design, operation and control of a single shot pneumatic pellet gun is described in detail including all supplies, the vacuum system and the diagnostics of the pellet. The arrangement of this injector in the torus hall and the interfaces to the JET system and CODAS are considered. A guide tube system for pellet injection is discussed but it will not be recommended for JET. (orig.)

Vortex breakdown in a supersonic jet

Science.gov (United States)

Cutler, Andrew D.; Levey, Brian S.

1991-01-01

This paper reports a study of a vortex breakdown in a supersonic jet. A supersonic vortical jets were created by tangential injection and acceleration through a convergent-divergent nozzle. Vortex circulation was varied, and the nature of the flow in vortical jets was investigated using several types of flow visualization, including focusing schlieren and imaging of Rayleigh scattering from a laser light sheet. Results show that the vortical jet mixed much more rapidly with the ambient air than a comparable straight jet. When overexpanded, the vortical jet exhibited considerable unsteadiness and showed signs of vortex breakdown.

In-flight imaging of transverse gas jets injected into transonic and supersonic crossflows: Design and development. M.S. Thesis, Mar. 1993

Science.gov (United States)

Wang, Kon-Sheng Charles

1994-01-01

The design and development of an airborne flight-test experiment to study nonreacting gas jets injected transversely into transonic and supersonic crossflows is presented. Free-stream/crossflow Mach numbers range from 0.8 to 2.0. Planar laser-induced fluorescence (PLIF) of an iodine-seeded nitrogen jet is used to visualize the jet flow. Time-dependent images are obtained with a high-speed intensified video camera synchronized to the laser pulse rate. The entire experimental assembly is configured compactly inside a unique flight-test-fixture (FTF) mounted under the fuselage of the F-104G research aircraft, which serves as a 'flying wind tunnel' at NASA Dryden Flight Research Center. The aircraft is flown at predetermined speeds and altitudes to permit a perfectly expanded (or slightly underexpanded) gas jet to form just outside the FTF at each free-stream Mach number. Recorded gas jet images are then digitized to allow analysis of jet trajectory, spreading, and mixing characteristics. Comparisons will be made with analytical and numerical predictions. This study shows the viability of applying highly sophisticated groundbased flow diagnostic techniques to flight-test vehicle platforms that can achieve a wide range of thermo/fluid dynamic conditions. Realistic flow environments, high enthalpies, unconstrained flowfields, and moderate operating costs are also realized, in contrast to traditional wind-tunnel testing.

A numerical study on transient high speed free jet into a confined enclosure

International Nuclear Information System (INIS)

Chae, K.M.; Yoo, S.Y.; Rhee, W.; Hangbok, Choi

2001-01-01

In a CANDU type reactor, one of the 2 independent shutdown systems is a liquid poison injection system (SDS2). The longest poison injector is 21 pitches long. There are 4 nozzle positions per lattice pitch (287.75 mm) and 4 holes per nozzle position. A numerical model is developed in this study to systematically and consistently estimate the concentration and diffusion of the poison injected from SDS2. In order to assess the source-jet model, a comparison was made against the real-jet calculation using actual boundary conditions. The simulation was performed in two-dimensional geometry with 4 nozzle holes aligned in 1 lattice pitch and an injection velocity of 20 m/s. The study has shown that the source-jet model agrees with the experimental results and real-jet simulation. It was also found that the source-jet model can be effectively used for the simulation of liquid poison injection through small holes, of which the simulation is restricted due to the limitation of number of grid points in the real-jet simulation. The source-term model of the liquid poison injection developed in this study is consistent with the actual poison injection system in a CANDU 6 reactor and, therefore, can generate poison concentration data for the safety analysis of the reactor. In the future, it is strongly recommended to perform further study to analyze the transient of the poison injection from helium tank to injection nozzle hole by applying Bernoulli equation

Use of a new ion-detector in the study of the jet plasma injected into a pulsed magnetic mirror configuration (deca I); Utilisation d'un nouveau detecteur d'ions dans l'etude du jet de plasma injecte dans deca I

Energy Technology Data Exchange (ETDEWEB)

Renaud, C [Association Euratom-CEA Cadarache, Groupe de Recherches sur la Fusion Controlee, 13 - Saint-Paul-lez-Durance (France). Centre d' Etudes Nucleaires

1963-07-01

The study of a high sensitivity ion detector coupled to an electrostatic analyser has permitted a large investigation of the plasma jet injected into a pulsed magnetic mirror configuration. In this detector the positive ions are accelerated through a potential of 30 kV; they strike a metallic target, on which they produce secondary electrons; these, in turn, are accelerated onto a plastic scintillator. The light pulses are detected with a photomultiplier. The gain of this device is about 10{sup 7}. If we make an admission of air into the vacuum system and again we make vacuum, the gain is not modified, since no special activated surfaces are situated in the detector. (author) [French] L'etude d'un detecteur d'ions de grande sensibilite, allie a un analyseur electrostatique a permis une investigation approfondie du jet de plasma injecte dans le dispositif d'Etude de Compression Adiabatique. Dans ce detecteur, les ions positifs sont acceleres par une difference de potentiel voisine de 30 kV, ils bombardent une cible metallique et creent des electrons secondaires qui sont a leur tour acceleres vers un scintillateur plastique. Les impulsions lumineuses sont alors detectees par un photomultiplicateur. Le gain obtenu pour l'ensemble du detecteur est voisin de 10{sup 7}. Le detecteur ne possedant pas de surfaces specialement activees, les remises a l'air n'entrainent pas de variation de gain. (auteur)

Modeling the effects of auxiliary gas injection and fuel injection rate shape on diesel engine combustion and emissions

Science.gov (United States)

Mather, Daniel Kelly

1998-11-01

The effect of auxiliary gas injection and fuel injection rate-shaping on diesel engine combustion and emissions was studied using KIVA a multidimensional computational fluid dynamics code. Auxiliary gas injection (AGI) is the injection of a gas, in addition to the fuel injection, directly into the combustion chamber of a diesel engine. The objective of AGI is to influence the diesel combustion via mixing to reduce emissions of pollutants (soot and NO x). In this study, the accuracy of modeling high speed gas jets on very coarse computational grids was addressed. KIVA was found to inaccurately resolve the jet flows near walls. The cause of this inaccuracy was traced to the RNG k - ɛ turbulence model with the law-of-the-wall boundary condition used by KIVA. By prescribing the lengthscale near the nozzle exit, excellent agreement between computed and theoretical jet penetration was attained for a transient gas jet into a quiescent chamber at various operating conditions. The effect of AGI on diesel engine combustion and emissions was studied by incorporating the coarse grid gas jet model into a detailed multidimensional simulation of a Caterpillar 3401 heavy-duty diesel engine. The effects of AGI timing, composition, amount, orientation, and location were investigated. The effects of AGI and split fuel injection were also investigated. AGI was found to be effective at reducing soot emissions by increasing mixing within the combustion chamber. AGI of inert gas was found to be effective at reducing emissions of NOx by depressing the peak combustion temperatures. Finally, comparison of AGI simulations with experiments were conducted for a TACOM-LABECO engine. The results showed that AGI improved soot oxidation throughout the engine cycle. Simulation of fuel injection rate-shaping investigated the effects of three injection velocity profiles typical of unit-injector type, high-pressure common-rail type, and accumulator-type fuel injectors in the Caterpillar 3401 heavy

Conceptual analysis of a tokamak reactor with lithium dust jet

International Nuclear Information System (INIS)

Kuteev, B.V.; Krylov, S.V.; Sergeev, V.Yu.; Skokov, V.G.; Timokhin, V.M.

2010-01-01

The steady-state operation of tokamak reactors requires radiating a substantial part of the fusion energy dissipated in plasma to make more uniform the heat loads onto the first wall and to reduce the erosion of the divertor plates. One of the approaches to realize this goal uses injection of lithium dust jet into the scrape-off layer (SOL). A quantitative conceptual analysis of the reactor parameters with lithium dust jet injection is presented here. The effects of the lithium on the core and SOL plasma are considered. The first results of developing the lithium jet injection technology and its application to the T-10 tokamak are also presented.

Acoustic signature analysis of the interaction between a dc plasma jet and a suspension liquid jet

International Nuclear Information System (INIS)

Rat, V; Coudert, J F

2009-01-01

Suspension plasma spraying allows forming finely structured coatings by injecting suspensions of ceramic particles within a dc plasma jet. The electric arc motion in dc plasma torch is the main acoustic source which is modified by the injection of suspension. The analyses of cross-correlations between the arc voltage and the acoustic signal show a decrease in time propagations due to local cooling of the plasma jet when injecting suspensions. Moreover, power spectra highlight acoustic amplifications below a certain frequency threshold and attenuations above. A simplified model of the frequency acoustic response of a two-phase vaporizing mixture is used to interpret experimental measurements. These acoustic effects are due to the dynamics of thermal transfers between vaporizing liquid and plasma.

Study on the Fluid Flow Characteristics of Coherent Jets with CO2 and O2 Mixed Injection in Electric Arc Furnace Steelmaking Processes

Science.gov (United States)

Wei, Guangsheng; Zhu, Rong; Wu, Xuetao; Yang, Lingzhi; Dong, Kai; Cheng, Ting; Tang, Tianping

2018-06-01

As an efficient oxygen supplying technology, coherent jets are widely applied in electric arc furnace (EAF) steelmaking processes to strengthen chemical energy input, speed up smelting rhythm, and promote the uniformity of molten bath temperature and compositions. Recently, the coherent jet with CO2 and O2 mixed injection (COMI) was proposed and demonstrated great application potentiality in reducing the dust production in EAF steelmaking. In the present study, based on the eddy dissipation concept model, a computational fluid dynamics model of coherent jets with COMI was built with the overall and detailed chemical kinetic mechanisms (GRI-Mech 3.0). Compared with one-step combustion reaction, GRI-Mech 3.0 consists of 325 elementary reactions with 53 components and can predict more accurate results. The numerical simulation results were validated by the combustion experiment data. The jet behavior and the fluid flow characteristics of coherent jets with COMI under 298 K and 1700 K (25 °C and 1427 °C) were studied and the results showed that for coherent jets with COMI, the chemical effect of CO2 significantly weakened the shrouding combustion reactions of CH4 and the relative importance of the chemical effect of CO2 increases with CO2 concentration increasing. The potential core length of coherent jet decreases with the volume fraction of CO2 increasing. Moreover, it also can be found that the potential core length of coherent jets was prolonged with higher ambient temperature.

Study on the Fluid Flow Characteristics of Coherent Jets with CO2 and O2 Mixed Injection in Electric Arc Furnace Steelmaking Processes

Science.gov (United States)

Wei, Guangsheng; Zhu, Rong; Wu, Xuetao; Yang, Lingzhi; Dong, Kai; Cheng, Ting; Tang, Tianping

2018-03-01

As an efficient oxygen supplying technology, coherent jets are widely applied in electric arc furnace (EAF) steelmaking processes to strengthen chemical energy input, speed up smelting rhythm, and promote the uniformity of molten bath temperature and compositions. Recently, the coherent jet with CO2 and O2 mixed injection (COMI) was proposed and demonstrated great application potentiality in reducing the dust production in EAF steelmaking. In the present study, based on the eddy dissipation concept model, a computational fluid dynamics model of coherent jets with COMI was built with the overall and detailed chemical kinetic mechanisms (GRI-Mech 3.0). Compared with one-step combustion reaction, GRI-Mech 3.0 consists of 325 elementary reactions with 53 components and can predict more accurate results. The numerical simulation results were validated by the combustion experiment data. The jet behavior and the fluid flow characteristics of coherent jets with COMI under 298 K and 1700 K (25 °C and 1427 °C) were studied and the results showed that for coherent jets with COMI, the chemical effect of CO2 significantly weakened the shrouding combustion reactions of CH4 and the relative importance of the chemical effect of CO2 increases with CO2 concentration increasing. The potential core length of coherent jet decreases with the volume fraction of CO2 increasing. Moreover, it also can be found that the potential core length of coherent jets was prolonged with higher ambient temperature.

Regeneration and tritium recovery from the large JET neutral injection cryopump system after the FTE

International Nuclear Information System (INIS)

Obert, W.; Bell, A.; Davies, J.; Mayaux, C.; Perinic, G.; Saibene, G.; Sartori, R.; Thompson, E.; Anderson, J.; Jenkins, E.; Walthers, C.

1992-01-01

Neutral Beam Injection (NBI) was used to introduce tritium into the plasma for the First Tritium Experiment In addition to the decisive advantage of depositing the tritium into the centre of the plasma, the use of NBI also minimized the total quantity of tritium introduced into the Torus and the contamination of the vacuum vessel. However, because of the relatively low gas efficiency of the positive ion injection system approximately 95% of the total quantity of tritium introduced was pumped by the large condensation cryopumps which form an integral part of the injector. Several hardware and associated software changes were implemented in order to making provision for possible fault scenarios during operation with tritium and to ensure complete regeneration of the tritium from the cryopumps. The tritium released after all subsequent regeneration's has been monitored carefully in order to determine the amount of tritium retained by the black anodized liquid nitrogen panel surfaces of the cryopump and to compare it with experiments at TSTA on JET samples before the FTE

A study of the wall/jet interaction on a transient spray. Application to diesel injection; Etude de l'interaction jet/paroi dans un spray transitoire. Application a l'injection diesel

Energy Technology Data Exchange (ETDEWEB)

Chale Gongora, H.G.

1998-07-01

The aim of this work is to better understand the mechanisms that govern the formation and development of the parietal flow occurring during the impact of a diesel fuel jet on a plate. In order to isolate the dynamical aspects of the phenomenon, a non-confined experimental configuration at ambient temperature and pressure has been used. The behaviour of the dispersed phase for different conditions of jet approach and different plate temperatures has been analyzed. Velocity and diameter fields of the free zone and of the parietal zone have been measured using a laser doppler apparatus up to a plate surface resolution of 0.2 mm. In a first step, an estimation of the average time value gives information about the global behaviour of the spray: the plate effect is sensible up to a very reduced distance but increases with the plate temperature, the momentum of the parietal jet is localized in a zone very close to the wall, an increase of the droplets size and of radial velocities in the parietal zone is observed when the nozzle is moved closer to the wall, and the increase of the plate temperature facilitates the jet penetration and leads to a reduction of the droplets size (increase of the shear stresses) and to a reduction of the liquid film thickness submitted to splashing. In order to examine the behaviour of velocity and droplets diameter with time, a processing has been defined which provides an average description of the phenomena. A laser tomography study in association with fast cinematography and CCD camera video recording has permitted to outline the main aspects of the evolution of the parietal spray with time: fast development of a swirl which drags most of the small droplets and limits their dispersion, effect of the temperature rise of the plate in the beginning of fuel injection, development of a more intense swirl which leads to an increase of velocity fluctuations, development of wavelet structures in the internal zone of the flow, near the wall, and

Multiple-jet thermal mixing in a piping tee

International Nuclear Information System (INIS)

Lykoudis, P.S.; Hagar, R.C.

1979-01-01

Piping tees that are used to mix fluid streams at different temperatures are subjected to possibly severe thermal and mechanical stresses. There is reason to suspect that mixing in a piping tee could be improved by injecting the fluid streams into the tee through multiple jets. This paper reports the results of an experimental investigation of the effects of multiple-jet injection on mixing in a piping tee. The experimental work involves the measurement of the temperature fluctuation intensity with a hot-film sensor downstream of a simple 22.22-mm(7/8-in.)-diam tee with mixed multiple-jet injected hot and cold streams of water. The jets were provided by holes drilled in plates that partially blocked the inlet streams; 26 pairs of plates were investigated. The number of holes per plate varied from 1 to 51; the jet diameters ranged from 5 to 68% of the tee diameter. The inlet stream Reynolds number upstream of the jet plates was roughly 15 500 for each stream. The data indicated that the root mean square (rms) temperature fluctuation intensity measured at the tee outlet decreased dramatically as the jet plate cross-sectional area void fraction was decreased. When the jets emanating from the tee plates were misaligned, the reduction of the rms temperature fluctuation was not as high as when the jets were aligned. The rate of decay of the intensity downstream of the tee for most ofthe plates investigated was found to agree well with the -3/4 power decay law predicted by Corrsin's theory of scalar decay. However, unusual features in the intensity decay data were also observed, such as an increase of the intensity several diameters downstream before continuing to decay

Improvement on reaction model for sodium-water reaction jet code and application analysis

International Nuclear Information System (INIS)

Itooka, Satoshi; Saito, Yoshinori; Okabe, Ayao; Fujimata, Kazuhiro; Murata, Shuuichi

2000-03-01

In selecting the reasonable DBL on steam generator (SG), it is necessary to improve analytical method for estimating the sodium temperature on failure propagation due to overheating. Improvement on sodium-water reaction (SWR) jet code (LEAP-JET ver.1.30) and application analysis to the water injection tests for confirmation of code propriety were performed. On the improvement of the code, a gas-liquid interface area density model was introduced to develop a chemical reaction model with a little dependence on calculation mesh size. The test calculation using the improved code (LEAP-JET ver.1.40) were carried out with conditions of the SWAT-3·Run-19 test and an actual scale SG. It is confirmed that the SWR jet behavior on the results and the influence to analysis result of a model are reasonable. For the application analysis to the water injection tests, water injection behavior and SWR jet behavior analyses on the new SWAT-1 (SWAT-1R) and SWAT-3 (SWAT-3R) tests were performed using the LEAP-BLOW code and the LEAP-JET code. In the application analysis of the LEAP-BLOW code, parameter survey study was performed. As the results, the condition of the injection nozzle diameter needed to simulate the water leak rate was confirmed. In the application analysis of the LEAP-JET code, temperature behavior of the SWR jet was investigated. (author)

Gas jet disruption mitigation studies on Alcator C-Mod

International Nuclear Information System (INIS)

Granetz, R.; Whyte, D.G.; Izzo, V.A.; Biewer, T.; Reinke, M.L.; Terry, J.; Bader, A.; Bakhtiari, M.; Jernigan, T.; Wurden, G.

2006-01-01

Damaging effects of disruptions are a major concern for Alcator C-Mod, ITER and future tokamak reactors. High-pressure noble gas jet injection is a mitigation technique which potentially satisfies the operational requirements of fast response time and reliability, while still being benign to subsequent discharges. Disruption mitigation experiments using an optimized gas jet injection system are being carried out on Alcator C-Mod to study the physics of gas jet penetration into high pressure plasmas, as well as the ability of the gas jet impurities to convert plasma energy into radiation on timescales consistent with C-Mod's fast quench times, and to reduce halo currents given C-Mod's high-current density. The dependence of impurity penetration and effectiveness on noble gas species (He, Ne, Ar, Kr) is also being studied. It is found that the high-pressure neutral gas jet does not penetrate deeply into the C-Mod plasma, and yet prompt core thermal quenches are observed on all gas jet shots. 3D MHD modelling of the disruption physics with NIMROD shows that edge cooling of the plasma triggers fast growing tearing modes which rapidly produce a stochastic region in the core of the plasma and loss of thermal energy. This may explain the apparent effectiveness of the gas jet in C-Mod despite its limited penetration. The higher-Z gases (Ne, Ar, Kr) also proved effective at reducing halo currents and decreasing thermal deposition to the divertor surfaces. In addition, noble gas jet injection proved to be benign for plasma operation with C-Mod's metal (Mo) wall, actually improving the reliability of the startup in the following discharge

Simulation of Sweep-Jet Flow Control, Single Jet and Full Vertical Tail

Science.gov (United States)

Childs, Robert E.; Stremel, Paul M.; Garcia, Joseph A.; Heineck, James T.; Kushner, Laura K.; Storms, Bruce L.

2016-01-01

This work is a simulation technology demonstrator, of sweep jet flow control used to suppress boundary layer separation and increase the maximum achievable load coefficients. A sweep jet is a discrete Coanda jet that oscillates in the plane parallel to an aerodynamic surface. It injects mass and momentum in the approximate streamwise direction. It also generates turbulent eddies at the oscillation frequency, which are typically large relative to the scales of boundary layer turbulence, and which augment mixing across the boundary layer to attack flow separation. Simulations of a fluidic oscillator, the sweep jet emerging from a nozzle downstream of the oscillator, and an array of sweep jets which suppresses boundary layer separation are performed. Simulation results are compared to data from a dedicated validation experiment of a single oscillator and its sweep jet, and from a wind tunnel test of a full-scale Boeing 757 vertical tail augmented with an array of sweep jets. A critical step in the work is the development of realistic time-dependent sweep jet inflow boundary conditions, derived from the results of the single-oscillator simulations, which create the sweep jets in the full-tail simulations. Simulations were performed using the computational fluid dynamics (CFD) solver Overow, with high-order spatial discretization and a range of turbulence modeling. Good results were obtained for all flows simulated, when suitable turbulence modeling was used.

Reverse-Tangent Injection in a Centrifugal Compressor

Science.gov (United States)

Skoch, Gary J.

2007-01-01

Injection of working fluid into a centrifugal compressor in the reverse tangent direction has been invented as a way of preventing flow instabilities (stall and surge) or restoring stability when stall or surge has already commenced. The invention applies, in particular, to a centrifugal compressor, the diffuser of which contains vanes that divide the flow into channels oriented partly radially and partly tangentially. In reverse-tangent injection, a stream or jet of the working fluid (the fluid that is compressed) is injected into the vaneless annular region between the blades of the impeller and the vanes of the diffuser. As used here, "reverse" signifies that the injected flow opposes (and thereby reduces) the tangential component of the velocity of the impeller discharge. At the same time, the injected jet acts to increase the radial component of the velocity of the impeller discharge.

Study of two-phase underexpanded jets by gas jet

International Nuclear Information System (INIS)

Uchida, Mitsunori; Someya, Satoshi; Okamoto, Koji

2008-01-01

When a heat exchange in a Fast Breeder Reactor cracks, a sodium-water reaction occurs. When a tube cracks, highly pressurized water or steam escapes into the surrounding liquid sodium and a sodium-water reaction occurs forming the disodium oxide. The disodium oxide caught in the steam jet strikes other tubes in the reactor. The struck disodium oxide can then cause these tubes to crack. The release of steam into the liquid sodium media is a two-phase flow involving underexpansion. In this paper qualitative measurement of the underexpanded gas jet which injected into water was carried our for the purpose of analyzing the behavior of the two-phase flow. (author)

Runaway beam studies during disruptions at JET-ILW

International Nuclear Information System (INIS)

Reux, C.; Plyusnin, V.; Alper, B.; Alves, D.; Bazylev, B.; Belonohy, E.; Brezinsek, S.; Decker, J.; Devaux, S.; Vries, P. de; Fil, A.

2015-01-01

Highlights: • Runaway electrons (RE) have been obtained at JET-ILW using massive argon injection. • The runaway electron domain entry points are similar between JET-C and JET-ILW. • Inside the runaway electron domain, higher RE currents are observed with JET-ILW. • RE impact has been observed without material melting up to 100 kA RE current. • Heat deposition of 2 ± 1 mm is confirmed by measurements and simulations. - Abstract: Runaway electrons (RE) during disruptions are a concern for future tokamaks including ITER with its metallic wall. Although RE are rare in spontaneous disruptions with the JET ITER-like Wall (JET-ILW), RE beams up to 380 kA were obtained using massive injection (MGI) of argon in JET-ILW divertor discharges. Entry points into the RE domain defined by operational parameters (toroidal field, argon fraction in MGI) are unchanged but higher RE currents have been obtained inside the JET-ILW MGI-generated RE domain when compared to JET-C. This might be due to the influence of the metallic wall on the current quench plasma. Temperatures of 900 °C have been observed following RE impacts on beryllium tiles. Heat deposition depth of ∼2 mm has to be assumed to match the tile cooling time. 3D simulations of the RE energy deposition using the ENDEP/MEMOS codes show that material melting is unlikely with 100 kA RE beams

Runaway beam studies during disruptions at JET-ILW

Energy Technology Data Exchange (ETDEWEB)

Reux, C., E-mail: cedric.reux@cea.fr [JET-EFDA, Culham Science Centre, Abingdon OX14 3DB (United Kingdom); CEA, IRFM, F-13108 Saint-Paul-lez-Durance (France); Plyusnin, V. [JET-EFDA, Culham Science Centre, Abingdon OX14 3DB (United Kingdom); Instituto de Plasmas e Fuso Nuclear, Instituto Superior Tcnico, Universidade de Lisboa, Lisboa (Portugal); Alper, B. [JET-EFDA, Culham Science Centre, Abingdon OX14 3DB (United Kingdom); CCFE, Culham Science Centre, Abingdon OX14 3DB (United Kingdom); Alves, D. [JET-EFDA, Culham Science Centre, Abingdon OX14 3DB (United Kingdom); Instituto de Plasmas e Fuso Nuclear, Instituto Superior Tcnico, Universidade de Lisboa, Lisboa (Portugal); Bazylev, B. [JET-EFDA, Culham Science Centre, Abingdon OX14 3DB (United Kingdom); Institut für Hochleistungsimpuls und Mikrowellentechnik, Karlsruhe Institute of Technology, Campus Nord, 76021 Karlsruhe (Germany); Belonohy, E. [JET-EFDA, Culham Science Centre, Abingdon OX14 3DB (United Kingdom); EFDA-CSU, Culham Science Centre, Abingdon OX14 3DB (United Kingdom); Brezinsek, S. [JET-EFDA, Culham Science Centre, Abingdon OX14 3DB (United Kingdom); Forschungszentrum Jülich GmbH, Institut für Energie-und Klimaforschung-Plasmaphysik, 52425 Jülich (Germany); Decker, J. [JET-EFDA, Culham Science Centre, Abingdon OX14 3DB (United Kingdom); CEA, IRFM, F-13108 Saint-Paul-lez-Durance (France); Devaux, S. [JET-EFDA, Culham Science Centre, Abingdon OX14 3DB (United Kingdom); CCFE, Culham Science Centre, Abingdon OX14 3DB (United Kingdom); Vries, P. de [JET-EFDA, Culham Science Centre, Abingdon OX14 3DB (United Kingdom); ITER Organization, Route de Vinon sur Verdon, 13115 St Paul Lez Durance (France); Fil, A. [JET-EFDA, Culham Science Centre, Abingdon OX14 3DB (United Kingdom); CEA, IRFM, F-13108 Saint-Paul-lez-Durance (France); and others

2015-08-15

Highlights: • Runaway electrons (RE) have been obtained at JET-ILW using massive argon injection. • The runaway electron domain entry points are similar between JET-C and JET-ILW. • Inside the runaway electron domain, higher RE currents are observed with JET-ILW. • RE impact has been observed without material melting up to 100 kA RE current. • Heat deposition of 2 ± 1 mm is confirmed by measurements and simulations. - Abstract: Runaway electrons (RE) during disruptions are a concern for future tokamaks including ITER with its metallic wall. Although RE are rare in spontaneous disruptions with the JET ITER-like Wall (JET-ILW), RE beams up to 380 kA were obtained using massive injection (MGI) of argon in JET-ILW divertor discharges. Entry points into the RE domain defined by operational parameters (toroidal field, argon fraction in MGI) are unchanged but higher RE currents have been obtained inside the JET-ILW MGI-generated RE domain when compared to JET-C. This might be due to the influence of the metallic wall on the current quench plasma. Temperatures of 900 °C have been observed following RE impacts on beryllium tiles. Heat deposition depth of ∼2 mm has to be assumed to match the tile cooling time. 3D simulations of the RE energy deposition using the ENDEP/MEMOS codes show that material melting is unlikely with 100 kA RE beams.

The JET multi-pellet injector launcher

International Nuclear Information System (INIS)

Kupschus, P.; Bailey, W.; Gadeberg, M.; Hedley, L.; Twyman, P.; Szabo, T.; Evans, D.

1987-01-01

Under a collaborative agreement between the Joint European Torus JET and the United States Department of Energy US DOE, JET and Oak Ridge National Laboratory (ORNL) jointly built a multi-pellet injector for fuelling and re-fuelling of the JET plasma. A three-barrel repetitive pneumatic pellet Launcher - built by ORNL - is attached to a JET pellet launcher-machine interface (in short: Pellet Interface) which is the subject of this paper. The present Launcher-Interface combination provides deuterium or hydrogen injection at moderate pellet speeds for the next two operational periods on JET. The Pellet Interface, however, takes into account the future requirements of JET. It was designed to allow the attachment of the high speed pellet launchers now under development at JET and complies with the requirements of remote handling and tritium operation. In addition, the use of tritium pellets is being considered

Numerical investigation on cryogenic liquid jet under transcritical and supercritical conditions

Science.gov (United States)

Li, Liang; Xie, Maozhao; Wei, Wu; Jia, Ming; Liu, Hongsheng

2018-01-01

Cryogenic fluid injection and mixing under transcritical and supercritical conditions is numerically investigated with emphasis on the difference of the mechanism and characteristics between the two injections. A new solver is developed which is capable of handling the nonideality of the equation of state and the anomalies in fluid transport properties and is incorporated into the CFD software OpenFOAM. The new solver has been validated against available experimental data and exhibits a good performance. Computational results indicates that the differences between transcritical and supercritical injections are mainly induced by the pseudo-boiling phenomenon, resulting in that the transcritical jet has a longer cold liquid core and an isothermal expansion occurs at the surface of the cold core. The thickness of the supercritical mixing layer and its increase value along the jet direction are greater than its transcritical counterpart. The high-temperature jet whose initial temperature is above the pseudo-boiling temperature has the ability of enhancing the mixing of the jet with the surrounding gas.

The energetics of relativistic jets in active galactic nuclei with various kinetic powers

Science.gov (United States)

Musoke, Gibwa Rebecca; Young, Andrew; Molnar, Sandor; Birkinshaw, Mark

2018-01-01

Numerical simulations are an important tool in understanding the physical processes behind relativistic jets in active galactic nuclei. In such simulations different combinations of intrinsic jet parameters can be used to obtain the same jet kinetic powers. We present a numerical investigation of the effects of varying the jet power on the dynamic and energetic characteristics of the jets for two kinetic power regimes; in the first regime we change the jet density whilst maintaining a fixed velocity, in the second the jet density is held constant while the velocity is varied. We conduct 2D axisymmetric hydrodynamic simulations of bipolar jets propagating through an isothermal cluster atmosphere using the FLASH MHD code in pure hydrodynamics mode. The jets are simulated with kinetic powers ranging between 1045 and 1046 erg/s and internal Mach numbers ranging from 5.6 to 21.5.As the jets begin to propagate into the intracluster medium (ICM), the injected jet energy is converted into the thermal, kinetic and gravitational potential energy components of the jet cocoon and ICM. We explore the temporal evolution of the partitioning of the injected jet energy into the cocoon and the ICM and quantify the importance of entrainment process on the energy partitioning. We investigate the fraction of injected energy transferred to the thermal energy component of the jet-ICM system in the context of heating the cluster environments, noting that the jets simulated display peak thermalisation efficiencies of least 65% and a marked dependence on the jet density. We compare the efficiencies of the energy partitioning between the cocoon and ICM for the two kinetic power regimes and discuss the resulting efficiency-power scaling relations of each regime.

Liquid jets for experiments on complex fluids

International Nuclear Information System (INIS)

Steinke, Ingo

2015-02-01

The ability of modern storage rings and free-electron lasers to produce intense X-ray beams that can be focused down to μm and nm sizes offers the possibility to study soft condensed matter systems on small length and short time scales. Gas dynamic virtual nozzles (GDVN) offer the unique possibility to investigate complex fluids spatially confined in a μm sized liquid jet with high flow rates, high pressures and shear stress distributions. In this thesis two different applications of liquid jet injection systems have been studied. The influence of the shear flow present in a liquid jet on colloidal dispersions was investigated via small angle X-ray scattering and a coherent wide angle X-ray scattering experiment on a liquid water jet was performed. For these purposes, liquid jet setups that are capable for X-ray scattering experiments have been developed and the manufacturing of gas dynamic virtual nozzles was realized. The flow properties of a liquid jet and their influences on the liquid were studied with two different colloidal dispersions at beamline P10 at the storage ring PETRA III. The results show that high shear flows present in a liquid jet lead to compressions and expansions of the particle structure and to particle alignments. The shear rate in the used liquid jet could be estimated to γ ≥ 5.4 . 10 4 Hz. The feasibility of rheology studies with a liquid jet injection system and the combined advantages is discussed. The coherent X-ray scattering experiment on a water jet was performed at the XCS instrument at the free-electron laser LCLS. First coherent single shot diffraction patterns from water were taken to investigate the feasibility of measuring speckle patterns from water.

Effects of local high-frequency perturbation on a turbulent boundary layer by synthetic jet injection

International Nuclear Information System (INIS)

Guo, Hao; Huang, Qian-Min; Liu, Pei-qing; Qu, Qiu-Lin

2015-01-01

An experimental study is performed to investigate the local high-frequency perturbation effects of a synthetic jet injection on a flat-plate turbulent boundary layer. Parameters of the synthetic jet are designed to force a high-frequency perturbation from a thin spanwise slot in the wall. In the test locations downstream of the slot, it is found that skin-friction is reduced by the perturbation, which is languishingly evolved downstream of the slot with corresponding influence on the near-wall regeneration mechanism of turbulent structures. The downstream slot region is divided into two regions due to the influence strength of the movement of spanwise vortices generated by the high-frequency perturbation. Interestingly, the variable interval time average technique is found to be disturbed by the existence of the spanwise vortices’ motion, especially in the region close to the slot. Similar results are obtained from the analysis of the probability density functions of the velocity fluctuation time derivatives, which is another indirect technique for detecting the enhancement or attenuation of streamwise vortices. However, both methods have shown consistent results with the skin-friction reduction mechanism in the far-away slot region. The main purpose of this paper is to remind researchers to be aware of the probable influence of spanwise vortices’ motion in wall-bounded turbulence control. (paper)

PIV measurements of turbulent jet and pool mixing produced by a steam jet discharge in a subcooled water pool

International Nuclear Information System (INIS)

Choo, Yeon Jun; Song, Chul-Hwa

2010-01-01

This experimental research is on the fluid-dynamic features produced by a steam injection into a subcooled water pool. The relevant phenomena could often be encountered in water cooled nuclear power plants. Two major topics, a turbulent jet and the internal circulation produced by a steam injection, were investigated separately using a particle image velocimetry (PIV) as a non-intrusive optical measurement technique. Physical domains of both experiments have a two-dimensional axi-symmetric geometry of which the boundary and initial conditions can be readily and well defined. The turbulent jet experiments with the upward discharging configuration provide the parametric values for quantitatively describing a turbulent jet such as the self-similar velocity profile, central velocity decay, spreading rate, etc. And in the internal circulation experiments with the downward discharging configuration, typical flow patterns in a whole pool region are measured in detail, which reveals both the local and macroscopic characteristics of the mixing behavior in a pool. This quantitative data on the condensing jet-induced mixing behavior in a pool could be utilized as benchmarking for a CFD simulation of relevant phenomena.

Experimental investigation of a reacting transverse jet in a high pressure oscillating vitiated crossflow

Science.gov (United States)

Fugger, Christopher A.

Staged combustion is one design approach in a gas turbine engine to reduce pollutant emission levels. In axially staged combustion, portions of the air and fuel are injected downstream of a lean premixed low NOx primary combustion zone. The gas residence time at elevated temperatures is decreased resulting in lower thermal NOx, and the reduced oxygen and high temperature vitiated primary zone flow further help to reduce pollutant emissions and quickly complete combustion. One implementation of axially staged combustion is transverse fuel jet injection. An important consideration for staged combustion systems, though, is how the primary and secondary combustion zones can couple through the acoustic resonances of the chamber. These couplings can lead to additional source terms that pump energy into the resonant acoustic field and help sustain the high-amplitude combustor pressure oscillations. An understanding of these couplings is important so that it may be possible to design a secondary combustion system that provides inherent damping to the combustor system. To systematically characterize the coupling of a reacting jet in unsteady crossflow in detail, the effects of an an unsteady pressure flowfield and an unsteady velocity flowfield are separately investigated. An optically accessible resonant combustion chamber was designed and built as part of this work to generate a standing wave unsteady vitiated crossflow at a chamber pressure of 0.9 MPa. The location of transverse jet injection corresponds to one of two locations, where one location is the pressure node and the other location the pressure anti-node of the resonant chamber acoustic mode. The injection location is optically accessible, and the dynamic interactions between the transverse jet flow and the 1st and 2nd axial combustor modes are measured using 10 kHz OH-PLIF and 2D PIV. This document analyzes five test cases: two non-reacting jets and three reacting jets. All cases correspond to jet injection

3D-CFD Simulation of Confined Cross-Flow Injection Process Using Single Piston Pump

Directory of Open Access Journals (Sweden)

M. Elashmawy

2017-12-01

Full Text Available Injection process into a confined cross flow is quite important for many applications including chemical engineering and water desalination technology. The aim of this study is to investigate the performance of the injection process into a confined cross-flow of a round pipe using a single piston injection pump. A computational fluid dynamics (CFD analysis has been carried out to investigate the effect of the locations of the maximum velocity and minimum pressure on the confined cross-flow process. The jet trajectory is analyzed and related to the injection pump shaft angle of rotation during the injection duty cycle by focusing on the maximum instant injection flow of the piston action. Results indicate a low effect of the jet trajectory within the range related to the injection pump operational conditions. Constant cross-flow was used and injection flow is altered to vary the jet to line flow ratio (QR. The maximum jet trajectory exhibits low penetration inside the cross-flow. The results showed three regions of the flow ratio effect zones with different behaviors. Results also showed that getting closer to the injection port causes a significant decrease on the locations of the maximum velocity and minimum pressure.

Heated water jet in coflowing turbulent stream

International Nuclear Information System (INIS)

Shirazi, M.A.; McQuivey, R.S.; Keefer, T.N.

1974-01-01

Effects of ambient turbulence on temperature and salinity distributions of heated water and neutrally buoyant saltwater jets were studied for a wide range of densimetric jet Froude numbers, jet discharge velocities, and ambient turbulence levels in a 4-ft-wide channel. Estimates of vertical and lateral diffusivity coefficients for heat and for salt were obtained from salinity and temperature distributions taken at several stations downstream of the injection point. Readily usable correlations are presented for plume center-line temperature, plume width, and trajectory. The ambient turbulence affects the gross behavior characteristics of the plume. The effects vary with the initial jet Froude number and the jet to ambient velocity ratio. Heat and salinity are transported similarly and the finite source dimensions and the initial jet characteristics alter the numerical value of the diffusivity

Jet arrays in supersonic crossflow — An experimental study

Science.gov (United States)

Ali, Mohd Yousuf; Alvi, Farrukh

2015-12-01

Jet injection into a supersonic crossflow is a classical fluid dynamics problem with many engineering applications. Several experimental and numerical studies have been taken up to analyze the interaction of a single jet with the incoming crossflow. However, there is a dearth of the literature on the interaction of multiple jets with one another and with the crossflow. Jets in a supersonic crossflow are known to produce a three-dimensional bow-shock structure due to the blockage of the flow. Multiple jets in a streamwise linear array interact with both one another and the incoming supersonic flow. In this paper, a parametric study is carried out to analyze the effect of microjet (sub-mm diameter) injection in a Mach 1.5 supersonic crossflow using flow visualization and velocity field measurements. The variation of the microjet orifice diameter and spacing within an array is used to study the three-dimensional nature of the flow field around the jets. The strength of the microjet-generated shock, scaling of the shock wave angle with the momentum coefficient, averaged streamwise, spanwise, and cross-stream velocity fields, and microjet array trajectories are detailed in the paper. It was found that shock angles of the microjet-generated shocks scale with the momentum coefficient for the three actuator configurations tested. As the microjets issue in the crossflow, a pair of longitudinal counter-rotating vortices (CVPs) are formed. The vortex pairs remain coherent for arrays with larger spanwise spacing between the micro-orifices and exhibit significant three-dimensionality similar to that of a single jet in crossflow. As the spacing between the jets is reduced, the CVPs merge resulting in a more two-dimensional flow field. The bow shock resulting from microjet injection also becomes nearly two-dimensional as the spacing between the micro-orifices is reduced. Trajectory estimations yield that microjets in an array have similar penetration as single jets. A notional

Transverse jet-cavity interactions with the influence of an impinging shock

International Nuclear Information System (INIS)

Zare-Behtash, H.; Lo, K.H.; Kontis, K.; Ukai, T.; Obayashi, S.

2015-01-01

Highlights: • Experimental study of shock-jet-cavity in a supersonic freestream is conducted. • Shock impingement at the cavity leading edge lifts the shear layer, encouraging momentum transfer. • Shock impingement close to the jet location increases the number of smaller turbulent structures. - Abstract: For high-speed air breathing engines, fuel injection and subsequent mixing with air is paramount for combustion. The high freestream velocity poses a great challenge to efficient mixing both in macroscale and microscale. Utilising cavities downstream of fuel injection locations, as a means to hold the flow and stabilise the combustion, is one mechanism which has attracted much attention, requiring further research to study the unsteady flow features and interactions occurring within the cavity. In this study we combine the transverse jet injection upstream of a cavity with an impinging shock to see how this interaction influences the cavity flow, since impinging shocks have been shown to enhance mixing of transverse jets. Utilising qualitative and quantitative methods: schlieren, oilflow, PIV, and PSP the induced flowfield is analysed. The impinging shock lifts the shear layer over the cavity and combined with the instabilities generated by the transverse jet creates a highly complicated flowfield with numerous vertical structures. The interaction between the oblique shock and the jet leads to a relatively uniform velocity distribution within the cavity

Experimental study of elliptical jet from supercritical to subcritical conditions using planar laser induced fluorescence

Energy Technology Data Exchange (ETDEWEB)

Muthukumaran, C. K.; Vaidyanathan, Aravind, E-mail: aravind7@iist.ac.in [Department of Aerospace Engineering, Indian Institute of Space Science and Technology, Trivandrum, Kerala 695547 (India)

2015-03-15

The study of fluid jet dynamics at supercritical conditions involves strong coupling between fluid dynamic and thermodynamic phenomena. Beyond the critical point, the liquid-vapor coexistence ceases to exist, and the fluid exists as a single phase known as supercritical fluid with its properties that are entirely different from liquids and gases. At the critical point, the liquids do not possess surface tension and latent heat of evaporation. Around the critical point, the fluid undergoes large changes in density and possesses thermodynamic anomaly like enhancement in thermal conductivity and specific heat. In the present work, the transition of the supercritical and near-critical elliptical jet into subcritical as well as supercritical environment is investigated experimentally with nitrogen and helium as the surrounding environment. Under atmospheric condition, a liquid jet injected from the elliptical orifice exhibits axis switching phenomena. As the injection temperature increases, the axis switching length also increases. Beyond the critical temperature, the axis switching is not observed. The investigation also revealed that pressure plays a major role in determining the thermodynamic transition of the elliptical jet only for the case of supercritical jet injected into subcritical chamber conditions. At larger pressures, the supercritical jet undergoes disintegration and formation of droplets in the subcritical environment is observed. However, for supercritical jet injection into supercritical environment, the gas-gas like mixing behavior is observed.

Experimental study of elliptical jet from supercritical to subcritical conditions using planar laser induced fluorescence

International Nuclear Information System (INIS)

Muthukumaran, C. K.; Vaidyanathan, Aravind

2015-01-01

The study of fluid jet dynamics at supercritical conditions involves strong coupling between fluid dynamic and thermodynamic phenomena. Beyond the critical point, the liquid-vapor coexistence ceases to exist, and the fluid exists as a single phase known as supercritical fluid with its properties that are entirely different from liquids and gases. At the critical point, the liquids do not possess surface tension and latent heat of evaporation. Around the critical point, the fluid undergoes large changes in density and possesses thermodynamic anomaly like enhancement in thermal conductivity and specific heat. In the present work, the transition of the supercritical and near-critical elliptical jet into subcritical as well as supercritical environment is investigated experimentally with nitrogen and helium as the surrounding environment. Under atmospheric condition, a liquid jet injected from the elliptical orifice exhibits axis switching phenomena. As the injection temperature increases, the axis switching length also increases. Beyond the critical temperature, the axis switching is not observed. The investigation also revealed that pressure plays a major role in determining the thermodynamic transition of the elliptical jet only for the case of supercritical jet injected into subcritical chamber conditions. At larger pressures, the supercritical jet undergoes disintegration and formation of droplets in the subcritical environment is observed. However, for supercritical jet injection into supercritical environment, the gas-gas like mixing behavior is observed

Recent results on confinement in JET

International Nuclear Information System (INIS)

Campbell, D.J.

1992-01-01

The JET device is the world's largest tokamak and has been utilized in plasma heating experiments at total powers of up to 35MW using both neutral beam injection (NBI) and ion cyclotron resonance heating (ICRH). At the highest performance, JET plasmas have achieved conditions equivalent to energy ''breakeven''. A principal aim of the JET experiment is the investigation of plasma heating and confinement in plasma regimes relevant to thermonuclear ignition. The central issues in confinement physics involved in these advances are briefly reviewed and the most recent investigations of transport in high performance plasmas are summarized. (Author)

Liquid jets for fast plasma termination in tokamaks

International Nuclear Information System (INIS)

Rosenbluth, M.N.; Putvinskij, S.V.; Parks, P.B.

1997-01-01

Recent simulations by Putvisnkij et al. (PSI Conference, 1996) have shown that introducing impurities into the plasma in order to mitigate adverse disruption effects in ITER may actually be deleterious because of a potentially unwelcome phenomenon: generation of multi-MeV runaway electrons by the collisional avalanche mechanism (Rosenbluth, M.N., et al., in Fusion Energy 1996 (Proc. 16th Int. Conf. Montreal, 1996) Vol. 2, IAEA, Vienna (in press) Paper FP-26). The injection of a liquid hydrogen jet to deliver a massive density increase is proposed as a means of avoiding runaways, while providing the same beneficial effects as impurities. A discussion of many jet related topics, such as ablation/penetration, jet breakup time and stability, is presented. Owing to an ablation pressure instability, it is predicted that the jet will quickly break up into a regular chain of droplets with dimensions of approximately the size of the jet radius. It is found that while deep penetration in the plasma can easily be achieved, bubble growth and disruptive boiling (flashing) during the propagation in the vacuum gap between the nozzle exit and the plasma are the main processes limiting the jet survival time. Calculations indicate that for ITER reference parameters, the jet can remain coherent in vacuum for a distance ∼ 1 m before disintegrating. On the basis of this present understanding, the prospect for the safe termination of ITER discharges by high density liquid jet injection appears promising. (author). 20 refs, 6 figs, 3 tabs

Curved wall-jet burner for synthesizing titania and silica nanoparticles

KAUST Repository

Ismail, Mohamed; Memon, Nasir; Mansour, Morkous S.; Anjum, Dalaver H.; Chung, Suk-Ho

2015-01-01

A novel curved wall-jet (CWJ) burner was designed for flame synthesis, by injecting precursors through a center tube and by supplying fuel/air mixtures as an annular-inward jet for rapid mixing of the precursors in the reaction zone. Titanium

Platelet activating factor receptor binding plays a critical role in jet fuel-induced immune suppression

International Nuclear Information System (INIS)

Ramos, Gerardo; Kazimi, Nasser; Nghiem, Dat X.; Walterscheid, Jeffrey P.; Ullrich, Stephen E.

2004-01-01

Applying military jet fuel (JP-8) or commercial jet fuel (Jet-A) to the skin of mice suppresses the immune response in a dose-dependant manner. The release of biological response modifiers, particularly prostaglandin E 2 (PGE 2 ), is a critical step in activating immune suppression. Previous studies have shown that injecting selective cyclooxygenase-2 inhibitors into jet fuel-treated mice blocks immune suppression. Because the inflammatory phospholipid mediator, platelet-activating factor (PAF), up-regulates cyclooxygenase-2 production and PGE 2 synthesis by keratinocytes, we tested the hypothesis that PAF-receptor binding plays a role in jet fuel-induced immune suppression. Treating keratinocyte cultures with PAF and/or jet fuel (JP-8 and Jet-A) stimulates PGE 2 secretion. Jet fuel-induced PGE 2 production was suppressed by treating the keratinocytes with specific PAF-receptor antagonists. Injecting mice with PAF, or treating the skin of the mice with JP-8, or Jet-A, induced immune suppression. Jet fuel-induced immune suppression was blocked when the jet fuel-treated mice were injected with PAF-receptor antagonists before treatment. Jet fuel treatment has been reported to activate oxidative stress and treating the mice with anti-oxidants (Vitamins C, or E or beta-hydroxy toluene), before jet fuel application, interfered with immune suppression. These findings confirm previous studies showing that PAF-receptor binding can modulate immune function. Furthermore, they suggest that PAF-receptor binding may be an early event in the induction of immune suppression by immunotoxic environmental agents that target the skin

Bifurcation in a buoyant horizontal laminar jet

Science.gov (United States)

Arakeri, Jaywant H.; Das, Debopam; Srinivasan, J.

2000-06-01

The trajectory of a laminar buoyant jet discharged horizontally has been studied. The experimental observations were based on the injection of pure water into a brine solution. Under certain conditions the jet has been found to undergo bifurcation. The bifurcation of the jet occurs in a limited domain of Grashof number and Reynolds number. The regions in which the bifurcation occurs has been mapped in the Reynolds number Grashof number plane. There are three regions where bifurcation does not occur. The various mechanisms that prevent bifurcation have been proposed.

Discussion on the Influence of Various Technological Parameters on Jet Grouting Columns Geometry

Directory of Open Access Journals (Sweden)

Bzówka Joanna

2015-06-01

Full Text Available One of the most popular elements created by using jet grouting technology are columns. During designing such columns, it is a problem of estimating their shape and dimensions. The main factors that influence on columns geometry are soil characteristic and technological parameters. At the frame of Authors scientific research, following technological factors were taken into account: system of jet grouting, injection pressure, dimension of nozzles and rotation speed during injection. In the paper some results of the field tests of jet grouting columns are presented

Numerical analyses of flashing jet structure and droplet size characteristics

International Nuclear Information System (INIS)

Duan Riqiang; Jiang Shengyao; Koshizuka, Seiichi; Oka, Yoshiaki; Yamaguchi, Akira; Takata, Takashi

2006-01-01

In this paper, flashing jets are numerically simulated using the MPS method. The boiling mode for flashing is identified as surface boiling mode, based on the postulation of jets from a short nozzle under high depressurization. The Homogeneous Non-equilibrium Relaxation Model (HRM) is used for calculating the evaporation rate of flashing. The numerical simulation results show that flashing jets comprise an inner intact core which is surrounded by two-phase droplet flow. The effect of degree of superheat on the jet topological geometry is investigated. With increasing degree of superheat, the topological shape of flashing jets evolves from cylindrical core for low degree of superheat to cone-shaped core for high degree of superheat, and meanwhile the extinction length comes to decrease and tends asymptotically constant as the injection temperature approaches the saturation temperature corresponding to the injection pressure. The analyses of the droplet size distribution engendered from primary breakup of flashing jets show that: two peaks exist for droplet size distribution at lower degree of superheat; however, merely one peak for higher degree of superheat. From droplet size distribution, it is revealed that the primary breakup mechanism of flashing jets can be attributed to dominant mechanical breakup mode plus enhancement via surface evaporation. (author)

Numerical investigation of the effect of injection strategy on mixture formation and combustion process in a port injection natural gas rotary engine

International Nuclear Information System (INIS)

Fan, Baowei; Pan, Jianfeng; Yang, Wenming; Liu, Yangxian; Bani, Stephen; Chen, Wei

2017-01-01

Highlights: • For injection timing, the fuel movement is controlled by the intensity of the vortex I. • For injection duration, the fuel movement is controlled by the value of jet flux. • The ideal fuel distribution at ignition timing for high combustion rate is studied. • The optimal injection strategy had an increase in the peak pressure and NO emissions. - Abstract: This work aimed to numerically study the influence of injection strategy on mixture formation and combustion process in a port injection natural gas rotary engine. On the base of a 3D dynamic simulation model which was established in our previous work, some critical information was obtained, which was difficult to obtain through experiment, in terms of the flow field, the fuel distribution, the temperature field and the concentration fields of some intermediates. Simulation results showed that for mixture formation, the movements of fuel in injection stage were mainly controlled by the intensity of the vortex I for injection timing, and the value of jet flux for injection duration respectively. With retarded injection timing, the decreasing intensity of the vortex I resulted in less fuel moving toward the back of the combustion chamber. With the extension in injection duration, the decreasing value of jet flux resulted in more fuel staying at the back of the combustion chamber. For combustion process, the overall combustion rate for injection strategy which had an injection timing of 390 °CA (BTDC) and injection duration of 51.5 °CA (case ID4) was the fastest. This was mainly due to the fact that the accumulation area of fuel was at the middle and front of the combustion chamber. Meanwhile, fuel concentration near the leading and trailing spark plugs was conducive for the flame kernel formation. Compared with the injection strategy which had an injection timing of 450 °CA (BTDC) and an injection duration of 55 °CA (case IT1), the improved combustion rate of case ID4 had a 23% increase in

Experimental study on spray break-up and atomization processes from GDI injector using high injection pressure up to 30 MPa

International Nuclear Information System (INIS)

Lee, Sanghoon; Park, Sungwook

2014-01-01

Highlights: • We obtain distribution of droplet velocity and diameter using PDPA system. • Transition of a jet break-up processes is visualized using Nd:Yag sheet laser system. • Elevated injection pressure can activate a jet break-up processes. • A limit in injection pressure to enhance droplet atomization is observed. -- Abstract: This paper focuses on the influence of injection pressures up to 30 MPa on single liquid jet break-up and atomization processes. For this purpose, a single jet from a multi-hole GDI injector has been characterized performing visualization and PDPA (phase Doppler particle analyzer) experiments. Using a thin sheet of light generated by a Nd:Yag laser and capturing a sequence of jet development images with a CCD camera, the internal structure was visualized. In order to quantify the droplet diameter and velocity, a 2-D PDPA system were carried out in addition to the spray visualization. Analyzing the images of the internal structure of jet and the result of PDPA, including droplet diameter and velocity distribution with increasing injection pressure up to 30 MPa, the elevated injection pressure on a jet break-up and atomization was characterized. Our experimental results show the existence of a leading edge of the jet observed at the initial stage of injection. This phenomenon revealed relatively large droplets ahead of the main jet then disappeared quickly as lose the droplets momentum. Furthermore, for all injection pressures, unique ‘branch-like structure’ was observed when the jet was fully developed. This structure had many counter rotating branches related to the effect of air-entrainment and rapidly broken down into droplet clusters and droplets. Especially, as increased injection pressure, the time to exhibit the structure and distance between two branches were decreased. In addition, based on the results of droplet diameter and velocity distribution at various injection pressures, we confirmed that the injection

Modelling auto ignition of hydrogen in a jet ignition pre-chamber

Energy Technology Data Exchange (ETDEWEB)

Boretti, Alberto A. [School of Science and Engineering, University of Ballarat, PO Box 663, Ballarat, Victoria 3353 (Australia)

2010-04-15

Spark-less jet ignition pre-chambers are enablers of high efficiencies and load control by quantity of fuel injected when coupled with direct injection of main chamber fuel, thus permitting always lean burn bulk stratified combustion. Towards the end of the compression stroke, a small quantity of hydrogen is injected within the pre-chamber, where it mixes with the air entering from the main chamber. Combustion of the air and fuel mixture then starts within the pre-chamber because of the high temperature of the hot glow plug, and then jets of partially combusted hot gases enter the main chamber igniting there in the bulk, over multiple ignition points, lean stratified mixtures of air and fuel. The paper describes the operation of the spark-less jet ignition pre-chamber coupling CFD and CAE engine simulations to allow component selection and engine performance evaluation. (author)

Turbulence production by a steam-driven jet in a water vessel

Energy Technology Data Exchange (ETDEWEB)

Wissen, R.J.E. van; Schreel, K.R.A.M.; Geld, C.W.M. van der [Eindhoven Univ. of Technology (Netherlands). Dept. of Mechanical Engineering; Wieringa, J. [Unilever Research and Development, Vlaardingen (Netherlands)

2004-04-01

Direct steam injection is an efficient means of heating a volume of liquid. Usually the steam is injected via a nozzle, yielding a strong jet that condenses rapidly and transforms into a self-similar single phase jet. In the experiments reported in this paper, superheated steam is injected, centrally, at the bottom of a vertical, cylindrical water vessel. The resulting jet is turbulent (Re=7.9 x 10{sup 4}-18.1 x 10{sup 4} with the length scale based on the width of the jet, r{sub 1/2} and the velocity scale based on the centerline velocity, U{sub 0}). Using PIV in a vertical plane through the central axis, instantaneous velocity fields have been measured at a rate of 15 Hz. Near the inlet, the jet is mainly steam that rapidly condenses. Further downstream, the jet is essentially single phase, although some residual air is present as microscopically small bubbles. In the area directly downstream of the steam part, the ratio of r{sub 1/2} to the vessel radius R (32.5 cm) is about 1/14. The production of turbulent kinetic energy has been quantified for the main process conditions. Its dependencies on temperature, nozzle opening and inlet steam pressure have been determined. This production of energy is related to the stresses exerted on small particles in the mixture, and break-up of particles is discussed. (author)

Reduction of Altitude Diffuser Jet Noise Using Water Injection

Science.gov (United States)

Allgood, Daniel C.; Saunders, Grady P.; Langford, Lester A.

2011-01-01

A feasibility study on the effects of injecting water into the exhaust plume of an altitude rocket diffuser for the purpose of reducing the far-field acoustic noise has been performed. Water injection design parameters such as axial placement, angle of injection, diameter of injectors, and mass flow rate of water have been systematically varied during the operation of a subscale altitude test facility. The changes in acoustic far-field noise were measured with an array of free-field microphones in order to quantify the effects of the water injection on overall sound pressure level spectra and directivity. The results showed significant reductions in noise levels were possible with optimum conditions corresponding to water injection at or just upstream of the exit plane of the diffuser. Increasing the angle and mass flow rate of water injection also showed improvements in noise reduction. However, a limit on the maximum water flow rate existed as too large of flow rate could result in un-starting the supersonic diffuser.

A new Disruption Mitigation System for deuterium–tritium operation at JET

Energy Technology Data Exchange (ETDEWEB)

Kruezi, Uron, E-mail: uron.kruezi@ccfe.ac.uk [CCFE, Culham Science Centre, Abingdon, Oxon OX14 3DB (United Kingdom); Jachmich, Stefan [Laboratory for Plasma Physic, ERM/KMS, B-1000 Brussels (Belgium); Koslowski, Hans Rudolf [Forschungszentrum Jülich GmbH, IEK-4, 52425 Jülich (Germany); Lehnen, Michael [ITER Organization, Route de Vinon-sur-Verdon, CS90046, 13067 St. Paul Lez Durance Cedex (France); Brezinsek, Sebastijan [Forschungszentrum Jülich GmbH, IEK-4, 52425 Jülich (Germany); Matthews, Guy [CCFE, Culham Science Centre, Abingdon, Oxon OX14 3DB (United Kingdom)

2015-10-15

Highlights: • A Disruption Mitigation System based on massive gas injections has been designed. • The DMS has been installed at the JET-tokamak for routine machine protection. • The DMS is capable of a throughput of up to 4.6 kPa m{sup 3}. • The new DMS is compatible with the deuterium–tritium operation at JET. - Abstract: Disruptions, the fast accidental losses of plasma current and stored energy in tokamaks, represent a significant risk to the mechanical structure as well as the plasma facing components of reactor-scale fusion facilities like ITER. At JET, the tokamak experiment closest to ITER in terms of operating parameters and size, massive gas injection has been established as a disruption mitigation method. As a “last resort” measure it reduces thermal and electromagnetic loads during disruptions which can potentially have a serious impact on the beryllium and tungsten plasma-facing materials of the main chamber and divertor. For the planned deuterium–tritium experiments, a new Disruption Mitigation System (DMS) has been designed and installed and is presented in this article. The new DMS at JET consists of an all metal gate valve compatible with gas injections, a fast high pressure eddy current driven valve, a high voltage power supply and a gas handling system providing six supply lines for pure and mixed noble and flammable gases (Ar, Ne, Kr, D{sub 2}, etc.). The valve throughput varies with the injection pressure and gas type (efficiency – injected/charged gas 50–97%); the maximum injected amount of gas is approximately 4.6 kPa m{sup 3} (at maximum system pressure of 5.0 MPa).

A new Disruption Mitigation System for deuterium–tritium operation at JET

International Nuclear Information System (INIS)

Kruezi, Uron; Jachmich, Stefan; Koslowski, Hans Rudolf; Lehnen, Michael; Brezinsek, Sebastijan; Matthews, Guy

2015-01-01

Highlights: • A Disruption Mitigation System based on massive gas injections has been designed. • The DMS has been installed at the JET-tokamak for routine machine protection. • The DMS is capable of a throughput of up to 4.6 kPa m"3. • The new DMS is compatible with the deuterium–tritium operation at JET. - Abstract: Disruptions, the fast accidental losses of plasma current and stored energy in tokamaks, represent a significant risk to the mechanical structure as well as the plasma facing components of reactor-scale fusion facilities like ITER. At JET, the tokamak experiment closest to ITER in terms of operating parameters and size, massive gas injection has been established as a disruption mitigation method. As a “last resort” measure it reduces thermal and electromagnetic loads during disruptions which can potentially have a serious impact on the beryllium and tungsten plasma-facing materials of the main chamber and divertor. For the planned deuterium–tritium experiments, a new Disruption Mitigation System (DMS) has been designed and installed and is presented in this article. The new DMS at JET consists of an all metal gate valve compatible with gas injections, a fast high pressure eddy current driven valve, a high voltage power supply and a gas handling system providing six supply lines for pure and mixed noble and flammable gases (Ar, Ne, Kr, D_2, etc.). The valve throughput varies with the injection pressure and gas type (efficiency – injected/charged gas 50–97%); the maximum injected amount of gas is approximately 4.6 kPa m"3 (at maximum system pressure of 5.0 MPa).

A contoured gap coaxial plasma gun with injected plasma armature.

Science.gov (United States)

Witherspoon, F Douglas; Case, Andrew; Messer, Sarah J; Bomgardner, Richard; Phillips, Michael W; Brockington, Samuel; Elton, Raymond

2009-08-01

A new coaxial plasma gun is described. The long term objective is to accelerate 100-200 microg of plasma with density above 10(17) cm(-3) to greater than 200 km/s with a Mach number above 10. Such high velocity dense plasma jets have a number of potential fusion applications, including plasma refueling, magnetized target fusion, injection of angular momentum into centrifugally confined mirrors, high energy density plasmas, and others. The approach uses symmetric injection of high density plasma into a coaxial electromagnetic accelerator having an annular gap geometry tailored to prevent formation of the blow-by instability. The injected plasma is generated by numerous (currently 32) radially oriented capillary discharges arranged uniformly around the circumference of the angled annular injection region of the accelerator. Magnetohydrodynamic modeling identified electrode profiles that can achieve the desired plasma jet parameters. The experimental hardware is described along with initial experimental results in which approximately 200 microg has been accelerated to 100 km/s in a half-scale prototype gun. Initial observations of 64 merging injector jets in a planar cylindrical testing array are presented. Density and velocity are presently limited by available peak current and injection sources. Steps to increase both the drive current and the injected plasma mass are described for next generation experiments.

A contoured gap coaxial plasma gun with injected plasma armature

International Nuclear Information System (INIS)

Witherspoon, F. Douglas; Case, Andrew; Messer, Sarah J.; Bomgardner, Richard II; Phillips, Michael W.; Brockington, Samuel; Elton, Raymond

2009-01-01

A new coaxial plasma gun is described. The long term objective is to accelerate 100-200 μg of plasma with density above 10 17 cm -3 to greater than 200 km/s with a Mach number above 10. Such high velocity dense plasma jets have a number of potential fusion applications, including plasma refueling, magnetized target fusion, injection of angular momentum into centrifugally confined mirrors, high energy density plasmas, and others. The approach uses symmetric injection of high density plasma into a coaxial electromagnetic accelerator having an annular gap geometry tailored to prevent formation of the blow-by instability. The injected plasma is generated by numerous (currently 32) radially oriented capillary discharges arranged uniformly around the circumference of the angled annular injection region of the accelerator. Magnetohydrodynamic modeling identified electrode profiles that can achieve the desired plasma jet parameters. The experimental hardware is described along with initial experimental results in which approximately 200 μg has been accelerated to 100 km/s in a half-scale prototype gun. Initial observations of 64 merging injector jets in a planar cylindrical testing array are presented. Density and velocity are presently limited by available peak current and injection sources. Steps to increase both the drive current and the injected plasma mass are described for next generation experiments.

Simulation Of Gas Focused Liquid Jets

OpenAIRE

Zahoor, Rizwan

2018-01-01

The main aim of dissertation is to develop an experimentally verified computational fluid dynamic (CFD) model of micron-sized liquid jet, produced by an injection molded Gas Dynamic Virtual Nozzle (GDVN). In these nozzles, liquid jets are efficiently orientedly transporting mass and momentum. They are produced by intelligently projecting hydrodynamic focusing effect from a high-speed stream of a co-flowing lower density and lower viscosity gas on a stream of liquid from a feeding capillary. L...

Observable Emission Features of Black Hole GRMHD Jets on Event Horizon Scales

Energy Technology Data Exchange (ETDEWEB)

Pu, Hung-Yi [Perimeter Institute for Theoretical Physics, 31 Caroline Street North, Waterloo, ON, N2L 2Y5 (Canada); Wu, Kinwah [Mullard Space Science Laboratory, University College London, Holmbury St. Mary, Dorking, Surrey, RH5 6NT (United Kingdom); Younsi, Ziri; Mizuno, Yosuke [Institut für Theoretische Physik, Max-von-Laue-Straße 1, D-60438 Frankfurt am Main (Germany); Asada, Keiichi; Nakamura, Masanori, E-mail: hpu@perimeterinstitute.ca, E-mail: asada@asiaa.sinica.edu.tw, E-mail: nakamura@asiaa.sinica.edu.tw, E-mail: kinwah.wu@ucl.ac.uk, E-mail: younsi@th.physik.uni-frankfurt.de, E-mail: mizuno@th.physik.uni-frankfurt.de [Institute of Astronomy and Astrophysics, Academia Sinica, 11F of Astronomy-Mathematics Building, AS/NTU No. 1, Taipei 10617, Taiwan (China)

2017-08-20

The general-relativistic magnetohydrodynamical (GRMHD) formulation for black hole-powered jets naturally gives rise to a stagnation surface, where inflows and outflows along magnetic field lines that thread the black hole event horizon originate. We derive a conservative formulation for the transport of energetic electrons, which are initially injected at the stagnation surface and subsequently transported along flow streamlines. With this formulation the energy spectra evolution of the electrons along the flow in the presence of radiative and adiabatic cooling is determined. For flows regulated by synchrotron radiative losses and adiabatic cooling, the effective radio emission region is found to be finite, and geometrically it is more extended along the jet central axis. Moreover, the emission from regions adjacent to the stagnation surface is expected to be the most luminous as this is where the freshly injected energetic electrons are concentrated. An observable stagnation surface is thus a strong prediction of the GRMHD jet model with the prescribed non-thermal electron injection. Future millimeter/submillimeter (mm/sub-mm) very-long-baseline interferometric observations of supermassive black hole candidates, such as the one at the center of M87, can verify this GRMHD jet model and its associated non-thermal electron injection mechanism.

Sub- and supercritical jet disintegration

Science.gov (United States)

DeSouza, Shaun; Segal, Corin

2017-04-01

Shadowgraph visualization and Planar Laser Induced Fluorescence (PLIF) are applied to single orifice injection in the same facility and same fluid conditions to analyze sub- to supercritical jet disintegration and mixing. The comparison includes jet disintegration and lateral spreading angle. The results indicate that the shadowgraph data are in agreement with previous visualization studies but differ from the PLIF results that provided quantitative measurement of central jet plane density and density gradients. The study further evaluated the effect of thermodynamic conditions on droplet production and quantified droplet size and distribution. The results indicate an increase in the normalized drop diameter and a decrease in the droplet population with increasing chamber temperatures. Droplet size and distribution were found to be independent of chamber pressure.

Development of liquid poison injection system (SDS-2) for 500 MWe PHWRs

International Nuclear Information System (INIS)

Nawathe, Shirish; Umashankari, P.; Balakrishnan, Kamala; Mahajan, S.C.; Kakodkar, A.

1991-01-01

A secondary shut-down system (SDS-2) in the form of a mecahnism for introducing poison into the moderator of the PHWR is under development in Reactor Engineering Division of BARC. The system, as conceived, consists of a tank containing pressurised helium connected to poison tanks through quick opening solenoid valves. The tanks are connected to horizontal injection tubes in the calandria. On system actuation, gadolinium nitrate solution from the tanks passes to the injection tubes which have a number of holes through which the poison enters the moderator. This report details the development work being done on this poison injection system. An experimental facility was set up to measure the poison jet growth rate and the jet spread after injection, and mathematical models were developed to convert the observed jets into reactivity worth values. A description of the work and the computed results are presented. (author). 21 graphs. , 15 tabs

Long Term Tritium Trapping in TFTR and JET

International Nuclear Information System (INIS)

Skinner, C.H.; Gentile, C.A.; Young, K.M.; Coad, J.P.; Hogan, J.T.; Penzhorn, R.-D.; Bekris, N.

2001-01-01

Tritium retention in TFTR [Tokamak Fusion Test Reactor] and JET [Joint European Torus] shows striking similarities and contrasts. In TFTR, 5 g of tritium were injected into circular plasmas over a 3.5 year period, mostly by neutral-beam injection. In JET, 35 g were injected into divertor plasmas over a 6 month campaign, mostly by gas puffing. In TFTR, the bumper limiter provided a large source of eroded carbon and a major part of tritium was co-deposited on the limiter and vessel wall. Only a small area of the co-deposit flaked off. In JET, the wall is a net erosion area, and co-deposition occurs principally in shadowed parts of the inner divertor, with heavy flaking. In both machines, the initial tritium retention, after a change from deuterium [D] to tritium [T] gas puffing, is high and is due to isotope exchange with deuterium on plasma-facing surfaces (dynamic inventory). The contribution of co-deposition is lower but cumulative, and is revealed by including periods of D fueling that reversed the T/D isotope exchange. Ion beam analysis of flakes from TFTR showed an atomic D/C ratio of 0.13 on the plasma facing surface, 0.25 on the back surface and 0.11 in the bulk. Data from a JET divertor tile showed a larger D/C ratio with 46% C, 30% D, 20% H and 4% O. Deuterium, tritium, and beryllium profiles have been measured and show a thin less than 50 micron co-deposited layer. Flakes retrieved from the JET vacuum vessel exhibited a high tritium release rate of 2e10 Bq/month/g. BBQ modeling of the effect of lithium on retention in TFTR showed overlapping lithium and tritium implantation and a 1.3x increase in local T retention

A contoured gap coaxial plasma gun with injected plasma armature

Energy Technology Data Exchange (ETDEWEB)

Witherspoon, F. Douglas; Case, Andrew; Messer, Sarah J.; Bomgardner, Richard II; Phillips, Michael W.; Brockington, Samuel; Elton, Raymond [HyperV Technologies Corp., Chantilly, Virginia 20151 (United States)

2009-08-15

A new coaxial plasma gun is described. The long term objective is to accelerate 100-200 {mu}g of plasma with density above 10{sup 17} cm{sup -3} to greater than 200 km/s with a Mach number above 10. Such high velocity dense plasma jets have a number of potential fusion applications, including plasma refueling, magnetized target fusion, injection of angular momentum into centrifugally confined mirrors, high energy density plasmas, and others. The approach uses symmetric injection of high density plasma into a coaxial electromagnetic accelerator having an annular gap geometry tailored to prevent formation of the blow-by instability. The injected plasma is generated by numerous (currently 32) radially oriented capillary discharges arranged uniformly around the circumference of the angled annular injection region of the accelerator. Magnetohydrodynamic modeling identified electrode profiles that can achieve the desired plasma jet parameters. The experimental hardware is described along with initial experimental results in which approximately 200 {mu}g has been accelerated to 100 km/s in a half-scale prototype gun. Initial observations of 64 merging injector jets in a planar cylindrical testing array are presented. Density and velocity are presently limited by available peak current and injection sources. Steps to increase both the drive current and the injected plasma mass are described for next generation experiments.

A study of transient jet and spray using a Schlieren method and digital image processing

Energy Technology Data Exchange (ETDEWEB)

Paulsen, H.

1995-12-31

This thesis discusses visualization and image-based data acquisition and analyses on transient gas jet, evaporating spray and burning jet in an attempt to find a method of measuring the transient behaviour of these phenomena, which influence the combustion process in diesel engines. The experimental approach is based on visualization of the injection process inside a constant volume air chamber. The influence of different experimental conditions such as fuel type, injection conditions, temperature and pressure of the chamber is investigated. To control the dynamics of the injection, a constant pressure injection system is used. The dynamics of the fuel injection system itself is not discussed. A full-field classical Schlieren technique is used, and the data recorded by means of a CCD camera and frame-grabber combination. The method has the unusual property of being particularly useful for measurements on a dynamic system, since the gradients in the light refraction index used by the Schlieren method are enhanced by the dynamics. The method was used to measure local gas concentration inside a room temperature methane gas jet, and vapour phase concentration evaporating propane spray. The system was also used to measure the local temperature of burning methane jet based on calculated density distribution. 47 refs., 92 figs., 3 tabs.

The injection of a highly focused microjet into a soft target

Science.gov (United States)

Endo, Nanami; Kawamoto, Sennosuke; Tagawa, Yoshiyuki

2016-11-01

Needle-free drug injection systems have been developed in order to supersede traditional syringe injection system with needles. However, in spite of its great potential, these systems are not commonly used. One of the main reasons is to use diffusive jets, which results in severe deceleration of the jets and causes insufficient penetration. Recently, a highly focused microjet generated by irradiating a laser pulse to a point inside a liquid filled in a capillary tube is gathering attention as a method to solve these problems. Although the microjet injection phenomena into a model material of the skin have been studied, the effect of the distance R (R is a distance between a gas-liquid interface and a target) on injection phenomena have not been researched. The distance R is not a parameter which controls the jet generation. However, considering the practical use of the needle-free injection, it is necessary to know appropriate value of the distance R. In this study, we change the distance R in a range of 0.3 mm to 5 mm to investigate its influence on the injection depth Di. As a target, we used 5 wt% gelatin. We show relationship between injection depth Di and distance R and rationalize it in this presentation. This work was supported by JSPS KAKENHI Grant Number JP26709007.

NUMERICAL SIMULATION OF THE MELTING OF PARTICLES INJECTED IN A PLASMA JET SIMULACIÓN NUMÉRICA DE LA FUSIÓN DE PARTÍCULAS INYECTADAS EN UN JET DE PLASMA

Directory of Open Access Journals (Sweden)

Jorge Romero Rojas

2009-12-01

Full Text Available This work presents the numerical simulation of the melting process of a particle injected in a plasma jet. The plasma process is nowadays applied to produce thin coatings on metal mechanical components with the aim of improving the surface resistance to different phenomena such as corrosion, temperature or wear. In this work we studied the heat transfer including phase-change of a bi-layer particle composed of a metallic iron core coated with ceramic alumina, inside a plasma jet. The model accounted for the environmental conditions along the particle path. The numerical simulation of this problem was performed via a temperature-based phase-change finite element formulation. The results obtained with this methodology satisfactorily described the melting process of the particle. Particularly, the results of the present work illustrate the phase change evolution in a bi-layer particle during its motion in the plasma jet. Moreover, the numerical trends agreed with those previously reported in the literature and computed with a finite volume enthalpy based formulation.Este trabajo presenta la simulación numérica de la fusión de una partícula inyectada en un jet de plasma. Este proceso es hoy en día aplicado para producir capas o recubrimientos delgados sobre componentes mecánicos metálicos, con el objetivo de mejorar su resistencia superficial frente a diferentes fenómenos tales como corrosión, temperatura y desgaste. En este trabajo se estudió la transferencia de calor incluyendo cambio de fase, de una partícula bimaterial compuesta por un centro metálico de hierro recubierto por una capa protectora de alúmina cerámica, dentro de un jet de plasma. El modelo numérico tomó en cuenta las condiciones ambientales a lo largo de toda su trayectoria en el jet. La simulación numérica de este problema fue realizada mediante una formulación de elementos finitos con cambio de fase que retiene como variable única la temperatura. Los

Jet joint undertaking. Annual report 1985

International Nuclear Information System (INIS)

1986-06-01

After a presentation of the Jet and nuclear fusion, the results of Jet operations in 1985 are given: energy confinement, MHD activity and disruptive instabilities, impurities and radiation losses, plasma evolution, plasma boundary phenomena, control of plasma current, position and shape, RF heating. Technical achievements in 1985 are summarized: vacuum systems, first wall, multi-pellet injection for fuelling and re-fuelling, containment of forces during vertical instabilities, magnet systems, safety systems, power supplies, neutral beam heating, radio-frequency heating, remote handling, tritium handling, control and data acquisition, diagnostic systems are implied

A NEW TECHNIQUE OF OIL TRANSPORTATION IN PIPELINE BY STEAM INJECTION

Institute of Scientific and Technical Information of China (English)

无

2002-01-01

The direct contact heating of crude oil with steam is promising technique for improving crude oil transportation in pipelines. Crude oil temperature is increased greatly by a small quantity of steam due to the high steam latent heat and direct contact heat transfer. A jet pump was developed for injecting steam into oil in order to get a high efficiency by transferring momentum and energy from a high-velocity jet to ambient fluid. The jet pump was designed based on the free injection principle, which has no rotation parts and no converging mixing chamber, therefore it would not be blocked by the viscous crude oil. The technical feasibility of this method has been tested in the Liaohe Oilfeld, China.

Development and validation of a model for CANDU-6 SDS2 poison injection analysis

International Nuclear Information System (INIS)

Lee, B. W.; Jung, C. J.; Min, B. J.; Yoon, H. J.; Choi, J. H.; Jang, D. S.

2002-01-01

In CANDU-6 reactor there are two independent reactor shutdown systems. The shutdown system no. 2(SDS2) injects the liquid poison into the moderator tank by high pressure via small holes on the 6 nozzle pipes and stops the nuclear chain reaction. To ensure the safe shutdown of a reactor loaded with either DUPIC or SEU fuels it is necessary for the poison curtains generated by jets provide quick, and enough negative reactivity to the reactor during the early stage of the accident. In order to produce the neutron cross section necessary to perform this work, the poison concentration distribution during the transient is necessary. The motivation for this work arose from the fact that the computer code package for performing this task is not transfered to Korea yet. In this study, a set of models for analyzing the transient poison concentration induced by this high pressure poison injection jet activated upon the reactor trip in a CANDU-6 reactor moderator tank has been developed and used to generate the poison concentration distribution of the poison curtains induced by the high pressure jets injected into the vacant region between the pressure tube banks. The poison injection rate through the jet holes drilled on the nozzle pipes is obtained by a 1-D transient hydrodynamic code called, ALITRIG, and this injection rate is used to provide the inlet boundary condition to a 3-D CFD model of the moderator tank based on CFX4.3, a commercial CFD code developed by AEA technology, to simulate the formation of the poison jet curtain inside the moderator tank. For the validation, a simulation for a generic CANDU-6 SDS2 design poison jet growth experiment was made to evaluate this model's capability against experiment. As no concentration field was measured and only the growth of the poison jet height was obtained by high speed camera, the validation was limited as such. The result showed that if one assume the jet front corresponds to 200 ppm of the poison the model succeed to

A new approach on anti-vortex devices at water intakes including a submerged water jet

Science.gov (United States)

Tahershamsi, Ahmad; Rahimzadeh, Hassan; Monshizadeh, Morteza; Sarkardeh, Hamed

2018-04-01

A new approach on anti-vortex methods as hydraulic-based anti-vortex was investigated experimentally in the present study. In the investigated method, a submerged water jet is used as the anti-vortex mechanism. The added jet acts as a source of external momentum. This leads to change the intake-induced hydrodynamic pattern in the near-field of the intake structure, which can prevent formation of undesirable intake vortices. The experiments were carried out on a horizontal pipe intake. By performing 570 test cases in two different categories, including the inclined jet with respect to the axis of the intake, and the inclined jet with respect to the water surface, the effects of the jet inclination angle on the anti-vortex performance were investigated. It was found that the inclined jet with respect to the water surface is the best alternative to consider as the water jet injection pattern. Results showed that using the inclined jet with respect to the water surface can simply reduce the amounts of the expected water jet momentum more than 50% compared to that of the similar condition of the horizontal injection pattern. Moreover, it was concluded that the intake critical submergence can easily be minimized using the inclined jet with respect to the water surface.

Needle-free injection into skin and soft matter with highly focused microjets.

Science.gov (United States)

Tagawa, Yoshiyuki; Oudalov, Nikolai; El Ghalbzouri, A; Sun, Chao; Lohse, Detlef

2013-04-07

The development of needle-free drug injection systems is of great importance to global healthcare. However, in spite of its great potential and research history over many decades, these systems are not commonly used. One of the main problems is that existing methods use diffusive jets, which result in scattered penetration and severe deceleration of the jets, causing frequent pain and insufficient penetration. Another long-standing challenge is the development of accurate small volume injections. In this paper we employ a novel method of needle-free drug injection, using highly-focused high speed microjets, which aims to solve these challenges. We experimentally demonstrate that these unique jets are able to penetrate human skin: the focused nature of these microjets creates an injection spot smaller than a mosquito's proboscis and guarantees a high percentage of the liquid being injected. The liquid substances can be delivered to a much larger depth than conventional methods, and create a well-controlled dispersion pattern. Thanks to the excellent controllability of the microjet, small volume injections become feasible. Furthermore, the penetration dynamics is studied through experiments performed on gelatin mixtures (human soft tissue equivalent) and human skin, agreeing well with a viscous stress model which we develop. This model predicts the depth of the penetration into both human skin and soft tissue. The results presented here take needle-free injections a step closer to widespread use.

The JET [Joint European Torus] multipellet launcher and fueling of JET plasmas by multipellet injection

International Nuclear Information System (INIS)

Milora, S.L.; Schmidt, G.L.; Jernigan, T.C.

1988-01-01

A new multipellet long-pulse plasma fueling system is in operation on JET. In the initial experimental phase, a variety of plasma density profile shapes have been produced with peak to average values ranging up to 2.5 and peak plasma density up to 1.2 /times/ 10 20 m/sup /minus/3/. 7 refs., 4 figs

Needle-less local anesthesia: clinical evaluation of the effectiveness of the jet anesthesia Injex in local anesthesia in dentistry.

Science.gov (United States)

Dabarakis, Nikolaos N; Alexander, Veis; Tsirlis, Anastasios T; Parissis, Nikolaos A; Nikolaos, Maroufidis

2007-01-01

To clinically evaluate the jet injection Injex (Rösch AG Medizintechnik) using 2 different anesthetic solutions, and to compare the jet injection and the standard needle injection techniques. Of the 32 patients in the study, 10 received mepivacaine 3% anesthetic solution by means of the jet injection technique, while the remaining 22 patients received lidocaine 2% with epinephrine 1:80,000 by the same method. The 14 patients in whom pulp anesthesia was achieved were selected for an additional evaluation of the pulp reaction using standard needle injection anesthesia. The differences between the 2 compounds with Injex were statistically evaluated by means of independent-samples t test analysis. The differences between subgroups receiving both jet injection and needle injection anesthesia were evaluated by means of paired t test analysis. The administration of mepivacaine 3% using Injex did not achieve pulp anesthesia in any of the 10 patients, although the soft tissue anesthesia was successful. The administration of lidocaine with epinephrine using Injex resulted in pulp anesthesia in only 14 patients; soft tissue anesthesia was observed in all patients of this group. There was no statistically significant difference between Injex and the needle injection technique in onset of anesthesia. However, the duration of anesthesia was significantly longer for the needle infiltration group than for the Injex injection group. The anesthetic solution should be combined with a vasoconstriction agent when the Injex technique is implemented.

Air-water mixing experiments for direct vessel injection of KNGR

International Nuclear Information System (INIS)

Hwang, Do Hyun

2000-02-01

Two air-water mixing experiments are conducted to understand the flow behavior in the downcomer for Direct Vessel Injection (DVI) of Korean Next Generation Reactor (KNGR). In the first experiment which is an air-water experiment in the rectangular channel with the gap size of 1cm, the width of water film is proportional to the water and air velocities and the inclined angle is proportional to the water velocity only, regardless of the water velocity injected in the rectangular channel. It is observed that the amount of entrained water is negligible. In the second experiment which is a full-scaled water jetting experiment without air flow, the width of water film is proportional to the flow rate injected from the pipe exit and the film thickness of water varies from 1.0mm to 5.0mm, and the maximum thickness does not exceed 5.0mm. The amount of water separated from the liquid film after striking of water jetting on the wall is measured. The amount of separation water is proportional to the flow rate, but the separation ratio in the full-scaled water jetting is not over 15%. A simplified physical model, which is designed to predict the trajectories of the width of water film, is validated through the comparison with experiment results. The 13 .deg. upward water droplet of the water injected from the pipe constitutes the outermost boundary at 1.7m below from pipe level, after the water impinges against the wall. In the model, the parameter, η which represents the relationship between the jetting velocity and the initial spreading velocity, is inversely proportional to the water velocity when it impinges against the wall. The error of the predictions by the model is decreased within 14% to the experimental data through use of exponential fitting of η for the jetting water velocity

Direct numerical simulation of a low momentum round jet in channel crossflow

Energy Technology Data Exchange (ETDEWEB)

Wu, Zhao, E-mail: zhao.wu@manchester.ac.uk; Laurence, Dominique; Afgan, Imran

2017-03-15

Highlights: • Detailed flow physics of jet in crossflow with low velocity ratio, R, is analysed. • The horseshoe vortex comes from the reversed jet fluid, different from high R JICF. • CVP comes from the stretching and reorientation of the injection-flow vorticity. • Recirculation is seen at the downstream low-pressure region. • The shear layer vortices are from shed crossflow boundary layer vortices. - Abstract: Results of a direct numerical simulation of a jet in crossflow with passive scalar mixing are presented. The laminar jet issues from a circular exit into the channel crossflow with a low jet-to-crossflow velocity ratio of 1/6. The governing equations are solved by Incompact3d, an open-source code combining the high-order compact scheme and Poisson spectral solver. An internal recycling approach is used to generate the fully turbulent channel flow profile. Four main flow structures are identified: 1) a large recirculation seen immediately downstream of the jet-exit; 2) a contour-rotating vortex pair formed from the stretching and reorientation of the injection-flow vorticity; 3) a horseshoe vortex generated as a result of the stretching of the vorticity at the jet-exit windward side; 4) shear layer vortices coming from the lifted and shed crossflow boundary layer vorticity. Passive scalar profiles show the mixing are strong in the shear layer where the crossflow fluid encounters the jet fluid. The database is made available online for public access.

Development and validation of a model for high pressure liquid poison injection for CANDU-6 shutdown system no.2

International Nuclear Information System (INIS)

Rhee, B.-W.; Jeong, C.J.; Choi, J.H.; Yoo, S.-Y.

2002-01-01

In CANDU reactor one of the two reactor shutdown systems is the liquid poison injection system which injects the highly pressurized liquid neutron poison into the moderator tank via small holes on the nozzle pipes. To ensure the safe shutdown of a reactor it is necessary for the poison curtains generated by jets provide quick, and enough negative reactivity to the reactor during the early stage of the accident. In order to produce the neutron cross section necessary to perform this work, the poison concentration distribution during the transient is necessary. In this study, a set of models for analyzing the transient poison concentration induced by this high pressure poison injection jet activated upon the reactor trip in a CANDU-6 reactor moderator tank has been developed and used to generate the poison concentration distribution of the poison curtains induced by the high pressure jets injected into the vacant region between the calandria tube banks. The poison injection rate through the jet holes drilled on the nozzle pipes is obtained by a 1-D transient hydrodynamic code called, ALITRIG, and this injection rate is used to provide the inlet boundary condition to a 3-D CFD model of the moderator tank based on CFX4.3, an AEA Technology CFD code, to simulate the formation and growth of the poison jet curtain inside the moderator tank. For validation, the current model is validated against a poison injection experiment performed at BARC, India and another poison jet experiment for Generic CANDU-6 performed at AECL, Canada. In conclusion this set of models is considered to predict the experimental results in a physically reasonable and consistent manner. (author)

Cumulative Distributions and Flow Structure of Two-Passage Shear Coaxial Injector with Various Gas Injection Ratio

Energy Technology Data Exchange (ETDEWEB)

Lee, Inchul; Kim, Dohun; Koo, Jaye [Korea Aerospace Univ., Goyang (Korea, Republic of)

2013-07-15

To verify the effect of inner- and outer-stage gas jets, a shear coaxial injector was designed to analyze the axial velocity profile and breakup phenomenon with an increase in the measurement distance. When the measurement position was increased to Z/d=100, the axial flow showed a fully developed shape due to the momentum transfer, aerodynamic drag effect, and viscous mixing. An inner gas injection, which induces a higher momentum flux ratio near the nozzle, produces the greater shear force on atomization than an outer gas injection. Inner- and Outer-stage gas injection do not affect the mixing between the inner and outer gas flow below Z/d=5. The experiment results showed that the main effect of liquid jet breakup was governed by the gas jet of an inner stage. As the nozzle exit of the outer-stage was located far from the liquid column, shear force and turbulence breaking up of the liquid jets do not fully affect the liquid column. In the case of an inner-stage gas injection momentum flux ratio within 0.84, with the increase in the outer gas momentum flux ratio, the Smd decreases. However, at an inner-stage gas jet momentum flux ratio over 1.38, the Smd shows the similar distribution.

Supersonic impinging jet noise reduction using a hybrid control technique

Science.gov (United States)

Wiley, Alex; Kumar, Rajan

2015-07-01

Control of the highly resonant flowfield associated with supersonic impinging jet has been experimentally investigated. Measurements were made in the supersonic impinging jet facility at the Florida State University for a Mach 1.5 ideally expanded jet. Measurements included unsteady pressures on a surface plate near the nozzle exit, acoustics in the nearfield and beneath the impingement plane, and velocity field using particle image velocimetry. Both passive control using porous surface and active control with high momentum microjet injection are effective in reducing nearfield noise and flow unsteadiness over a range of geometrical parameters; however, the type of noise reduction achieved by the two techniques is different. The passive control reduces broadband noise whereas microjet injection attenuates high amplitude impinging tones. The hybrid control, a combination of two control methods, reduces both broadband and high amplitude impinging tones and surprisingly its effectiveness is more that the additive effect of the two control techniques. The flow field measurements show that with hybrid control the impinging jet is stabilized and the turbulence quantities such as streamwise turbulence intensity, transverse turbulence intensity and turbulent shear stress are significantly reduced.

Development of key fusion technologies at JET

International Nuclear Information System (INIS)

2001-01-01

The recent operational phase in JET in which Deuterium-Tritium fuel was used (DTE1) resulted in record breaking fusion performance. In addition to important contributions in plasma physics, the JET Team has also made major advances in demonstrating the viability of some of the key technologies required for the realisation of future fusion power. Two of the most important technological areas which have been successfully demonstrated in JET are the ITER scale tritium processing plant and the exchange of the divertor and maintenance of the interior of JET by totally remote means. The experiment also provided the first data on tritium retention and co-deposition in a diverted tokamak. Of the 35g of tritium injected into the JET torus, about 6g remained in the tokamak. The amount resides mainly on cool surfaces at the inboard divertor side. The precise, safe and timely execution of the remote handling shutdown proved that the design, function, performance and operational methodology of the RH equipment prepared over the years at JET are appropriate for the successful and rapid replacement of components in an activated tokamak environment. (author)

Development of key fusion technologies at JET

International Nuclear Information System (INIS)

1999-01-01

The recent operational phase in JET in which Deuterium-Tritium fuel was used (DTE1) resulted in record breaking fusion performance. In addition to important contributions in plasma physics, the JET Team has also made major advances in demonstrating the viability of some of the key technologies required for the realisation of future fusion power. Two of the most important technological areas which have been successfully demonstrated in JET are the ITER scale tritium processing plant and the exchange of the divertor and maintenance of the interior of JET by totally remote means. The experiment also provided the first data on tritium retention and co-deposition in a diverted tokamak. Of the 35g of tritium injected into the JET torus, about 6g remained in the tokamak. The amount resides mainly on cool surfaces at the inboard divertor side. The precise, safe and timely execution of the remote handling shutdown proved that the design, function, performance and operational methodology of the RH equipment prepared over the years at JET are appropriate for the successful and rapid replacement of components in an activated tokamak environment. (author)

Gas jet disruption mitigation studies on Alcator C-Mod and DIII-D

International Nuclear Information System (INIS)

Granetz, R.S.; Hollmann, E.M.; Whyte, D.G.; Izzo, V.A.; Antar, G.Y.; Bader, A.; Bakhtiari, M.; Biewer, T.; Boedo, J.A.; Evans, T.E.; Hutchinson, I.H.; Jernigan, T.C.; Gray, D.S.; Groth, M.; Humphreys, D.A.; Lasnier, C.J.; Moyer, R.A.; Parks, P.B.; Reinke, M.L.; Rudakov, D.L.; Strait, E.J.; Terry, J.L.; Wesley, J.; West, W.P.; Wurden, G.; Yu, J.

2007-01-01

High-pressure noble gas jet injection is a mitigation technique which potentially satisfies the requirements of fast response time and reliability, without degrading subsequent discharges. Previously reported gas jet experiments on DIII-D showed good success at reducing deleterious disruption effects. In this paper, results of recent gas jet disruption mitigation experiments on Alcator C-Mod and DIII-D are reported. Jointly, these experiments have greatly improved the understanding of gas jet dynamics and the processes involved in mitigating disruption effects. In both machines, the sequence of events following gas injection is observed to be quite similar: the jet neutrals stop near the plasma edge, the edge temperature collapses and large MHD modes are quickly destabilized, mixing the hot plasma core with the edge impurity ions and radiating away the plasma thermal energy. High radiated power fractions are achieved, thus reducing the conducted heat loads to the chamber walls and divertor. A significant (2 x or more) reduction in halo current is also observed. Runaway electron generation is small or absent. These similar results in two quite different tokamaks are encouraging for the applicability of this disruption mitigation technique to ITER

Hybrid model for simulation of plasma jet injection in tokamak

Science.gov (United States)

Galkin, Sergei A.; Bogatu, I. N.

2016-10-01

Hybrid kinetic model of plasma treats the ions as kinetic particles and the electrons as charge neutralizing massless fluid. The model is essentially applicable when most of the energy is concentrated in the ions rather than in the electrons, i.e. it is well suited for the high-density hyper-velocity C60 plasma jet. The hybrid model separates the slower ion time scale from the faster electron time scale, which becomes disregardable. That is why hybrid codes consistently outperform the traditional PIC codes in computational efficiency, still resolving kinetic ions effects. We discuss 2D hybrid model and code with exact energy conservation numerical algorithm and present some results of its application to simulation of C60 plasma jet penetration through tokamak-like magnetic barrier. We also examine the 3D model/code extension and its possible applications to tokamak and ionospheric plasmas. The work is supported in part by US DOE DE-SC0015776 Grant.

Investigations about the structure of the transient diesel fuel injection jet near the nozzle with the method of radio-frequency cinematography. Untersuchungen zur Struktur des instationaeren Dieseloeleinspritzstrahles im Duesennahbereich mit der Methode der Hochfrequenz-Kinematografie

Energy Technology Data Exchange (ETDEWEB)

Eifler, W.

1990-03-22

Precise knowledge on the flow processes in interior of a fuel injector and of a diesel jet near the nozzle are required in order to reduce the pollutant emissions of a diesel engine through selective optimization of mixing. A radio-frequency cinematography system on the basis of a pulsed laser and streak camera was developed in order to make such flow processes visible. Transparent nozzle caps were used for isolation of the start parameters. The 'supercavitation' inside the nozzles, which in this way was made visible, continues far into the pressure chamber and governs the jet structure near the nozzle. The real diesel injection jet was examined subsequently systematically by different hydraulic start parameters. It was found out that in the case of all bag hole compressions that are relevant for mixing, the jet pattern is determined essentially through the protrusions resulting from implosion. First investigations about evaporation behavior pointed to a preferred ignition site in the marginal zone of the jet. (HWJ).

A Novel Bearing Lubricating Device Based on the Piezoelectric Micro-Jet

Directory of Open Access Journals (Sweden)

Kai Li

2016-02-01

Full Text Available A novel bearing lubricating device, which is embedded in gyroscope’s bearing system and based on the theory of the piezoelectric micro-jet, was designed for this study. The embedded structure of a bearing lubricating system can make effective use of the limited space of bearing systems without increasing the whole mass of the system. The drop-on-demand (DOD lubrication can be realized by the piezoelectric micro-jet system to implement the long acting lubrication of the bearing system. A mathematical model of inlet boundary conditions was established to carry on the numerical simulation based on CFD. The motion states of the droplets with different voltage excitations were analyzed via numerical simulations, and the injection performances of the piezoelectric micro-jet lubricating device were tested in accordance with past experiments. The influences of different parameters of voltage excitation on injection performance were obtained, and the methods of adjusting the injection performance to meet different requirements are given according to the analyses of the results. The mathematical model and numerical simulation method were confirmed by comparing the results of past simulations and experiments.

Effect of Stand-Off Distance on Impact Pressure of High Speed Water Jets

Science.gov (United States)

Sittiwong, Wuttichai; Seehanam, Wirapan; Pianthong, Kulachate; Matthujak, Anirut

2010-06-01

High speed liquid jets may be applied to jet cutting, drilling and cleaning. Recently, in the automotive industries, the spray injection pressure becomes higher and higher to enhance the fuel mixing for the improved combustion efficiency. However, the ultra high injection pressure may cause the damage to the nozzle and also the combustion chamber. In the medical application, the high speed liquid injection might be applied for the drug delivery through the skin where the needle is not required anymore. From the above mentioned application, the investigation on the impact pressure of the high speed liquid jet relative to the stand-off distant is significant. The high speed liquid jets are generated by the projectile impact driven method. The high speed projectile is launched by the horizontal single stage powder gun. The experimental study focuses on the stand-off between 1.5 cm to 6.0 cm, while the nozzle contains approximately 1.5cm3 of water in its cavity. The nozzle conical angles are 30° and 60° with the orifice diameter of 0.7 mm. The jet velocities are measured by laser beam interruptions method. The target material is the Polymethyl Methacrylate (PMMA) which the impact pressure is measured by using a piezoelectric Polyvinylidene Fluoride (PVDF) film. From the experiments, the maximum water jet velocity of 2290 m/s can be obtained from the 30° conical angle nozzle. The maximum impact pressures of nozzle conical angle of 30° and 60° are 3.4 GPa and 2.6 GPa respectively, at stand-off distance 3 cm. However, at the stand-off distance more than 3 cm, the impact pressure significantly decreases, because of aerodynamic drag, jets core break-up, and atomization of the water.

LPWA using supersonic gas jet with tailored density profile

Science.gov (United States)

Kononenko, O.; Bohlen, S.; Dale, J.; D'Arcy, R.; Dinter, M.; Erbe, J. H.; Indorf, G.; di Lucchio, L.; Goldberg, L.; Gruse, J. N.; Karstensen, S.; Libov, V.; Ludwig, K.; Martinez de La Ossa, A.; Marutzky, F.; Niroula, A.; Osterhoff, J.; Quast, M.; Schaper, L.; Schwinkendorf, J.-P.; Streeter, M.; Tauscher, G.; Weichert, S.; Palmer, C.; Horbatiuk, Taras

2016-10-01

Laser driven plasma wakefield accelerators have been explored as a potential compact, reproducible source of relativistic electron bunches, utilising an electric field of many GV/m. Control over injection of electrons into the wakefield is of crucial importance in producing stable, mono-energetic electron bunches. Density tailoring of the target, to control the acceleration process, can also be used to improve the quality of the bunch. By using gas jets to provide tailored targets it is possible to provide good access for plasma diagnostics while also producing sharp density gradients for density down-ramp injection. OpenFOAM hydrodynamic simulations were used to investigate the possibility of producing tailored density targets in a supersonic gas jet. Particle-in-cell simulations of the resulting density profiles modelled the effect of the tailored density on the properties of the accelerated electron bunch. Here, we present the simulation results together with preliminary experimental measurements of electron and x-ray properties from LPWA experiments using gas jet targets and a 25 TW, 25 fs Ti:Sa laser system at DESY.

Fundamental Investigation of Jet Fuel Spray and Ignition Process in an Optically Accessible Piston Engine

Science.gov (United States)

2015-01-16

pressures up to 5 MPa using a single-hole common-rail diesel injector with high-speed imaging. The authors found that for the initial period during the...total nozzle flow area or decreasing the injection pressure increases the ramp-up period. This type of injector operates by using the fuel injection...design of Almy engines. Tests were perf01med using #2 diesel fuel, jet fuel (JP8), and a hydroprocessed renewable jet fuel (HRJ). Ambient the1modynamic

Effects of Supercritical Environment on Hydrocarbon-fuel Injection

Institute of Scientific and Technical Information of China (English)

Bongchul Shin; Dohun Kim; Min Son; Jaye Koo

2017-01-01

In this study,the effects of environment conditions on decane were investigated.Decane was injected in subcritical and supercritical ambient conditions.The visualization chamber was pressurized to 1.68 MPa by using nitrogen gas at a temperature of 653 K for subcritical ambient conditions.For supercritical ambient conditions,the visualization chamber was pressurized to 2.52 MPa by using helium at a temperature of 653 K.The decane injection in the pressurized chamber was visualized via a shadowgraph technique and gradient images were obtained by a post processing method.A large variation in density gradient was observed at jet interface in the case of subcritical injection in subcritical ambient conditions.Conversely,for supercritical injection in supercritical ambient conditions,a small density gradient was observed at the jet interface.In a manner similar to that observed in other cases,supercritical injection in subcritical ambient conditions differed from supercritical ambient conditions such as sphere shape liquid.Additionally,there were changes in the interface,and the supercritical injection core width was thicker than that in the subcritical injection.Furthermore,in cases with the same injection conditions,the change in the supercritical ambient normalized core width was smaller than the change in the subcritical ambient normalized core width owing to high specific heat at the supercritical injection and small phase change at the interface.Therefore,the interface was affected by the changing ambient condition.Given that the effect of changing the thermodynamic properties of propellants could be essential for a variable thrust rocket engine,the effects of the ambient conditions were investigated experimentally.

Effects of supercritical environment on hydrocarbon-fuel injection

Science.gov (United States)

Shin, Bongchul; Kim, Dohun; Son, Min; Koo, Jaye

2017-04-01

In this study, the effects of environment conditions on decane were investigated. Decane was injected in subcritical and supercritical ambient conditions. The visualization chamber was pressurized to 1.68 MPa by using nitrogen gas at a temperature of 653 K for subcritical ambient conditions. For supercritical ambient conditions, the visualization chamber was pressurized to 2.52 MPa by using helium at a temperature of 653 K. The decane injection in the pressurized chamber was visualized via a shadowgraph technique and gradient images were obtained by a post processing method. A large variation in density gradient was observed at jet interface in the case of subcritical injection in subcritical ambient conditions. Conversely, for supercritical injection in supercritical ambient conditions, a small density gradient was observed at the jet interface. In a manner similar to that observed in other cases, supercritical injection in subcritical ambient conditions differed from supercritical ambient conditions such as sphere shape liquid. Additionally, there were changes in the interface, and the supercritical injection core width was thicker than that in the subcritical injection. Furthermore, in cases with the same injection conditions, the change in the supercritical ambient normalized core width was smaller than the change in the subcritical ambient normalized core width owing to high specific heat at the supercritical injection and small phase change at the interface. Therefore, the interface was affected by the changing ambient condition. Given that the effect of changing the thermodynamic properties of propellants could be essential for a variable thrust rocket engine, the effects of the ambient conditions were investigated experimentally.

Analysis of experimental characteristics of multistage steam-jet electors of steam turbines

Science.gov (United States)

Aronson, K. E.; Ryabchikov, A. Yu.; Brodov, Yu. M.; Brezgin, D. V.; Zhelonkin, N. V.; Murmanskii, I. B.

2017-02-01

A series of questions for specification of physical gas dynamics model in flow range of steam-jet unit and ejector computation methodology, as well as functioning peculiarities of intercoolers, was formulated based on analysis of experimental characteristics of multistage team-jet steam turbines. It was established that coefficient defining position of critical cross-section of injected flow depends on characteristics of the "sound tube" zone. Speed of injected flow within this tube may exceed that of sound, and pressure jumps in work-steam decrease at the same time. Characteristics of the "sound tube" define optimal axial sizes of the ejector. According to measurement results, the part of steam condensing in the first-stage coolant constitutes 70-80% of steam amount supplied into coolant and is almost independent of air content in steam. Coolant efficiency depends on steam pressure defined by operation of steam-jet unit of ejector of the next stage after coolant of steam-jet stage, temperature, and condensing water flow. As a rule, steam entering content of steam-air mixture supplied to coolant is overheated with respect to saturation temperature of steam in the mixture. This should be taken into account during coolant computation. Long-term operation causes changes in roughness of walls of the ejector's mixing chamber. The influence of change of wall roughness on ejector characteristic is similar to the influence of reverse pressure of the steam-jet stage. Until some roughness value, injection coefficient of the ejector stage operating in superlimiting regime hardly changed. After reaching critical roughness, the ejector switches to prelimiting operating regime.

Spray-Wall Impingement of Diesel-CNG Dual Fuel Jet using Schlieren Imaging Technique

Directory of Open Access Journals (Sweden)

Ismael Mhadi Abaker

2014-07-01

Full Text Available Natural gas is a low cost fuel with high availability in nature. However, it cannot be used by itself in conventional diesel engines due to its low flame speed and high ignition temperature. The addition of a secondary fuel to enhance the mixture formation and combustion process facilitate its wider use as an alternative fuel. An experimental study was performed to investigate the diesel-CNG dual fuel jet-wall impingement. A constant volume optical chamber was designed to facilitate maximum optical access for the study of the jet-wall impingement at different injection pressures, temperatures and injector-wall distances. The bottom plate of the test rig was made of aluminum (piston material and it was heated up to 500 K at ambient pressure. An injector driver was used to control the single-hole nozzle diesel injector combined with a natural gas injector. The injection timing of both injectors was synchronized with a camera trigger. The jet-wall impingement of diesel and diesel-CNG dual fuel jets was recorded with a high speed camera using Schlieren imaging technique and associated image processing software. The measurements of the jet radial penetration were higher in diesel-CNG dual fuel while the jet height travel along were higher in the case of diesel single fuel.

Atomization of liquids in a Pease-Anthony Venturi scrubber. Part I. Jet dynamics.

Science.gov (United States)

Gonçalves, J A S; Costa, M A M; Henrique, P R; Coury, J R

2003-02-28

Jet dynamics, in particular jet penetration, is an important design parameter affecting the collection efficiency of Venturi scrubbers. A mathematical description of the trajectory, break-up and penetration of liquid jets initially transversal to a subsonic gas stream is presented. Experimental data obtained from a laboratory scale Venturi scrubber, operated with liquid injected into the throat through a single orifice, jet velocities between 6.07 and 15.9 m/s, and throat gas velocities between 58.3 and 74.9 m/s, is presented and used to validate the model.

Active Control Strategies to Optimize Supersonic Fuel-Air Mixing for Combustion Associated with Fully Modulated Transverse Jet in Cross Flow

National Research Council Canada - National Science Library

Ghenai, C; Philippidis, G. P; Lin, C. X

2005-01-01

... (subsonic- supersonic) combustion studies. A high-speed imaging system was used for the visualization of pure liquid jet, aerated liquid jet and pulsed aerated jet injection into a supersonic cross flow at Mach number 1.5...

CFD analysis of poison injection in AHWR calandria

International Nuclear Information System (INIS)

Kansal, A.K.; Kamble, M.T.; Maheshwari, N.K.; Vijayan, P.K.

2014-01-01

The present work intends to give details of design and performance validation of SDS-2. The performance is evaluated on the basis of dispersion of poison in calandria in a given period of time. Location of injection tube and injection holes, size of jet hole and number of holes are some of the design parameters which greatly affect dispersion of poison in calandria. A Computational Fluid Dynamic (CFD) study for axial and radial injection of poison was carried out using open source CFD code OpenFOAM. CFD benchmarking was done using experiments performed by Johari (Johari et al. 1997) to identify suitable turbulence model for this problem. An experimental facility simulating poison injection in moderator in presence of calandria tubes was used to further validate the CFD model is shown in the paper. CFD analysis was carried out for axial as well as radial injection for AHWR geometry. CFD analysis using OpenFOAM has been carried out to study high pressure poison injection for single jet of Shut Down System - 2 (SDS- 2) of Advanced Heavy Water Reactor (AHWR) for various design options. CFD model used in analysis have been validated with experimental data available in literature as well as experiments performed for AHWR specific geometry. Various turbulence models are tested and their adequacy for such flow problems has been established. The CFD model is then used to simulate poison injection for two design options for AHWR and their performance is compared. (author)

Visualization of interfacial behavior of liquid jet in pool

International Nuclear Information System (INIS)

Uchiyama, Yuta; Abe, Yutaka; Fujiwara, Akiko; Nariai, Hideki; Matsuo, Eiji; Chitose, Keiko; Koyama, Kazuya; Itoh, Kazuhiro

2008-01-01

For the safety design of the Fast Breeder Reactor (FBR), it is strongly required that the post accident heat removal (PAHR) is achieved after a postulated core disruptive accident (CDA). In the PAHR, it is important that the molten core material is quenched (breakup) in sodium coolant. In the previous studies, it is pointed out that the jet breakup behavior is significantly influenced by the fragmentation behavior on the jet surface in the coolant. However, the process from interfacial instability to fragmentation on the jet surface to jet breakup is not elucidated in detail yet. In the present study, the jet breakup behavior is observed to obtain the fragmentation behavior on the jet surface in coolant in detail. The transparent fluid is used as the core material and is injected into the water as the coolant. The velocity distribution of internal flow of the jet is measured by PIV technique and shear stress is calculated from PIV results. From experimental results, unstable interfacial wave is confirmed as upstream and grown up toward downstream. The fragments are torn apart at the end of developed wave. Shear stress is strongly acted on jet surface. From the results, the correlation between the interfacial behavior of the jet and the generation process of fragments are discussed. (author)

Implementation of a new Disruption Mitigation System into the control system of JET

Energy Technology Data Exchange (ETDEWEB)

Jachmich, Stefan, E-mail: s.jachmich@fz-juelich.de [Laboratory for Plasma Physics, Ecole Royale Militaire/Koninklijke Militaire School, B-1000 Brussels (Belgium); Kruezi, Uron; Card, Peter; Deakin, Kieron; Kinna, David [Culham Centre for Fusion Energy, Abingdon, Oxon OX14 3DB (United Kingdom); Koslowski, Hans Rudolf; Lambertz, Horst Toni [Forschungszentrum Jülich GmbH, IEK-4, 52425 Jülich (Germany); Lehnen, Michael [ITER Organization, Route de Vinon-sur-Verdon, CS90046, 13067 St Paul Lez Durance Cedex (France)

2015-10-15

Highlights: • A new Disruption Mitigation System based on Massive Gas Injection has been installed at JET. • The control of the attached gas handling system had to be integrated into the JET-operation. • An interlock system has been built to cope with the interaction of the DMS with other auxiliary systems. • The system has been commissioned and first example of DMS used to ameliorate a disruption are shown. - Abstract: A new Disruption Mitigation System (DMS) based on Massive Gas Injections (MGI) has been installed at the JET-tokamak. The key component of this system is a fast eddy current driven valve, which is capable of injecting up to 4.6 × 10{sup −3} MPa m{sup 3} in less than 5 ms. Along with this valve a new gas handling system has been installed, whose control had to be integrated into the JET-operation. The operation of the DMS requires interaction with several other systems. Although Massive Gas Injections are used to ameliorate potentially severe damage to the tokamak plant and plasma facing components caused by disruptions, they introduce a high risk for example to auxiliary heating systems or diagnostics, which could be damaged by high vacuum pressures. In addition to this, the presence of high pressure (of noble and flammable gases) in combination with high voltages represents a risk not only to the actual DMS plant itself (in case of a failure) but also to personnel in the vicinity. These varieties of risks have been addressed and are described in this article.

Turbulent structure and emissions of strongly-pulsed jet diffusion flames

Science.gov (United States)

Fregeau, Mathieu

This current research project studied the turbulent flame structure, the fuel/air mixing, the combustion characteristics of a nonpremixed pulsed (unsteady) and unpulsed (steady) flame configuration for both normal- and microgravity conditions, as well as the flame emissions in normal gravity. The unsteady flames were fully-modulated, with the fuel flow completely shut off between injection pulses using an externally controlled valve, resulting in the generation of compact puff-like flame structures. Conducting experiments in normal and microgravity environments enabled separate control over the relevant Richardson and Reynolds numbers to clarify the influence of buoyancy on the flame behavior, mixing, and structure. Experiments were performed in normal gravity in the laboratory at the University of Washington and in microgravity using the NASA GRC 2.2-second Drop Tower facility. High-speed imaging, as well as temperature and emissions probes were used to determine the large-scale structure dynamics, the details of the flame structure and oxidizer entrainment, the combustion temperatures, and the exhaust emissions of the pulsed and steady flames. Of particular interest was the impact of changes in flame structure due to pulsing on the combustion characteristics of this system. The turbulent flame puff celerity (i.e., the bulk velocity of the puffs) was strongly impacted by the jet-off time, increasing markedly as the time between pulses was decreased, which caused the degree of puff interaction to increase and the strongly-pulsed flame to more closely resemble a steady flame. This increase occurred for all values of injection time as well as for constant fuelling rate and in both the presence and absence of buoyancy. The removal of positive buoyancy in microgravity resulted in a decrease in the flame puff celerity in all cases, amounting to as much as 40%, for both constant jet injection velocity and constant fuelling rate. The mean flame length of the strongly

Jet observables without jet algorithms

Energy Technology Data Exchange (ETDEWEB)

Bertolini, Daniele; Chan, Tucker; Thaler, Jesse [Center for Theoretical Physics, Massachusetts Institute of Technology,Cambridge, MA 02139 (United States)

2014-04-02

We introduce a new class of event shapes to characterize the jet-like structure of an event. Like traditional event shapes, our observables are infrared/collinear safe and involve a sum over all hadrons in an event, but like a jet clustering algorithm, they incorporate a jet radius parameter and a transverse momentum cut. Three of the ubiquitous jet-based observables — jet multiplicity, summed scalar transverse momentum, and missing transverse momentum — have event shape counterparts that are closely correlated with their jet-based cousins. Due to their “local” computational structure, these jet-like event shapes could potentially be used for trigger-level event selection at the LHC. Intriguingly, the jet multiplicity event shape typically takes on non-integer values, highlighting the inherent ambiguity in defining jets. By inverting jet multiplicity, we show how to characterize the transverse momentum of the n-th hardest jet without actually finding the constituents of that jet. Since many physics applications do require knowledge about the jet constituents, we also build a hybrid event shape that incorporates (local) jet clustering information. As a straightforward application of our general technique, we derive an event-shape version of jet trimming, allowing event-wide jet grooming without explicit jet identification. Finally, we briefly mention possible applications of our method for jet substructure studies.

Cross-field plasma injection into mirror geometry

Energy Technology Data Exchange (ETDEWEB)

Uzun-Kaymak, I U; Clary, R; Ellis, R; Elton, R; Teodorescu, C; Young, W [Institute for Research in Electronics and Applied Physics, University of Maryland, College Park, MD 20742 (United States); Messer, S; Bomgardner, R; Case, A; Witherspoon, F D, E-mail: uzunkaymak@wisc.ed [HyperV Technologies Corp., Chantilly, VA 20151 (United States)

2009-09-15

The Maryland Centrifugal Experiment (MCX) and HyperV Technologies Corp. are collaborating on a series of experiments to test the use of a plasma gun to inject mass and momentum into a magnetic-confinement device. HyperV has designed, built and installed a prototype coaxial gun to drive rotation in MCX. The gun has been designed to avoid the blow-by instability via a combination of electrode shaping and a tailored plasma armature. Preliminary measurements at HyperV indicate the gun generates plasma jets with a mass of 160 {mu}g, velocities up to 90 km s{sup -1} and plasma density in the high 10{sup 14} cm{sup -3}. This paper emphasizes characteristics of the plasma gun and penetration of the plasma jet through the MCX magnetic field. Plans for future injection experiments are briefly discussed.

Mixing by turbulent buoyant jets in slender containers

International Nuclear Information System (INIS)

Voropayev, S.I.; Nath, C.; Fernando, H.J.S.

2012-01-01

A turbulent buoyant jet injected vertically into a slender cylinder containing a stratified fluid is investigated experimentally. The working fluid is water, and salt is used to change its density to obtain either a positively or negatively buoyant jet. The interest is the vertical density distribution in container and its dependence on time and other parameters. For each case (lighter or heavier jet) the experimental data could be collapsed into a ‘universal’ time dependent behavior, when properly non-dimensionalized. A theoretical model is advanced to explain the results. Possible applications include refilling of crude oil into U.S. strategic petroleum reserves caverns. -- Highlights: ► We addresses a critical issue on refill of Strategic Petroleum Reserves. ► We conduct experiments on negatively/positively buoyant turbulent jets in long cavern. ► Basing on results of experiments we developed theoretical model for refill operations.

ISTTOK tokamak plasmas influence on a liquid gallium jet dynamic behavior

International Nuclear Information System (INIS)

Gomes, R.B.; Silva, C.; Fernandes, H.; Duarte, P.; Nedzelskiy, I.; Lielausis, O.; Klyukin, A.; Platacis, E.

2011-01-01

The main concern in using free flowing liquid metals in fusion devices is related to their interaction with magnetic fields. On ISTTOK tokamak, liquid gallium jets are injected deep into the plasma along a vertical direction. The influence of the plasma interaction on the jet has been investigated monitoring the liquid metal behavior using a fast frame camera. A radial shift on its trajectory has been detected and found to depend on the toroidal magnetic field magnitude and principally on the plasma position within the chamber. The analysis performed to understand the dynamics of the jet perturbation by the plasma is presented in this paper. The jet surface temperature increase during this interaction has also been measured, using absolutely calibrated multichannel IR sensors, to evaluate the jet power exhaustion capability.

ISTTOK tokamak plasmas influence on a liquid gallium jet dynamic behavior

Energy Technology Data Exchange (ETDEWEB)

Gomes, R.B., E-mail: gomes@ipfn.ist.utl.pt [Associacao EURATOM/IST, Instituto de Plasmas e Fusao Nuclear - Laboratorio Associado, Instituto Superior Tecnico, 1049-001 Lisboa (Portugal); Silva, C.; Fernandes, H.; Duarte, P.; Nedzelskiy, I. [Associacao EURATOM/IST, Instituto de Plasmas e Fusao Nuclear - Laboratorio Associado, Instituto Superior Tecnico, 1049-001 Lisboa (Portugal); Lielausis, O.; Klyukin, A.; Platacis, E. [Association EURATOM/University of Latvia, Institute of Solid State Physics, 8 Kengaraga Str., LV-1063 Riga (Latvia)

2011-08-01

The main concern in using free flowing liquid metals in fusion devices is related to their interaction with magnetic fields. On ISTTOK tokamak, liquid gallium jets are injected deep into the plasma along a vertical direction. The influence of the plasma interaction on the jet has been investigated monitoring the liquid metal behavior using a fast frame camera. A radial shift on its trajectory has been detected and found to depend on the toroidal magnetic field magnitude and principally on the plasma position within the chamber. The analysis performed to understand the dynamics of the jet perturbation by the plasma is presented in this paper. The jet surface temperature increase during this interaction has also been measured, using absolutely calibrated multichannel IR sensors, to evaluate the jet power exhaustion capability.

Photospheric Emission from Collapsar Jets in 3D Relativistic Hydrodynamics

Science.gov (United States)

Ito, Hirotaka; Matsumoto, Jin; Nagataki, Shigehiro; Warren, Donald C.; Barkov, Maxim V.

2015-12-01

We explore the photospheric emission from a relativistic jet breaking out from a massive stellar envelope based on relativistic hydrodynamical simulations and post-process radiation transfer calculations in three dimensions. To investigate the impact of three-dimensional (3D) dynamics on the emission, two models of injection conditions are considered for the jet at the center of the progenitor star: one with periodic precession and another without precession. We show that structures developed within the jet due to the interaction with the stellar envelope, as well as due to the precession, have a significant imprint on the resulting emission. Particularly, we find that the signature of precession activity by the central engine is not smeared out and can be directly observed in the light curve as a periodic signal. We also show that non-thermal features, which can account for observations of gamma-ray bursts, are produced in the resulting spectra even though only thermal photons are injected initially and the effect of non-thermal particles is not considered.

Registration of ELF waves in rocket-satellite experiment with plasma injection

Science.gov (United States)

Korobeinikov, V. G.; Oraevskii, V. N.; Ruzhin, Iu. Ia.; Sobolev, Ia. P.; Skomarovskii, V. S.; Chmyrev, V. M.; Namazov, C. A.; Pokhunkov, A. A.; Nesmeianov, V. I.

1992-12-01

Two rocket KOMBI-SAMA experiments with plasma injection at height 100-240 km were performed in August 1987 in the region of Brazilian magnetic anomaly (L = 1.25). The launching time of the rocket was determined so that plasma injection was at the time when COSMOS 1809 satellite passed as close as possible to magnetic tube of injection. Caesium plasma jet was produced during not less than 300 s by an electric plasma generator separated from the payload. When the satellite passed the geomagnetic tube intersecting the injection region an enhancement of ELF emission at 140 Hz, 450 Hz by a factor of 2 was registered on board the satellite. An enhancement of energetic particle flux by a factor of 4-5 was registered on board the rocket. Observed ELF emission below 100 Hz is interpreted as the generation of oblique electromagnetic ion-cyclotron waves due to drift plasma instability at the front of the plasma jet.

Hydrogen injection device in BWR type reactor

International Nuclear Information System (INIS)

Takagi, Jun-ichi; Kubo, Koji.

1988-01-01

Purpose: To reduce the increasing ratio of main steam system dose rate due to N-16 activity due to excess hydrogen injection in the hydrogen injection operation of BWR type reactors. Constitution: There are provided a hydrogen injection mechanism for injecting hydrogen into primary coolants of a BWR type reactor, and a chemical injection device for injecting chemicals such as methanol, which makes nitrogen radioisotopes resulted in the reactor water upon hydrogen injection non-volatile, into the pressure vessel separately from hydrogen. Injected hydrogen and the chemicals are not reacted in the feedwater system, but the reaction proceeds due to the presence of radioactive rays after the injection into the pressure vessel. Then, hydrogen causes re-combination in the downcomer portion to reduce the dissolved oxygen concentration. Meanwhile, about 70 % of the chemicals is supplied by means of a jet pump directly to the reactor core, thereby converting the chemical form of N-16 in the reactor core more oxidative (non-volatile). (Kawakami, Y.)

Flow transport and mixing induced by horizontal jets impinging on a vertical wall of the multi-compartment PANDA facility

International Nuclear Information System (INIS)

Paladino, Domenico; Zboray, Robert; Andreani, Michele; Dreier, Joerg

2010-01-01

In the frame of the OECD/NEA SETH project an experimental campaign has been carried out in the PANDA facility to investigate gas transport and mixing induced by a plume or a jet in the large-scale multi-compartment PANDA facility. The paper summarizes the results of the horizontal jet test series consisting of eight tests. Horizontal jets impinging on a vertical wall of one of the cylindrical PANDA containment vessels have been generated by changing various parameters, such as: type of injected fluid (steam or a mixture of steam and helium), fluid injection velocity, elevation (with respect to the containment vessel) of the injection exit, initial fluid composition in the vessels, and location of the vent line. The initial jet Froude number has been varied between 17 and 36 and in one of the test condensation occurred. The paper shows the effect of these parameters variation on the test evolution with respect to jet impingement location in the vertical curved wall and variation of impingement location as a function of buoyancy variation. Fluid mixing and stratification, characteristics of gas transport between the compartment and the effect of condensation on the overall phenomena evolution are analyzed in the paper.

Control of electron injection and acceleration in laser-wakefield accelerators

International Nuclear Information System (INIS)

Guillaume, E.

2015-01-01

Laser-plasma accelerators provide a promising compact alternative to conventional accelerators. Plasma waves with extremely strong electric fields are generated when a high intensity laser is focused into an underdense gas target. Electrons that are trapped in these laser-driven plasma waves can be accelerated up to energies of a few GeVs. Despite their great potential, laser-wakefield accelerators face some issues, regarding notably the stability and reproducibility of the beam when electrons are injected in the accelerating structure. In this manuscript, different techniques of electron injection are presented and compared, notably injection in a sharp density gradient and ionization injection. It is shown that combining these two methods allows for the generation of stable and tunable electron beams. We have also studied a way to manipulate the electron bunch in the phase-space in order to accelerate the bunch beyond the dephasing limit. Such a technique was used with quasi-monoenergetic electron beams to enhance their energy. Moreover, the origin of the evolution of the angular momentum of electrons observed experimentally was investigated. Finally, we demonstrated experimentally a new method - the laser-plasma lens - to strongly reduce the divergence of the electron beam. This laser-plasma lens consists of a second gas jet placed at the exit of the accelerator. The laser pulse drives a wakefield in this second jet whose focusing forces take advantage to reduce the divergence of the trailing electron bunch. A simple analytical model describing the principle is presented, underlining the major importance of the second jet length, density and distance from the first jet. Experimental demonstration of the laser-plasma lens shows a divergence reduction by a factor of 2.6 for electrons up to 300 MeV, in accordance with the model predictions

The effect of CO{sub 2} dissolved in a diesel fuel on the jet flame characteristics

Energy Technology Data Exchange (ETDEWEB)

Xiao Jin; Huang Zhen; Qiao Xinqi; Hou Yuchun [Shanghai Jiao Tong University, Shanghai (China). Research Institute of Internal Combustion Engine

2008-03-15

This paper is concerned with an experimental study of the jet diffusion flame characteristics of fuel containing CO{sub 2}. Using diesel fuel containing dissolved CO{sub 2} gas, experiments were performed under atmospheric conditions with a diesel hole-type nozzle of 0.19 mm orifice diameter at constant injection pressure. In this study, four different CO{sub 2} mass fraction in diesel fuel such as 3.13%, 7.18%, 12.33% and 17.82% were used to study the effect of CO{sub 2} concentration on the jet flame characteristics. Jet flame characteristics were measured by direct photography, meanwhile the image colorimetry is used to assess the qualitative features of jet flame temperature. Experimental results show that the CO{sub 2} gas dilution effect and the atomization effect have a great influence on the flame structure and average temperature. When the injection pressure of diesel fuel increased from 4 MPa to 6 MPa, the low temperature flame length increased from 18.4 cm to 21.7 cm and the full temperature flame length decreased from 147.6 cm to 134.7 cm. With the increase of CO{sub 2} gas dissolved in the diesel fuel, the jet flame full length decreased for the jet atomization being improved greatly meanwhile the low temperature flame length increased for the CO{sub 2} gas dilution effect; with the increase of CO{sub 2} gas dissolved in the diesel fuel, the average temperature of flame increases firstly and then falls. Experimental results validate that higher injection pressure will improve jet atomization and then increased the flame average temperature. 27 refs., 13 figs.

Very forward jet, Mueller Navelet jets and jet gap jet measurements in CMS

CERN Document Server

Cerci, Salim

2018-01-01

The measurements of very forward jet, Mueller-Navelet jets and jet-gap-jet events are presented for different collision energies. The analyses are based on data collected with the CMS detector at the LHC. Jets are defined through the anti-$k_\\mathrm{t}$ clustering algorithm for different cone sizes. Jet production studies provide stringent tests of quantum chromodynamics (QCD) and contribute to tune Monte Carlo (MC) simulations and phenomenological models. The measurements are compared to predictions from various Monte Carlo event generators.

Thermal shocks and magnetohydrodynamics in high power mercury jet targets

CERN Document Server

Lettry, Jacques; Gilardoni, S S; Benedikt, Michael; Farhat, M; Robert, E

2003-01-01

The response of mercury samples submitted to a pulsed proton beam and the magnetohydrodynamic (MHD) effects of a mercury jet injected into a 20 T magnetic field are reported. The experimental conditions differ from those of proposed neutrino factories and the purpose of these measurements is to provide benchmarks for simulation tools of a realistic free mercury jet target. These measurements were completed in June 2002. Analysis is ongoing and the presented results are preliminary. (12 refs).

Effect of water injection on nitric oxide emissions of a gas turbine combustor burning natural gas fuel

Science.gov (United States)

Marchionna, N. R.; Diehl, L. A.; Trout, A. M.

1973-01-01

The effect of direct water injection on the exhaust gas emissions of a turbojet combustor burning natural gas fuel was investigated. The results are compared with the results from similar tests using ASTM Jet-A fuel. Increasing water injection decreased the emissions of oxides of nitrogen (NOX) and increased the emissions of carbon monoxide and unburned hydrocarbons. The greatest percentage decrease in NOX with increasing water injection was at the lowest inlet-air temperature tested. The effect of increasing inlet-air temperature was to decrease the effect of the water injection. The reduction in NOX due to water injection was almost identical to the results obtained with Jet-A fuel. However, the emission indices of unburned hydrocarbons, carbon monoxide, and percentage nitric oxide in NOX were not.

Use of a new ion-detector in the study of the jet plasma injected into a pulsed magnetic mirror configuration (deca I)

International Nuclear Information System (INIS)

Renaud, C.

1963-01-01

The study of a high sensitivity ion detector coupled to an electrostatic analyser has permitted a large investigation of the plasma jet injected into a pulsed magnetic mirror configuration. In this detector the positive ions are accelerated through a potential of 30 kV; they strike a metallic target, on which they produce secondary electrons; these, in turn, are accelerated onto a plastic scintillator. The light pulses are detected with a photomultiplier. The gain of this device is about 10 7 . If we make an admission of air into the vacuum system and again we make vacuum, the gain is not modified, since no special activated surfaces are situated in the detector. (author) [fr

In-Flight Formation of Nano-Crystalline Titanium Dioxide Powder in a Plasma Jet and Its Characterization

International Nuclear Information System (INIS)

Ananthapadmanabhan, P. V.; Thiyagarajan, T. K.; Sreekumar, K. P.; Vijay, M.; Selvarajan, V.; Yu, Jiaguo; Liu, Shengwei

2010-01-01

Nanocrystalline titanium dioxide powder was synthesized by in-flight oxidation of titanium dihydride (TiH 2 ) powder in a thermal plasma jet. TiH 2 powder was injected into the thermal plasma jet and allowed to react with oxygen injected downstream the jet. Characterization of the powder by various analytical tools indicated that the powder consisted of nano-sized titanium dioxide particles consisting predominantly of the anatase phase. It is suggested that the thermo-chemistry of the oxidation process contributes significantly to the formation of nano-sized titania. The large energy released during the oxidation process dissociates the TiO 2 particles into TiO (g) and titanium vapour, which recombine downstream with oxygen and form nano particles of TiO 2 .

Simulation of MGI efficiency for plasma energy conversion into Ar radiation in JET and implications for ITER

Energy Technology Data Exchange (ETDEWEB)

Pestchanyi, Serguei, E-mail: serguei.pestchanyi@kit.edu [Association EURATOM-KIT, Karlsruhe (Germany); Koslowski, Rudi; Reux, Cedric [JET-EFDA, Culham Science Centre, Abingdon OX14 3DB (United Kingdom); Lehnen, Michael [Route de Vinon-sur-Verdon, CS 90 046, 13067 St. Paul Lez Durance Cedex (France)

2015-10-15

Highlights: • We simulated disruption mitigation using massive gas injection with the TOKES code. • Cross-reference analysis of JET experiments on MGI and their simulations have been done. • The analysis allows suggesting the mechanism for saturation of radiated energy fraction at 70–80%. • Rough extrapolation of the result on ITER conditions has been done. - Abstract: Effectiveness of massive gas injection (MGI) for mitigation of disruptive wall damage has been investigated. Cross-reference analysis of the available JET experiments on MGI and their simulations with the TOKES code allow suggesting that in JET conditions one can convert into radiation the electron thermal energy and the plasma current energy, but the ion thermal energy does not convert into radiation because of very ineffective excitation of injected noble gas (NG) ions by D ions and long equipartition time between D ions and electrons. The model assumes rather high electron temperature during current quench (CQ), which contradicts with its time duration. Rough extrapolation of the result on ITER conditions shows that one can expect irradiation of total plasma energy if CQ duration in ITER is not shorter as in JET.

Transverse liquid fuel jet breakup, burning, and ignition

Energy Technology Data Exchange (ETDEWEB)

Li, H.

1990-01-01

An analytical/numerical study of the breakup, burning, and ignition of liquid fuels injected transversely into a hot air stream is conducted. The non-reacting liquid jet breakup location is determined by the local sonic point criterion first proposed by Schetz, et al. (1980). Two models, one employing analysis of an elliptical jet cross-section and the other employing a two-dimensional blunt body to represent the transverse jet, have been used for sonic point calculations. An auxiliary criterion based on surface tension stability is used as a separate means of determining the breakup location. For the reacting liquid jet problem, a diffusion flame supported by a one-step chemical reaction within the gaseous boundary layer is solved along the ellipse surface in subsonic crossflow. Typical flame structures and concentration profiles have been calculated for various locations along the jet cross-section as a function of upstream Mach numbers. The integrated reaction rate along the jet cross-section is used to predict ignition position, which is found to be situated near the stagnation point. While a multi-step reaction is needed to represent the ignition process more accurately, the present calculation does yield reasonable predictions concerning ignition along a curved surface.

Direct-injection strategies for a hydrogen-fueled engine : an optical and numerical investigation

Energy Technology Data Exchange (ETDEWEB)

Kaiser, S.; Salazar, V. [Sandia National Labs, Albuquerque, NM (United States); Scarcelli, R.; Wallner, T. [Argonne National Lab, Argonne, IL (United States)

2009-07-01

Vehicles with hydrogen-fueled engines are competitive with systems based on fuel cells. There is a lack of fundamental knowledge about in-cylinder processes in hydrogen direct injection engines. This presentation discussed a study that used a variety of injector configurations to establish a broad database. A light-load conditions that can profit from stratification was investigated. Several results were presented, including the 5-hole nozzle produced an asymmetric jet pattern which may be good for late injection. Very lean regions in the wake of the transient jets were found to be similar to those found in diesel injection. The 13-hole nozzle demonstrated complete jet collapse, consistent with Schlieren imaging by Petersen. Stratification made efficiency sensitive to the targeting of the single-hole injector. Computational fluid dynamics with a commercially available code aimed to improve the process of design optimization. The simulation predicted less fuel dispersion than was experimentally measured. Details of the fuel penetration were captured. It was concluded that for the single-hole nozzle, the pre-spark fuel distribution is consistent with results from the fired engine. tabs., figs.

Influences of hydrodynamic conditions, nozzle geometry on appearance of high submerged cavitating jets

Directory of Open Access Journals (Sweden)

Hutli Ezddin

2013-01-01

Full Text Available Based on visualization results of highly-submerged cavitating water jet obtained with digital camera, the influences of related parameters such as: injection pressure, nozzle diameter and geometry, nozzle mounting (for convergent / divergent flow, cavitation number and exit jet velocity, were investigated. In addition, the influence of visualization system position was also studied. All the parameters have been found to be of strong influence on the jet appearance and performance. Both hydro-dynamical and geometrical parameters are playing the main role in behavior and intensity of cavitation phenomenon produced by cavitating jet generator. Based on our considerable previous experience in working with cavitating jet generator, the working conditions were chosen in order to obtain measurable phenomenon. [Projekat Ministarstva nauke Republike Srbije, br. TR35046

The design of a new JET divertor for high triangularity and high current scenarios

Energy Technology Data Exchange (ETDEWEB)

Chappuis, P. E-mail: philippe.chappuis@cea.fr; Damiani, C.; Guerin, C.; Hurd, F.; Loarte, A.; Lomas, P.; Lorenz, A.; Pamela, J.; Peacock, A.; Portafaix, C.; Rapp, J.; Riccardo, V.; Rimini, F.; Saibene, G.; Salavy, J.F.; Sauce, Y.; Sartori, R.; Solano, E.; Thomas, E.; Thomas, P.; Tsitrone, E.; Valeta, M.P

2003-09-01

A new divertor (MKII-HP) has been designed to be implemented in JET as part of a possible enhancement programme of the JET facility (JET EP). The aim is to handle up to 40 MW of injected power for 10 s with plasma triangularities up to 0.5 while keeping enough flexibility for other scenarios. The divertor is shaped to optimise the wetting fraction without exposing sharp edges or metallic parts and the general design allows for high halo currents.

Novel laboratory simulations of astrophysical jets

Science.gov (United States)

Brady, Parrish Clawson

This thesis was motivated by the promise that some physical aspects of astrophysical jets and collimation processes can be scaled to laboratory parameters through hydrodynamic scaling laws. The simulation of astrophysical jet phenomena with laser-produced plasmas was attractive because the laser- target interaction can inject energetic, repeatable plasma into an external environment. Novel laboratory simulations of astrophysical jets involved constructing and using the YOGA laser, giving a 1064 nm, 8 ns pulse laser with energies up to 3.7 + 0.2 J . Laser-produced plasmas were characterized using Schlieren, interferometry and ICCD photography for their use in simulating jet and magnetosphere physics. The evolution of the laser-produced plasma in various conditions was compared with self-similar solutions and HYADES computer simulations. Millimeter-scale magnetized collimated outflows were produced by a centimeter scale cylindrically symmetric electrode configuration triggered by a laser-produced plasma. A cavity with a flared nozzle surrounded the center electrode and the electrode ablation created supersonic uncollimated flows. This flow became collimated when the center electrode changed from an anodeto a cathode. The plasma jets were in axially directed permanent magnetic fields with strengths up to 5000 Gauss. The collimated magnetized jets were 0.1-0. 3 cm wide, up to 2.0 cm long, and had velocities of ~4.0 × 10 6 cm/s. The dynamics of the evolution of the jet were compared qualitatively and quantitatively with fluxtube simulations from Bellan's formulation [6] giving a calculated estimate of ~2.6 × 10 6 cm/s for jet evolution velocity and evidence for jet rotation. The density measured with interferometry was 1.9 ± 0.2 × 10 17 cm -3 compared with 2.1 × 10 16 cm -3 calculated with Bellan's pressure balance formulation. Kinks in the jet column were produced consistent with the Kruskal-Shafranov condition which allowed stable and symmetric jets to form with

Break-up of a non-Newtonian jet injected downwards in a ...

Indian Academy of Sciences (India)

atomization and spray coating, crop spraying, ink jet printing, printing of polymer transis- tors, and ... particular ones used in printing and coating, the liquids encountered are non-Newtonian. For breakup of ...... In-Press. Sussman M and Pukett E G 2000 A coupled level set and volume-of-fluid method for computing 3D and.

Water Spray Flow Characteristics Under Synthetic Jet Driven By a Piezoelectric Actuator

Science.gov (United States)

Marchitto, L.; Valentino, G.; Chiatto, M.; de Luca, L.

2017-01-01

Particle Image Velocimetry (PIV) and Phase Doppler Anemometry (PDA) have been applied to investigate the droplets size and velocity distribution of a water spray, under the control of a piezo-element driven synthetic jet (SJ). Tests were carried out under atmospheric conditions within a chamber test rig equipped with optical accesses at two injection pressures, namely 5 and 10 MPa, exploring the variation of the main spray parameters caused by the synthetic jet perturbations. The SJ orifice has been placed at 45° with respect to the water spray axis; the nozzle body has been moved on its own axis and three different nozzle quotes were tested. PIV measurements have been averaged on 300 trials whereas about 105 samples have been acquired for the PDA tests. For each operative condition, the influence region of the SJ device on the spray has been computed through a T-Test algorithm. The synthetic jet locally interacts with the spray, energizing the region downstream the impact. The effect of the actuator decreases at higher injection pressures and moving the impact region upwards. Droplets coalescence can be detected along the synthetic jet axis, while no significant variations are observed along a direction orthogonal to it.

Experimental study of elliptical jet from sub to supercritical conditions

Energy Technology Data Exchange (ETDEWEB)

Muthukumaran, C. K.; Vaidyanathan, Aravind, E-mail: aravind7@iist.ac.in [Department of Aerospace Engineering, Indian Institute of Space Science and Technology, Trivandrum, Kerala 695547 (India)

2014-04-15

The jet mixing at supercritical conditions involves fluid dynamics as well as thermodynamic phenomena. All the jet mixing studies at critical conditions to the present date have focused only on axisymmetric jets. When the liquid jet is injected into supercritical environment, the thermodynamic transition could be well understood by considering one of the important fluid properties such as surface tension since it decides the existence of distinct boundary between the liquid and gaseous phase. It is well known that an elliptical liquid jet undergoes axis-switching phenomena under atmospheric conditions due to the presence of surface tension. The experimental investigations were carried out with low speed elliptical jet under supercritical condition. Investigation of the binary component system with fluoroketone jet and N{sub 2} gas as environment shows that the surface tension force dominates for a large downstream distance, indicating delayed thermodynamic transition. The increase in pressure to critical state at supercritical temperature is found to expedite the thermodynamic transition. The ligament like structures has been observed rather than droplets for supercritical pressures. However, for the single component system with fluoroketone jet and fluoroketone environment shows that the jet disintegrates into droplets as it is subjected to the chamber conditions even for the subcritical pressures and no axis switching phenomenon is observed. For a single component system, as the pressure is increased to critical state, the liquid jet exhibits gas-gas like mixing behavior and that too without exhibiting axis-switching behavior.

Active Control of High-Speed Free Jets Using High-Frequency Excitation

Science.gov (United States)

Upadhyay, Puja

Control of aerodynamic noise generated by high-performance jet engines continues to remain a serious problem for the aviation community. Intense low frequency noise produced by large-scale coherent structures is known to dominate acoustic radiation in the aft angles. A tremendous amount of research effort has been dedicated towards the investigation of many passive and active flow control strategies to attenuate jet noise, while keeping performance penalties to a minimum. Unsteady excitation, an active control technique, seeks to modify acoustic sources in the jet by leveraging the naturally-occurring flow instabilities in the shear layer. While excitation at a lower range of frequencies that scale with the dynamics of large-scale structures, has been attempted by a number of studies, effects at higher excitation frequencies remain severely unexplored. One of the major limitations stems from the lack of appropriate flow control devices that have sufficient dynamic response and/or control authority to be useful in turbulent flows, especially at higher speeds. To this end, the current study seeks to fulfill two main objectives. First, the design and characterization of two high-frequency fluidic actuators (25 and 60 kHz) are undertaken, where the target frequencies are guided by the dynamics of high-speed free jets. Second, the influence of high-frequency forcing on the aeroacoustics of high-speed jets is explored in some detail by implementing the nominally 25 kHz actuator on a Mach 0.9 (Re D = 5 x 105) free jet flow field. Subsequently, these findings are directly compared to the results of steady microjet injection experiments performed in the same rig and to prior jet noise control studies, where available. Finally, limited acoustic measurements were also performed by implementing the nominally 25 kHz actuators on jets at higher Mach numbers, including shock containing jets, and elevated temperatures. Using lumped element modeling as an initial guide, the current

Non-Boussinesq turbulent buoyant jet of a low-density gas leaks into high-density ambient

KAUST Repository

El-Amin, Mohamed

2010-12-01

In this article, we study the problem of low-density gas jet injected into high-density ambient numerically which is important in applications such as fuel injection and leaks. It is assumed that the local rate of entrainment is consisted of two components; one is the component of entrainment due to jet momentum while the other is the component of entrainment due to buoyancy. The integral models of the mass, momentum and concentration fluxes are obtained and transformed to a set of ordinary differential equations using some similarity transformations. The resulting system is solved to determine the centerline quantities which are used to get the mean axial velocity, mean concentration and mean density of the jet. Therefore, the centerline and mean quantities are used together with the governing equation to determine some important turbulent quantities such as, cross-stream velocity, Reynolds stress, velocity- concentration correlation, turbulent eddy viscosity and turbulent eddy diffusivity. Throughout this paper the developed model is verified by comparing the present results with experimental results and jet/plume theory from the literature. © 2010 Elsevier Inc. All rights reserved.

Non-Boussinesq turbulent buoyant jet of a low-density gas leaks into high-density ambient

KAUST Repository

El-Amin, Mohamed; Sun, Shuyu; Kanayama, Hiroshi

2010-01-01

In this article, we study the problem of low-density gas jet injected into high-density ambient numerically which is important in applications such as fuel injection and leaks. It is assumed that the local rate of entrainment is consisted of two components; one is the component of entrainment due to jet momentum while the other is the component of entrainment due to buoyancy. The integral models of the mass, momentum and concentration fluxes are obtained and transformed to a set of ordinary differential equations using some similarity transformations. The resulting system is solved to determine the centerline quantities which are used to get the mean axial velocity, mean concentration and mean density of the jet. Therefore, the centerline and mean quantities are used together with the governing equation to determine some important turbulent quantities such as, cross-stream velocity, Reynolds stress, velocity- concentration correlation, turbulent eddy viscosity and turbulent eddy diffusivity. Throughout this paper the developed model is verified by comparing the present results with experimental results and jet/plume theory from the literature. © 2010 Elsevier Inc. All rights reserved.

Dynamics of Plasma Jets and Bubbles Launched into a Transverse Background Magnetic Field

Science.gov (United States)

Zhang, Yue

2017-10-01

A coaxial magnetized plasma gun has been utilized to launch both plasma jets (open B-field) and plasma bubbles (closed B-field) into a transverse background magnetic field in the HelCat (Helicon-Cathode) linear device at the University of New Mexico. These situations may have bearing on fusion plasmas (e.g. plasma injection for tokamak fueling, ELM pacing, or disruption mitigation) and astrophysical settings (e.g. astrophysical jet stability, coronal mass ejections, etc.). The magnetic Reynolds number of the gun plasma is 100 , so that magnetic advection dominates over magnetic diffusion. The gun plasma ram pressure, ρjetVjet2 >B02 / 2μ0 , the background magnetic pressure, so that the jet or bubble can easily penetrate the background B-field, B0. When the gun axial B-field is weak compared to the gun azimuthal field, a current-driven jet is formed with a global helical magnetic configuration. Applying the transverse background magnetic field, it is observed that the n = 1 kink mode is stabilized, while magnetic probe measurements show contrarily that the safety factor q(a) drops below unity. At the same time, a sheared axial jet velocity is measured. We conclude that the tension force arising from increasing curvature of the background magnetic field induces the measured sheared flow gradient above the theoretical kink-stabilization threshold, resulting in the emergent kink stabilization of the injected plasma jet. In the case of injected bubbles, spheromak-like plasma formation is verified. However, when the spheromak plasma propagates into the transverse background magnetic field, the typical self-closed global symmetry magnetic configuration does not hold any more. In the region where the bubble toroidal field opposed the background B-field, the magneto-Rayleigh-Taylor (MRT) instability has been observed. Details of the experiment setup, diagnostics, experimental results and theoretical analysis will be presented. Supported by the National Science Foundation

Artificial plasma jet in the ionosphere

International Nuclear Information System (INIS)

Haerendel, G.; Sagdeev, R.Z.

1981-01-01

The dynamics of an artificially injected plasma beam in the near-earth space are analyzed in terms of the beam structure, its propagation across the magnetic field, and the resulting wave phenomena (Porcupine Project, flight 4, March 31, 1979). Out of the four ejectable canisters attached to the main payload, two were instrumented by the U.S., one by the USSR (the Xenon plasma beam experiment), and one by West Germany (carrying a barium ion jet experiment). The propagation of the plasma seems to occur in three stages, with high-frequency broad-band oscillations mainly localized in the 'core' of the jet, while low-frequency oscillations were spatially separated from it. The generation region of LF oscillations was found to be much wider than the jet core. As a result of the interaction between the plasma beam and the ambient medium a heating of electrons, up to energies of about 20 eV, associated with LF noise was observed. The behavior of high-energy ions and the observed HF wave phenomena need further analysis

A new flow focusing technique to produce very thin jets

International Nuclear Information System (INIS)

Acero, A J; Rebollo-Muñoz, N; Montanero, J M; Gañán-Calvo, A M; Vega, E J

2013-01-01

A new technique is proposed in this paper to produce jets, droplets, and emulsions with sizes ranging from tens of microns down to the submicrometer scale. Liquid is injected at a constant flow rate through a hypodermic needle to form a film over the needle's outer surface. This film flows toward the needle tip until a liquid ligament is steadily ejected. Both the film motion and the liquid ejection are driven by the viscous and pressure forces exerted by a coflowing fluid stream. If this stream is a high-speed gas current, the outcome is a capillary jet which breaks up into droplets due to the Rayleigh instability. Micrometer emulsions are also produced by this instability mechanism when the injected liquid is focused by a viscous liquid stream. The minimum flow rates reached with the proposed technique are two orders of magnitude lower than those of the standard flow focusing configuration. This sharp reduction of the minimum flow rate allows one to form steady jets with radii down to the submicrometer scale. The stability of this new configuration is analyzed experimentally for both gas–liquid and liquid–liquid systems. In most of the cases, the loss of stability must be attributed to the liquid source because the critical Weber (capillary) number for the gas–liquid (liquid–liquid) case was significantly greater than the value corresponding to the convective/absolute instability transition in the jet. (paper)

Shear layer characteristics of supersonic free and impinging jets

Science.gov (United States)

Davis, T. B.; Kumar, R.

2015-09-01

The initial shear layer characteristics of a jet play an important role in the initiation and development of instabilities and hence radiated noise. Particle image velocimetry has been utilized to study the initial shear layer development of supersonic free and impinging jets. Microjet control employed to reduce flow unsteadiness and jet noise appears to affect the development of the shear layer, particularly near the nozzle exit. Velocity field measurements near the nozzle exit show that the initially thin, uncontrolled shear layer develops at a constant rate while microjet control is characterized by a rapid nonlinear thickening that asymptotes downstream. The shear layer linear growth rate with microjet control, in both the free and the impinging jet, is diminished. In addition, the thickened shear layer with control leads to a reduction in azimuthal vorticity for both free and impinging jets. Linear stability theory is used to compute unstable growth rates and convection velocities of the resultant velocity profiles. The results show that while the convection velocity is largely unaffected, the unstable growth rates are significantly reduced over all frequencies with microjet injection. For the case of the impinging jet, microjet control leads to near elimination of the impingement tones and an appreciable reduction in broadband levels. Similarly, for the free jet, significant reduction in overall sound pressure levels in the peak radiation direction is observed.

Study on effect of mixing mechanism by the transverse gaseous injection flow in scramjet engine with variable parameters

Science.gov (United States)

Yadav, Siddhita; Pandey, K. M.

2018-04-01

In scramjet engine the mixing mechanism of fuel and atmospheric air is very complicated, because the fuel have time in milliseconds for mixing with atmospheric air in combustion chamber having supersonic speed. Mixing efficiency of fuel and atmospheric air depends on mainly these parameters: Aspect ratio of injector, vibration amplitude, shock type, number of injector, jet to transverse flow momentum flux ratio, injector geometry, injection angle, molecular weight, incoming air stream angle, jet to transverse flow pressure ratio, spacing variation, mass flow rate of fuel etc. here is a very brief study of these parameters from previously done research on these parameters for the improvement of mixing efficiency. The mixing process have the significant role for the working of engine, and mixing between the atmospheric air and the jet fuel is significant factor for improving the overall thrust of the engine. The results obtained by study of papers are obtained by the 3D-Reynolds Average-Nervier-Stokes(RANS) equations along with the 2-equation k-ω shear-stress-transport (SST) turbulence model. Engine having multi air jets have 60% more mixing efficiency than single air jet, thus if the jets are increased, the mixing efficiency of engine can also be increased up to 150% by changing jet from 1 to 16. When using delta shape of injector the mixing efficiency is inversely proportional to the pressure ratio. When the fuel is injected inside the combustor from the top and bottom walls of the engine efficiency of mixing in reacting zone is higher than the single wall injection and in comparison to parallel flow, the transverse type flow is better as the atmospheric air jet can penetrate smoothly in the fuel jets and mixes well in less time. Hence this study of parameters and their effects on mixing can enhance the efficiency of mixing in engine.

Parametric dependences of momentum pinch and Prandtl number in JET

NARCIS (Netherlands)

Tala, T.; Salmi, A.; Angioni, C.; Casson, F. J.; Corrigan, G.; Ferreira, J.; Giroud, C.; Mantica, P.; Naulin, V.; Peeters, A.G.; Solomon, W. M.; Strintzi, D.; Tsalas, M.; Versloot, T. W.; de Vries, P. C.; Zastrow, K. D.

2011-01-01

Several parametric scans have been performed to study momentum transport on JET. A neutral beam injection modulation technique has been applied to separate the diffusive and convective momentum transport terms. The magnitude of the inward momentum pinch depends strongly on the inverse density

Investigation of PVdF active diaphragms for synthetic jets

Science.gov (United States)

Bailo, Kelly C.; Brei, Diann E.; Calkins, Frederick T.

2000-06-01

Current research has shown that aircraft can gain significant aerodynamic performance benefits by employing active flow control (AFC). One of the enabling technologies of AFC is the synthetic jet. Synthetic jets, also known as zero-net-mass flux actuators, act as bi-directional pumps injecting high momentum air into the local aerodynamic flow. Previous work has concentrated on high frequency synthetic jets based on piezoelectric active diaphragms such as Thunder actuators. Low frequency synthetic jets present a unique challenge requiring large displacements, which current technology has difficulty meeting. Boeing is investigating novel shaped low frequency synthetic jets that can modify the flow over fixed aircraft wings. This paper present the initial study of two promising active diaphragm concepts: a crescent shape and an opposing bender shape. These active diaphragms were numerically modeled utilizing the general-purpose finite element code ABAQUS. Using the ABAQUS results, the dynamic volume change within each jet was calculated and incorporated into an analytical linear Bernoulli model to predict the velocities and pressures at the nozzle. Simulations were performed to determine trends to assist in selection of prototype configurations. Prototypes of both diaphragm concepts were constructed from polyvinylidene fluoride and experimentally tested at Boeing with promising results.

ePLAS Development for Jet Modeling and Applications

International Nuclear Information System (INIS)

Mason, Rodney J.

2011-01-01

Plasma jets provide an alternate approach to the creation of high energy density laboratory plasmas (HEDLP). For the Plasma Liner Experiment (PLX), typically 30 partially ionized argon jets, produced with mini-rail guns, will be focused into a central volume for subsequent magnetic compression into high density plasma liners that can reach high (0.1 Mbar) peak pressures upon stagnation. The jets are typically 2.5 cm in radius traveling at Mach number 30. Ultimate success will require optimized tuning of the rail configurations, the nozzles injecting the gases, and the careful implementation of pre-ionization. The modeling of plasma jet transport is particularly challenging, due the large space (100 sq cm) and time scales (microseconds) involved. Even traditional implicit methods are insufficient, due to the usual need to track electrons explicitly on the mesh. Wall emission and chemistry must be managed, as must ionization of the jet plasma. Ions in the jets are best followed as particles to account properly for collisions upon jet merger. This Phase I Project developed the code ePLAS to attack and successfully surmount many of these challenges. It invented a new 'super implicit' electromagnetic scheme, using implicit electron moment currents that allowed for modeling of jets over multi-cm and multi-picoseconds on standard, single processor 2 GHz PCs. It enabled merger studies of two jets, in preparation for the multi-jet merger problem. The Project explored particle modeling for the ions, and prepared for the future addition of a grid-base jet ion collision model. Access was added to tabular equations of state for the study of ionization effects in merging jets. The improved code was discussed at the primary plasma meetings (IEEE and APS) during the Project period. Collaborations with National Laboratory and industrial partners were nurtured. Code improvements were made to facilitate code use. See: http://www.researchapplicationscorp.com. The ePLAS code enjoys EAR

Active Suppression of Rotating Stall Inception with Distributed Jet Actuation

Directory of Open Access Journals (Sweden)

Huu Duc Vo

2007-01-01

Full Text Available An analytical and experimental investigation of the effectiveness of full-span distributed jet actuation for active suppression of long length-scale rotating stall inception is carried out. Detailed modeling and experimental verification highlight the important effects of mass addition, discrete injectors, and feedback dynamics, which may be overlooked in preliminary theoretical studies of active control with jet injection. A model of the compression system incorporating nonideal injection and feedback dynamics is verified with forced response measurements to predict the right trends in the movement of the critical pole associated with the stall precursor. Active control experiments with proportional feedback control show that the predicted stall precursors are suppressed to give a 5.5% range extension in compressor flow coefficient. In addition, results suggest that the proposed model could be used to design a more sophisticated controller to further improve performance while reducing actuator bandwidth requirements.

Numerical Investigation on Sensitivity of Liquid Jet Breakup to Physical Fuel Properties with Experimental Comparison

Science.gov (United States)

Kim, Dokyun; Bravo, Luis; Matusik, Katarzyna; Duke, Daniel; Kastengren, Alan; Swantek, Andy; Powell, Christopher; Ham, Frank

2016-11-01

One of the major concerns in modern direct injection engines is the sensitivity of engine performance to fuel characteristics. Recent works have shown that even slight differences in fuel properties can cause significant changes in efficiency and emission of an engine. Since the combustion process is very sensitive to the fuel/air mixture formation resulting from disintegration of liquid jet, the precise assessment of fuel sensitivity on liquid jet atomization process is required first to study the impact of different fuels on the combustion. In the present study, the breaking process of a liquid jet from a diesel injector injecting into a quiescent gas chamber is investigated numerically and experimentally for different liquid fuels (n-dodecane, iso-octane, CAT A2 and C3). The unsplit geometric Volume-of-Fluid method is employed to capture the phase interface in Large-eddy simulations and results are compared against the radiography measurement from Argonne National Lab including jet penetration, liquid mass distribution and volume fraction. The breakup characteristics will be shown for different fuels as well as droplet PDF statistics to demonstrate the influences of the physical properties on the primary atomization of liquid jet. Supported by HPCMP FRONTIER award, US DOD, Office of the Army.

An experimental study of injection and spray characteristics of diesel and gasoline blends on a common rail injection system

International Nuclear Information System (INIS)

Han, Dong; Wang, Chunhai; Duan, Yaozong; Tian, Zhisong; Huang, Zhen

2014-01-01

The injection and spray characteristics of diesel and gasoline blends are investigated on a common rail injection system. The injection rate, fuel spray evolution process (tip penetration distance, spray cone angle, projected spray area and relative brightness intensity contour) and microscopic droplet features are analyzed. The results show that diesel and gasoline blends have higher volumetric injection rates, earlier starts of injection and shorter injection delays, but little variances are observed in the mass injection rates for different test fuels. Increased gasoline proportion in the test blends causes slightly decreased spray tip penetration distance but increased spray cone angle. Also, more smaller-size droplets are observed in the fuel jet of the diesel and gasoline blends, indicating that the spray breakup and atomization processes are promoted. - Highlights: • Injection rate and spray characteristics of diesel and gasoline blends are studied. • Diesel and gasoline blends have higher volumetric injection rates. • Earlier starts of injection are found when using diesel and gasoline blends. • Diesel and gasoline blends produce shorter spray penetration but higher cone angle. • The number of small droplets increases in the spray of diesel and gasoline blends

Analytical model for performance verification of liquid poison injection system of a nuclear reactor

International Nuclear Information System (INIS)

Kansal, Anuj Kumar; Maheshwari, Naresh Kumar; Vijayan, Pallippattu Krishnan

2014-01-01

Highlights: • One-dimensional modelling of shut down system-2. • Semi-empirical correlation poison jet progression. • Validation of code. - Abstract: Shut down system-2 (SDS-2) in advanced vertical pressure tube type reactor, provides rapid reactor shutdown by high pressure injection of a neutron absorbing liquid called poison, into the moderator in the calandria. Poison inside the calandria is distributed by poison jets issued from holes provided in the injection tubes. Effectiveness of the system depends on the rate and spread of the poison in the moderator. In this study, a transient one-dimensional (1D) hydraulic code, COPJET is developed, to predict the performance of system by predicting progression of poison jet with time. Validation of the COPJET is done with the data available in literature. Thereafter, it is applied for advanced vertical pressure type reactor

Development on JET of Advanced Tokamak Operations for ITER

International Nuclear Information System (INIS)

Tuccillo, A.A.; Crisanti, F.; Litaudon, X.

2005-01-01

Recent research on Advanced Tokamak in JET has focused on scenarii with both monotonic and reversed shear q profiles having plasma parameters as relevant as possible for extrapolation to ITER. Wide ITBs, R∼3.7m, are formed at ITER relevant triangularity δ∼0.45, with n e /n G ∼60% and ELMs moderated by Ne injection. At higher current (I P ≤3.5MA, δ∼0.25) wide ITBs sitting at R≥ 3.5m (positive shear region) have been developed, generally MHD events terminate these barrier otherwise limited in strength by power availability. ITBs with core density close to Greenwald value are obtained with plasma target preformed by opportune timing of LHCD, pellet injection and small amount of NBI power. ITB start with toroidal rotation 4 times lower than the standard NBI heated ITBs. Full CD is achieved in reversed shear ITBs at 3T/1.8 MA, by using 10MW NBI, 5MW ICRH and 3MW LH. Wide ITBs located at R=3.6m, without impurity accumulation and type-III ELMs edge can be sustained for a time close to neo-classical resistive time. These discharges have been extended to the maximum duration allowed by subsystems (20s) with the JET record of injected energy: E∼330 MJ. Integrated control of pressure and current profile isit; feature used in these discharges. Central ICRF mode conversion electron heating, added to about 14MW NBI power, produced impressive ITBs with equivalent Q DT ∼ 0.25. Conversely ion ITBs are obtained with low torque injection, by ICRH 3 He minority heating of ions, on pure LHCD electron ITBs. Similarity experiments between JET and AUG have compared the dynamics of ITBs and have been the starting point of Hybrid Scenarios activity, then developed at ρ* as low as ρ*∼3*10 -3 . The development of hybrid regime with dominant electron heating has also started. Injection of trace of tritium and a mixture of Ar/Ne allowed studying fuel and impurities transport in many of the explored AT scenarios. (author)

Large-Eddy Simulation of Subsonic Jets

International Nuclear Information System (INIS)

Vuorinen, Ville; Wehrfritz, Armin; Yu Jingzhou; Kaario, Ossi; Larmi, Martti; Boersma, Bendiks Jan

2011-01-01

The present study deals with development and validation of a fully explicit, compressible Runge-Kutta-4 (RK4) Navier-Stokes solver in the opensource CFD programming environment OpenFOAM. The background motivation is to shift towards explicit density based solution strategy and thereby avoid using the pressure based algorithms which are currently proposed in the standard OpenFOAM release for Large-Eddy Simulation (LES). This shift is considered necessary in strongly compressible flows when Ma > 0.5. Our application of interest is related to the pre-mixing stage in direct injection gas engines where high injection pressures are typically utilized. First, the developed flow solver is discussed and validated. Then, the implementation of subsonic inflow conditions using a forcing region in combination with a simplified nozzle geometry is discussed and validated. After this, LES of mixing in compressible, round jets at Ma = 0.3, 0.5 and 0.65 are carried out. Respectively, the Reynolds numbers of the jets correspond to Re = 6000, 10000 and 13000. Results for two meshes are presented. The results imply that the present solver produces turbulent structures, resolves a range of turbulent eddy frequencies and gives also mesh independent results within satisfactory limits for mean flow and turbulence statistics.

An experimental setup for visualizations and measurements on free hypersonic jets

Directory of Open Access Journals (Sweden)

Tordella Daniela

2012-04-01

Full Text Available The free hypersonic jets can be found in several technological applications and even in astrophysical observations. This article is mainly devoted to explain an experiment about visualizations and measurements on free hypersonic jets extending on length scales in the order of hundreds of initial diameters and traveling in a medium not necessarily made of the same gas of the jets. The experiments are performed by means of special facilities where the jet Mach numbers and the jetto-ambient density ratios can be set independently of each other, what permits the investigation of a wide parameters range in the relevant physics. The Mach number of the jets ranges from 5 to 20 and the jet-to ambient density ratio, which plays an important role in the jets morphology, can be set from 0.1 up to values exceeding 100. The present setup produces the jets by means of a fast piston system (for high Mach numbers or injection valves (for low Mach numbers, both coupled with de Laval nozzles. The visualizations and measurements are based on the electron beam technique: the jets are weakly ionized, then a fast CMOS camera captures images that are analyzed by image processing techniques. A sample of the results obtained by this experimental system is included at the end of this work.

Experimental and analytical study on biodiesel and diesel spray characteristics under ultra-high injection pressure

International Nuclear Information System (INIS)

Wang Xiangang; Huang Zuohua; Kuti, Olawole Abiola; Zhang Wu; Nishida, Keiya

2010-01-01

Spray characteristics of biodiesels (from palm and cooked oil) and diesel under ultra-high injection pressures up to 300 MPa were studied experimentally and analytically. Injection delay, spray penetration, spray angle, spray projected area and spray volume were measured in a spray vessel using a high speed video camera. Air entrainment and atomization characteristics were analyzed with the quasi-steady jet theory and an atomization model respectively. The study shows that biodiesels give longer injection delay and spray tip penetration. Spray angle, projected area and volume of biodiesels are smaller than those of diesel fuel. The approximately linear relationship of non-dimensional spray tip penetration versus time suggests that the behavior of biodiesel and diesel sprays is similar to that of gaseous turbulent jets. Calculation from the quasi-steady jet theory shows that the air entrainment of palm oil is worse than that of diesel, while the cooked oil and diesel present comparable air entrainment characteristics. The estimation on spray droplet size shows that biodiesels generate larger Sauter mean diameter due to higher viscosity and surface tension.

Experimental investigation of the mixing processes in a Jet-in-Crossflow arrangement; Experimentelle Untersuchung von Vermischungsvorgaengen in einer Jet-in-Crossflow-Anordnung

Energy Technology Data Exchange (ETDEWEB)

Cardenas, C.; Suntz, R.; Bockhorn, H. [Karlsruhe Univ. (T.H.) (Germany). Inst. fuer Technische Chemie und Polymerchemie

2008-07-15

The Jet-in-Crossflow flow arrangement is a geometrically simple flow configuration in which an open jet is injected vertically into a constant crossflow and the two flows are thus mixed with one another. This flow arrangement is frequently encountered in industrial applications and also in nature. Examples can be found in industrial burners, RQL gas turbines, T-mixers, smoke plumes from stacks and volcanoes, and the jets emitted by aviation gas-turbines and by rockets. The subject of this publication is quantitative experimental determination of the Reynolds flows and stresses in a Jet-in-Crossflow arrangement. The variables stated reflect turbulence-induced elevated mass transfer in a turbulent vis-a-vis a laminar flow and are thus intimately linked to mixing processes. Their experimental determination is of great importance for the generation and validation of numerical turbulence models. Simultaneous use of two laser-diagnosis methods, 2D LIF (Two-dimensional Laser-induced Fluorescence) and PIV (Particle Image Velocimetry) makes it possible to establish 2D concentration and velocity fields simultaneously and determine the variables mentioned directly. (orig.)

Particle retention during long discharges in Tore Supra and JET

International Nuclear Information System (INIS)

Loarer, T.; Tsitrone, E.; Brosset, C.; Bucalossi, J.; Gunn, J.; Joffrin, E.; Monier-Garbet, P.; Pegourie, B.; Thomas, P.; Lomas, P.; Ongena, J.

2003-01-01

The particle balances and the associated particle retentions for the long discharge experiments performed in Tore-Supra and for the L and H mode discharges carried out in JET are reported in this paper. From the reported experiments, the same particle retention behaviors are observed in Tore-Supra and JET in spite of the differences between the plasma geometry and the confinement mode (respectively limiter L-mode and divertor H-mode). A particle retention up to 70-80% of Γ(puff) for the larger gas injection has been obtained in JET. The particle retention behavior observed with the gas puff appears to be strongly dominant in the particle retention process. Indeed, no influence has been noticed from the active pumping, the saturation of the recycling area (0.4 D/C), the precedent discharges history (in terms of total 'particles retained' in the vessel) and even from the disruptions (conditioning). Also, the outgassing between discharges becomes negligible in terms of particle recovering when Γ(puff) and/or the discharge duration are increased. Finally, neither the edge localized modes (ELMs type-I or III) nor the disruptions modify the reported behaviour. For ITER, the particle retention is strictly limited and from the presented results it seems that strong gas injection should be avoided. (A.C.)

Experimental investigation of coaxial-gun-formed plasmas injected into a background transverse magnetic field or plasma

Science.gov (United States)

Zhang, Yue; Fisher, Dustin M.; Gilmore, Mark; Hsu, Scott C.; Lynn, Alan G.

2018-05-01

Injection of coaxial-gun-formed magnetized plasmas into a background transverse vacuum magnetic field or into a background magnetized plasma has been studied in the helicon-cathode (HelCat) linear plasma device at the University of New Mexico [M. Gilmore et al., J. Plasma Phys. 81, 345810104 (2015)]. A magnetized plasma jet launched into a background transverse magnetic field shows emergent kink stabilization of the jet due to the formation of a sheared flow in the jet above the kink stabilization threshold 0.1kVA [Y. Zhang et al., Phys. Plasmas 24, 110702 (2017)]. Injection of a spheromak-like plasma into a transverse background magnetic field led to the observation of finger-like structures on the side with a stronger magnetic field null between the spheromak and the background field. The finger-like structures are consistent with magneto-Rayleigh-Taylor instability. Jets or spheromaks launched into a background, low-β magnetized plasma show similar behavior as above, respectively, in both cases.

Confinement and stability in JET: recent results

International Nuclear Information System (INIS)

Campbell, D.J.

1990-01-01

The versatility of the JET device allows a wide range of tokamak operating regimes to be explored and plasmas bounded both by material limiters and by a magnetic separatrix have been investigated extensively. This has permitted the confinement and mhd stability properties of plasmas heated to temperatures above 10keV by neutral beam injection or ion cyclotron resonance heating to be studied in detail. The results of recent analyses of transport and confinement in the L- and H-mode regimes in JET are discussed and the properties of H-mode plasmas produced by both major forms of heating are compared. Several aspects of the mhd stability of such plasmas, particularly at high toroidal beta, β θ , and at the density limit, are reviewed. (author)

The gas introduction system of JET

International Nuclear Information System (INIS)

Boschi, A.; Dietz, K.J.; Rebut, P.H.

1984-01-01

The Gas Introduction System of JET is designed to handle, measure, transfer and inject into the machine, at given rates and times, the quantities of gases required to feel the plasma discharges. The System is composed by a Gas Handling Unit for the gas preparation, and four identical Gas Introduction Modules which are positioned symmetrically at the machine. The lay-out and design of the different components is described and operational experience is presented. (author)

An automatic injection system for rapid radiochemistry

International Nuclear Information System (INIS)

Nurmia, M.J.; Kreek, S.A.; Kadkhodayan, B.; Gregorich, K.E.; Lee, D.M.; Hoffman, D.C.

1992-01-01

A description is given of the Automated Injection System (AIS), a pneumatically actuated device for automated collection of nuclear reaction products from a He/KCl gas jet transport system. The AIS is used with the Automated Chemical Chromatographic Element Separation System; together these two devices facilitate completely automated separation procedures with improved speed and reproducibility

Shock wave calibration of under-expanded natural gas fuel jets

Science.gov (United States)

White, T. R.; Milton, B. E.

2008-10-01

Natural gas, a fuel abundant in nature, cannot be used by itself in conventional diesel engines because of its low cetane number. However, it can be used as the primary fuel with ignition by a pilot diesel spray. This is called dual-fuelling. The gas may be introduced either into the inlet manifold or, preferably, directly into the cylinder where it is injected as a short duration, intermittent, sonic jet. For accurate delivery in the latter case, a constant flow-rate from the injector is required into the constantly varying pressure in the cylinder. Thus, a sonic (choked) jet is required which is generally highly under-expanded. Immediately at the nozzle exit, a shock structure develops which can provide essential information about the downstream flow. This shock structure, generally referred to as a “barrel” shock, provides a key to understanding the full injection process. It is examined both experimentally and numerically in this paper.

Modeling of liquid ceramic precursor droplets in a high velocity oxy-fuel flame jet

International Nuclear Information System (INIS)

Basu, Saptarshi; Cetegen, Baki M.

2008-01-01

Production of coatings by high velocity oxy-fuel (HVOF) flame jet processing of liquid precursor droplets can be an attractive alternative method to plasma processing. This article concerns modeling of the thermophysical processes in liquid ceramic precursor droplets injected into an HVOF flame jet. The model consists of several sub-models that include aerodynamic droplet break-up, heat and mass transfer within individual droplets exposed to the HVOF environment and precipitation of ceramic precursors. A parametric study is presented for the initial droplet size, concentration of the dissolved salts and the external temperature and velocity field of the HVOF jet to explore processing conditions and injection parameters that lead to different precipitate morphologies. It is found that the high velocity of the jet induces shear break-up into several μm diameter droplets. This leads to better entrainment and rapid heat-up in the HVOF jet. Upon processing, small droplets (<5 μm) are predicted to undergo volumetric precipitation and form solid particles prior to impact at the deposit location. Droplets larger than 5 μm are predicted to form hollow or precursor containing shells similar to those processed in a DC arc plasma. However, it is found that the lower temperature of the HVOF jet compared to plasma results in slower vaporization and solute mass diffusion time inside the droplet, leading to comparatively thicker shells. These shell-type morphologies may further experience internal pressurization, resulting in possibly shattering and secondary atomization of the trapped liquid. The consequences of these different particle states on the coating microstructure are also discussed in this article

Numerical simulations of turbulent jet ignition and combustion

Science.gov (United States)

Validi, Abdoulahad; Irannejad, Abolfazl; Jaberi, Farhad

2013-11-01

The ignition and combustion of a homogeneous lean hydrogen-air mixture by a turbulent jet flow of hot combustion products injected into a colder gas mixture are studied by a high fidelity numerical model. Turbulent jet ignition can be considered as an efficient method for starting and controlling the reaction in homogeneously charged combustion systems used in advanced internal combustion and gas turbine engines. In this work, we study in details the physics of turbulent jet ignition in a fundamental flow configuration. The flow and combustion are modeled with the hybrid large eddy simulation/filtered mass density function (LES/FMDF) approach, in which the filtered form the compressible Navier-Stokes equations are solved with a high-order finite difference scheme for the turbulent velocity and the FMDF transport equations are solved with a Lagrangian stochastic method to obtain the scalar (temperature and species mass fractions) field. The hydrogen oxidation is described by a detailed reaction mechanism with 37 elementary reactions and 9 species.

Mixing characterization of highly underexpanded fluid jets with real gas expansion

Science.gov (United States)

Förster, Felix J.; Baab, Steffen; Steinhausen, Christoph; Lamanna, Grazia; Ewart, Paul; Weigand, Bernhard

2018-03-01

We report a comprehensive speed of sound database for multi-component mixing of underexpanded fuel jets with real gas expansion. The paper presents several reference test cases with well-defined experimental conditions providing quantitative data for validation of computational simulations. Two injectant fluids, fundamentally different with respect to their critical properties, are brought to supercritical state and discharged into cold nitrogen at different pressures. The database features a wide range of nozzle pressure ratios covering the regimes that are generally classified as highly and extremely highly underexpanded jets. Further variation is introduced by investigating different injection temperatures. Measurements are obtained along the centerline at different axial positions. In addition, an adiabatic mixing model based on non-ideal thermodynamic mixture properties is used to extract mixture compositions from the experimental speed of sound data. The concentration data obtained are complemented by existing experimental data and represented by an empirical fit.

Experimental investigation on the effect of liquid injection by multiple orifices in the formation of droplets in a Venturi scrubber

Energy Technology Data Exchange (ETDEWEB)

Guerra, V.G.; Goncalves, J.A.S. [Department of Chemical Engineering, Federal University of Sao Carlos, Via Washington Luiz, Km. 235, 13565-905 Sao Carlos, SP (Brazil); Coury, J.R. [Department of Chemical Engineering, Federal University of Sao Carlos, Via Washington Luiz, Km. 235, 13565-905 Sao Carlos, SP (Brazil)], E-mail: jcoury@ufscar.br

2009-01-15

Venturi scrubbers are widely utilized in gas cleaning. The cleansing elements in these scrubbers are droplets formed from the atomization of a liquid into a dust-laden gas. In industrial scrubbers, this liquid is injected through several orifices so that the cloud of droplets can be evenly distributed throughout the duct. The interaction between droplets when injected through many orifices, where opposite clouds of atomized liquid can reach each other, is to be expected. This work presents experimental measurements of droplet size measured in situ and the evidence of cloud interaction within a Venturi scrubber operating with multi-orifice jet injection. The influence of gas velocity, liquid flow rate and droplet size variation in the axial position after the point of the injection of the liquid were also evaluated for the different injection configurations. The experimental results showed that an increase in the liquid flow rate generated greater interaction between jets. The number of orifices had a significant influence on droplet size. In general, the increase in the velocity of the liquid jet and in the gas velocity favored the atomization process by reducing the size of the droplets.

Experimental investigation on the effect of liquid injection by multiple orifices in the formation of droplets in a Venturi scrubber

International Nuclear Information System (INIS)

Guerra, V.G.; Goncalves, J.A.S.; Coury, J.R.

2009-01-01

Venturi scrubbers are widely utilized in gas cleaning. The cleansing elements in these scrubbers are droplets formed from the atomization of a liquid into a dust-laden gas. In industrial scrubbers, this liquid is injected through several orifices so that the cloud of droplets can be evenly distributed throughout the duct. The interaction between droplets when injected through many orifices, where opposite clouds of atomized liquid can reach each other, is to be expected. This work presents experimental measurements of droplet size measured in situ and the evidence of cloud interaction within a Venturi scrubber operating with multi-orifice jet injection. The influence of gas velocity, liquid flow rate and droplet size variation in the axial position after the point of the injection of the liquid were also evaluated for the different injection configurations. The experimental results showed that an increase in the liquid flow rate generated greater interaction between jets. The number of orifices had a significant influence on droplet size. In general, the increase in the velocity of the liquid jet and in the gas velocity favored the atomization process by reducing the size of the droplets

Experimental investigation on the effect of liquid injection by multiple orifices in the formation of droplets in a Venturi scrubber.

Science.gov (United States)

Guerra, V G; Gonçalves, J A S; Coury, J R

2009-01-15

Venturi scrubbers are widely utilized in gas cleaning. The cleansing elements in these scrubbers are droplets formed from the atomization of a liquid into a dust-laden gas. In industrial scrubbers, this liquid is injected through several orifices so that the cloud of droplets can be evenly distributed throughout the duct. The interaction between droplets when injected through many orifices, where opposite clouds of atomized liquid can reach each other, is to be expected. This work presents experimental measurements of droplet size measured in situ and the evidence of cloud interaction within a Venturi scrubber operating with multi-orifice jet injection. The influence of gas velocity, liquid flow rate and droplet size variation in the axial position after the point of the injection of the liquid were also evaluated for the different injection configurations. The experimental results showed that an increase in the liquid flow rate generated greater interaction between jets. The number of orifices had a significant influence on droplet size. In general, the increase in the velocity of the liquid jet and in the gas velocity favored the atomization process by reducing the size of the droplets.

Numerical simulations of negatively buoyant jets in an immiscible fluid using the Particle Finite Element Method

Science.gov (United States)

Mier-Torrecilla, Monica; Geyer, Adelina; Phillips, Jeremy C.; Idelsohn, Sergio R.; Oñate, Eugenio

2010-05-01

In this work we investigate numerically the injection of a negatively buoyant jet into a homogenous immiscible ambient fluid using the Particle Finite Element Method (PFEM), a newly developed tool that combines the flexibility of particle-based methods with the accuracy of the finite element discretization. In order to test the applicability of PFEM to the study of negatively buoyant jets, we have compared the two-dimensional numerical results with experiments investigating the injection of a jet of dyed water through a nozzle in the base of a cylindrical tank containing rapeseed oil. In both simulations and experiments, the fountain inlet flow velocity and nozzle diameter were varied to cover a wide range of Reynolds Re and Froude numbers Fr, such that 0.1 < Fr < 30, reproducing both weak and strong fountains in a laminar regime (8 < Re < 1350). Numerical results, together with the experimental observations, allow us to describe three different fountain behaviors that have not been previously reported. Based on the Re and Fr values for the numerical and experimental simulations, we have built a regime map to define how these values may control the occurrence of each of the observed flow types. Whereas the Fr number itself provides a prediction of the maximum penetration height of the jet, its combination with the Re number provides a prediction of the flow behavior for a specific nozzle diameter and injection velocity. Conclusive remarks concerning the dynamics of negatively buoyant jets may be applied later on to several geological situations, e.g. the flow structure of a fully submerged subaqueous eruptive vent discharging magma or the replenishment of magma chambers in the Earth's crust.

Experimental evidence for collisional shock formation via two obliquely merging supersonic plasma jets

Energy Technology Data Exchange (ETDEWEB)

Merritt, Elizabeth C., E-mail: emerritt@lanl.gov; Adams, Colin S. [Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States); University of New Mexico, Albuquerque, New Mexico 87131 (United States); Moser, Auna L.; Hsu, Scott C., E-mail: scotthsu@lanl.gov; Dunn, John P.; Miguel Holgado, A. [Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States); Gilmore, Mark A. [University of New Mexico, Albuquerque, New Mexico 87131 (United States)

2014-05-15

We report spatially resolved measurements of the oblique merging of two supersonic laboratory plasma jets. The jets are formed and launched by pulsed-power-driven railguns using injected argon, and have electron density ∼10{sup 14} cm{sup −3}, electron temperature ≈1.4 eV, ionization fraction near unity, and velocity ≈40 km/s just prior to merging. The jet merging produces a few-cm-thick stagnation layer, as observed in both fast-framing camera images and multi-chord interferometer data, consistent with collisional shock formation [E. C. Merritt et al., Phys. Rev. Lett. 111, 085003 (2013)].

Interaction of Acoustic Waves with a Cryogenic Nitrogen Jet at Sub- and Supercritical Pressures

National Research Council Canada - National Science Library

Chehroudi, B

2001-01-01

To better understand the nature of the interaction between acoustic waves and liquid fuel jets in rocket engines, cryogenic liquid nitrogen is injected into a room temperature high-pressure chamber...

The gas introduction system of JET

International Nuclear Information System (INIS)

Boschi, A.; Dietz, K.J.; Rebut, P.H.

1985-01-01

The Gas Introduction System of JET is designed to handle, measure, transfer and inject into the machine, at given rates and times, the quantitites of gases required to feed the plasma discharges. The System is composed by a Gas Handling Unit for the gas preparation, and four identical Gas Introduction Modules which are positioned symmetrically at the machine. In this paper the lay-out and design of the different components is described and operational experience is presented

On the Surface Breakup of a Non-turbulent Round Liquid Jet in Cross-flow

Science.gov (United States)

Behzad, Mohsen; Ashgriz, Nasser

2011-11-01

The atomization of a non-turbulent liquid jet injected into a subsonic cross-flow consists of two parts: (1) primary breakup and (2) secondary breakup. Two distinct regimes for the liquid jet primary breakup have been recognized; the so called column breakup and surface breakup. In the column breakup mode, the entire liquid jet undergoes disintegration into large liquid lumps. Quiet differently in the surface breakup regime, liquid fragments with various sizes and shapes are separated from the surface of the jet. Despite many experimental studies the mechanisms of jet surface breakup is not fully understood. Thus this study aims at providing useful observations regarding the underlying physics involving the surface breakup mechanism of a liquid jet in cross-flow, using detailed numerical simulations. The results show that a two-stage mechanism can be responsible for surface breakup. In the first stage, a sheet-like structure extrudes towards the downstream, and in the second stage it disintegrates into ligaments and droplets due to aerodynamic instability.

Visualization of supersonic diesel fuel jets using a shadowgraph technique

Science.gov (United States)

Pianthong, Kulachate; Behnia, Masud; Milton, Brian E.

2001-04-01

High-speed liquid jets have been widely used to cut or penetrate material. It has been recently conjectured that the characteristics of high-speed fuel jets may also be of benefit to engines requiring direct fuel injection into the combustion chamber. Important factors are combustion efficiency and emission control enhancement for better atomization. Fundamental studies of very high velocity liquid jets are therefore very important. The characteristics and behavior of supersonic liquid jets have been studied with the aid of a shadowgraph technique. The high-speed liquid jet (in the supersonic range) is generated by the use of a vertical, single stage powder gun. The performance of the launcher and its relation to the jet exit velocity, with a range of nozzle shapes, has been examined. This paper presents the visual evidence of supersonic diesel fuel jets (velocity around 2000 m/s) investigated by the shadowgraph method. An Argon jet has been used as a light source. With a rise time of 0.07 microseconds, light duration of 0.2 microseconds and the use of high speed Polaroid film, the shadowgraph method can effectively capture the hypersonic diesel fuel jet and its strong leading edge shock waves. This provides a clearer picture of each stage of the generation of hypersonic diesel fuel jets and makes the study of supersonic diesel fuel jet characteristics and the potential for auto-ignition possible. Also, in the experiment, a pressure relief section has been used to minimize the compressed air or blast wave ahead of the projectile. However, the benefit of using a pressure relief section in the design is not clearly known. To investigate this effect, additional experiments have been performed with the use of the shadowgraph method, showing the projectile leaving and traveling inside the nozzle at a velocity around 1100 m/s.

The technological achievements and experience at JET

International Nuclear Information System (INIS)

Pick, M.

1998-12-01

The Joint European Torus, JET, the largest and most successful Tokamak in the world, was conceived from the start as a research project with very ambitious aims and a bold approach to extrapolations of the physics and technology base as well as the international nature of its organisation. Throughout its operating life JET has maintained this approach and, with its innovative and flexible design, has extended its performance far beyond the initially intended boundaries thereby retaining a lead in virtually all areas of fusion research. JET has shown a willingness to venture far beyond the technology base of the time into new areas and dimensions. The paper will highlight a few examples which illustrate the approach taken in JET to work closely with industry and the European Associations to extend the technology beyond the current state of the art whilst maintaining a tight grip on the fundamental requirements of cost and time schedule. These range from large scale integrated systems as well as small scale technological breakthroughs. Large scale systems include the Active Gas Handling System for the on-line reprocessing of the tritium-deuterium fuel, the Remote Handling System which was integrated into the JET machine from the very beginning, the JET Power Supply system as well as, most importantly, the design of the JET structure itself which permitted the fast maintenance and repair of all major sub-units. Other notable advances include the Neutral Beam Injection and Radio Frequency Heating systems, the large open structure cryo-pumps and the novel cryo-transmission lines. Some of the associated technologies required major advances in the area of diagnostics, high power handling components, carbon fibre reinforced carbon materials as well as in the whole field of beryllium technology and beryllium handling. The success of JET has shown that it serves as a model for future machines both from an engineering point of view as well as in its approach to management

Jet mass spectra in Higgs+one jet at NNLL

International Nuclear Information System (INIS)

Jouttenus, Teppo T.; Stewart, Iain W.; Waalewijn, Wouter J.

2013-02-01

The invariant mass of a jet is a benchmark variable describing the structure of jets at the LHC. We calculate the jet mass spectrum for Higgs plus one jet at the LHC at next-to-next-to-leading logarithmic (NNLL) order using a factorization formula. At this order, the cross section becomes sensitive to perturbation theory at the soft m 2 jet /p jet T scale. Our calculation is exclusive and uses the 1-jettiness global event shape to implement a veto on additional jets. The dominant dependence on the jet veto is removed by normalizing the spectrum, leaving residual dependence from non-global logarithms depending on the ratio of the jet mass and jet veto variables. For our exclusive jet cross section these non-global logarithms are parametrically smaller than in the inclusive case, allowing us to obtain a complete NNLL result. Results for the dependence of the jet mass spectrum on the kinematics, jet algorithm, and jet size R are given. Using individual partonic channels we illustrate the difference between the jet mass spectra for quark and gluon jets. We also study the effect of hadronization and underlying event on the jet mass in Pythia. To highlight the similarity of inclusive and exclusive jet mass spectra, a comparison to LHC data is presented.

Experimental study on spray characteristics of alternate jet fuels using Phase Doppler Anemometry

Science.gov (United States)

Kannaiyan, Kumaran; Sadr, Reza

2013-11-01

Gas-to-Liquid (GTL) fuels have gained global attention due to their cleaner combustion characteristics. The chemical and physical properties of GTL jet fuels are different from conventional jet fuels owing to the difference in their production methodology. It is important to study the spray characteristics of GTL jet fuels as the change of physical properties can affect atomization, mixing, evaporation and combustion process, ultimately affecting emission process. In this work, spray characteristics of two GTL synthetic jet fuels are studied using a pressure-swirl nozzle at different injection pressures and atmospheric ambient condition. Phase Doppler Anemometry (PDA) measurements of droplet size and velocity are compared with those of regular Jet A-1 fuel at several axial and radial locations downstream of the nozzle exit. Experimental results show that although the GTL fuels have different physical properties such as viscosity, density, and surface tension, among each other the resultant change in the spray characteristics is insignificant. Furthermore, the presented results show that GTL fuel spray characteristics exhibit close similarity to those of Jet A-1 fuel. Funded by Qatar Science and Technology Park.

Jet angularity measurements for single inclusive jet production

Science.gov (United States)

Kang, Zhong-Bo; Lee, Kyle; Ringer, Felix

2018-04-01

We study jet angularity measurements for single-inclusive jet production at the LHC. Jet angularities depend on a continuous parameter a allowing for a smooth interpolation between different traditional jet shape observables. We establish a factorization theorem within Soft Collinear Effective Theory (SCET) where we consistently take into account in- and out-of-jet radiation by making use of semi-inclusive jet functions. For comparison, we elaborate on the differences to jet angularities measured on an exclusive jet sample. All the necessary ingredients for the resummation at next-to-leading logarithmic (NLL) accuracy are presented within the effective field theory framework. We expect semiinclusive jet angularity measurements to be feasible at the LHC and we present theoretical predictions for the relevant kinematic range. In addition, we investigate the potential impact of jet angularities for quark-gluon discrimination.

Jet mass spectra in Higgs+one jet at NNLL

Energy Technology Data Exchange (ETDEWEB)

Jouttenus, Teppo T.; Stewart, Iain W. [Massachusetts Institute of Technology, Cambridge, MA (United States). Center for Theoretical Physics; Tackmann, Frank J. [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany); Waalewijn, Wouter J. [California Univ., San Diego, La Jolla, CA (United States). Dept. of Physics

2013-02-15

The invariant mass of a jet is a benchmark variable describing the structure of jets at the LHC. We calculate the jet mass spectrum for Higgs plus one jet at the LHC at next-to-next-to-leading logarithmic (NNLL) order using a factorization formula. At this order, the cross section becomes sensitive to perturbation theory at the soft m{sup 2}{sub jet}/p{sup jet}{sub T} scale. Our calculation is exclusive and uses the 1-jettiness global event shape to implement a veto on additional jets. The dominant dependence on the jet veto is removed by normalizing the spectrum, leaving residual dependence from non-global logarithms depending on the ratio of the jet mass and jet veto variables. For our exclusive jet cross section these non-global logarithms are parametrically smaller than in the inclusive case, allowing us to obtain a complete NNLL result. Results for the dependence of the jet mass spectrum on the kinematics, jet algorithm, and jet size R are given. Using individual partonic channels we illustrate the difference between the jet mass spectra for quark and gluon jets. We also study the effect of hadronization and underlying event on the jet mass in Pythia. To highlight the similarity of inclusive and exclusive jet mass spectra, a comparison to LHC data is presented.

Simulating the interaction of jets with the intracluster medium

Science.gov (United States)

Weinberger, Rainer; Ehlert, Kristian; Pfrommer, Christoph; Pakmor, Rüdiger; Springel, Volker

2017-10-01

Jets from supermassive black holes in the centres of galaxy clusters are a potential candidate for moderating gas cooling and subsequent star formation through depositing energy in the intracluster gas. In this work, we simulate the jet-intracluster medium interaction using the moving-mesh magnetohydrodynamics code arepo. Our model injects supersonic, low-density, collimated and magnetized outflows in cluster centres, which are then stopped by the surrounding gas, thermalize and inflate low-density cavities filled with cosmic rays. We perform high-resolution, non-radiative simulations of the lobe creation, expansion and disruption, and find that its dynamical evolution is in qualitative agreement with simulations of idealized low-density cavities that are dominated by a large-scale Rayleigh-Taylor instability. The buoyant rising of the lobe does not create energetically significant small-scale chaotic motion in a volume-filling fashion, but rather a systematic upward motion in the wake of the lobe and a corresponding back-flow antiparallel to it. We find that, overall, 50 per cent of the injected energy ends up in material that is not part of the lobe, and about 25 per cent remains in the inner 100 kpc. We conclude that jet-inflated, buoyantly rising cavities drive systematic gas motions that play an important role in heating the central regions, while mixing of lobe material is subdominant. Encouragingly, the main mechanisms responsible for this energy deposition can be modelled already at resolutions within reach in future, high-resolution cosmological simulations of galaxy clusters.

A modified stratified model for the 3C 273 jet

International Nuclear Information System (INIS)

Liu Wenpo; Shen Zhiqiang

2009-01-01

We present a modified stratified jet model to interpret the observed spectral energy distributions of knots in the 3C 273 jet. Based on the hypothesis of the single index of the particle energy spectrum at injection and identical emission processes among all the knots, the observed difference of spectral shape among different 3C 273 knots can be understood as a manifestation of the deviation of the equivalent Doppler factor of stratified emission regions in an individual knot from a characteristic one. The summed spectral energy distributions of all ten knots in the 3C 273 jet can be well fitted by two components: a low-energy component (radio to optical) dominated by synchrotron radiation and a high-energy component (UV, X-ray and γ-ray) dominated by inverse Compton scattering of the cosmic microwave background. This gives a consistent spectral index of α = 0.88 (S v ∝ v -α ) and a characteristic Doppler factor of 7.4. Assuming the average of the summed spectrum as the characteristic spectrum of each knot in the 3C 273 jet, we further get a distribution of Doppler factors. We discuss the possible implications of these results for the physical properties in the 3C 273 jet. Future GeV observations with GLAST could separate the γ-ray emission of 3C 273 from the large scale jet and the small scale jet (i.e. the core) through measuring the GeV spectrum.

POPULATION III GAMMA-RAY BURSTS AND BREAKOUT CRITERIA FOR ACCRETION-POWERED JETS

Energy Technology Data Exchange (ETDEWEB)

Nagakura, Hiroki; Suwa, Yudai [Yukawa Institute for Theoretical Physics, Kyoto University, Oiwake-cho, Kitashirakawa, Sakyo-ku, Kyoto 606-8502 (Japan); Ioka, Kunihito, E-mail: hiroki@heap.phys.waseda.ac.jp [KEK Theory Center, 1-1 Oho, Tsukuba 305-0801 (Japan)

2012-08-01

We investigate the propagation of accretion-powered jets in various types of massive stars such as Wolf-Rayet stars, light Population III (Pop III) stars, and massive Pop III stars, all of which are the progenitor candidates of gamma-ray bursts (GRBs). We perform two-dimensional axisymmetric simulations of relativistic hydrodynamics, taking into account both the envelope collapse and the jet propagation (i.e., the negative feedback of the jet on the accretion). Based on our hydrodynamic simulations, we show for the first time that the accretion-powered jet can potentially break out relativistically from the outer layers of Pop III progenitors. In our simulations, the accretion rate is estimated by the mass flux going through the inner boundary, and the jet is injected with a fixed accretion-to-jet conversion efficiency {eta}. By varying the efficiency {eta} and opening angle {theta}{sub op} for more than 40 models, we find that the jet can make a relativistic breakout from all types of progenitors for GRBs if a simple condition {eta} {approx}> 10{sup -4}({theta}{sub op}/8 Degree-Sign ){sup 2} is satisfied, which is consistent with analytical estimates. Otherwise no explosion or some failed spherical explosions occur.

DNS and LES/FMDF of turbulent jet ignition and combustion

Science.gov (United States)

Validi, Abdoulahad; Jaberi, Farhad

2014-11-01

The ignition and combustion of lean fuel-air mixtures by a turbulent jet flow of hot combustion products injected into various geometries are studied by high fidelity numerical models. Turbulent jet ignition (TJI) is an efficient method for starting and controlling the combustion in complex propulsion systems and engines. The TJI and combustion of hydrogen and propane in various flow configurations are simulated with the direct numerical simulation (DNS) and the hybrid large eddy simulation/filtered mass density function (LES/FMDF) models. In the LES/FMDF model, the filtered form of the compressible Navier-Stokes equations are solved with a high-order finite difference scheme for the turbulent velocity and the FMDF transport equation is solved with a Lagrangian stochastic method to obtain the scalar field. The DNS and LES/FMDF data are used to study the physics of TJI and combustion for different turbulent jet igniter and gas mixture conditions. The results show the very complex and different behavior of the turbulence and the flame structure at different jet equivalence ratios.

Quark jets, gluon jets and the three-gluon vertex

International Nuclear Information System (INIS)

Fodor, Z.

1989-11-01

Using hadronic jets in electron-positron annihilation, we suggest a simple and model-independent method to see the differences between quark and gluon jets. We define and analyse special energy dependent moments of jets and choose those which are the most characteristic to the jet type. The method handles the energy of a jet in an adequate way. We discuss new methods using jet flavor tagging, ordinary flavor tagging of a definite quark jet or discrimination between quark and gluon jets, to test the triple-gluon vertex in electron-positron annihilation. An enriched sample of gluon jets, jets with the smallest energy in four-jet events, as well as a continuous tagging variable are also studied. 21 refs., 6 figs. (Author)

Particle Acceleration, Magnetic Field Generation and Emission from Relativistic Jets

Science.gov (United States)

Nishikawa, K.-I.; Hardee, P.; Hededal, C.; Mizuno, Yosuke; Fishman, G. Jerry; Hartmann, D. H.

2006-01-01

Nonthermal radiation observed from astrophysical systems containing relativistic jets and shocks, e.g., active galactic nuclei (AGNs), gamma-ray bursts (GRBs), supernova remnants, and Galactic microquasar systems usually have power-law emission spectra. Fermi acceleration is the mechanism usually assumed for the acceleration of particles in astrophysical environments. Recent PIC simulations using injected relativistic electron-ion (electro-positron) jets show that particle acceleration occurs within the downstream jet, rather than by the scattering of particles back and forth across the shock as in Fermi acceleration. Shock acceleration' is a ubiquitous phenomenon in astrophysical plasmas. Plasma waves and their associated instabilities (e.g., the Buneman instability, other two-streaming instability, and the Weibel instability) created in the shocks are responsible for particle (electron, positron, and ion) acceleration. The simulation results show that the Weibel instability is responsible for generating and amplifying highly nonuniform, small-scale magnetic fields. These magnetic fields contribute to the electron's transverse deflection behind the jet head. The "jitter" radiation from deflected electrons has different spectral properties than synchrotron radiation which is calculated in a uniform magnetic field. This jitter radiation may be important to understanding the complex time evolution and/or spectral structure in gamma-ray bursts, relativistic jets, and supernova remnants. We will review recent PIC simulations of relativistic jets and try to make a connection with observations.

Particle Acceleration, Magnetic Field Generation and Associated Emission in Collisionless Relativistic Jets

Science.gov (United States)

Nishikawa, K. I.; Ramirez-Ruiz, E.; Hardee, P.; Mizuno, Y.; Fishman. G. J.

2007-01-01

Nonthermal radiation observed from astrophysical systems containing relativistic jets and shocks, e.g., active galactic nuclei (AGNs), gamma-ray bursts (GRBs), and Galactic microquasar systems usually have power-law emission spectra. Recent PIC simulations using injected relativistic electron-ion (electro-positron) jets show that acceleration occurs within the downstream jet. Shock acceleration is a ubiquitous phenomenon in astrophysical plasmas. Plasma waves and their associated instabilities (e.g., the Buneman instability, other two-streaming instability, and the Weibel instability) created in the shocks are responsible for particle (electron, positron, and ion) acceleration. The simulation results show that the Weibel instability is responsible for generating and amplifying highly nonuniform, small-scale magnetic fields. These magnetic fields contribute to the electron's transverse deflection behind the jet head. The "jitter" radiation from deflected electrons has different properties than synchrotron radiation which is calculated in a uniform magnetic field. This jitter radiation may be important to understanding the complex time evolution and/or spectral structure in gamma-ray bursts, relativistic jets, and supernova remnants.

Experimental investigation of coaxial-gun-formed plasmas injected into a background transverse magnetic field or plasma

OpenAIRE

Zhang, Yue; Fisher, Dustin M.; Gilmore, Mark; Hsu, Scott C.; Lynn, Alan G.

2017-01-01

Injection of coaxial-gun-formed magnetized plasmas into a background transverse vacuum magnetic field or into a background magnetized plasma has been studied in the helicon-cathode (HelCat) linear plasma device at the University of New Mexico [M. Gilmore et al., J. Plasma Phys.81, 345810104 (2015)]. Magnetized plasma jet launched into a background transverse magnetic field shows emergent kink stabilization of the jet due to the formation of a sheared flow in the jet above the kink-stabilizati...

Heat transfer characteristics around a single heated rod immersed in sodium pool with gas jet injection

International Nuclear Information System (INIS)

Hideto Niikura; Kazuo Soga; Ken-ichiro Sugiyama; Akira Yamaguchi

2005-01-01

In a steam generator using liquid sodium, water intensely reacts with sodium when it leaks out from a heat transfer tube. It is important to evaluate the influence of sodium-water reaction to surrounding tubes and the shell. Hence, it has been desired to develop the simulation code for the evaluation of sodium-water reaction. From this viewpoint, the Japan Nuclear Cycle is now developing the SERAPHIM code. We reported a preliminary study to establish an experimental method for a single heated rod immersed in sodium pool with steam jet impingement planned in the near future as well as to obtain a preliminary data to verify the adequacy of SERAPHIM code. We first measured local and mean heat transfer coefficients around a horizontal single heated rod immersed in a water pool and a sodium pool with a limited volume in the experimental apparatus. It was confirmed that the mean heat transfer coefficients fairly agreed with the existing data for natural convection in water and sodium. Secondary we measured local and mean heat transfer coefficients around a horizontal single heated rod with Ar gas jet impingement immersed in the limited water pool and in the limited sodium pool. It was clearly observed that the local heat transfer coefficients in the sodium pool keep almost the same values in every angle regardless of increase in Ar gas jet velocity varied from about 8.7m/s to about 78m/s. On the other hand, it was confirmed in the water pool that local heat transfer coefficients on the forward stagnation side exposed in the Ar gas jet impingement increase with increasing the jet velocity while the local heat transfer coefficients on the opposite surface keep almost same values regardless of increase in the velocity. (authors)

Study on the quench behavior of molten fuel material jet into coolant

International Nuclear Information System (INIS)

Abe, Yutaka; Kizu, Tetsuya; Arai, Takahiro; Nariai, Hideki; Chitose, Keiko; Koyama, Kazuya

2004-01-01

In a core disruptive accident (CDA) of a Fast Breeder Reactor, the post accident heat removal (PAHR) is crucial for the accident mitigation. The molten core material should be solidified in the sodium coolant in the reactor vessel. In the present experiment, molten material jet is injected into water to experimentally obtain fragments and the visualized information of the fragmentation. The distributed particle behavior of the molten material jet is observed with high-speed video camera. The distributions of the fragmented droplet diameter from the molten material jet are evaluated by correcting the solidified particles. The experimental results of the mean fragmented droplet diameter are compared with the existing theories. Consequently, the fragmented droplet diameter is close to the value estimated based on the Kelvin-Helmholtz instability. Once the particle diameter of the fragmented molten material could be known from a hydrodynamic model, it becomes possible to estimate the mass ratio of the molten particle to the total injected mass by combining an appropriate heat transfer model. The heat transfer model used in the present study is composed of the fragmentation model based on the Kelvin-Helmholtz instability. The mass ratio of the molten fragment to total mass of the melted mixed oxide fuel in sodium coolant estimated in the present study is very small. The result means that most of the molten mixed oxide fuel material injected into the sodium coolant can be cooled down under the solidified temperature, that is so called quenched, if the amount of the coolant is sufficient. (author)

Vector boson tagged jets and jet substructure

Directory of Open Access Journals (Sweden)

Vitev Ivan

2018-01-01

Full Text Available In these proceedings, we report on recent results related to vector boson-tagged jet production in heavy ion collisions and the related modification of jet substructure, such as jet shapes and jet momentum sharing distributions. Z0-tagging and γ-tagging of jets provides new opportunities to study parton shower formation and propagation in the quark-gluon plasma and has been argued to provide tight constrains on the energy loss of reconstructed jets. We present theoretical predictions for isolated photon-tagged and electroweak boson-tagged jet production in Pb+Pb collisions at √sNN = 5.02 TeV at the LHC, addressing the modification of their transverse momentum and transverse momentum imbalance distributions. Comparison to recent ATLAS and CMS experimental measurements is performed that can shed light on the medium-induced radiative corrections and energy dissipation due to collisional processes of predominantly quark-initiated jets. The modification of parton splitting functions in the QGP further implies that the substructure of jets in heavy ion collisions may differ significantly from the corresponding substructure in proton-proton collisions. Two such observables and the implication of tagging on their evaluation is also discussed.

The technological achievements and experience at JET

International Nuclear Information System (INIS)

Pick, M.A.

1999-01-01

The Joint European Torus, JET, the largest and most successful Tokamak in the world, was conceived from the start as a research project with very ambitious aims and a bold approach to extrapolations of the physics and technology base as well as the international nature of its organisation. Throughout its operating life the JET team has maintained this approach and, with its innovative and flexible design, has extended its performance far beyond the initially intended boundaries thereby retaining a lead in virtually all areas of fusion research. The team has shown a willingness to venture far beyond the technology base of the time into new areas and dimensions. The paper will highlight a few examples which illustrate the approach taken in JET to work closely with industry and the European Associations to extend the technology beyond the current state of the art whilst maintaining a tight grip on the fundamental requirements of cost and time schedule. These range from large scale integrated systems as well as small scale technological breakthroughs. Large scale systems include the Active Gas Handling System for the on-line reprocessing of the tritium-deuterium fuel, the Remote Handling System which was integrated into the JET machine from the very beginning, the JET Power Supply system as well as, most importantly, the design of the JET structure itself which permitted the fast maintenance and repair of all major sub-units. Other notable advances include the Neutral Beam Injection and Radio Frequency Heating systems, the large open structure cryo-pumps and the novel cryo-transmission lines. Some of the associated technologies required major advances in the area of diagnostics, high power handling components, carbon fibre reinforced carbon materials as well as in the whole field of beryllium technology and beryllium handling. (orig.)

The JET high frequency pellet injector project

International Nuclear Information System (INIS)

Geraud, Alain; Dentan, M.; Whitehead, A.; Butcher, P.; Communal, D.; Faisse, F.; Gedney, J.; Gros, G.; Guillaume, D.; Hackett, L.; Hennion, V.; Homfray, D.; Lucock, R.; McKivitt, J.; Sibbald, M.; Portafaix, C.; Perin, J.P.; Reade, M.; Sands, D.; Saille, A.

2007-01-01

A new deuterium ice pellet injector is in preparation for JET. It is designed to inject both small pellets (variable volume within 1-2 mm 3 ) at high frequency (up to 60 Hz) for ELM mitigation experiments and large pellets (volume within 35-70 mm 3 ) at moderate frequency (up to 15 Hz) for plasma fuelling. It is based on the screw extruder technology developed by PELIN and pneumatic acceleration. An injection line will connect the injector to the flight tubes already in place to convey the pellets toward the plasma either from the low field side or from the high field side of the torus. This injection line enables: (i) the pumping of the propellant gas, (ii) the provision of the vacuum interface with the torus and (iii) the selection of the flight tube to be used via a fast selector. All the interfaces have been designed and a prototype injector is being built, to demonstrate that the required performance is achievable

Turbulent structure and dynamics of swirled, strongly pulsed jet diffusion flames

KAUST Repository

Liao, Ying-Hao

2013-11-02

The structure and dynamics of swirled, strongly pulsed, turbulent jet diffusion flames were examined experimentally in a co-flow swirl combustor. The dynamics of the large-scale flame structures, including variations in flame dimensions, the degree of turbulent flame puff interaction, and the turbulent flame puff celerity were determined from high-speed imaging of the luminous flame. All of the tests presented here were conducted with a fixed fuel injection velocity at a Reynolds number of 5000. The flame dimensions were generally found to be more impacted by swirl for the cases of longer injection time and faster co-flow flow rate. Flames with swirl exhibited a flame length up to 34% shorter compared to nonswirled flames. Both the turbulent flame puff separation and the flame puff celerity generally decreased when swirl was imposed. The decreased flame length, flame puff separation, and flame puff celerity are consistent with a greater momentum exchange between the flame and the surrounding co-flow, resulting from an increased rate of air entrainment due to swirl. Three scaling relations were developed to account for the impact of the injection time, the volumetric fuel-to-air flow rate ratio, and the jet-on fraction on the visible flame length. © 2013 Copyright Taylor and Francis Group, LLC.

The collective emission of electromagnetic waves from astrophysical jets - Luminosity gaps, BL Lacertae objects, and efficient energy transport

Science.gov (United States)

Baker, D. N.; Borovsky, Joseph E.; Benford, Gregory; Eilek, Jean A.

1988-01-01

A model of the inner portions of astrophysical jets is constructed in which a relativistic electron beam is injected from the central engine into the jet plasma. This beam drives electrostatic plasma wave turbulence, which leads to the collective emission of electromagnetic waves. The emitted waves are beamed in the direction of the jet axis, so that end-on viewing of the jet yields an extremely bright source (BL Lacertae object). The relativistic electron beam may also drive long-wavelength electromagnetic plasma instabilities (firehose and Kelvin-Helmholtz) that jumble the jet magnetic field lines. After a sufficient distance from the core source, these instabilities will cause the beamed emission to point in random directions and the jet emission can then be observed from any direction relative to the jet axis. This combination of effects may lead to the gap turn-on of astrophysical jets. The collective emission model leads to different estimates for energy transport and the interpretation of radio spectra than the conventional incoherent synchrotron theory.

Potential design modifications for the High Yield Lithium Injection Fusion Energy (HYLIFE) reaction chamber

International Nuclear Information System (INIS)

Pitts, J.H.; Hovingh, J.; Meier, W.R.; Monsler, M.J.; Powell, E.G.; Walker, P.E.

1979-01-01

Generation of electric power from inertial confinement fusion requires a reaction chamber. One promising type, the High Yield Lithium Injection Fusion Energy (HYLIFE) chamber, includes a falling array of liquid lithium jets. These jets act as: (1) a renewable first wall and blanket to shield metal components from x-ray and neutron exposure, (2) a tritium breeder to replace tritium burned during the fusion process, and (3) an absorber and transfer medium for fusion energy. Over 90% of the energy produced in the reaction chamber is absorbed in the lithium jet fall. Design aspects are included

Investigation on the influence of jetting equipment on the characteristics of centrifugal pump

Directory of Open Access Journals (Sweden)

Qiaorui Si

2016-08-01

Full Text Available To reduce radial noises from the motor of centrifugal pumps, this study designed a water cooling system called jetting equipment to replace traditional fan cooling systems in pump motors. By measuring radiated noises, head, efficiency, and cavitation performance, the research compared the differences among experimental results of the original pump unit, the one with a normal design jetting pipe and another one with a larger jetting pipe. Results show that the radiated sound pressure level of the model pump was significantly reduced by 8.3 dB after integrating the jetting pipe. With a normal jetting pipe, no significant changes were observed in the head, efficiency, and shaft power curves, and cavitation performance improved under small flow rate. However, the performance with the larger jetting pipe worsened, except the hump phenomenon of the model pump under a small flow rate was enhanced. Computational fluid dynamics method was used to calculate the internal flow of three model pumps in order to investigate the jetting flow effect. A comparison among the flow fields at the inlet of the three types of pumps indicated that high-pressure water injection can effectively control inlet recirculation and improve velocity distribution in the inlet flow field with decreased recirculation vortex strength and recirculation onset critical flow rate.

Use of the disruption mitigation valve in closed loop for routine protection at JET

International Nuclear Information System (INIS)

Reux, Cédric; Lehnen, Michael; Kruezi, Uron; Jachmich, Stefan; Card, Peter; Heinola, Kalle; Joffrin, Emmanuel; Lomas, Peter J.; Marsen, Stefan; Matthews, Guy; Riccardo, Valeria; Rimini, Fernanda; Vries, Peter de

2013-01-01

Highlights: ► A massive gas injection valve was used for disruption routine mitigation at JET. ► A disruption mitigation valve was integrated in JET real time systems. ► Simple triggering schemes such as mode lock were used for disruption detection. ► High forces disruptions were prevented by the use of the gas valve. ► Radiated energy is higher in mitigated disruption than in unmitigated ones. -- Abstract: Disruptions are a major concern for next-generation tokamaks, including ITER. Heat loads, electromagnetic forces and runaway electrons generated by disruptions have to be mitigated for a reliable operation of future machines. Massive gas injection is one of the methods proposed for disruption mitigation. This article reports the first use of massive gas injection as an active disruption protection system at JET. During the 2011–2012 campaigns, 67 disruptions have been mitigated by the disruption mitigation valve (DMV) following a detection by mode lock amplitude and loop voltage changes. Most of disruptions where the valve was intended to be used were successfully mitigated by the DMV, although at different stages of the typical slow disruptions of the ITER-like wall. The fraction of magnetic and thermal energy radiated during the disruption was found to be increased by the action of the DMV. Vertical forces dispersion was also reduced. No non-sustained breakdown was observed following pulses terminated by the disruption mitigation valve

Use of the disruption mitigation valve in closed loop for routine protection at JET

Energy Technology Data Exchange (ETDEWEB)

Reux, Cédric, E-mail: cedric.reux@ccfe.ac.uk [Ecole Polytechnique, LPP, CNRS UMR 7648, 91128 Palaiseau (France); JET-EFDA, Culham Science Centre, Abingdon OX14 3DB (United Kingdom); Lehnen, Michael; Kruezi, Uron [Association EURATOM-FZJ, Trilateral Euregio Cluster, 52425 Julich (Germany); Jachmich, Stefan [Laboratoire de Physique des Plasmas-Laboratorium voor Plasmafysica, Association EURATOM-Belgian State Institute ERM/KMS, B-1000 Brussels (Belgium); EFDA-CSU, Culham Science Centre, Abingdon OX14 3DB (United Kingdom); Card, Peter [Culham Science Centre, EURATOM/CCFE Association, Abingdon OX14 3DB (United Kingdom); Heinola, Kalle [Department of Physics, University of Helsinki, P.O. Box 64, 00014 University of Helsinki (Finland); Joffrin, Emmanuel [CEA, IRFM, F-13108 Saint-Paul-lez-Durance (France); Lomas, Peter J. [Culham Science Centre, EURATOM/CCFE Association, Abingdon OX14 3DB (United Kingdom); Marsen, Stefan [Max-Planck-Institut für Plasmaphysik, Teilinstitut Greifswald, EURATOM-Assoziation, D-17491 Greifswald (Germany); Matthews, Guy; Riccardo, Valeria; Rimini, Fernanda [Culham Science Centre, EURATOM/CCFE Association, Abingdon OX14 3DB (United Kingdom); Vries, Peter de [FOM Institute DIFFER, P.O. Box 1207, 3430 BE Nieuwegein (Netherlands)

2013-10-15

Highlights: ► A massive gas injection valve was used for disruption routine mitigation at JET. ► A disruption mitigation valve was integrated in JET real time systems. ► Simple triggering schemes such as mode lock were used for disruption detection. ► High forces disruptions were prevented by the use of the gas valve. ► Radiated energy is higher in mitigated disruption than in unmitigated ones. -- Abstract: Disruptions are a major concern for next-generation tokamaks, including ITER. Heat loads, electromagnetic forces and runaway electrons generated by disruptions have to be mitigated for a reliable operation of future machines. Massive gas injection is one of the methods proposed for disruption mitigation. This article reports the first use of massive gas injection as an active disruption protection system at JET. During the 2011–2012 campaigns, 67 disruptions have been mitigated by the disruption mitigation valve (DMV) following a detection by mode lock amplitude and loop voltage changes. Most of disruptions where the valve was intended to be used were successfully mitigated by the DMV, although at different stages of the typical slow disruptions of the ITER-like wall. The fraction of magnetic and thermal energy radiated during the disruption was found to be increased by the action of the DMV. Vertical forces dispersion was also reduced. No non-sustained breakdown was observed following pulses terminated by the disruption mitigation valve.

Connection of a He-jet recoil transport system to an ion source

International Nuclear Information System (INIS)

Sheppard, G.A.

1977-02-01

In an effort to make non-gaseous fission products available for on-line separation and study with the TRISTAN facility, an investigation of the operational characteristics of a He-jet recoil transport system and a TRISTAN-type ion source was conducted after interfacing them with a skimmer. So that experimental results could be understood and controlled, studies of the dynamics of choked flow in a capillary and of the transport characteristics were made. Satisfactory performance of the He-jet system was obtained, but large temperature and pressure gradients thwarted early attempts to efficiently couple the He-jet to the ion source. The pressure-related difficulties have been overcome by employing a skimmer to remove extraneous gases before injection of the activities into the ion source, but efforts to conquer the temperature-related problems continue

Formula for radial profiles of temperature in steam-liquid sodium reactive jets

International Nuclear Information System (INIS)

Hobbes, P.; Mora-Perez, J.L.; Carreau, J.L.; Gbahoue, L.; Roger, F.

1987-01-01

One of the important problems of the study of distribution of temperatures in the reactive steam-liquid sodium jet rests in the mathematical formulation of their radial effects. During the experiment, two forms have been brought to light: from a certain distance of the injector, the radial distribution of temperature can be represented, in a classical way, by an error function curve; close to the injector, the radial profile allows for a minimum located on the axis of the jet. An energy balance permits, by dividing the jet in three parts: a central nucleus composed of practically pure gas, a gas ring plus drops and a liquid peripheral area plus bubbles, to obtain a mathematical formulation of the profiles, close to the injection which accounts quite well for the experimental points and their form

Numerical study of an impinging jet to a turbulent channel flow in a T-Junction configuration

Science.gov (United States)

Georgiou, Michail; Papalexandris, Miltiadis

2016-11-01

In this talk we report on Large Eddy Simulations of an impinging planar jet to a turbulent channel flow in a T-Junction configuration. Due to its capacity for mixing and heat transfer enhancement, this type of flow is encountered in various industrial applications. In particular, our work is related to the emergency cooling systems of pressurized water reactors. As is well known, this type of flow is dominated by a large separation bubble downstream the jet impingement location. Secondary regions of flow separation are predicted both upstream and downstream the impinging jet. We describe how these separation regions interact with the shear layer that is formed by the injection of the jet to the crossflow, and how they affect the mixing process. In our talk we further examine the influence of the jet's velocity to characteristic quantities of the jet, such as penetration length and expansion angle, as well as to the first and second-order statistics of the flow.

Experimental verification of the thermodynamic properties for a jet-A fuel

Science.gov (United States)

Graciasalcedo, Carmen M.; Brabbs, Theodore A.; Mcbride, Bonnie J.

1988-01-01

Thermodynamic properties for a Jet-A fuel were determined by Shell Development Company in 1970 under a contract for NASA Lewis Research Center. The polynomial fit necessary to include Jet-A fuel (liquid and gaseous phases) in the library of thermodynamic properties of the NASA Lewis Chemical Equilibrium Program is calculated. To verify the thermodynamic data, the temperatures of mixtures of liquid Jet-A injected into a hot nitrogen stream were experimentally measured and compared to those calculated by the program. Iso-octane, a fuel for which the thermodynamic properties are well known, was used as a standard to calibrate the apparatus. The measured temperatures for the iso-octane/nitrogen mixtures reproduced the calculated temperatures except for a small loss due to the non-adiabatic behavior of the apparatus. The measurements for Jet-A were corrected for this heat loss and showed excellent agreement with the calculated temperatures. These experiments show that this process can be adequately described by the thermodynamic properties fitted for the Chemical Equilibrium Program.

DeepJet: a deep-learned multiclass jet-tagger for slim and fat jets

CERN Multimedia

CERN. Geneva; Qu, Huilin; Stoye, Markus; Kieseler, Jan; Verzetti, Mauro

2018-01-01

We present a customized neural network architecture for both, slim and fat jet tagging. It is based on the idea to keep the concept of physics objects, like particle flow particles, as a core element of the network architecture. The deep learning algorithm works for most of the common jet classes, i.e. b, c, usd and gluon jets for slim jets and W, Z, H, QCD and top classes for fat jets. The developed architecture promising gains in performance as shown in simulation of the CMS collaboration. Currently the tagger is under test in real data in the CMS experiment.

A diagnostic for time-resolved spatial profiles measurements on the ion temperature on JET

International Nuclear Information System (INIS)

Brocken, H.J.B.M.; Ven, H.W van der.

1980-05-01

A neutral particle scattering experiment for a continuous measurement of the ion temperature and ion density of the JET plasma in the hydrogen and deuterium phase is proposed. Space- and time-resolved measurements are possible by injection of a mono-energetic particle beam into the plasma and from the analysis of the velocity distribution of the scattered particles. The requirements on the injection system are specified and a suitable analyzer system is described

Experimental study of hydrogen jet ignition and jet extinguishment

International Nuclear Information System (INIS)

Wierman, R.W.

1979-04-01

Two phases are described of an experimental study that investigated: (1) the ignition characteristics of hydrogen--sodium jets, (2) the formation of hydrogen in sodium--humid air atmospheres, and (3) the extinguishment characteristics of burning hydrogen--sodium jets. Test conditions were similar to those postulated for highly-improbable breeder reactor core melt-through accidents and included: jet temperature, jet velocity, jet hydrogen concentration, jet sodium concentration, atmospheric oxygen concentration, and atmospheric water vapor concentration

Cryogenically assisted abrasive jet micromachining of polymers

International Nuclear Information System (INIS)

Getu, H; Papini, M; Spelt, J K

2008-01-01

The abrasive jet micromachining (AJM) of elastomers and polymers such as polydimethylsiloxane (PDMS), acrylonitrile butadiene styrene (ABS) and polytetrafluoroethylene (PTFE) for use in micro-fluidic devices was found to be very slow or impossible at room temperature. To enhance the material removal rate in such materials, a stream of liquid nitrogen (LN 2 ) was injected into the abrasive jet, cooling the target to cryogenic temperatures. Erosion rate measurements on the three polymeric materials (PDMS, ABS and PTFE) with and without the use of LN 2 were compared along with the profiles of micromachined channels and holes. It was found that the use of LN 2 cooling caused brittle erosion in PDMS, allowing it to be micromachined successfully. An erosion rate increase was also observed in PTFE and ABS at high and intermediate impact angles. The use of LN 2 also was found to reduce particle embedding

Quark and gluon jet properties in symmetric three-jet events

Science.gov (United States)

Buskulic, D.; Casper, D.; de Bonis, I.; Decamp, D.; Ghez, P.; Goy, C.; Lees, J.-P.; Lucotte, A.; Minard, M.-N.; Odier, P.; Pietrzyk, B.; Chmeissani, M.; Crespo, J. M.; Efthymiopoulos, I.; Fernandez, E.; Fernandez-Bosman, M.; Garrido, Ll.; Juste, A.; Martinez, M.; Orteu, S.; Pacheco, A.; Padilla, C.; Palla, F.; Pascual, A.; Perlas, J. A.; Riu, I.; Sanchez, F.; Teubert, F.; Colaleo, A.; Creanza, D.; de Palma, M.; Farilla, A.; Gelao, G.; Girone, M.; Iaselli, G.; Maggi, G.; Maggi, M.; Marinelli, N.; Natali, S.; Nuzzo, S.; Ranieri, A.; Raso, G.; Romano, F.; Ruggieri, F.; Selvaggi, G.; Silvestris, L.; Tempesta, P.; Zito, G.; Huang, X.; Lin, J.; Ouyang, Q.; Wang, T.; Xie, Y.; Xu, R.; Xue, S.; Zhang, J.; Zhang, L.; Zhao, W.; Alemany, R.; Bazarko, A. O.; Bonvicini, G.; Cattaneo, M.; Comas, P.; Coyle, P.; Drevermann, H.; Forty, R. W.; Frank, M.; Hagelberg, R.; Harvey, J.; Jacobsen, R.; Janot, P.; Jost, B.; Kneringer, E.; Knobloch, J.; Lehraus, I.; Martin, E. B.; Mato, P.; Minten, A.; Miquel, R.; Mir, Ll. M.; Moneta, L.; Oest, T.; Palazzi, P.; Pater, J. R.; Pusztaszeri, J.-F.; Ranjard, F.; Rensing, P.; Rolandi, L.; Schlatter, D.; Schmelling, M.; Schneider, O.; Tejessy, W.; Tomalin, I. R.; Venturi, A.; Wachsmuth, H.; Wildish, T.; Witzeling, W.; Wotschack, J.; Ajaltouni, Z.; Barrès, A.; Boyer, C.; Falvard, A.; Gay, P.; Guicheney, C.; Henrard, P.; Jousset, J.; Michel, B.; Monteil, S.; Montret, J.-C.; Pallin, D.; Perret, P.; Podlyski, F.; Proriol, J.; Rossignol, J.-M.; Fearnley, T.; Hansen, J. B.; Hansen, J. D.; Hansen, J. R.; Hansen, P. H.; Nilsson, B. S.; Wäänänen, A.; Kyriakis, A.; Markou, C.; Simopoulou, E.; Siotis, I.; Vayaki, A.; Zachariadou, K.; Blondel, A.; Bonneaud, G.; Brient, J. C.; Bourdon, P.; Rougé, A.; Rumpf, M.; Tanaka, R.; Valassi, A.; Verderi, M.; Videau, H.; Candlin, D. J.; Parsons, M. I.; Focardi, E.; Parrini, G.; Corden, M.; Delfino, M.; Georgiopoulos, C.; Jaffe, D. E.; Antonelli, A.; Bencivenni, G.; Bologna, G.; Bossi, F.; Campana, P.; Capon, G.; Chiarella, V.; Felici, G.; Laurelli, P.; Mannocchi, G.; Murtas, F.; Murtas, G. P.; Passalacqua, L.; Pepe-Altarelli, M.; Curtis, L.; Dorris, S. J.; Halley, A. W.; Knowles, I. G.; Lynch, J. G.; O'Shea, V.; Raine, C.; Reeves, P.; Scarr, J. M.; Smith, K.; Thompson, A. S.; Thomson, F.; Thorn, S.; Turnbull, R. M.; Becker, U.; Braun, O.; Geweniger, C.; Graefe, G.; Hanke, P.; Hepp, V.; Kluge, E. E.; Putzer, A.; Rensch, B.; Schmidt, M.; Sommer, J.; Stenzel, H.; Tittel, K.; Werner, S.; Wunsch, M.; Abbaneo, D.; Beuselinck, R.; Binnie, D. M.; Cameron, W.; Colling, D. J.; Dornan, P. J.; Moutoussi, A.; Nash, J.; San Martin, G.; Sedgbeer, J. K.; Stacey, A. M.; Dissertori, G.; Girtler, P.; Kuhn, D.; Rudolph, G.; Bowdery, C. K.; Brodbeck, T. J.; Colrain, P.; Crawford, G.; Finch, A. J.; Foster, F.; Hughes, G.; Sloan, T.; Whelan, E. P.; Williams, M. I.; Galla, A.; Greene, A. M.; Kleinknecht, K.; Quast, G.; Renk, B.; Rohne, E.; Sander, H.-G.; van Gemmeren, P.; Zeitnitz, C.; Aubert, J. J.; Bencheikh, A. M.; Benchouk, C.; Bonissent, A.; Bujosa, G.; Calvet, D.; Carr, J.; Diaconu, C.; Etienne, F.; Konstantinidis, N.; Nicod, D.; Payre, P.; Rousseau, D.; Talby, M.; Sadouki, A.; Thulasidas, M.; Trabelsi, K.; Abt, I.; Assmann, R.; Bauer, C.; Blum, W.; Brown, D.; Dietl, H.; Dydak, F.; Ganis, G.; Gotzhein, C.; Jakobs, K.; Kroha, H.; Lütjens, G.; Lutz, G.; Männer, W.; Moser, H.-G.; Richter, R.; Rosado-Schlosser, A.; Schael, S.; Settles, R.; Seywerd, H.; Denis, R. St.; Wiedenmann, W.; Wolf, G.; Boucrot, J.; Callot, O.; Cordier, A.; Davier, M.; Duflot, L.; Grivaz, J.-F.; Heusse, Ph.; Jacquet, M.; Kim, D. W.; Le Diberder, F.; Lefrançois, J.; Lutz, A.-M.; Nikolic, I.; Park, H. J.; Park, I. C.; Schune, M.-H.; Simion, S.; Veillet, J.-J.; Videau, I.; Azzurri, P.; Bagliesi, G.; Batignani, G.; Bettarini, S.; Bozzi, C.; Calderini, G.; Carpinelli, M.; Ciocci, M. A.; Ciulli, V.; Dell'Orso, R.; Fantechi, R.; Ferrante, I.; Foà, L.; Forti, F.; Giassi, A.; Giorgi, M. A.; Gregorio, A.; Ligabue, F.; Lusiani, A.; Marrocchesi, P. S.; Messineo, A.; Rizzo, G.; Sanguinetti, G.; Sciabà, A.; Spagnolo, P.; Steinberger, J.; Tenchini, R.; Tonelli, G.; Vannini, C.; Verdini, P. G.; Walsh, J.; Betteridge, A. P.; Blair, G. A.; Bryant, L. M.; Cerutti, F.; Chambers, J. T.; Gao, Y.; Green, M. G.; Johnson, D. L.; Medcalf, T.; Perrodo, P.; Strong, J. A.; von Wimmersperg-Toeller, J. H.; Botterill, D. R.; Clifft, R. W.; Edgecock, T. R.; Haywood, S.; Edwards, M.; Maley, P.; Norton, P. R.; Thompson, J. C.; Bloch-Devaux, B.; Colas, P.; Emery, S.; Kozanecki, W.; Lançon, E.; Lemaire, M. C.; Locci, E.; Marx, B.; Perez, P.; Rander, J.; Renardy, J.-F.; Roussarie, A.; Schuller, J.-P.; Schwindling, J.; Trabelsi, A.; Vallage, B.; Johnson, R. P.; Kim, H. Y.; Litke, A. M.; McNeil, M. A.; Taylor, G.; Beddall, A.; Booth, C. N.; Boswell, R.; Brew, C. A. J.; Cartwright, S.; Combley, F.; Koksal, A.; Letho, M.; Newton, W. M.; Rankin, C.; Reeve, J.; Thompson, L. F.; Böhrer, A.; Brandt, S.; Cowan, G.; Feigl, E.; Grupen, C.; Lutters, G.; Minguet-Rodriguez, J.; Rivera, F.; Saraiva, P.; Smolik, L.; Stephan, F.; Apollonio, M.; Bosisio, L.; Della Marina, R.; Giannini, G.; Gobbo, B.; Musolino, G.; Ragusa, F.; Rothberg, J.; Wasserbaech, S.; Armstrong, S. R.; Bellantoni, L.; Elmer, P.; Feng, Z.; Ferguson, D. P. S.; Gao, Y. S.; González, S.; Grahl, J.; Greening, T. C.; Harton, J. L.; Hayes, O. J.; Hu, H.; McNamara, P. A.; Nachtman, J. M.; Orejudos, W.; Pan, Y. B.; Saadi, Y.; Schmitt, M.; Scott, I. J.; Sharma, V.; Turk, J. D.; Walsh, A. M.; Wu, Sau Lan; Wu, X.; Yamartino, J. M.; Zheng, M.; Zobernig, G.; Aleph Collaboration

1996-02-01

Quark and gluon jets with the same energy, 24 GeV, are compared in symmetric three-jet configurations from hadronic Z decays observed by the ALEPH detector. Jets are defined using the Durham algorithm. Gluon jets are identified using an anti-tag on b jets, based on a track impact parameter method. The comparison of gluon and mixed flavour quark jets shows that gluon jets have a softer fragmentation function, a larger angular width and a higher particle multiplicity, Evidence is presented which shows that the corresponding differences between gluon and b jets are significantly smaller. In a statistically limited comparison the multiplicity in c jets was found to be comparable with that observed for the jets of mixed quark flavour.

Runaway electron beam generation and mitigation during disruptions at JET-ILW

Czech Academy of Sciences Publication Activity Database

Reux, C.; Plyusnin, V.; Alper, B.; Alves, D.; Bazylev, B.; Belonohy, E.; Boboc, A.; Brezinsek, S.; Coffey, I.; Decker, J.; Drewelow, P.; Devaux, S.; de Vries, P.C.; Fil, A.; Gerasimov, S.; Giacomelli, L.; Jachmich, S.; Khilkevitch, E.M.; Kiptily, V.; Koslowski, R.; Kruezi, U.; Lehnen, M.; Lupelli, I.; Lomas, P. J.; Manzanares, A.; Martin De Aguilera, A.; Matthews, G.F.; Mlynář, Jan; Nardon, E.; Nilsson, E.; Perez von Thun, C.; Riccardo, V.; Saint-Laurent, F.; Shevelev, A.E.; Sips, G.; Sozzi, C.

2015-01-01

Roč. 55, č. 9 (2015), 093013-093013 ISSN 0029-5515 Institutional support: RVO:61389021 Keywords : runaway electrons * disruptions * tokamak * JET * massive gas injection * disruption mitigation * runaway background plasma Subject RIV: BL - Plasma and Gas Discharge Physics Impact factor: 4.040, year: 2015 http://iopscience.iop.org/article/10.1088/0029-5515/55/9/093013

Jet substructure using semi-inclusive jet functions in SCET

International Nuclear Information System (INIS)

Kang, Zhong-Bo; Ringer, Felix; Vitev, Ivan

2016-01-01

We propose a new method to evaluate jet substructure observables in inclusive jet measurements, based upon semi-inclusive jet functions in the framework of Soft Collinear Effective Theory (SCET). As a first example, we consider the jet fragmentation function, where a hadron h is identified inside a fully reconstructed jet. We introduce a new semi-inclusive fragmenting jet function G_i"h(z=ω_J/ω,z_h=ω_h/ω_J,ω_J,R,μ), which depends on the jet radius R and the large light-cone momenta of the parton ‘i’ initiating the jet (ω), the jet (ω_J), and the hadron h (ω_h). The jet fragmentation function can then be expressed as a semi-inclusive observable, in the spirit of actual experimental measurements, rather than as an exclusive one. We demonstrate the consistency of the effective field theory treatment and standard perturbative QCD calculations of this observable at next-to-leading order (NLO). The renormalization group (RG) equation for the semi-inclusive fragmenting jet function G_i"h(z,z_h,ω_J,R,μ) are also derived and shown to follow exactly the usual timelike DGLAP evolution equations for fragmentation functions. The newly obtained RG equations can be used to perform the resummation of single logarithms of the jet radius parameter R up to next-to-leading logarithmic (NLL_R) accuracy. In combination with the fixed NLO calculation, we obtain NLO+NLL_R results for the hadron distribution inside the jet. We present numerical results for pp→(jet h)X in the new framework, and find excellent agreement with existing LHC experimental data.

Exploring Jets from a Supermassive Black Hole

Science.gov (United States)

Kohler, Susanna

2018-06-01

What are the feeding and burping habits of the supermassive black holes peppering the universe? In a new study, observations of one such monster reveal more about the behavior of its powerful jets.Beams from BehemothsAcross the universe, supermassive black holes of millions to billions of solar masses lie at the centers of galaxies, gobbling up surrounding material. But not all of the gas and dust that spirals in toward a black hole is ultimately swallowed! A large fraction of it can instead be flung out into space again, in the form of enormous, powerful jets that extend for thousands or even millions of light-years in opposite directions.M87, shown in this Hubble image, is a classic example of a nearby (55 million light-years distant) supermassive black hole with a visible, collimated jet. Its counter-jet isnt seen because relativistic effects make the receding jet appear less bright. [The Hubble Heritage Team (STScI/AURA) and NASA/ESA]What causes these outflows to be tightly beamed collimated in the form of jets, rather than sprayed out in all directions? Does the pressure of the ambient medium the surrounding gas and dust that the jet is injected into play an important role? In what regions do these jets accelerate and decelerate? There are many open questions that scientists hope to understand by studying some of the active black holes with jets that live closest to us.Eyes on a Nearby GiantIn a new study led by Satomi Nakahara (The Graduate University for Advanced Studies in Japan), a team of scientists has used multifrequency Very Long Baseline Array (VLBA) and Very Long Array (VLA) images to explore jets emitted from a galaxy just 100 million light-years away: NGC 4261.This galaxys (relatively) close distance as well as the fact that were viewing it largely from the side, so we can clearly see both of its polar jets allows us to observe in detail the structure and intensity of its jets as a function of their distance from the black hole. Nakahara and

Cooling water injection system

International Nuclear Information System (INIS)

Inai, Nobuhiko.

1989-01-01

In a BWR type reactor, ECCS system is constituted as a so-called stand-by system which is not used during usual operation and there is a significant discontinuity in relation with the usual system. It is extremely important that ECCS operates upon occurrence of accidents just as specified. In view of the above in the present invention, the stand-by system is disposed along the same line with the usual system. That is, a driving water supply pump for supplying driving water to a jet pump is driven by a driving mechanism. The driving mechanism drives continuously the driving water supply pump in a case if an expected accident such as loss of the function of the water supply pump, as well as during normal operation. That is, all of the water supply pump, jet pump, driving water supply pump and driving mechanism therefor are caused to operate also during normal operation. The operation of them are not initiated upon accident. Thus, the cooling water injection system can perform at high reliability to remarkably improve the plant safety. (K.M.)

CORRELATIONS OF DISK AND JET EMISSION DEVIATING FROM THE FUNDAMENTAL PLANE

Energy Technology Data Exchange (ETDEWEB)

Lin, Da-Bin; Mu, Hui-Jun; Lu, Zu-Jia; Liang, En-Wei [GXU-NAOC Center for Astrophysics and Space Sciences, Department of Physics, Guangxi University, Nanning 530004 (China); Gu, Wei-Min; Ma, Ren-Yi, E-mail: lindabin@gxu.edu.cn [Department of Astronomy and Institute of Theoretical Physics and Astrophysics, Xiamen University, Xiamen, Fujian 361005 (China)

2015-07-01

The variability of the accretion rate, which is believed to induce the aperiodic variability of X-ray emission from disks, may affect the energy injection into a jet. In this spirit, a correlation between disk emission and jet emission can be formed even if the mean luminosity of disk emission remains constant. In this work, these correlations are found in the situation in which the luminosity of disk emission is variable and kept at a constant mean value. The obtained correlations may be shallower than that of the fundamental plane of black hole activity. In addition, the slope of correlation may increase with increasing observed frequency of jet emission. For the luminosities spaced over three days, the slope of correlation decreases with increasing black hole mass. The deviation of our found correlations from that of the fundamental plane is related to the suppression of variability in the jet emission in comparison with that in the disk emission. This mechanism may work in some sources in which shallower correlations have been reported. Moreover, it implies that luminosities used to estimate the relation of the fundamental plane should cover an appropriate timescale, in which the variability of jet emission is not significantly suppressed.

Jets from jets: re-clustering as a tool for large radius jet reconstruction and grooming at the LHC

Energy Technology Data Exchange (ETDEWEB)

Nachman, Benjamin; Nef, Pascal; Schwartzman, Ariel; Swiatlowski, Maximilian [SLAC National Accelerator Laboratory, Stanford University,2575 Sand Hill Rd, Menlo Park, CA 94025 (United States); Wanotayaroj, Chaowaroj [Center for High Energy Physics, University of Oregon,1371 E. 13th Ave, Eugene, OR 97403 (United States)

2015-02-12

Jets with a large radius R≳1 and grooming algorithms are widely used to fully capture the decay products of boosted heavy particles at the Large Hadron Collider (LHC). Unlike most discriminating variables used in such studies, the jet radius is usually not optimized for specific physics scenarios. This is because every jet configuration must be calibrated, insitu, to account for detector response and other experimental effects. One solution to enhance the availability of large-R jet configurations used by the LHC experiments is jet re-clustering. Jet re-clustering introduces an intermediate scale rjets are calibrated and used as the inputs to reconstruct large radius jets. In this paper we systematically study and propose new jet re-clustering configurations and show that re-clustered large radius jets have essentially the same jet mass performance as large radius groomed jets. Jet re-clustering has the benefit that no additional large-R calibration is necessary, allowing the re-clustered large radius parameter to be optimized in the context of specific precision measurements or searches for new physics.

Jets from jets: re-clustering as a tool for large radius jet reconstruction and grooming at the LHC

International Nuclear Information System (INIS)

Nachman, Benjamin; Nef, Pascal; Schwartzman, Ariel; Swiatlowski, Maximilian; Wanotayaroj, Chaowaroj

2015-01-01

Jets with a large radius R≳1 and grooming algorithms are widely used to fully capture the decay products of boosted heavy particles at the Large Hadron Collider (LHC). Unlike most discriminating variables used in such studies, the jet radius is usually not optimized for specific physics scenarios. This is because every jet configuration must be calibrated, insitu, to account for detector response and other experimental effects. One solution to enhance the availability of large-R jet configurations used by the LHC experiments is jet re-clustering. Jet re-clustering introduces an intermediate scale rjets are calibrated and used as the inputs to reconstruct large radius jets. In this paper we systematically study and propose new jet re-clustering configurations and show that re-clustered large radius jets have essentially the same jet mass performance as large radius groomed jets. Jet re-clustering has the benefit that no additional large-R calibration is necessary, allowing the re-clustered large radius parameter to be optimized in the context of specific precision measurements or searches for new physics.

Laser driven pellet refuelling for JET (and reactor) uses

International Nuclear Information System (INIS)

Spalding, I.J.

1978-11-01

Published estimates of pellet sizes and velocities required to refuel JET and post-JET experiments are summarized. Possible advantages and difficulties of accelerating solid, unconstrained hydrogenic (and also jacketed) pellets to these velocities using laser techniques are then discussed. An essential problem to be solved is adequate axial guidance of the pellet during its acceleration, since laser pulse durations of many sound-transit times (in the solid D 2 ) are necessary to avoid shock-heating the pellet. It is shown that Culham's multikilojoule CO 2 TROJAN laser facility is well suited to testing many of the concepts proposed. In particular it is shown that successful verification, and subsequent optimization, of such (novel) techniques would permit single shot tests of contemporary pellet ablation theories by the injection of approximately 1 mm diameter D 2 pellets at velocities 6 cm s -1 into the JET plasma. Means for scaling these techniques to repetition rates of order 10 Hz, and to the 1 cm pellet diameters possibly required in a working Tokamak reactor, are also discussed. (author)

Horizontal H 2-air turbulent buoyant jet resulting from hydrogen leakage

KAUST Repository

El-Amin, Mohamed

2012-02-01

The current article is devoted to introducing mathematical and physical analyses with numerical investigation of a buoyant jet resulting from hydrogen leakage in air from a horizontal round source. H 2-air jet is an example of the non-Boussinesq buoyant jet in which a low-density gas jet is injected/leak into a high-density ambient. The density of the mixture is a function of the concentration only, the binary gas mixture is assumed to be of a linear mixing type and the rate of entrainment is assumed to be a function of the plume centerline velocity and the ratio of the mean plume and ambient densities. On the other hand, the local rate of entrainment consists of two components; one is the component of entrainment due to jet momentum while the other is the component of entrainment due to buoyancy. The top-hat profile assumption is used to obtain the mean centerline velocity, width, density and concentration of the H 2-air horizontal jet in addition to kinematic relations which govern the jet trajectories. A set of ordinary differential equations is obtained and solved numerically using Runge-Kutta method. In the second step, the mean axial velocity, mean concentration and mean density of the jet are obtained based on Gaussian model. Finally, several quantities of interest, including the cross-stream velocity, Reynolds stress, velocity-concentration correlation (radial flux), turbulent eddy viscosity and turbulent eddy diffusivity, are obtained by solving the governing partial differential equations. Additionally, the turbulent Schmidt number is estimated and the normalized jet-feed material density and the normalized momentum flux density are correlated. © 2011, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.

Jet substructure using semi-inclusive jet functions in SCET

Energy Technology Data Exchange (ETDEWEB)

Kang, Zhong-Bo [Theoretical Division, Los Alamos National Laboratory,Los Alamos, NM 87545 (United States); Department of Physics and Astronomy, University of California,Los Angeles, CA 90095 (United States); Ringer, Felix; Vitev, Ivan [Theoretical Division, Los Alamos National Laboratory,Los Alamos, NM 87545 (United States)

2016-11-25

We propose a new method to evaluate jet substructure observables in inclusive jet measurements, based upon semi-inclusive jet functions in the framework of Soft Collinear Effective Theory (SCET). As a first example, we consider the jet fragmentation function, where a hadron h is identified inside a fully reconstructed jet. We introduce a new semi-inclusive fragmenting jet function G{sub i}{sup h}(z=ω{sub J}/ω,z{sub h}=ω{sub h}/ω{sub J},ω{sub J},R,μ), which depends on the jet radius R and the large light-cone momenta of the parton ‘i’ initiating the jet (ω), the jet (ω{sub J}), and the hadron h (ω{sub h}). The jet fragmentation function can then be expressed as a semi-inclusive observable, in the spirit of actual experimental measurements, rather than as an exclusive one. We demonstrate the consistency of the effective field theory treatment and standard perturbative QCD calculations of this observable at next-to-leading order (NLO). The renormalization group (RG) equation for the semi-inclusive fragmenting jet function G{sub i}{sup h}(z,z{sub h},ω{sub J},R,μ) are also derived and shown to follow exactly the usual timelike DGLAP evolution equations for fragmentation functions. The newly obtained RG equations can be used to perform the resummation of single logarithms of the jet radius parameter R up to next-to-leading logarithmic (NLL{sub R}) accuracy. In combination with the fixed NLO calculation, we obtain NLO+NLL{sub R} results for the hadron distribution inside the jet. We present numerical results for pp→(jet h)X in the new framework, and find excellent agreement with existing LHC experimental data.

First Production of C60 Nanoparticle Plasma Jet for Study of Disruption Mitigation for ITER

Science.gov (United States)

Bogatu, I. N.; Thompson, J. R.; Galkin, S. A.; Kim, J. S.; Brockington, S.; Case, A.; Messer, S. J.; Witherspoon, F. D.

2012-10-01

Unique fast response and large mass-velocity delivery of nanoparticle plasma jets (NPPJs) provide a novel application for ITER disruption mitigation, runaway electrons diagnostics and deep fueling. NPPJs carry a much larger mass than usual gases. An electromagnetic plasma gun provides a very high injection velocity (many km/s). NPPJ has much higher ram pressure than any standard gas injection method and penetrates the tokamak confining magnetic field. Assimilation is enhanced due to the NP large surface-to-volume ratio. Radially expanding NPPJs help achieving toroidal uniformity of radiation power. FAR-TECH's NPPJ system was successfully tested: a coaxial plasma gun prototype (˜35 cm length, 96 kJ energy) using a solid state TiH2/C60 pulsed power cartridge injector produced a hyper-velocity (>4 km/s), high-density (>10^23 m-3), C60 plasma jet in ˜0.5 ms, with ˜1-2 ms overall response-delivery time. We present the TiH2/C60 cartridge injector output characterization (˜180 mg of sublimated C60 gas) and first production results of a high momentum C60 plasma jet (˜0.6 g.km/s).

Liquid mixing enhanced by pulse width modulation in a Y-shaped jet configuration

Science.gov (United States)

Xia, Qingfeng; Zhong, Shan

2013-04-01

In this paper, mixing between two fluid streams, which are injected into a planar mixing channel via a Y-shaped confluence section at the same volume flow rate, is studied experimentally. The injection of the two fluid streams is controlled by two separate solenoid valves, which are operated with a phase difference of 180°, using pulse width modulation. The experiments are conducted using water at a mean Reynolds number between 83 and 250, a range of pulsation frequencies and two duty cycles (25 and 50%). Both particle-image velocimetry and planar laser-induced fluorescence technique are used to visualize the flow patterns and to quantify the mixing degree in the mixing channel. This experiment shows that the pulsation of each jet produces vortical structures, which promotes mixing via vortex entrainment and vortex breakup, and at the same time the mixing is also greatly enhanced by sequential segmentation produced by a 180° out-of-phase pulsation of the two jets. This mixing enhancement method is effective at a Reynolds number greater than 125 with a mixing degree of 0.9 being achieved. For the Reynolds numbers studied in the present experiments, an optimal frequency exists, which corresponds to a Strouhal number in the range of 0.5-2. Furthermore, at a given mean Reynolds number a lower duty cycle is found to produce a better mixing due to the resultant higher instantaneous Reynolds number in the jet flow. It is also found that pulsation of only one jet can produce a similar mixing effect.

Liquid mixing enhanced by pulse width modulation in a Y-shaped jet configuration

Energy Technology Data Exchange (ETDEWEB)

Xia Qingfeng; Zhong Shan, E-mail: shan.zhong@manchester.ac.uk [School of Mechanical, Aerospace and Civil Engineering, University of Manchester, Manchester M13 9PL (United Kingdom)

2013-04-15

In this paper, mixing between two fluid streams, which are injected into a planar mixing channel via a Y-shaped confluence section at the same volume flow rate, is studied experimentally. The injection of the two fluid streams is controlled by two separate solenoid valves, which are operated with a phase difference of 180 Degree-Sign , using pulse width modulation. The experiments are conducted using water at a mean Reynolds number between 83 and 250, a range of pulsation frequencies and two duty cycles (25 and 50%). Both particle-image velocimetry and planar laser-induced fluorescence technique are used to visualize the flow patterns and to quantify the mixing degree in the mixing channel. This experiment shows that the pulsation of each jet produces vortical structures, which promotes mixing via vortex entrainment and vortex breakup, and at the same time the mixing is also greatly enhanced by sequential segmentation produced by a 180 Degree-Sign out-of-phase pulsation of the two jets. This mixing enhancement method is effective at a Reynolds number greater than 125 with a mixing degree of 0.9 being achieved. For the Reynolds numbers studied in the present experiments, an optimal frequency exists, which corresponds to a Strouhal number in the range of 0.5-2. Furthermore, at a given mean Reynolds number a lower duty cycle is found to produce a better mixing due to the resultant higher instantaneous Reynolds number in the jet flow. It is also found that pulsation of only one jet can produce a similar mixing effect. (paper)

Boosted Jet Tagging with Jet-Images and Deep Neural Networks

International Nuclear Information System (INIS)

Kagan, Michael; Oliveira, Luke de; Mackey, Lester; Nachman, Benjamin; Schwartzman, Ariel

2016-01-01

Building on the jet-image based representation of high energy jets, we develop computer vision based techniques for jet tagging through the use of deep neural networks. Jet-images enabled the connection between jet substructure and tagging with the fields of computer vision and image processing. We show how applying such techniques using deep neural networks can improve the performance to identify highly boosted W bosons with respect to state-of-the-art substructure methods. In addition, we explore new ways to extract and visualize the discriminating features of different classes of jets, adding a new capability to understand the physics within jets and to design more powerful jet tagging methods

Quark and gluon jet properties in symmetric three-jet events

CERN Document Server

Buskulic, Damir; De Bonis, I; Décamp, D; Ghez, P; Goy, C; Lees, J P; Lucotte, A; Minard, M N; Odier, P; Pietrzyk, B; Chmeissani, M; Crespo, J M; Efthymiopoulos, I; Fernández, E; Fernández-Bosman, M; Garrido, L; Juste, A; Martínez, M; Orteu, S; Pacheco, A; Padilla, C; Palla, Fabrizio; Pascual, A; Perlas, J A; Riu, I; Sánchez, F; Teubert, F; Colaleo, A; Creanza, D; De Palma, M; Farilla, A; Gelao, G; Girone, M; Iaselli, Giuseppe; Maggi, G; Maggi, M; Marinelli, N; Natali, S; Nuzzo, S; Ranieri, A; Raso, G; Romano, F; Ruggieri, F; Selvaggi, G; Silvestris, L; Tempesta, P; Zito, G; Huang, X; Lin, J; Ouyang, Q; Wang, T; Xie, Y; Xu, R; Xue, S; Zhang, J; Zhang, L; Zhao, W; Alemany, R; Bazarko, A O; Bonvicini, G; Cattaneo, M; Comas, P; Coyle, P; Drevermann, H; Forty, Roger W; Frank, M; Hagelberg, R; Harvey, J; Jacobsen, R; Janot, P; Jost, B; Kneringer, E; Knobloch, J; Lehraus, Ivan; Martin, E B; Mato, P; Minten, Adolf G; Miquel, R; Mir, L M; Moneta, L; Oest, T; Palazzi, P; Pater, J R; Pusztaszeri, J F; Ranjard, F; Rensing, P E; Rolandi, Luigi; Schlatter, W D; Schmelling, M; Schneider, O; Tejessy, W; Tomalin, I R; Venturi, A; Wachsmuth, H W; Wildish, T; Witzeling, W; Wotschack, J; Ajaltouni, Ziad J; Barrès, A; Boyer, C; Falvard, A; Gay, P; Guicheney, C; Henrard, P; Jousset, J; Michel, B; Monteil, S; Montret, J C; Pallin, D; Perret, P; Podlyski, F; Proriol, J; Rossignol, J M; Fearnley, Tom; Hansen, J B; Hansen, J D; Hansen, J R; Hansen, P H; Nilsson, B S; Wäänänen, A; Kyriakis, A; Markou, C; Simopoulou, Errietta; Siotis, I; Vayaki, Anna; Zachariadou, K; Blondel, A; Bonneaud, G R; Brient, J C; Bourdon, P; Rougé, A; Rumpf, M; Tanaka, R; Valassi, Andrea; Verderi, M; Videau, H L; Candlin, D J; Parsons, M I; Focardi, E; Parrini, G; Corden, M; Delfino, M C; Georgiopoulos, C H; Jaffe, D E; Antonelli, A; Bencivenni, G; Bologna, G; Bossi, F; Campana, P; Capon, G; Chiarella, V; Felici, G; Laurelli, P; Mannocchi, G; Murtas, F; Murtas, G P; Passalacqua, L; Pepé-Altarelli, M; Curtis, L; Dorris, S J; Halley, A W; Knowles, I G; Lynch, J G; O'Shea, V; Raine, C; Reeves, P; Scarr, J M; Smith, K; Thompson, A S; Thomson, F; Thorn, S; Turnbull, R M; Becker, U; Braun, O; Geweniger, C; Graefe, G; Hanke, P; Hepp, V; Kluge, E E; Putzer, A; Rensch, B; Schmidt, M; Sommer, J; Stenzel, H; Tittel, K; Werner, S; Wunsch, M; Abbaneo, D; Beuselinck, R; Binnie, David M; Cameron, W; Colling, D J; Dornan, Peter J; Moutoussi, A; Nash, J; San Martin, G; Sedgbeer, J K; Stacey, A M; Dissertori, G; Girtler, P; Kuhn, D; Rudolph, G; Bowdery, C K; Brodbeck, T J; Colrain, P; Crawford, G; Finch, A J; Foster, F; Hughes, G; Sloan, Terence; Whelan, E P; Williams, M I; Galla, A; Greene, A M; Kleinknecht, K; Quast, G; Renk, B; Rohne, E; Sander, H G; Van Gemmeren, P; Zeitnitz, C; Aubert, Jean-Jacques; Bencheikh, A M; Benchouk, C; Bonissent, A; Bujosa, G; Calvet, D; Carr, J; Diaconu, C A; Etienne, F; Konstantinidis, N P; Nicod, D; Payre, P; Rousseau, D; Talby, M; Sadouki, A; Thulasidas, M; Trabelsi, K; Abt, I; Assmann, R W; Bauer, C; Blum, Walter; Brown, D; Dietl, H; Dydak, Friedrich; Ganis, G; Gotzhein, C; Jakobs, K; Kroha, H; Lütjens, G; Lutz, Gerhard; Männer, W; Moser, H G; Richter, R H; Rosado-Schlosser, A; Schael, S; Settles, Ronald; Seywerd, H C J; Saint-Denis, R; Wiedenmann, W; Wolf, G; Boucrot, J; Callot, O; Cordier, A; Davier, M; Duflot, L; Grivaz, J F; Heusse, P; Jacquet, M; Kim, D W; Le Diberder, F R; Lefrançois, J; Lutz, A M; Nikolic, I A; Park, H J; Park, I C; Schune, M H; Simion, S; Veillet, J J; Videau, I; Azzurri, P; Bagliesi, G; Batignani, G; Bettarini, S; Bozzi, C; Calderini, G; Carpinelli, M; Ciocci, M A; Ciulli, V; Dell'Orso, R; Fantechi, R; Ferrante, I; Foà, L; Forti, F; Giassi, A; Giorgi, M A; Gregorio, A; Ligabue, F; Lusiani, A; Marrocchesi, P S; Messineo, A; Rizzo, G; Sanguinetti, G; Sciabà, A; Spagnolo, P; Steinberger, Jack; Tenchini, Roberto; Tonelli, G; Vannini, C; Verdini, P G; Walsh, J; Betteridge, A P; Blair, G A; Bryant, L M; Cerutti, F; Chambers, J T; Gao, Y; Green, M G; Johnson, D L; Medcalf, T; Perrodo, P; Strong, J A; Von Wimmersperg-Töller, J H; Botterill, David R; Clifft, R W; Edgecock, T R; Haywood, S; Edwards, M; Maley, P; Norton, P R; Thompson, J C; Bloch-Devaux, B; Colas, P; Emery, S; Kozanecki, Witold; Lançon, E; Lemaire, M C; Locci, E; Marx, B; Pérez, P; Rander, J; Renardy, J F; Roussarie, A; Schuller, J P; Schwindling, J; Trabelsi, A; Vallage, B; Johnson, R P; Kim, H Y; Litke, A M; McNeil, M A; Taylor, G; Beddall, A; Booth, C N; Boswell, R; Brew, C A J; Cartwright, S L; Combley, F; Köksal, A; Letho, M; Newton, W M; Rankin, C; Reeve, J; Thompson, L F; Böhrer, A; Brandt, S; Cowan, G D; Feigl, E; Grupen, Claus; Lutters, G; Minguet-Rodríguez, J A; Rivera, F; Saraiva, P; Smolik, L; Stephan, F; Apollonio, M; Bosisio, L; Della Marina, R; Giannini, G; Gobbo, B; Musolino, G; Ragusa, F; Rothberg, J E; Wasserbaech, S R; Armstrong, S R; Bellantoni, L; Elmer, P; Feng, Z; Ferguson, D P S; Gao, Y S; González, S; Grahl, J; Greening, T C; Harton, J L; Hayes, O J; Hu, H; McNamara, P A; Nachtman, J M; Orejudos, W; Pan, Y B; Saadi, Y; Schmitt, M; Scott, I J; Sharma, V; Turk, J; Walsh, A M; Wu Sau Lan; Wu, X; Yamartino, J M; Zheng, M; Zobernig, G

1996-01-01

Quark and gluon jets with the same energy, 24GeV, are compared in symmetric three-jet configurations from hadronic Z decays observed by the ALEPH detector. Jets are defined using the Durham algorithm. Gluon jets are identified using an anti-tag on b jets, based on either a track impact parameter method or a high transverse momentum lepton tag. The comparison of gluon and mixed flavour quark jets shows that gluon jets have a softer fragmentation function, a larger angular width and a higher particle multiplicity. Evidence is also presented which shows that the corresponding differences between gluon and heavy flavour jets are significantly smaller.

Research on Pulsed Jet Flow Control without External Energy in a Blade Cascade

Directory of Open Access Journals (Sweden)

Jie Chen

2017-12-01

Full Text Available To control the flow separation in the compressors, a novel pulsed jet concept without external energy injection is proposed. The new concept designs a slot in the middle of the blade and sets a micro device to switch the slot periodically. Such a structure is expected to generate a pulsed jet by the pressure difference between the pressure side and the suction side of the blade. In order to analyze the interaction between the pulsed jet and unsteady separated flow, our numerical and experimental study is based on a specific cascade (with a flow separation inside and a pulsed jet (one of the unsteady flow control method. The experimental and numerical results both show that when the frequency of pulsed jet is approximate to that of the separation vortex, then the control tends to be more effective. Based on the numerical simulations, the proper orthogonal decomposition (POD is then used to reveal the control mechanism, extracting the different time-space structures from the original field. The results with the aid of POD show that the pulsed jet can redistribute the kinetic energy of each mode, and strengthen or weaken certain modes, particularly, while the steady jet reduces the kinetic energy of high-order modes in whole. Also, pulsed jet with proper parameters can transfer the energy from higher modes to the first flow mode (averaged flow, which is due to the conversion of the spatial vortical structures and the time evolution of the modes.

The structure of a jet in cross flow at low velocity ratios

International Nuclear Information System (INIS)

Gopalan, Shridhar; Abraham, Bruce M.; Katz, Joseph

2004-01-01

This paper examines in detail the flow structure and associated wall pressure fluctuations caused by the injection of a round, turbulent jet into a turbulent boundary layer. The velocity ratio, r, ratio of mean jet velocity to the mean cross flow, varies from 0.5 to 2.5 and the Reynolds number based on the cross flow speed and jet diameter is 1.9x10 4 . Particle image velocimetry is used to measure the flow and flush mounted pressure sensors installed at several locations used to determine the wall pressure. The results consist of sample instantaneous flow structures, distributions of mean velocity, vorticity and turbulence intensity, as well as wall pressure spectra. The flow structure depends strongly on the velocity ratio and there are two distinctly different regions. At low velocity ratios, namely r 2, the near-wall flow behind the jet resembles a Karman vortex street and the wall-normal vortical structures contain cross flow boundary layer vorticity. Autospectra of the pressure signals show that the effect of the jet is mainly in the 15-100 Hz range. At r 2, the wall pressure levels reach a plateau demonstrating the diminishing effect of the jet on the near-wall flow. Consistent with the flow structure, the highest wall pressure fluctuations occur off the jet centerline for r 2. Also, the advection speed of near-wall vortical structures increase with r at r 2 it is a constant

Ducted combustion chamber for direct injection engines and method

Science.gov (United States)

Mueller, Charles

2015-03-03

An internal combustion engine includes an engine block having a cylinder bore and a cylinder head having a flame deck surface disposed at one end of the cylinder bore. A piston connected to a rotatable crankshaft and configured to reciprocate within the cylinder bore has a piston crown portion facing the flame deck surface such that a combustion chamber is defined within the cylinder bore and between the piston crown and the flame deck surface. A fuel injector having a nozzle tip disposed in fluid communication with the combustion chamber has at least one nozzle opening configured to inject a fuel jet into the combustion chamber along a fuel jet centerline. At least one duct defined in the combustion chamber between the piston crown and the flame deck surface has a generally rectangular cross section and extends in a radial direction relative to the cylinder bore substantially along the fuel jet centerline.

Jet-images: computer vision inspired techniques for jet tagging

Energy Technology Data Exchange (ETDEWEB)

Cogan, Josh; Kagan, Michael; Strauss, Emanuel; Schwarztman, Ariel [SLAC National Accelerator Laboratory,Menlo Park, CA 94028 (United States)

2015-02-18

We introduce a novel approach to jet tagging and classification through the use of techniques inspired by computer vision. Drawing parallels to the problem of facial recognition in images, we define a jet-image using calorimeter towers as the elements of the image and establish jet-image preprocessing methods. For the jet-image processing step, we develop a discriminant for classifying the jet-images derived using Fisher discriminant analysis. The effectiveness of the technique is shown within the context of identifying boosted hadronic W boson decays with respect to a background of quark- and gluon-initiated jets. Using Monte Carlo simulation, we demonstrate that the performance of this technique introduces additional discriminating power over other substructure approaches, and gives significant insight into the internal structure of jets.

Jet-images: computer vision inspired techniques for jet tagging

International Nuclear Information System (INIS)

Cogan, Josh; Kagan, Michael; Strauss, Emanuel; Schwarztman, Ariel

2015-01-01

We introduce a novel approach to jet tagging and classification through the use of techniques inspired by computer vision. Drawing parallels to the problem of facial recognition in images, we define a jet-image using calorimeter towers as the elements of the image and establish jet-image preprocessing methods. For the jet-image processing step, we develop a discriminant for classifying the jet-images derived using Fisher discriminant analysis. The effectiveness of the technique is shown within the context of identifying boosted hadronic W boson decays with respect to a background of quark- and gluon-initiated jets. Using Monte Carlo simulation, we demonstrate that the performance of this technique introduces additional discriminating power over other substructure approaches, and gives significant insight into the internal structure of jets.

Investigation of strut-ramp injector in a Scramjet combustor: Effect of strut geometry, fuel and jet diameter on mixing characteristics

Energy Technology Data Exchange (ETDEWEB)

Soni, Rahul Kumar; De, Ashoke De [Indian Institute of Technology Kanpur, Kanpur (India)

2017-03-15

The strut-based injector has been found to be one of the most promising injector designs for a supersonic combustor, offering enhanced mixing of fuel and air. The mixing and flow field characteristics of the straight (SS) and Tapered strut (TS), with fixed ramp angle and height at free stream Mach number 2 in conjunction with fuel injection at Mach 2.3 have been investigated numerically and reported. In the present investigation, hydrogen (H{sub 2}) and ethylene (C{sub 2}H{sub 4}) are injected in oncoming supersonic flow from the back of the strut, where jet to free stream momentum ratio is maintained at 0.79 and 0.69 for H2 and C{sub 2}H{sub 4}, respectively. The predicted wall static pressure and species mole fractions at various downstream locations are compared with the experimental data for TS case with 0.6 mm jet diameter and found to be in good agreement. Further, the effect of jet diameter and strut geometry on the near field mixing in strut ramp configuration is discussed for both the fuels. The numerical results are assessed based on various parameters for the performance evaluation of different strut ramp configurations. The SS configuration for both the injectant has been found to be an optimum candidate; also it is observed that for higher jet diameter larger combustor length is required to achieve satisfactory near field mixing.

Triggering of internal transport barrier in JET

Energy Technology Data Exchange (ETDEWEB)

Joffrin, E. [Association Euratom-CEA pour la Fusion, CEA Cadarache, St. Paul lez Durance (France); Gorini, G. [Istituto di Fisica del Plasma, EURATOM-ENEA-CNR Association, Milan (Italy); Challis, C.D. [Euratom/UKAEA Fusion Association, Culham Science Centre, Abingdon, Oxon (United Kingdom)] [and others

2002-08-01

Internal transport barriers (ITBs) can be produced in JET by the application of strong additional heating during the current rise phase of the plasma discharge. Using up to 3 MW of lower hybrid power to tailor the q-profile prior to the main heating phase, a large variety of q-profiles ranging from low positive to strong negative central shear have been obtained during the current rise (0.4 MA s{sup -1}). With negative central magnetic shear s=(r/q)(r/q), the analysis of ITB triggering reveals a correlation between the formation of the ITB and q{sub andmin;} reaching an integer value (q=2 or q=3). This observation is confirmed by the analysis of the Alfven cascades. The minimum power required to access regimes with ITBs is probably related to the transport and magnetohydrodynamic properties of integer magnetic surfaces. Laser ablation and shallow pellet injection have also been attempted in recent JET ITB triggering experiments. (author)

Modeling of noble gas injection into tokamak plasmas

International Nuclear Information System (INIS)

Morozov, D.Kh.; Yurchenko, E.I.; Lukash, V.E.; Baronova, E.O.; Rozhansky, V.A.; Senichenkov, I.Yu.; Veselova, I.Yu.; Schneider, R.

2005-01-01

Noble gas injection for mitigation of the disruption in DIII-D is simulated. The simulation of the first two stages is performed: of the neutral gas jet penetration through the background plasmas, and of the thermal quench. In order to simulate the first stage the 1.5-dimensional numerical code LLP with improved radiation model for noble gas is used. It is demonstrated that the jet remains mainly neutral and thus is able to penetrate to the central region of the tokamak in accordance with experimental observations. Plasma cooling at this stage is provided by the energy exchange with the jet. The radiation is relatively small, and the plasma thermal energy is spent mainly on the jet expansion. The magnetic surfaces in contact with the jet are cooled significantly. The cooling front propagates towards the plasma center. The simulations of the plasma column dynamics in the presence of moving jet is performed by means of the free boundary transport modeling DINA code. It has been shown that the cooling front is accompanied by strongly localized 'shark fin-like' perturbation in toroidal current density profile. After few milliseconds the jet (together with the current perturbation) achieves the region where safety factor is slightly higher than unity and a new type of the non-local kink mode develops. The unstable kink perturbation is non-resonant for any magnetic surface, both inside the plasma column, and in the vacuum space. The mode disturbs mainly the core region. The growth time of the 'shark fin-like' mode is higher than the Alfven time by a factor of 100 for DIII-D parameters. Hence, the simulation describes the DIII-D experimental results, at least, qualitatively. (author)

JET neutral beam duct Optical Interlock

Energy Technology Data Exchange (ETDEWEB)

Ash, A.D.; Jones, T.T.C.; Surrey, E.; Ćirić, D.; Hall, S.I.; Young, D.; Afzal, M.; Hackett, L.; Day, I.E.; King, R.

2015-10-15

Highlights: • Optical Interlocks were installed on the JET NBI system as part of the EP2 upgrade. • The system protects the JET tokamak and NBI systems from thermal load damage. • Balmer-α beam emission is used to monitor the neutral beam-line pressure. • We demonstrate an improved trip delay of 2 ms compared to 50 ms before EP2. - Abstract: The JET Neutral Beam Injection (NBI) system is the most powerful neutral beam plasma heating system currently operating. Optical Interlocks were installed on the beam lines in 2011 for the JET Enhancement Project 2 (EP2), when the heating power was increased from 23 MW to 34 MW. JET NBI has two beam lines. Each has eight positive ion injectors operating in deuterium at 80 kV–125 kV (accelerator voltage) and up to 65 A (beam current). Heating power is delivered through two ducts where the central power density can be more than 100 MW/m{sup 2}. In order to deliver this safely, the beam line pressure should be below 2 × 10{sup −5} mbar otherwise the power load on the duct from the re-ionised fraction of the beam is excessive. The new Optical Interlock monitors the duct pressure by measuring the Balmer-α beam emission (656 nm). This is proportional to the instantaneous beam flux and the duct pressure. Light is collected from a diagnostic window and focused into 1-mm diameter fibres. The Doppler shifted signal is selected using an angle-tuned interference filter. The light is measured by a photo-multiplier module with a logarithmic amplifier. The interlock activation time of 2 ms is sufficient to protect the system from a fully re-ionised beam—a significant improvement on the previous interlock. The dynamic range is sufficient to see bremsstrahlung emission from JET plasma and not saturate during plasma disruptions. For high neutron flux operations the optical fibres within the biological shield can be annealed to 350 °C. A self-test is possible by illuminating the diagnostic window with a test lamp and measuring

A Series of Jets that Drove Streamer-Puff CMEs from Giant Active Region of 2014

Science.gov (United States)

Panesar, Navdeep K.; Sterling, Alphonse C.; Moore, Ronald L.

2016-01-01

We investigate characteristics of solar coronal jets that originated from active region NOAA 12192 and produced coronal mass ejections (CMEs). This active region produced many non­-jet major flare eruptions (X and M class) that made no CME. A multitude of jets occurred from the southeast edge of the active region, and in contrast to the major-­flare eruptions in the core, six of these jets resulted in CMEs. Our jet observations are from SDO/AIA EUV channels and from Hinode/XRT, and CME observations are from the SOHO/LASCO C2 coronograph. Each jet-­driven CME was relatively slow-­moving (approx. 200 - 300 km/s) compared to most CMEs; had angular width (20deg - 50deg) comparable to that of the streamer base; and was of the "streamer­-puff" variety, whereby a pre-existing streamer was transiently inflated but not removed (blown out) by the passage of the CME. Much of the chromospheric-­temperature plasma of the jets producing the CMEs escaped from the Sun, whereas relatively more of the chromospheric plasma in the non-CME-producing jets fell back to the solar surface. We also found that the CME-producing jets tended to be faster in speed and longer in duration than the non-CME-­producing jets. We expect that the jets result from eruptions of mini-filaments. We further propose that the CMEs are driven by magnetic twist injected into streamer-­base coronal loops when erupting twisted mini-filament field reconnects with the ambient field at the foot of those loops.

Appearance of high submerged cavitating jet: The cavitation phenomenon and sono luminescence

Directory of Open Access Journals (Sweden)

Hutli Ezddin

2013-01-01

Full Text Available In order to study jet structure and behaviour of cloud cavitation within time and space, visualization of highly submerged cavitating water jet has been done using Stanford Optics 4 Quick 05 equipment, through endoscopes and other lenses with Drello3244 and Strobex Flash Chadwick as flashlight stroboscope. This included obligatory synchronization with several types of techniques and lenses. Images of the flow regime have been taken, allowing calculation of the non-dimensional cavitation cloud length under working conditions. Consequently a certain correlation has been proposed. The influencing parameters, such as; injection pressure, downstream pressure and cavitation number were experimentally proved to be very significant. The recordings of sono-luminescence phenomenon proved the collapsing of bubbles everywhere along the jet trajectory. In addition, the effect of temperature on sono-luminescence recordings was also a point of investigation. [Projekat Ministarstva nauke Republike Srbije, br. TR35046

Long-circulating Janus nanoparticles made by electrohydrodynamic co-jetting for systemic drug delivery applications

Science.gov (United States)

Rahmani, Sahar; Villa, Carlos H.; Dishman, Acacia F.; Grabowski, Marika E.; Pan, Daniel C.; Durmaz, Hakan; Misra, Asish C; Colón-Meléndez, Laura; Solomon, Michael J.; Muzykantov, Vladimir R.; Lahann, Joerg

2016-01-01

Background Nanoparticles with controlled physical properties have been widely used for controlled release applications. In addition to shape, the anisotropic nature of the particles can be an important design criterion to ensure selective surface modification or independent release of combinations of drugs. Purpose Electrohydrodynamic (EHD) co-jetting is used for the fabrication of uniform anisotropic nanoparticles with individual compartments and initial physicochemical and biological characterization is reported. Methods EHD co-jetting is used to create nanoparticles, which are characterized at each stage with scanning electron microscopy (SEM), structured illumination microscopy (SIM), dynamic light scattering (DLS) and nanoparticle tracking analysis (NTA). Surface immobilization techniques are used to incorporate polyethylene glycol (PEG) and I125 radiolabels into the nanoparticles. Particles are injected in mice and the particle distribution after 1, 4 and 24 hours is assessed. Results and discussion Nanoparticles with an average diameter of 105.7 nm are prepared by EHD co-jetting. The particles contain functional chemical groups for further surface modification and radiolabeling. The density of PEG molecules attached to the surface of nanoparticles is determined to range between 0.02 and 6.04 ligands per square nanometer. A significant fraction of the nanoparticles (1.2% injected dose per mass of organ) circulates in the blood after 24 h. Conclusion EHD co-jetting is a versatile method for the fabrication of nanoparticles for drug delivery. Circulation of the nanoparticles for 24 h is a pre-requisite for subsequent studies to explore defined targeting of the nanoparticles to a specific anatomic site. PMID:26453170

Elucidating Jet Energy Loss Using Jets: Prospects from ATLAS

International Nuclear Information System (INIS)

Grau, N.

2009-01-01

Jets at the LHC are expected to provide the testing ground for studying QCD energy loss. In this contribution, we briefly outline the strategy that will be used to measure jets in ATLAS and how we will go about studying energy loss. We describe the utility of measuring the jet R AA , the fragmentation function, and heavy flavor jets. Utilizing the collision energy provided by the LHC and the nearly hermetic and highly segmented calorimeter, ATLAS is expected to make important contributions to the understanding of parton energy loss using fully reconstructed jets.

Elucidating Jet Energy Loss Using Jets Prospects from ATLAS

CERN Document Server

Grau, N

2009-01-01

Jets at the LHC are expected to provide the testing ground for studying QCD energy loss. In this contribution, we briefly outline the strategy that will be used to measure jets in ATLAS and how we will go about studying energy loss. We describe the utility of measuring the jet $R_{AA}$, the fragmentation function, and heavy flavor jets. Utilizing the collision energy provided by the LHC and the nearly hermetic and highly segmented calorimeter, ATLAS is expected to make important contributions to the understanding of parton energy loss using fully reconstructed jets.

Solid reactors in sequential injection analysis: Recent trends in the environmental field

DEFF Research Database (Denmark)

Miró, Manuel; Hansen, Elo Harald

2006-01-01

-bead injection (SI-BI), used in either the jet-ring or lab-on-valve configurations, is presented as a front-end to many detectors. This article also outlines recent trends focused on exploiting SI as an automated tool for handling solid samples of environmental concern and accommodating dynamic fractionation...

Needle-free injection into skin and soft matter with highly focused microjets

NARCIS (Netherlands)

Tagawa, Y.; Oudalov, Nikolai; El Ghalbzouri, A; Sun, Chao; Lohse, Detlef

2013-01-01

The development of needle-free drug injection systems is of great importance to global healthcare. However, in spite of its great potential and research history over many decades, these systems are not commonly used. One of the main problems is that existing methods use diffusive jets, which result

Use of fundamental condensation heat transfer experiments for the development of a sub-grid liquid jet condensation model

Energy Technology Data Exchange (ETDEWEB)

Buschman, Francis X., E-mail: Francis.Buschman@unnpp.gov; Aumiller, David L.

2017-02-15

Highlights: • Direct contact condensation data on liquid jets up to 1.7 MPa in pure steam and in the presence of noncondensable gas. • Identified a pressure effect on the impact of noncondensables to suppress condensation heat transfer not captured in existing data or correlations. • Pure steam data is used to develop a new correlation for condensation heat transfer on subcooled liquid jets. • Noncondensable data used to develop a modification to the renewal time estimate used in the Young and Bajorek correlation for condensation suppression in the presence of noncondensables. • A jet injection boundary condition, using a sub-grid jet condensation model, is developed for COBRA-IE which provides a more detailed estimate of the condensation rate on the liquid jet and allows the use of jet specific closure relationships. - Abstract: Condensation on liquid jets is an important phenomenon for many different facets of nuclear power plant transients and analyses such as containment spray cooling. An experimental facility constructed at the Pennsylvania State University, the High Pressure Liquid Jet Condensation Heat Transfer facility (HPLJCHT), has been used to perform steady-state condensation heat transfer experiments in which the temperature of the liquid jet is measured at different axial locations allowing the condensation rate to be determined over the jet length. Test data have been obtained in a pure steam environment and with varying concentrations of noncondensable gas. This data extends the available jet condensation data from near atmospheric pressure up to a pressure of 1.7 MPa. An empirical correlation for the liquid side condensation heat transfer coefficient has been developed based on the data obtained in pure steam. The data obtained with noncondensable gas were used to develop a correlation for the renewal time as used in the condensation suppression model developed by Young and Bajorek. This paper describes a new sub-grid liquid jet

Use of fundamental condensation heat transfer experiments for the development of a sub-grid liquid jet condensation model

International Nuclear Information System (INIS)

Buschman, Francis X.; Aumiller, David L.

2017-01-01

Highlights: • Direct contact condensation data on liquid jets up to 1.7 MPa in pure steam and in the presence of noncondensable gas. • Identified a pressure effect on the impact of noncondensables to suppress condensation heat transfer not captured in existing data or correlations. • Pure steam data is used to develop a new correlation for condensation heat transfer on subcooled liquid jets. • Noncondensable data used to develop a modification to the renewal time estimate used in the Young and Bajorek correlation for condensation suppression in the presence of noncondensables. • A jet injection boundary condition, using a sub-grid jet condensation model, is developed for COBRA-IE which provides a more detailed estimate of the condensation rate on the liquid jet and allows the use of jet specific closure relationships. - Abstract: Condensation on liquid jets is an important phenomenon for many different facets of nuclear power plant transients and analyses such as containment spray cooling. An experimental facility constructed at the Pennsylvania State University, the High Pressure Liquid Jet Condensation Heat Transfer facility (HPLJCHT), has been used to perform steady-state condensation heat transfer experiments in which the temperature of the liquid jet is measured at different axial locations allowing the condensation rate to be determined over the jet length. Test data have been obtained in a pure steam environment and with varying concentrations of noncondensable gas. This data extends the available jet condensation data from near atmospheric pressure up to a pressure of 1.7 MPa. An empirical correlation for the liquid side condensation heat transfer coefficient has been developed based on the data obtained in pure steam. The data obtained with noncondensable gas were used to develop a correlation for the renewal time as used in the condensation suppression model developed by Young and Bajorek. This paper describes a new sub-grid liquid jet

Jets from jets: re-clustering as a tool for large radius jet reconstruction and grooming at the LHC

Science.gov (United States)

Nachman, Benjamin; Nef, Pascal; Schwartzman, Ariel; Swiatlowski, Maximilian; Wanotayaroj, Chaowaroj

2015-02-01

Jets with a large radius R ≳ 1 and grooming algorithms are widely used to fully capture the decay products of boosted heavy particles at the Large Hadron Collider (LHC). Unlike most discriminating variables used in such studies, the jet radius is usually not optimized for specific physics scenarios. This is because every jet configuration must be calibrated, insitu, to account for detector response and other experimental effects. One solution to enhance the availability of large- R jet configurations used by the LHC experiments is jet re-clustering. Jet re-clustering introduces an intermediate scale r groomed jets. Jet re-clustering has the benefit that no additional large-R calibration is necessary, allowing the re-clustered large radius parameter to be optimized in the context of specific precision measurements or searches for new physics.

Modeling of under-expanded reactive CO2-into-sodium jets, in the frame of sodium fast reactors

International Nuclear Information System (INIS)

Vivaldi, D.

2013-01-01

This PhD work was motivated by the investigations in the frame of supercritical CO 2 Brayton cycles as possible energy conversion cycles for the Sodium-cooled Fast nuclear Reactors (SFRs). This technology represents an alternative to conventional steam Rankine cycles, with the main advantage represented by the elimination of the accidental sodium-water reaction scenario. Nevertheless, CO 2 chemically reacts with sodium, through an exothermic reaction leading to solid reaction products, mainly sodium carbonate. Following an accidental leakage inside the sodium-CO 2 heat exchanger of a SFR, the CO 2 , having an operating pressure of about 200 bars, would be injected into the low-operating pressure liquid sodium, creating an under-expanded reactive CO 2 -into-sodium jet. The under-expanded jet features a sonic gas injection velocity and an under-expansion in the first region downstream the leakage, where the CO 2 is accelerated to supersonic velocities. The exothermic reaction between the CO 2 and the sodium causes an increasing of the temperature inside the heat exchanger. An experimental facility was built at CEA Cadarache, for the realization of CO 2 -into-sodium jets: this facility has provided preliminary results in terms of temperature variations inside the jet due to the exothermic reaction. However, this type of experimental tests are complicated to realize and to analyse, due to the technical difficulties of realizing the contact between CO 2 and sodium, and to the incertitude of temperature measurement inside a two-phase high velocity jet. It follows that a numerical model of this kind of jets is required, in order to understand the CO 2 -sodium kinetics of reaction inside the jet and being able to transpose the phenomenon to relevant SFR sodium-CO 2 heat exchangers. This would allow to understand the consequences of a leakage inside a sodium-CO 2 heat exchanger, in terms of, for instance, temperature profiles inside the heat exchanger and on tube surfaces

Special Aspects of Dynamic Properties of Combination Jet Effectors for Flying Vehicle Control

Directory of Open Access Journals (Sweden)

Val. V. Zelencov

2015-01-01

Full Text Available The paper considers an experimental study of special aspects of disturbed flow region dynamics that is formed when an injected high-pressure gas jet interacts with a supersonic crossflow of gas nearby a surface of a nozzle or a plate. The study objective was to determine a difference of the pressure distribution in the region and its sizes under dynamic action from stationary flow characteristics.The experiment involved measuring pressure distribution on the surface of a nozzle or a plate along with high-speed filming of the flow.The study has revealed that the difference in size of the disturbed flow region and the flow distribution is observed only in transition segments: under injected jet stagnation pressure increase or decrease. The region is formed with a time lag close to zero under pulsation frequencies used. The disturbed flow region size and boundary shape and pressure distribution in constant pressure segment are independent of jet pulsation.It was determined that the dynamic properties (i.e. time of formation of disturbed flow region depend of induced force and crossflow properties.Disturbed flow region size behavior in time domain can be represented by an aperiodic element with a time constant significantly smaller than that of the gas-feed circuit.The results gained make it possible to state that in assessing dynamic properties of combination jet effectors it is sufficient to take into account gas generator and gas-feed circuit which response is significantly slower than that of the disturbed flow region.The recommendations based on the study results can be used for supersonic and hypersonic flying vehicle design.

Neoclassical impurity transport and observations of poloidal asymmetries in JET

International Nuclear Information System (INIS)

Feneberg, W.; Mast, F.K.; Martin, P.; Gottardi, N.

1986-01-01

Bolometrically measured asymmetries of emissivity for some characteristic JET discharges are presented and are in good agreement with theoretical results of calculations worked out in the frame of neoclassical theory. Application of theory to the case of strong toroidal rotation as induced with neutral injection shows a sensitive dependance of the impurity transport perpendicular to the magnetic surfaces from the parameter of poloidal rotation. The main result is the existence of a classical flow reversal. Without any poloidal rotation of the background ions, a large inward flow of impurities for co- and counter-injection is always predicted, while poloidal rotation in the direction of the ion diamagnetic drift motion leads to a strong outward drift. (author)

High-Fidelity Simulations of Electrically-Charged Atomizing Diesel-Type Jets

Science.gov (United States)

Gaillard, Benoit; Owkes, Mark; van Poppel, Bret

2015-11-01

Combustion of liquid fuels accounts for over a third of the energy usage today. Improving efficiency of combustion systems is critical to meet the energy needs while limiting environmental impacts. Additionally, a shift away from traditional fossil fuels to bio-derived alternatives requires fuel injection systems that can atomize fuels with a wide range of properties. In this work, the potential benefits of electrically-charged atomization is investigated using numerical simulations. Particularly, the electrostatic forces on the hydrodynamic jet are quantified and the impact of the forces is analyzed by comparing simulations of Diesel-type jets at realistic flow conditions. The simulations are performed using a state-of-the-art numerical framework that globally conserves mass, momentum, and the electric charge density even at the gas-liquid interface where discontinuities exist.

IMPINGEMENT COOLING OF A SEMI-CIRCULAR CONCAVE CHANNEL BY 2D AIR-JET

Directory of Open Access Journals (Sweden)

Serhan KÜÇÜKA

1998-01-01

Full Text Available This study provides a numerical solution to the flow in a cylindrical cavity of which the upper wall contains a twodimensional slot. The air injected through the slot impinges and diffuses laterally on the lower wall. The jet enfluxed through the slot is assumed to have uniform velocity and temperature, and the temperature at the lower wall is kept constant. The resulting Navier-Stokes equations are solved by transforming simpler algorithm into a form useably in cylindrical co-ordinate system. The effect of cavity curvature, and the height ratio on velocity and pressure distribution is analyzed. The jet Reynolds number ranged from 100 to 1500 in the analysis.

Curved wall-jet burner for synthesizing titania and silica nanoparticles

KAUST Repository

Ismail, Mohamed

2015-01-01

A novel curved wall-jet (CWJ) burner was designed for flame synthesis, by injecting precursors through a center tube and by supplying fuel/air mixtures as an annular-inward jet for rapid mixing of the precursors in the reaction zone. Titanium dioxide (TiO2) and silicon dioxide (SiO2) nanoparticles were produced in ethylene (C2H4)/air premixed flames using titanium tetraisopropoxide (TTIP) and hexamethyldisiloxane (HMDSO) as the precursors, respectively. Particle image velocimetry measurements confirmed that the precursors can be injected into the flames without appreciably affecting flow structure. The nanoparticles were characterized using X-ray diffraction, Raman spectroscopy, the Brunauer-Emmett-Teller (BET) method, and high-resolution transmission electron microscopy. In the case of TiO2, the phase of nanoparticles could be controlled by adjusting the equivalence ratio, while the particle size was dependent on the precursor loading rate and the flame temperature. The synthesized TiO2 nanoparticles exhibited high crystallinity and the anatase phase was dominant at high equivalence ratios (φ > 1.3). In the case of SiO2, the particle size could be controlled from 11 to 18 nm by adjusting the precursor loading rate. © 2014 The Combustion Institute. Published by Elsevier Inc. All rights reserved.

A numerical study of a supercritical fluid jet

International Nuclear Information System (INIS)

Sierra-Pallares, J.; Garcia-Serna, J.; Cocero, M.J.; Parra-Santos, M.T.; Castro-Ruiz, F.

2009-01-01

This study affords the numerical solution of the mixing of a submerged turbulent jet under supercritical conditions and near-critical conditions. Turbulence plays a very important role in the behaviour of chemical engineering equipment. An accurate prediction of the turbulence at supercritical conditions with low computational cost is crucial in designing new processes such as reactions in supercritical media, high pressure separation processes, nanomaterials processing and heterogeneous catalysis. At high-pressure, the flow cannot be modelled accurately using the ideal-gas assumption. Therefore, the real gas models must be used in order to solve accurately the fluid flow and heat transfer problems where the working fluid behaviour deviate seriously from the ideal-gas assumption. The jet structure has three parts clearly distinguished: the injection, the transition and the fully developed jet. Once the flow is dominated by the turbulent eddies of the shear layer, the flow is fully developed and the radial profiles match a similarity profile. This work reports the state of the project that is not completed and is being processed now. This work is devoted to establish the distance downstream from the injector where the jet become self-preserving and the shape of the similarity profiles. This system is of interest in the design of supercritical reactor inlets, where two streams should be mixed in the shortest length, or mixing conditions strongly affect the behaviour of the processes. The numerical results have been validated with experimental measurements made in the jet mixing region. The radial profiles for average velocity, density and temperature are analyzed. The parameters of the profile that match better the numerical results are summarized in Table 1. The density requires a lower value of n than these for velocity and temperature, which reflect smoother profiles. These conclusions are in good agreement with the results from Oschwald and Schik. (author)

Fluidic Vectoring of a Planar Incompressible Jet Flow

Science.gov (United States)

Mendez, Miguel Alfonso; Scelzo, Maria Teresa; Enache, Adriana; Buchlin, Jean-Marie

2018-06-01

This paper presents an experimental, a numerical and a theoretical analysis of the performances of a fluidic vectoring device for controlling the direction of a turbulent, bi-dimensional and low Mach number (incompressible) jet flow. The investigated design is the co-flow secondary injection with Coanda surface, which allows for vectoring angles up to 25° with no need of moving mechanical parts. A simple empirical model of the vectoring process is presented and validated via experimental and numerical data. The experiments consist of flow visualization and image processing for the automatic detection of the jet centerline; the numerical simulations are carried out solving the Unsteady Reynolds Average Navier- Stokes (URANS) closed with the k - ω SST turbulence model, using the PisoFoam solver from OpenFOAM. The experimental validation on three different geometrical configurations has shown that the model is capable of providing a fast and reliable evaluation of the device performance as a function of the operating conditions.

STAR FORMATION SUPPRESSION DUE TO JET FEEDBACK IN RADIO GALAXIES WITH SHOCKED WARM MOLECULAR GAS

International Nuclear Information System (INIS)

Lanz, Lauranne; Ogle, Patrick M.; Appleton, Philip N.; Alatalo, Katherine

2016-01-01

We present Herschel observations of 22 radio galaxies, selected for the presence of shocked, warm molecular hydrogen emission. We measured and modeled spectral energy distributions in 33 bands from the ultraviolet to the far-infrared to investigate the impact of jet feedback on star formation activity. These galaxies are massive, early-type galaxies with normal gas-to-dust ratios, covering a range of optical and infrared colors. We find that the star formation rate (SFR) is suppressed by a factor of ∼3–6, depending on how molecular gas mass is estimated. We suggest that this suppression is due to the shocks driven by the radio jets injecting turbulence into the interstellar medium (ISM), which also powers the luminous warm H 2 line emission. Approximately 25% of the sample shows suppression by more than a factor of 10. However, the degree of SFR suppression does not correlate with indicators of jet feedback including jet power, diffuse X-ray emission, or intensity of warm molecular H 2 emission, suggesting that while injected turbulence likely impacts star formation, the process is not purely parameterized by the amount of mechanical energy dissipated into the ISM. Radio galaxies with shocked warm molecular gas cover a wide range in SFR–stellar mass space, indicating that these galaxies are in a variety of evolutionary states, from actively star-forming and gas-rich to quiescent and gas-poor. SFR suppression appears to have the largest impact on the evolution of galaxies that are moderately gas-rich.

Transport studies during sawteeth and H-modes on JET using laser ablation

International Nuclear Information System (INIS)

Wang, Z.; Barnsley, R.; Denne, B.; Edwards, A.; Gianella, R.; Gill, R.; Magyar, G.; Pasini, D.; Behringer, K.; Schumacher, U.; Zaschke, D.; Cohen, S.

1989-01-01

A system for the controlled injection of trace impurities by laser ablation has recently been commissioned on JET. Small amounts of metallic impurities have been injected in order to study transport phenomena. In all cases the amounts, corresponding to an injected quantity of a few 10 18 atoms (an impurity concentration of 0.01% of n e ), were sufficiently small to avoid perturbing any plasma parameter apart from the radiation (ΔP rad imp ) and observations of impurity transport effects using this technique. A suite of spectrometers viewing fixed lines of sight was used to gather information on the time behaviour of a range of ionisation stages. In addition measurements of the soft X-ray emission were obtained with good spatial and temporal resolution from two X-ray cameras. (author) 4 refs., 6 figs

Q-profiles in JET

International Nuclear Information System (INIS)

Gill, R.D.; Edwards, A.W.; Keegan, B.; Lazzaro, E.; O'Rourke, J.; Weller, A.; Zasche, D.

1989-01-01

Tokamak q-profiles play a central role in the determination of plasma stability and q(r) towards the plasma centre is particularly important for the sawtooth instability. On JET, q(r) has been determined from magnetic measurements and Faraday rotation. Further information about the position of the q=1 surface has been found from the sawtooth inversion radius, the position of the snake and the resonance effect observed on visible light and X-ray emission during pellet injection. In addition the shear at the q=1 surface has been measured from pellet ablation. This result is supported by the movement of the snake caused by a sawtooth crash. A summary of these data will be made after presenting the new results from pellet ablation. (author) 5 refs., 8 figs

First experiments in JET

International Nuclear Information System (INIS)

Rebut, P.H.; Bartlett, D.V.; Baeumel, G.

1985-01-01

Results obtained from JET since June 1983 are described which show that this large tokamak behaves in a similar manner to smaller tokamaks, but with correspondingly improved plasma parameters. Long-duration hydrogen and deuterium plasmas (>10 s) have been obtained with electron temperatures reaching >4 keV for power dissipations =1.6), loss of vertical stability occurred, as expected from previous calculations. Forces of several hundred tonnes (at Isub(p)=2.7 MA) were transmitted to the vacuum vessel. Measured confinement times are larger than the corresponding INTOR values. The maximum achievable density is limited by disruptions. Impurity levels determine this limiting density, and the paper concludes with proposals to reduce these. In addition, progress in neutral injection and RF heating is described, as well as preparations for D-T operation. (author)

Jet fragmentation

International Nuclear Information System (INIS)

Saxon, D.H.

1985-10-01

The paper reviews studies on jet fragmentation. The subject is discussed under the topic headings: fragmentation models, charged particle multiplicity, bose-einstein correlations, identified hadrons in jets, heavy quark fragmentation, baryon production, gluon and quark jets compared, the string effect, and two successful models. (U.K.)

JET Joint Undertaking

International Nuclear Information System (INIS)

Keen, B.E.; Lallia, P.; O'Hara, G.W.; Pollard, I.E.

1987-06-01

The paper presents the annual report of the Joint European Torus (JET) Joint Undertaking, 1986. The report is divided into two parts: a part on the scientific and technical programme of the project, and a part setting out the administration and organisation of the Project. The first part includes: a summary of the main features of the JET apparatus, the JET experimental programme, the position of the Project in the overall Euratom programme, and how JET relates to other large fusion devices throughout the world. In addition, the technical status of JET is described, as well as the results of the JET operations in 1986. The final section of the first part outlines the proposed future programme of JET. (U.K.)

PROPAGATION OF RELATIVISTIC, HYDRODYNAMIC, INTERMITTENT JETS IN A ROTATING, COLLAPSING GRB PROGENITOR STAR

Energy Technology Data Exchange (ETDEWEB)

Geng, Jin-Jun [School of Astronomy and Space Science, Nanjing University, Nanjing 210046 (China); Zhang, Bing [Department of Physics and Astronomy, University of Nevada Las Vegas, NV 89154 (United States); Kuiper, Rolf, E-mail: gengjinjun@gmail.com, E-mail: zhang@physics.unlv.edu [Institute of Astronomy and Astrophysics, University of Tübingen, Auf der Morgenstelle 10, D-72076 Tübingen (Germany)

2016-12-10

The prompt emission of gamma-ray bursts (GRBs) is characterized by rapid variabilities, which may be a direct reflection of the unsteady central engine. We perform a series of axisymmetric 2.5-dimensional simulations to study the propagation of relativistic, hydrodynamic, intermittent jets through the envelope of a GRB progenitor star. A realistic rapidly rotating star is incorporated as the background of jet propagation, and the star is allowed to collapse due to the gravity of the central black hole. By modeling the intermittent jets with constant-luminosity pulses with equal on and off durations, we investigate how the half period, T , affects the jet dynamics. For relatively small T values (e.g., 0.2 s), the jet breakout time t {sub bo} depends on the opening angle of the jet, with narrower jets more penetrating and reaching the surface at shorter times. For T  ≤ 1 s, the reverse shock (RS) crosses each pulse before the jet penetrates through the stellar envelope. As a result, after the breakout of the first group of pulses at t {sub bo}, several subsequent pulses vanish before penetrating the star, causing a quiescent gap. For larger half periods ( T = 2.0 and 4.0 s), all the pulses can successfully penetrate through the envelope, since each pulse can propagate through the star before the RS crosses the shell. Our results may interpret the existence of a weak precursor in some long GRBs, given that the GRB central engine injects intermittent pulses with a half period T  ≤ 1 s. The observational data seem to be consistent with such a possibility.

Investigation of low emission combustors using hydrogen lean direct injection

Directory of Open Access Journals (Sweden)

Robert ISAC

2011-09-01

Full Text Available One of the key technology challenges for the use of hydrogen in gas turbine engines is the performance of the combustion system, in particular the fuel injectors. Tests were conducted to measure the nitrogen oxide (NOx emissions and combustion performance at inlet conditions of 588 to 811 K, 0.4 to 1.4 MPa, and equivalence ratios up to 0.48. All the injectors were based on Lean Direct Injection (LDI technology with multiple injection points and quick mixing. One challenge to hydrogen-based premixing combustion systems is flashback since hydrogen has a reaction rate over 7 times that of Jet-A.

Modelling third harmonic ion cyclotron acceleration of deuterium beams for JET fusion product studies experiments

DEFF Research Database (Denmark)

Schneider, M.; Johnson, T.; Dumont, R.

2016-01-01

Recent JET experiments have been dedicated to the studies of fusion reactions between deuterium (D) and Helium-3 (3He) ions using neutral beam injection (NBI) in synergy with third harmonic ion cyclotron radio-frequency heating (ICRH) of the beam. This scenario generates a fast ion deuterium tail...... enhancing DD and D3He fusion reactions. Modelling and measuring the fast deuterium tail accurately is essential for quantifying the fusion products. This paper presents the modelling of the D distribution function resulting from the NBI+ICRF heating scheme, reinforced by a comparison with dedicated JET fast...

Active control of continuous air jet with bifurcated synthetic jets

Directory of Open Access Journals (Sweden)

Dančová Petra

2017-01-01

Full Text Available The synthetic jets (SJs have many significant applications and the number of applications is increasing all the time. In this research the main focus is on the primary flow control which can be used effectively for the heat transfer increasing. This paper deals with the experimental research of the effect of two SJs worked in the bifurcated mode used for control of an axisymmetric air jet. First, the control synthetic jets were measured alone. After an adjustment, the primary axisymmetric jet was added in to the system. For comparison, the primary flow without synthetic jets control was also measured. All experiments were performed using PIV method whereby the synchronization between synthetic jets and PIV system was necessary to do.

Quark versus Gluon Jet Tagging Using Jet Images with the ATLAS Detector

CERN Document Server

The ATLAS collaboration

2017-01-01

Distinguishing quark-initiated from gluon-initiated jets is useful for many measurements and searches at the LHC. This note presents a jet tagger for distinguishing quark-initiated from gluon-initiated jets, which uses the full radiation pattern inside a jet processed as an image in a deep neural network classifier. The study is conducted using simulated dijet events in $\\sqrt{s}$=13 TeV pp collisions with the ATLAS detector. Across a wide range of quark jet identification efficiencies, the neural network tagger achieves a gluon jet rejection that is comparable to or better than the performance of the jet width and track multiplicity observables conventionally used for quark-versus-gluon jet tagging.

Forward Jets and Forward-Central Jets at CMS

CERN Document Server

INSPIRE-00176215

2012-01-01

We report on cross section measurements for inclusive forward jet production and for the simultaneous production of a forward and a central jet in sqrt{s} = 7 TeV pp-collisions. Data collected in 2010, corresponding to an integrated luminosity of 3.14 pb^{-1}, is used for the measurements. Jets in the transverse momentum range pT = 35 - 140 GeV/c are reconstructed with the anti-kT (R = 0.5) algorithm. The extended coverage of large pseudo-rapidities is provided by the Hadronic Forward calorimeter (3.2 < \\eta < 4.7), while central jets are limited to \\eta < 2.8, covered by the main detector components. The two differential cross sections are presented as a function of the jet transverse momentum. Comparisons to next-to-leading order perturbative calculations, and predictions from event generators based on different parton showering mechanisms (PYTHIA and HERWIG) and parton dynamics (CASCADE) are shown.

Hybrid Reynolds-Averaged/Large-Eddy Simulations of a Coaxial Supersonic Free-Jet Experiment

Science.gov (United States)

Baurle, Robert A.; Edwards, Jack R.

2010-01-01

Reynolds-averaged and hybrid Reynolds-averaged/large-eddy simulations have been applied to a supersonic coaxial jet flow experiment. The experiment was designed to study compressible mixing flow phenomenon under conditions that are representative of those encountered in scramjet combustors. The experiment utilized either helium or argon as the inner jet nozzle fluid, and the outer jet nozzle fluid consisted of laboratory air. The inner and outer nozzles were designed and operated to produce nearly pressure-matched Mach 1.8 flow conditions at the jet exit. The purpose of the computational effort was to assess the state-of-the-art for each modeling approach, and to use the hybrid Reynolds-averaged/large-eddy simulations to gather insight into the deficiencies of the Reynolds-averaged closure models. The Reynolds-averaged simulations displayed a strong sensitivity to choice of turbulent Schmidt number. The initial value chosen for this parameter resulted in an over-prediction of the mixing layer spreading rate for the helium case, but the opposite trend was observed when argon was used as the injectant. A larger turbulent Schmidt number greatly improved the comparison of the results with measurements for the helium simulations, but variations in the Schmidt number did not improve the argon comparisons. The hybrid Reynolds-averaged/large-eddy simulations also over-predicted the mixing layer spreading rate for the helium case, while under-predicting the rate of mixing when argon was used as the injectant. The primary reason conjectured for the discrepancy between the hybrid simulation results and the measurements centered around issues related to the transition from a Reynolds-averaged state to one with resolved turbulent content. Improvements to the inflow conditions were suggested as a remedy to this dilemma. Second-order turbulence statistics were also compared to their modeled Reynolds-averaged counterparts to evaluate the effectiveness of common turbulence closure

Jet Joint Undertaking

International Nuclear Information System (INIS)

Keen, B.E.; O'Hara, G.W.; Pollard, I.E.

1988-07-01

The paper presents the Jet Joint Undertaking annual report 1987. A description is given of the JET and Euratom and International Fusion Programmes. The technical status of JET is outlined, including the development and improvements made to the system in 1987. The results of JET Operation in 1987 are described within the areas of: density effects, temperature improvements, energy confinement studies and other material effects. The contents also contain a summary of the future programme of JET. (U.K.)

Understanding jet noise.

Science.gov (United States)

Karabasov, S A

2010-08-13

Jets are one of the most fascinating topics in fluid mechanics. For aeronautics, turbulent jet-noise modelling is particularly challenging, not only because of the poor understanding of high Reynolds number turbulence, but also because of the extremely low acoustic efficiency of high-speed jets. Turbulent jet-noise models starting from the classical Lighthill acoustic analogy to state-of-the art models were considered. No attempt was made to present any complete overview of jet-noise theories. Instead, the aim was to emphasize the importance of sound generation and mean-flow propagation effects, as well as their interference, for the understanding and prediction of jet noise.

Applying rotary jet heads for mixing and mass transfer in a forced recirculation tank reactor system

DEFF Research Database (Denmark)

Nordkvist, Mikkel; Grotkjær, Thomas; Hummer, J.S.

2003-01-01

or an external loop.In this study, we determine mixing times in water and CMC solutions and oxygen mass transfer coefficients in water for a tank reactor system where a small fraction of the total liquid volume is rapidly circulated through an external loop and injected through the nozzles of rotary jet heads....... The system has a very simple design with no internal baffles or heat exchange area, and between batches the rotary jet heads are used for cleaning in place.Mixing time decreases and mass transfer increases with increasing circulation flow rate. For nozzle diameters between 5.5 and 10 mm and with one or two...... rotary jet heads, it is shown that a remarkable saving in power input for a fixed mixing time or mass transfer coefficient can be obtained by using a large nozzle diameter and two rather than one rotary jet heads.At the experimental conditions of the study the system is scaleable by simple formulas...

Breakup Behavior of Molten Wood's Metal Jet in Subcooled Water

Energy Technology Data Exchange (ETDEWEB)

Heo, Hyo; Park, Seong Dae; Bang, In Cheol [Ulsan National Institute of Science and Technology, Ulsan (Korea, Republic of); Jerng, Dong Wook [Chung-Ang Univ., Seoul (Korea, Republic of)

2014-10-15

There are safety characteristics of the metal fueled sodium fast-cooled reactor (SFR), by identifying the possibility of early termination of severe accidents. If the molten fuel is ejected from the cladding, the ejected molten fuel can interact with the coolant in the reactor vessel. This phenomenon is called as fuel-coolant interaction (FCI). The FCI occurs at the initial phase leading to severe accidents like core disruptive accident (CDA) in the SFR. A part of the corium energy is intensively transferred to the coolant in a very short time during the FCI. The coolant vaporizes at high pressure and expands so results in steam explosion that can threat to the integrity of nuclear reactor. The intensity of steam explosion is determined by jet breakup and the fragmentation behavior. Therefore, it is necessary to understand the jet breakup between the molten fuel jet and the coolant in order to evaluate whether the steam explosion occurs or not. The liquid jet breakup has been studied in various areas, such as aerosols, spray and combustion. In early studies, small diameter jets of low density liquids were studied. The jet breakup for large density liquids has been studied in nuclear reactor field with respect to safety. The existence of vapor film layer between the melt and liquid fluid is only in case of large density breakup. This paper deals with the jet breakup experiment in non-boiling conditions in order to analyze hydraulic effect on the jet behavior. In the present study, the wood's metal was used as the jet material. It has similar properties to the metal fuel. The physical properties of molten materials and coolants are listed in Table I, respectively. It is easy to conduct the experiment due to low melting point of the wood's metal. In order to clarify the dominant factors determining jet breakup and size distribution of the debris, the experiment that the molten wood's metal was injected into the subcooled condition was conducted. The

Emerging Jets

CERN Document Server

Schwaller, Pedro; Weiler, Andreas

2015-01-01

In this work, we propose a novel search strategy for new physics at the LHC that utilizes calorimeter jets that (i) are composed dominantly of displaced tracks and (ii) have many different vertices within the jet cone. Such emerging jet signatures are smoking guns for models with a composite dark sector where a parton shower in the dark sector is followed by displaced decays of dark pions back to SM jets. No current LHC searches are sensitive to this type of phenomenology. We perform a detailed simulation for a benchmark signal with two regular and two emerging jets, and present and implement strategies to suppress QCD backgrounds by up to six orders of magnitude. At the 14 TeV LHC, this signature can be probed with mediator masses as large as 1.5 TeV for a range of dark pion lifetimes, and the reach is increased further at the high-luminosity LHC. The emerging jet search is also sensitive to a broad class of long-lived phenomena, and we show this for a supersymmetric model with R-parity violation. Possibilit...

Multiple Jets at the LHC with High Energy Jets

DEFF Research Database (Denmark)

Andersen, Jeppe Rosenkrantz; Smillie, Jennifer M.

2011-01-01

We present a flexible Monte Carlo implementation of the perturbative framework of High Energy Jets, describing multi-jet events at hadron colliders. The description includes a resummation which ensures leading logarithmic accuracy for large invariant mass between jets, and is matched to tree......-level accuracy for multiplicities up to 4 jets. The resummation includes all-order hard corrections, which become important for increasing centre-of-mass energy of the hadronic collision. We discuss observables relevant for confronting the perturbative framework with 7 TeV data from the LHC, and the impact...

Real-time sensing and gas jet mitigation of VDEs on Alcator C-Mod

Science.gov (United States)

Granetz, R. S.; Wolfe, S. M.; Izzo, V. A.; Reinke, M. L.; Terry, J. L.; Hughes, J. W.; Zhurovich, K.; Whyte, D. G.; Bakhtiari, M.; Wurden, G.

2006-10-01

Experiments have been carried out in Alcator C-Mod to test the effectiveness of gas jet disruption mitigation of VDEs with real-time detection and triggering by the C-Mod digital plasma control system (DPCS). The DPCS continuously computes the error in the plasma vertical position from the magnetics diagnostics. When this error exceeds an adjustable preset value, the DPCS triggers the gas jet valve (with a negligible latency time). The high-pressure gas (argon) only takes a few milliseconds to enter the vacuum chamber and begin affecting the plasma, but this is comparable to the VDE timescale on C-Mod. Nevertheless, gas jet injection reduced the halo current, increased the radiated power fraction, and reduced the heating of the divertor compared to unmitigated disruptions, but not quite as well as in earlier mitigation experiments with vertically stable plasmas. Presumably a faster overall response time would be beneficial, and several ways to achieve this will also be discussed.

On the jets, kinks, and spheromaks formed by a planar magnetized coaxial gun

International Nuclear Information System (INIS)

Hsu, S.C.; Bellan, P.M.

2005-01-01

Measurements of the various plasma configurations produced by a planar magnetized coaxial gun provide insight into the magnetic topology evolution resulting from magnetic helicity injection. Important features of the experiments are a very simple coaxial gun design so that all observed geometrical complexity is due to the intrinsic physical dynamics rather than the source shape and use of a fast multiple-frame digital camera which provides direct imaging of topologically complex shapes and dynamics. Three key experimental findings were obtained: (1) formation of an axial collimated jet [Hsu and Bellan, Mon. Not. R. Astron. Soc. 334, 257 (2002)] that is consistent with a magnetohydrodynamic description of astrophysical jets (2) identification of the kink instability when this jet satisfies the Kruskal-Shafranov limit, and (3) the nonlinear properties of the kink instability providing a conversion of toroidal to poloidal flux as required for spheromak formation by a coaxial magnetized source [Hsu and Bellan, Phys. Rev. Lett. 90, 215002 (2003)]. An interpretation is proposed for how the n=1 central column instability provides flux amplification during spheromak formation and sustainment, and it is shown that jet collimation can occur within one rotation of the background poloidal field

Complex astrophysical experiments relating to jets, solar loops, and water ice dusty plasma

Science.gov (United States)

Bellan, P. M.; Zhai, X.; Chai, K. B.; Ha, B. N.

2015-10-01

> Recent results of three astrophysically relevant experiments at Caltech are summarized. In the first experiment magnetohydrodynamically driven plasma jets simulate astrophysical jets that undergo a kink instability. Lateral acceleration of the kinking jet spawns a Rayleigh-Taylor instability, which in turn spawns a magnetic reconnection. Particle heating and a burst of waves are observed in association with the reconnection. The second experiment uses a slightly different setup to produce an expanding arched plasma loop which is similar to a solar corona loop. It is shown that the plasma in this loop results from jets originating from the electrodes. The possibility of a transition from slow to fast expansion as a result of the expanding loop breaking free of an externally imposed strapping magnetic field is investigated. The third and completely different experiment creates a weakly ionized plasma with liquid nitrogen cooled electrodes. Water vapour injected into this plasma forms water ice grains that in general are ellipsoidal and not spheroidal. The water ice grains can become quite long (up to several hundred microns) and self-organize so that they are evenly spaced and vertically aligned.

Injection, Atomization, Ignition and Combustion of Liquid Fuels in High-Speed Air Streams.

Science.gov (United States)

1983-01-01

and ~~’m~po 317.6 %Ui es*l11uhes fte e*oints in the heating process for the hot flow case ad te beatl for fte flow p"Islm -to be model led. The task now...Or THIS PA06MRhi DO* Matueoo -r 20. #d) , mitS for ’oe simulated case using chilled Freon-12 injected into the /. ....... .... Tech 23 23 ca. blow...sults showed a clear picture of the meineisms of jet decomposition in the presence of rapid vaporization. -’ Inmedately after injection a vapor

On jet substructure methods for signal jets

Energy Technology Data Exchange (ETDEWEB)

Dasgupta, Mrinal [Consortium for Fundamental Physics, School of Physics & Astronomy, University of Manchester,Oxford Road, Manchester M13 9PL (United Kingdom); Powling, Alexander [School of Physics & Astronomy, University of Manchester,Oxford Road, Manchester M13 9PL (United Kingdom); Siodmok, Andrzej [Institute of Nuclear Physics, Polish Academy of Sciences,ul. Radzikowskiego 152, 31-342 Kraków (Poland); CERN, PH-TH,CH-1211 Geneva 23 (Switzerland)

2015-08-17

We carry out simple analytical calculations and Monte Carlo studies to better understand the impact of QCD radiation on some well-known jet substructure methods for jets arising from the decay of boosted Higgs bosons. Understanding differences between taggers for these signal jets assumes particular significance in situations where they perform similarly on QCD background jets. As an explicit example of this we compare the Y-splitter method to the more recently proposed Y-pruning technique. We demonstrate how the insight we gain can be used to significantly improve the performance of Y-splitter by combining it with trimming and show that this combination outperforms the other taggers studied here, at high p{sub T}. We also make analytical estimates for optimal parameter values, for a range of methods and compare to results from Monte Carlo studies.

A new method of thermal protection by opposing jet for a hypersonic aeroheating strut

Science.gov (United States)

Qin, Jiang; Ning, Dongpo; Feng, Yu; Zhang, Junlong; Feng, Shuo; Bao, Wen

2017-06-01

This paper presents the numerical investigation of thermal protection of scramjet strut by opposing jet in supersonic stream of Mach number 6 with a hydrogen fueled scramjet strut model using CFD software. Simulation results indicate that when a small amount of fuel is injected from the nose of the strut, the bow shock is pushed away from the strut, and the heat flux is reduced in the strut, especially at the leading edge. Opposing jet forms a recirculation region near the nozzle so that the strut is covered with low temperature fuel and separated from free stream. An appropriate total pressure ratio can be used to reduce not only aerodynamic heating but also the drag of strut. It is therefore concluded that thermal protection of scramjet strut by opposing jet is one of the promising ways to protect scramjet strut in high enthalpy stream.

A multimaterial electrohydrodynamic jet (E-jet) printing system

International Nuclear Information System (INIS)

Sutanto, E; Shigeta, K; Kim, Y K; Graf, P G; Hoelzle, D J; Barton, K L; Alleyne, A G; Ferreira, P M; Rogers, J A

2012-01-01

Electrohydrodynamic jet (E-jet) printing has emerged as a high-resolution alternative to other forms of direct solution-based fabrication approaches, such as ink-jet printing. This paper discusses the design, integration and operation of a unique E-jet printing platform. The uniqueness lies in the ability to utilize multiple materials in the same overall print-head, thereby enabling increased degrees of heterogeneous integration of different functionalities on a single substrate. By utilizing multiple individual print-heads, with a carrousel indexing among them, increased material flexibility is achieved. The hardware design and system operation for a relatively inexpensive system are developed and presented. Crossover interconnects and multiple fluorescent tagged proteins, demonstrating printed electronics and biological sensing applications, respectively. (paper)

Injection of electrons by colliding laser pulses in a laser wakefield accelerator

Energy Technology Data Exchange (ETDEWEB)

Hansson, M., E-mail: martin.hansson@fysik.lth.se; Aurand, B.; Ekerfelt, H.; Persson, A.; Lundh, O.

2016-09-01

To improve the stability and reproducibility of laser wakefield accelerators and to allow for future applications, controlling the injection of electrons is of great importance. This allows us to control the amount of charge in the beams of accelerated electrons and final energy of the electrons. Results are presented from a recent experiment on controlled injection using the scheme of colliding pulses and performed using the Lund multi-terawatt laser. Each laser pulse is split into two parts close to the interaction point. The main pulse is focused on a 2 mm diameter gas jet to drive a nonlinear plasma wave below threshold for self-trapping. The second pulse, containing only a fraction of the total laser energy, is focused to collide with the main pulse in the gas jet under an angle of 150°. Beams of accelerated electrons with low divergence and small energy spread are produced using this set-up. Control over the amount of accelerated charge is achieved by rotating the plane of polarization of the second pulse in relation to the main pulse. Furthermore, the peak energy of the electrons in the beams is controlled by moving the collision point along the optical axis of the main pulse, and thereby changing the acceleration length in the plasma. - Highlights: • Compact colliding pulse injection set-up used to produce low energy spread e-beams. • Beam charge controlled by rotating the polarization of injection pulse. • Peak energy controlled by point of collision to vary the acceleration length.

High-Yield Lithium-Injection Fusion-Energy (HYLIFE) reactor

International Nuclear Information System (INIS)

Blink, J.A.; Hogam, W.J.; Hovingh, J.; Meier, E.R.; Pitts, J.H.

1985-01-01

The High-Yield Lithium-Injection Fusion Energy (HYLIFE) concept to convent inertial confinement fusion energy into electric power has undergone intensive research and refinement at LLNL since 1978. This paper reports on the final HYLIFE design, focusing on five major areas: the HYLIFE reaction chamber (which includes neutronics, liquid-metal jet-array hydrocynamics, and structural design), supporting systems, primary steam system and balance of plant, safety and environmental protection, and costs. An annotated bibliography of reports applicable to HYLIFE is also provided. We conclude that HYLIFE is a particularly viable concept for the safe, clean production of electrical energy. The liquid-metal jet array, HYLIFE's key design feature, protects the surrounding structural components from x-rays, fusion fuel-pellet debris, neutron damage and activation, and high temperatures and stresses, allowing the structure to last for the plant's entire 30-year lifetime without being replaced. 127 refs., 18 figs

Flow visualization studies of transverse fuel injection patterns in a nonreacting Mach 2 combustor

Science.gov (United States)

Mcdaniel, J. C.

1987-01-01

Planar visualization images are recorded of transverse jet mixing in a supersonic combustor flowfield, without chemical reaction, using laser-induced fluorescence from iodine molecules. Digital image processing and three-dimensional display enable complete representations of fuel penetration boundary and shock surfaces corresponding to several injection geometries and pressures.

Emerging jets

Energy Technology Data Exchange (ETDEWEB)

Schwaller, Pedro; Stolarski, Daniel [European Organization for Nuclear Research (CERN), Geneva (Switzerland). TH-PH Div.; Weiler, Andreas [European Organization for Nuclear Research (CERN), Geneva (Switzerland). TH-PH Div.; Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany)

2015-02-15

In this work, we propose a novel search strategy for new physics at the LHC that utilizes calorimeter jets that (i) are composed dominantly of displaced tracks and (ii) have many different vertices within the jet cone. Such emerging jet signatures are smoking guns for models with a composite dark sector where a parton shower in the dark sector is followed by displaced decays of dark pions back to SM jets. No current LHC searches are sensitive to this type of phenomenology. We perform a detailed simulation for a benchmark signal with two regular and two emerging jets, and present and implement strategies to suppress QCD backgrounds by up to six orders of magnitude. At the 14 TeV LHC, this signature can be probed with mediator masses as large as 1.5 TeV for a range of dark pion lifetimes, and the reach is increased further at the high-luminosity LHC. The emerging jet search is also sensitive to a broad class of long-lived phenomena, and we show this for a supersymmetric model with R-parity violation. Possibilities for discovery at LHCb are also discussed.

Emerging jets

International Nuclear Information System (INIS)

Schwaller, Pedro; Stolarski, Daniel

2015-02-01

In this work, we propose a novel search strategy for new physics at the LHC that utilizes calorimeter jets that (i) are composed dominantly of displaced tracks and (ii) have many different vertices within the jet cone. Such emerging jet signatures are smoking guns for models with a composite dark sector where a parton shower in the dark sector is followed by displaced decays of dark pions back to SM jets. No current LHC searches are sensitive to this type of phenomenology. We perform a detailed simulation for a benchmark signal with two regular and two emerging jets, and present and implement strategies to suppress QCD backgrounds by up to six orders of magnitude. At the 14 TeV LHC, this signature can be probed with mediator masses as large as 1.5 TeV for a range of dark pion lifetimes, and the reach is increased further at the high-luminosity LHC. The emerging jet search is also sensitive to a broad class of long-lived phenomena, and we show this for a supersymmetric model with R-parity violation. Possibilities for discovery at LHCb are also discussed.

Using neural networks with jet shapes to identify b jets in e+e- interactions

International Nuclear Information System (INIS)

Bellantoni, L.; Conway, J.S.; Jacobsen, J.E.; Pan, Y.B.; Wu Saulan

1991-01-01

A feed-forward neural network trained using backpropagation was used to discriminate between b and light quark jets in e + e - → Z 0 → qanti q events. The information presented to the network consisted of 25 jet shape variables. The network successfully identified b jets in two- and three-jet events modeled using a detector simulation. The jet identification efficiency for two-jet events was 61% and the probability to call a light quark jet a b jet equal to 20%. (orig.)

Intracellular Targeting of CEA Results in Th1-Type Antibody Responses Following Intradermal Genetic Vaccination by a Needle-Free Jet Injection Device

Directory of Open Access Journals (Sweden)

Susanne Johansson

2007-01-01

Full Text Available The route and method of immunization, as well as the cellular localization of the antigen, can influence the generation of an immune response. In general, intramuscular immunization results in Th1 responses, whereas intradermal delivery of DNA by gene gun immunization often results in more Th2 responses. Here we investigate how altering the cellular localization of the tumor antigen CEA (carcinoembryonic antigen affects the quality and amplitude of DNA vaccine-induced antibody responses in mice following intradermal delivery of DNA by a needle-free jet injection device (Biojector. CEA was expressed either in a membrane-bound form (wild-type CEA or in two truncated forms (CEA6 and CEA66 with cytoplasmic localization, where CEA66 was fused to a promiscuous T-helper epitope from tetanus toxin. Repeated intradermal immunization of BALB/c mice with DNA encoding wild-type CEA produced high antibody titers of a mixed IgG1/IgG2a ratio. In contrast, utilizing the DNA construct that resulted in intracellular targeting of CEA led to a reduced capacity to induce CEA-specific antibodies, but instead induced a Th1-biased immune response.

Analysis of jet flames and unignited jets from unintended releases of hydrogen

Energy Technology Data Exchange (ETDEWEB)

Houf, W.G.; Evans, G.H.; Schefer, R.W. [Sandia National Laboratories, Livermore, CA 94551-0969 (United States)

2009-07-15

A combined experimental and modeling program is being carried out at Sandia National Laboratories to characterize and predict the behavior of unintended hydrogen releases. In the case where the hydrogen leak remains unignited, knowledge of the concentration field and flammability envelope is an issue of importance in determining consequence distances for the safe use of hydrogen. In the case where a high-pressure leak of hydrogen is ignited, a classic turbulent jet flame forms. Knowledge of the flame length and thermal radiation heat flux distribution is important to safety. Depending on the effective diameter of the leak and the tank source pressure, free jet flames can be extensive in length and pose significant radiation and impingement hazard, resulting in consequence distances that are unacceptably large. One possible mitigation strategy to potentially reduce the exposure to jet flames is to incorporate barriers around hydrogen storage equipment. The reasoning is that walls will reduce the extent of unacceptable consequences due to jet releases resulting from accidents involving high-pressure equipment. While reducing the jet extent, the walls may introduce other hazards if not configured properly. The goal of this work is to provide guidance on configuration and placement of these walls to minimize overall hazards using a quantitative risk assessment approach. The program includes detailed CFD calculations of jet flames and unignited jets to predict how hydrogen leaks and jet flames interact with barriers, complemented by an experimental validation program that considers the interaction of jet flames and unignited jets with barriers. As a first step in this work on barrier release interaction the Sandia CFD model has been validated by computing the concentration decay of unignited turbulent free jets and comparing the results with the classic concentration decay laws for turbulent free jets taken from experimental data. Computations for turbulent hydrogen

Production of radiatively cooled hypersonic plasma jets and links to astrophysical jets

International Nuclear Information System (INIS)

Lebedev, S V; Ciardi, A; Ampleford, D J; Bland, S N; Bott, S C; Chittenden, J P; Hall, G N; Rapley, J; Jennings, C; Sherlock, M; Frank, A; Blackman, E G

2005-01-01

We present results of high energy density laboratory experiments on the production of supersonic radiatively cooled plasma jets with dimensionless parameters (Mach number ∼30, cooling parameter ∼1 and density contrast ρ j /ρ a ∼ 10) similar to those in young stellar objects jets. The jets are produced using two modifications of wire array Z-pinch driven by 1 MA, 250 ns current pulse of MAGPIE facility at Imperial College, London. In the first set of experiments the produced jets are purely hydrodynamic and are used to study deflection of the jets by the plasma cross-wind, including the structure of internal oblique shocks in the jets. In the second configuration the jets are driven by the pressure of the toroidal magnetic field and this configuration is relevant to the astrophysical models of jet launching mechanisms. Modifications of the experimental configuration allowing the addition of the poloidal magnetic field and angular momentum to the jets are also discussed. We also present three-dimensional resistive magneto-hydrodynamic simulations of the experiments and discuss the scaling of the experiments to the astrophysical systems

Jet Vertex Charge Reconstruction

CERN Document Server

Nektarijevic, Snezana; The ATLAS collaboration

2015-01-01

A newly developed algorithm called the jet vertex charge tagger, aimed at identifying the sign of the charge of jets containing $b$-hadrons, referred to as $b$-jets, is presented. In addition to the well established track-based jet charge determination, this algorithm introduces the so-called \\emph{jet vertex charge} reconstruction, which exploits the charge information associated to the displaced vertices within the jet. Furthermore, the charge of a soft muon contained in the jet is taken into account when available. All available information is combined into a multivariate discriminator. The algorithm has been developed on jets matched to generator level $b$-hadrons provided by $t\\bar{t}$ events simulated at $\\sqrt{s}$=13~TeV using the full ATLAS detector simulation and reconstruction.

Phenomenology of jets

International Nuclear Information System (INIS)

Walsh, T.F.

1980-05-01

The basic idea of these lectures is very simple. Quarks and gluons - the elementary quanta of quantum chromodynamics or QCD - are produced with perturbarively calculable rates in short distance processes. This is because of asymptotic freedom. These quanta produced at short distances are, in a sense, 'visible' as jets of hadrons. (The jets do not contain the colored QCD quanta if - as we will assume - color is confined. The jets contain only colorless hadrons.) The distribution of these jets is the distribution of the original quanta, apart from fluctuations generated in the (long distance) jet formation process. The distribution of the jets can thus thest QCD in a particularly clear way at the parton level, at distance of order 5 x 10 -16 cm (PETRA/PEP energies). (orig.)

NASA Jet Noise Research

Science.gov (United States)

Henderson, Brenda

2016-01-01

The presentation highlights NASA's jet noise research for 2016. Jet-noise modeling efforts, jet-surface interactions results, acoustic characteristics of multi-stream jets, and N+2 Supersonic Aircraft system studies are presented.

Effect of outer stagnation pressure on jet structure in supersonic coaxial jet

International Nuclear Information System (INIS)

Kim, Myoung Jong; Woo, Sang Woo; Lee, Byeong Eun; Kwon, Soon Bum

2001-01-01

The characteristics of dual coaxial jet which composed of inner supersonic nozzle of 26500 in constant expansion rate with 1.91 design Mach number and outer converging one with 40 .deg. C converging angle with the variation of outer nozzle stagnation pressure are experimentally investigated in this paper. In which the stagnation pressure for the inner supersonic nozzle is 750kPa thus, the inner jet leaving the nozzle is slightly underexpanded. The plenum pressure of outer nozzle are varied from 200 to 600kPa. Flow visualizations by shadowgraph method, impact pressure and centerline static pressure measurements of dual coaxial jet are presented. The results show that the presence of outer jet affects significantly the structures and pressure distributions of inner jet. And outer jet causes Mach disk which does not appear for the case of single jet stream. As the stagnation pressure of outer jet increases, impact pressure undulation is severe, but the average impact pressure keeps high far downstream

Comparison of runaway electron generation parameters in small, medium-sized and large tokamaks—A survey of experiments in COMPASS, TCV, ASDEX-Upgrade and JET

Science.gov (United States)

Plyusnin, V. V.; Reux, C.; Kiptily, V. G.; Pautasso, G.; Decker, J.; Papp, G.; Kallenbach, A.; Weinzettl, V.; Mlynar, J.; Coda, S.; Riccardo, V.; Lomas, P.; Jachmich, S.; Shevelev, A. E.; Alper, B.; Khilkevitch, E.; Martin, Y.; Dux, R.; Fuchs, C.; Duval, B.; Brix, M.; Tardini, G.; Maraschek, M.; Treutterer, W.; Giannone, L.; Mlynek, A.; Ficker, O.; Martin, P.; Gerasimov, S.; Potzel, S.; Paprok, R.; McCarthy, P. J.; Imrisek, M.; Boboc, A.; Lackner, K.; Fernandes, A.; Havlicek, J.; Giacomelli, L.; Vlainic, M.; Nocente, M.; Kruezi, U.; COMPASS Team; TCV Team; ASDEX-Upgrade Team; EUROFusion MST1 Team; contributors, JET

2018-01-01

This paper presents a survey of the experiments on runaway electrons (RE) carried out recently in frames of EUROFusion Consortium in different tokamaks: COMPASS, ASDEX-Upgrade, TCV and JET. Massive gas injection (MGI) has been used in different scenarios for RE generation in small and medium-sized tokamaks to elaborate the most efficient and reliable ones for future RE experiments. New data on RE generated at disruptions in COMPASS and ASDEX-Upgrade was collected and added to the JET database. Different accessible parameters of disruptions, such as current quench rate, conversion rate of plasma current into runaways, etc have been analysed for each tokamak and compared to JET data. It was shown, that tokamaks with larger geometrical sizes provide the wider limits for spatial and temporal variation of plasma parameters during disruptions, thus extending the parameter space for RE generation. The second part of experiments was dedicated to study of RE generation in stationary discharges in COMPASS, TCV and JET. Injection of Ne/Ar have been used to mock-up the JET MGI runaway suppression experiments. Secondary RE avalanching was identified and quantified for the first time in the TCV tokamak in RE generating discharges after massive Ne injection. Simulations of the primary RE generation and secondary avalanching dynamics in stationary discharges has demonstrated that RE current fraction created via avalanching could achieve up to 70-75% of the total plasma current in TCV. Relaxations which are reminiscent the phenomena associated to the kinetic instability driven by RE have been detected in RE discharges in TCV. Macroscopic parameters of RE dominating discharges in TCV before and after onset of the instability fit well to the empirical instability criterion, which was established in the early tokamaks and examined by results of recent numerical simulations.

Jets in Planetary Atmospheres

Science.gov (United States)

Dowling, Tim

2018-05-01

Jet streams, "jets" for short, are remarkably coherent streams of air found in every major atmosphere. They have a profound effect on a planet's global circulation, and have been an enigma since the belts and zones of Jupiter were discovered in the 1600s. The study of jets, including what processes affect their size, strength, direction, shear stability, and predictability, are active areas of research in geophysical fluid dynamics. Jet research is multidisciplinary and global, involving collaborations between observers, experimentalists, numerical modelers, and applied mathematicians. Jets in atmospheres have strong analogies with shear instability in nonneutral plasmas, and these connections are highlighted throughout the article. The article begins with a description of four major challenges that jet researchers face: nonlinearity, non-intuitive wave physics, non-constant-coefficients, and copious nondimensional numbers. Then, two general fluid-dynamical tenets, the practice of rendering expressions dimensionally homogeneous (nondimensional), and the universal properties of shocks are applied to the open question of what controls the on-off switch of shear instability. The discussion progresses to how the physics of jets varies in equatorial, midlatitude, and polar regions, and how jets are observed to behave in each of these settings. The all-in-one conservation law of potential vorticity (PV), which combines the conservation laws of mass, momentum, and thermal energy into a single expression, is the common language of jet research. Earth and Uranus have weak retrograde equatorial jets, but most planets exhibit super-rotating equatorial jets, which require eddies to transport momentum up gradient in a non-intuitive manner. Jupiter and Saturn exhibit multiple alternating jets in their midlatitudes. The theory for why jets are invariably zonal (east-west orientated) is reviewed, and the particular challenges that Jupiter's sharp westward jets present to existing

Fluid and gyrokinetic simulations of impurity transport at JET

DEFF Research Database (Denmark)

Nordman, H; Skyman, A; Strand, P

2011-01-01

Impurity transport coefficients due to ion-temperature-gradient (ITG) mode and trapped-electron mode turbulence are calculated using profile data from dedicated impurity injection experiments at JET. Results obtained with a multi-fluid model are compared with quasi-linear and nonlinear gyrokinetic...... simulation results obtained with the code GENE. The sign of the impurity convective velocity (pinch) and its various contributions are discussed. The dependence of the impurity transport coefficients and impurity peaking factor −∇nZ/nZ on plasma parameters such as impurity charge number Z, ion logarithmic...

JET Radiative Mantle Experiments in ELMy H-Mode

International Nuclear Information System (INIS)

Budny, R.; Coffey, I.; Dumortier, P.; Grisolia, C.; Strachan, J.D.

1999-01-01

Radiative mantle experiments were performed on JET ELMy H-mode plasmas. The Septum configuration was used where the X-point is embedded into the top of the Septum. Argon radiated 50% of the input power from the bulk plasma while Z eff rose from an intrinsic level of 1.5 to about 1.7 due to the injected Argon. The total energy content and global energy confinement time decreased 15% when the impurities were introduced. In contrast, the effective thermal diffusivity in the core confinement region (r/a = .4--.8) decreased by 30%. Usually, JET ELMy H-mode plasmas have confinement that is correlated to the edge pedestal pressure. The radiation lowered the edge pedestal and consequently lowered the global confinement. Thus the confinement was changed by a competition between the edge pedestal reduction lowering the confinement and the weaker RI effect upon the core transport coefficients raising the confinement. The ELM frequency increased from 10 Hz Type I ELMs, to 200 Hz type III ELMs. The energy lost by each ELM reduced to 0.5% of the plasma energy content

Performance of large-R jets and jet substructure reconstruction with the ATLAS detector

CERN Document Server

The ATLAS collaboration

2012-01-01

This paper presents the application of techniques to study jet substructure. The performance of modified jet algorithms for a variety of jet types and event topologies is investigated. Properties of jets subjected to the mass-drop filtering, trimming and pruning algorithms are found to have a reduced sensitivity to multiple proton-proton interactions and exhibit improved stability at high luminosity. Monte Carlo studies of the signal-background discrimination with jet grooming in new physics searches based on jet invariant mass and jet substructure properties are also presented. The application of jet trimming is shown to improve the robustness of large-R jet measurements, reduce sensitivity to the superfluous effects due to the intense environment of the high luminosity LHC, and improve the physics potential of searches for heavy boosted objects. The analyses presented in this note use the full 2011 ATLAS dataset, corresponding to an integrated luminosity of 4.7 \\pm 0.2 fb−1 .

Technical and Scientific Aspects of the JET Trace-Tritium Experimental Campaign

International Nuclear Information System (INIS)

Jones, T.T.C.; Brennan, D; Pearce, R.J.H.; Stork, D.; Zastrow, K.-D.; Balshaw, N.; Bell, A.C.; Bertalot, L.; Boyer, H.; Butcher, P.R.; Challis, C.D.; Ciric, D.; Clarke, R.; Conroy, S.; Darke, A.C.; Davies, N.; Edlington, T.; Ericsson, G.; Gibbons, C.; Hackett, L.J.; Haupt, T.; Hitchin, M.; Kaye, A.S.; King, R.; Kiptily, V.G.; Knipe, S.; Lawrence, G.; Lobel, R.; Mason, A.; Morgan, P.D.; Patel, B.; Popovichev, S.; Stamp, M.; Surrey, E.; Terrington, A.; Worth, L.; Young, D.

2005-01-01

The JET Trace Tritium (TTE) programme marked the first use of tritium in experiments under the managerial control of UKAEA, which operates the JET Facility on behalf of EFDA. The introduction of tritium into the plasma by gas fuelling and neutral beam injection, even in trace quantities, required the mobilisation of gram-quantities of tritium gas from the Active Gas Handling System (AGHS) product storage units into the supply lines connected to the torus gas valve and the neutral beam injectors. All systems for DT gas handling, recovery and reprocessing were therefore recommissioned and operating procedures re-established, involving extensive operations staff training. The validation of Key Safety Related Equipment (KSRE) is described with reference to specific examples. The differences between requirements for TTE and full DT operations are shown to be relatively small. The scientific motivation for TTE, such as the possibility to obtain high-quality measurements in key areas such as fuel-ion transport and fast ion dynamics, is described, and the re-establishment and development of JET's 14MeV neutron diagnostic capability for TTE and future DT campaigns are outlined. Some scientific highlights from the TTE campaign are presented

Transport studies during sawteeth and H-modes on JET using laser ablation

Energy Technology Data Exchange (ETDEWEB)

Wang, Z; Barnsley, R; Denne, B; Edwards, A; Gianella, R; Gill, R; Magyar, G; Pasini, D [Commission of the European Communities, Abingdon (UK). JET Joint Undertaking; Hawkes, N; Peacock, N [UKAEA Culham Lab., Abingdon (UK); Behringer, K; Schumacher, U; Zaschke, D [Max-Planck-Institut fuer Plasmaphysik, Garching (Germany, F.R.); Cohen, S [Princeton Univ., NJ (USA). Plasma Physics Lab.; Vieider, C [Uppsala Institute of Technology, Uppsala (Sweden)

1989-01-01

A system for the controlled injection of trace impurities by laser ablation has recently been commissioned on JET. Small amounts of metallic impurities have been injected in order to study transport phenomena. In all cases the amounts, corresponding to an injected quantity of a few 10/sup 18/ atoms (an impurity concentration of 0.01% of n/sub e/), were sufficiently small to avoid perturbing any plasma parameter apart from the radiation ({Delta}P/sub rad/<0.5 MW). We report here on measurements of impurity confinement time (tau/sub imp/) and observations of impurity transport effects using this technique. A suite of spectrometers viewing fixed lines of sight was used to gather information on the time behaviour of a range of ionisation stages. In addition measurements of the soft X-ray emission were obtained with good spatial and temporal resolution from two X-ray cameras. (author) 4 refs., 6 figs.

Fabrication of Microglass Nozzle for Microdroplet Jetting

Directory of Open Access Journals (Sweden)

Dan Xie

2015-02-01

Full Text Available An ejection aperture nozzle is the essential part for all microdrop generation techniques. The diameter size, the flow channel geometry, and fluid impedance are the key factors affecting the ejection capacity. A novel low-cost fabrication method of microglass nozzle involving four steps is developed in this work. In the first heating step, the glass pipette is melted and pulled. Then, the second heating step is to determine the tip cone angle and modify the flow channel geometry. The desired included angle is usually of 30~45 degrees. Fine grind can determine the exact diameter of the hole. Postheating step is the final process and it can reduce the sharpness of the edges of the hole. Micronozzles with hole diameters varying from 30 to 100 µm are fabricated by the homemade inexpensive and easy-to-operate setup. Hydrophobic treating method of microglass nozzle to ensure stable and accurate injection is also introduced in this work. According to the jetting results of aqueous solution, UV curing adhesive, and solder, the fabricated microglass nozzle can satisfy the need of microdroplet jetting of multimaterials.

Studies of jet mass in dijet and W/Z + jet events

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M.; Hirschauer, J.; Hooberman, B.; Jindariani, S.; Johnson, M.; Joshi, U.; Klima, B.; Kunori, S.; Kwan, S.; Leonidopoulos, C.; Linacre, J.; Lincoln, D.; Lipton, R.; Lykken, J.; Maeshima, K.; Marraffino, J. M.; Martinez Outschoorn, V. I.; Maruyama, S.; Mason, D.; McBride, P.; Mishra, K.; Mrenna, S.; Musienko, Y.; Newman-Holmes, C.; O’Dell, V.; Sexton-Kennedy, E.; Sharma, S.; Spalding, W. J.; Spiegel, L.; Taylor, L.; Tkaczyk, S.; Tran, N. V.; Uplegger, L.; Vaandering, E. W.; Vidal, R.; Whitmore, J.; Wu, W.; Yang, F.; Yun, J. C.; Acosta, D.; Avery, P.; Bourilkov, D.; Chen, M.; Cheng, T.; Das, S.; De Gruttola, M.; Di Giovanni, G. P.; Dobur, D.; Drozdetskiy, A.; Field, R. D.; Fisher, M.; Fu, Y.; Furic, I. K.; Gartner, J.; Hugon, J.; Kim, B.; Konigsberg, J.; Korytov, A.; Kropivnitskaya, A.; Kypreos, T.; Low, J. 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D.; Ma, T.; Nahn, S.; Paus, C.; Ralph, D.; Roland, C.; Roland, G.; Rudolph, M.; Stephans, G. S. F.; Stöckli, F.; Sumorok, K.; Sung, K.; Velicanu, D.; Wenger, E. A.; Wolf, R.; Wyslouch, B.; Yang, M.; Yilmaz, Y.; Yoon, A. S.; Zanetti, M.; Zhukova, V.; Dahmes, B.; De Benedetti, A.; Franzoni, G.; Gude, A.; Haupt, J.; Kao, S. C.; Klapoetke, K.; Kubota, Y.; Mans, J.; Pastika, N.; Rusack, R.; Sasseville, M.; Singovsky, A.; Tambe, N.; Turkewitz, J.; Cremaldi, L. M.; Kroeger, R.; Perera, L.; Rahmat, R.; Sanders, D. A.; Avdeeva, E.; Bloom, K.; Bose, S.; Claes, D. R.; Dominguez, A.; Eads, M.; Keller, J.; Kravchenko, I.; Lazo-Flores, J.; Malik, S.; Snow, G. R.; Godshalk, A.; Iashvili, I.; Jain, S.; Kharchilava, A.; Kumar, A.; Rappoccio, S.; Wan, Z.; Alverson, G.; Barberis, E.; Baumgartel, D.; Chasco, M.; Haley, J.; Nash, D.; Orimoto, T.; Trocino, D.; Wood, D.; Zhang, J.; Anastassov, A.; Hahn, K. A.; Kubik, A.; Lusito, L.; Mucia, N.; Odell, N.; Ofierzynski, R. 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T.; Leonardo, N.; Maroussov, V.; Merkel, P.; Miller, D. H.; Neumeister, N.; Shipsey, I.; Silvers, D.; Svyatkovskiy, A.; Vidal Marono, M.; Yoo, H. D.; Zablocki, J.; Zheng, Y.; Guragain, S.; Parashar, N.; Adair, A.; Akgun, B.; Boulahouache, C.; Ecklund, K. M.; Geurts, F. J. M.; Li, W.; Padley, B. P.; Redjimi, R.; Roberts, J.; Zabel, J.; Betchart, B.; Bodek, A.; Chung, Y. S.; Covarelli, R.; de Barbaro, P.; Demina, R.; Eshaq, Y.; Ferbel, T.; Garcia-Bellido, A.; Goldenzweig, P.; Han, J.; Harel, A.; Miner, D. C.; Vishnevskiy, D.; Zielinski, M.; Bhatti, A.; Ciesielski, R.; Demortier, L.; Goulianos, K.; Lungu, G.; Malik, S.; Mesropian, C.; Arora, S.; Barker, A.; Chou, J. 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W.; Balazs, M.; Boutle, S.; Cox, B.; Francis, B.; Goodell, J.; Hirosky, R.; Ledovskoy, A.; Lin, C.; Neu, C.; Wood, J.; Gollapinni, S.; Harr, R.; Karchin, P. E.; Kottachchi Kankanamge Don, C.; Lamichhane, P.; Sakharov, A.; Anderson, M.; Belknap, D. A.; Borrello, L.; Carlsmith, D.; Cepeda, M.; Dasu, S.; Friis, E.; Gray, L.; Grogg, K. S.; Grothe, M.; Hall-Wilton, R.; Herndon, M.; Hervé, A.; Klabbers, P.; Klukas, J.; Lanaro, A.; Lazaridis, C.; Loveless, R.; Mohapatra, A.; Mozer, M. U.; Ojalvo, I.; Palmonari, F.; Pierro, G. A.; Ross, I.; Savin, A.; Smith, W. H.; Swanson, J.

2013-05-01

Invariant mass spectra for jets reconstructed using the anti-kt and Cambridge-Aachen algorithms are studied for different jet "grooming" techniques in data corresponding to an integrated luminosity of 5 inverse femtobarns, recorded with the CMS detector in proton-proton collisions at the LHC at a center-of-mass energy of 7 TeV. Leading-order QCD predictions for inclusive dijet and W/Z+jet production combined with parton-shower Monte Carlo models are found to agree overall with the data, and the agreement improves with the implementation of jet grooming methods used to distinguish merged jets of large transverse momentum from softer QCD gluon radiation.

Studies of jet mass in dijet and W/Z+jet events

CERN Document Server

Chatrchyan, Serguei; Sirunyan, Albert M; Tumasyan, Armen; Adam, Wolfgang; Aguilo, Ernest; Bergauer, Thomas; Dragicevic, Marko; Erö, Janos; Fabjan, Christian; Friedl, Markus; Fruehwirth, Rudolf; Ghete, Vasile Mihai; Hörmann, Natascha; Hrubec, Josef; Jeitler, Manfred; Kiesenhofer, Wolfgang; Knünz, Valentin; Krammer, Manfred; Krätschmer, Ilse; Liko, Dietrich; Mikulec, Ivan; Pernicka, Manfred; Rabady, Dinyar; Rahbaran, Babak; Rohringer, Christine; Rohringer, Herbert; Schöfbeck, Robert; Strauss, Josef; Taurok, Anton; Waltenberger, Wolfgang; Wulz, Claudia-Elisabeth; Mossolov, Vladimir; Shumeiko, Nikolai; Suarez Gonzalez, Juan; Alderweireldt, Sara; Bansal, Monika; Bansal, Sunil; Cornelis, Tom; De Wolf, Eddi A; Janssen, Xavier; Luyckx, Sten; Mucibello, Luca; Ochesanu, Silvia; Roland, Benoit; Rougny, Romain; Van Haevermaet, Hans; Van Mechelen, Pierre; Van Remortel, Nick; Van Spilbeeck, Alex; Blekman, Freya; Blyweert, Stijn; D'Hondt, Jorgen; Gonzalez Suarez, Rebeca; Kalogeropoulos, Alexis; Maes, Michael; Olbrechts, Annik; Tavernier, Stefaan; Van Doninck, Walter; Van Mulders, Petra; Van Onsem, Gerrit Patrick; Villella, Ilaria; Clerbaux, Barbara; De Lentdecker, Gilles; Dero, Vincent; Gay, Arnaud; Hreus, Tomas; Léonard, Alexandre; Marage, Pierre Edouard; Mohammadi, Abdollah; Reis, Thomas; Thomas, Laurent; Vander Velde, Catherine; Vanlaer, Pascal; Wang, Jian; Adler, Volker; Beernaert, Kelly; Cimmino, Anna; Costantini, Silvia; Garcia, Guillaume; Grunewald, Martin; Klein, Benjamin; Lellouch, Jérémie; Marinov, Andrey; Mccartin, Joseph; Ocampo Rios, Alberto Andres; Ryckbosch, Dirk; Sigamani, Michael; Strobbe, Nadja; Thyssen, Filip; Tytgat, Michael; Walsh, Sinead; Yazgan, Efe; Zaganidis, Nicolas; Basegmez, Suzan; Bruno, Giacomo; Castello, Roberto; Ceard, Ludivine; Delaere, Christophe; Du Pree, Tristan; Favart, Denis; Forthomme, Laurent; Giammanco, Andrea; Hollar, Jonathan; Lemaitre, Vincent; Liao, Junhui; Militaru, Otilia; Nuttens, Claude; Pagano, Davide; Pin, Arnaud; Piotrzkowski, Krzysztof; Selvaggi, Michele; Vizan Garcia, Jesus Manuel; Beliy, Nikita; Caebergs, Thierry; Daubie, Evelyne; Hammad, Gregory Habib; Alves, Gilvan; Correa Martins Junior, Marcos; Martins, Thiago; Pol, Maria Elena; Henrique Gomes E Souza, Moacyr; Aldá Júnior, Walter Luiz; Carvalho, Wagner; Chinellato, Jose; Custódio, Analu; Melo Da Costa, Eliza; De Jesus Damiao, Dilson; De Oliveira Martins, Carley; Fonseca De Souza, Sandro; Malbouisson, Helena; Malek, Magdalena; Matos Figueiredo, Diego; Mundim, Luiz; Nogima, Helio; Prado Da Silva, Wanda Lucia; Santoro, Alberto; Soares Jorge, Luana; Sznajder, Andre; Tonelli Manganote, Edmilson José; Vilela Pereira, Antonio; Souza Dos Anjos, Tiago; Bernardes, Cesar Augusto; De Almeida Dias, Flavia; Tomei, Thiago; De Moraes Gregores, Eduardo; Lagana, Caio; Da Cunha Marinho, Franciole; Mercadante, Pedro G; Novaes, Sergio F; Padula, Sandra; Genchev, Vladimir; Iaydjiev, Plamen; Piperov, Stefan; Rodozov, Mircho; Stoykova, Stefka; Sultanov, Georgi; Tcholakov, Vanio; Trayanov, Rumen; Vutova, Mariana; Dimitrov, Anton; Hadjiiska, Roumyana; Kozhuharov, Venelin; Litov, Leander; Pavlov, Borislav; Petkov, Peicho; Bian, Jian-Guo; Chen, Guo-Ming; Chen, He-Sheng; Jiang, Chun-Hua; Liang, Dong; Liang, Song; Meng, Xiangwei; Tao, Junquan; Wang, Jian; Wang, Xianyou; Wang, Zheng; Xiao, Hong; Xu, Ming; Zang, Jingjing; Zhang, Zhen; Asawatangtrakuldee, Chayanit; Ban, Yong; Guo, Yifei; Li, Qiang; Li, Wenbo; Liu, Shuai; Mao, Yajun; Qian, Si-Jin; Wang, Dayong; Zhang, Linlin; Zou, Wei; Avila, Carlos; Carrillo Montoya, Camilo Andres; Gomez, Juan Pablo; Gomez Moreno, Bernardo; Osorio Oliveros, Andres Felipe; Sanabria, Juan Carlos; Godinovic, Nikola; Lelas, Damir; Plestina, Roko; Polic, Dunja; Puljak, Ivica; Antunovic, Zeljko; Kovac, Marko; Brigljevic, Vuko; Duric, Senka; Kadija, Kreso; Luetic, Jelena; Mekterovic, Darko; Morovic, Srecko; Tikvica, Lucija; Attikis, Alexandros; Galanti, Mario; Mavromanolakis, Georgios; Mousa, Jehad; Nicolaou, Charalambos; Ptochos, Fotios; Razis, Panos A; Finger, Miroslav; Finger Jr, Michael; Assran, Yasser; Elgammal, Sherif; Ellithi Kamel, Ali; Mahmoud, Mohammed; Radi, Amr; Kadastik, Mario; Müntel, Mait; Murumaa, Marion; Raidal, Martti; Rebane, Liis; Tiko, Andres; Eerola, Paula; Fedi, Giacomo; Voutilainen, Mikko; Härkönen, Jaakko; Heikkinen, Mika Aatos; Karimäki, Veikko; Kinnunen, Ritva; Kortelainen, Matti J; Lampén, Tapio; Lassila-Perini, Kati; Lehti, Sami; Lindén, Tomas; Luukka, Panja-Riina; Mäenpää, Teppo; Peltola, Timo; Tuominen, Eija; Tuominiemi, Jorma; Tuovinen, Esa; Ungaro, Donatella; Wendland, Lauri; Korpela, Arja; Tuuva, Tuure; Besancon, Marc; Choudhury, Somnath; Couderc, Fabrice; Dejardin, Marc; Denegri, Daniel; Fabbro, Bernard; Faure, Jean-Louis; Ferri, Federico; Ganjour, Serguei; Givernaud, Alain; Gras, Philippe; Hamel de Monchenault, Gautier; Jarry, Patrick; Locci, Elizabeth; Malcles, Julie; Millischer, Laurent; Nayak, Aruna; Rander, John; Rosowsky, André; Titov, Maksym; Baffioni, Stephanie; Beaudette, Florian; Benhabib, Lamia; Bianchini, Lorenzo; Bluj, Michal; Busson, Philippe; Charlot, Claude; Daci, Nadir; Dahms, Torsten; Dalchenko, Mykhailo; Dobrzynski, Ludwik; Florent, Alice; Granier de Cassagnac, Raphael; Haguenauer, Maurice; Miné, Philippe; Mironov, Camelia; Naranjo, Ivo Nicolas; Nguyen, Matthew; Ochando, Christophe; Paganini, Pascal; Sabes, David; Salerno, Roberto; Sirois, Yves; Veelken, Christian; Zabi, Alexandre; Agram, Jean-Laurent; Andrea, Jeremy; Bloch, Daniel; Bodin, David; Brom, Jean-Marie; Cardaci, Marco; Chabert, Eric Christian; Collard, Caroline; Conte, Eric; Drouhin, Frédéric; Fontaine, Jean-Charles; Gelé, Denis; Goerlach, Ulrich; Juillot, Pierre; Le Bihan, Anne-Catherine; Van Hove, Pierre; Beauceron, Stephanie; Beaupere, Nicolas; Bondu, Olivier; Boudoul, Gaelle; Brochet, Sébastien; Chasserat, Julien; Chierici, Roberto; Contardo, Didier; Depasse, Pierre; El Mamouni, Houmani; Fay, Jean; Gascon, Susan; Gouzevitch, Maxime; Ille, Bernard; Kurca, Tibor; Lethuillier, Morgan; Mirabito, Laurent; Perries, Stephane; Sgandurra, Louis; Sordini, Viola; Tschudi, Yohann; Verdier, Patrice; Viret, Sébastien; Tsamalaidze, Zviad; Autermann, Christian; Beranek, Sarah; Calpas, Betty; Edelhoff, Matthias; Feld, Lutz; Heracleous, Natalie; Hindrichs, Otto; Jussen, Ruediger; Klein, Katja; Merz, Jennifer; Ostapchuk, Andrey; Perieanu, Adrian; Raupach, Frank; Sammet, Jan; Schael, Stefan; Sprenger, Daniel; Weber, Hendrik; Wittmer, Bruno; Zhukov, Valery; Ata, Metin; Caudron, Julien; Dietz-Laursonn, Erik; Duchardt, Deborah; Erdmann, Martin; Fischer, Robert; Güth, Andreas; Hebbeker, Thomas; Heidemann, Carsten; Hoepfner, Kerstin; Klingebiel, Dennis; Kreuzer, Peter; Merschmeyer, Markus; Meyer, Arnd; Olschewski, Mark; Padeken, Klaas; Papacz, Paul; Pieta, Holger; Reithler, Hans; Schmitz, Stefan Antonius; Sonnenschein, Lars; Steggemann, Jan; Teyssier, Daniel; Thüer, Sebastian; Weber, Martin; Bontenackels, Michael; Cherepanov, Vladimir; Erdogan, Yusuf; Flügge, Günter; Geenen, Heiko; Geisler, Matthias; Haj Ahmad, Wael; Hoehle, Felix; Kargoll, Bastian; Kress, Thomas; Kuessel, Yvonne; Lingemann, Joschka; Nowack, Andreas; Nugent, Ian Michael; Perchalla, Lars; Pooth, Oliver; Sauerland, Philip; Stahl, Achim; Aldaya Martin, Maria; Asin, Ivan; Bartosik, Nazar; Behr, Joerg; Behrenhoff, Wolf; Behrens, Ulf; Bergholz, Matthias; Bethani, Agni; Borras, Kerstin; Burgmeier, Armin; Cakir, Altan; Calligaris, Luigi; Campbell, Alan; Castro, Elena; Costanza, Francesco; Dammann, Dirk; Diez Pardos, Carmen; Dorland, Tyler; Eckerlin, Guenter; Eckstein, Doris; Flucke, Gero; Geiser, Achim; Glushkov, Ivan; Gunnellini, Paolo; Habib, Shiraz; Hauk, Johannes; Hellwig, Gregor; Jung, Hannes; Kasemann, Matthias; Katsas, Panagiotis; Kleinwort, Claus; Kluge, Hannelies; Knutsson, Albert; Krämer, Mira; Krücker, Dirk; Kuznetsova, Ekaterina; Lange, Wolfgang; Leonard, Jessica; Lohmann, Wolfgang; Lutz, Benjamin; Mankel, Rainer; Marfin, Ihar; Marienfeld, Markus; Melzer-Pellmann, Isabell-Alissandra; Meyer, Andreas Bernhard; Mnich, Joachim; Mussgiller, Andreas; Naumann-Emme, Sebastian; Novgorodova, Olga; Nowak, Friederike; Olzem, Jan; Perrey, Hanno; Petrukhin, Alexey; Pitzl, Daniel; Raspereza, Alexei; Ribeiro Cipriano, Pedro M; Riedl, Caroline; Ron, Elias; Rosin, Michele; Salfeld-Nebgen, Jakob; Schmidt, Ringo; Schoerner-Sadenius, Thomas; Sen, Niladri; Spiridonov, Alexander; Stein, Matthias; Walsh, Roberval; Wissing, Christoph; Blobel, Volker; Enderle, Holger; Erfle, Joachim; Gebbert, Ulla; Görner, Martin; Gosselink, Martijn; Haller, Johannes; Hermanns, Thomas; Höing, Rebekka Sophie; Kaschube, Kolja; Kaussen, Gordon; Kirschenmann, Henning; Klanner, Robert; Lange, Jörn; Peiffer, Thomas; Pietsch, Niklas; Rathjens, Denis; Sander, Christian; Schettler, Hannes; Schleper, Peter; Schlieckau, Eike; Schmidt, Alexander; Schröder, Matthias; Schum, Torben; Seidel, Markus; Sibille, Jennifer; Sola, Valentina; Stadie, Hartmut; Steinbrück, Georg; Thomsen, Jan; Vanelderen, Lukas; Barth, Christian; Baus, Colin; Berger, Joram; Böser, Christian; Chwalek, Thorsten; De Boer, Wim; Descroix, Alexis; Dierlamm, Alexander; Feindt, Michael; Guthoff, Moritz; Hackstein, Christoph; Hartmann, Frank; Hauth, Thomas; Heinrich, Michael; Held, Hauke; Hoffmann, Karl-Heinz; Husemann, Ulrich; Katkov, Igor; Komaragiri, Jyothsna Rani; Lobelle Pardo, Patricia; Martschei, Daniel; Mueller, Steffen; Müller, Thomas; Niegel, Martin; Nürnberg, Andreas; Oberst, Oliver; Oehler, Andreas; Ott, Jochen; Quast, Gunter; Rabbertz, Klaus; Ratnikov, Fedor; Ratnikova, Natalia; Röcker, Steffen; Schilling, Frank-Peter; Schott, Gregory; Simonis, Hans-Jürgen; Stober, Fred-Markus Helmut; Troendle, Daniel; Ulrich, Ralf; Wagner-Kuhr, Jeannine; Wayand, Stefan; Weiler, Thomas; Zeise, Manuel; Anagnostou, Georgios; Daskalakis, Georgios; Geralis, Theodoros; Kesisoglou, Stilianos; Kyriakis, Aristotelis; Loukas, Demetrios; Manolakos, Ioannis; Markou, Athanasios; Markou, Christos; Ntomari, Eleni; Gouskos, Loukas; Mertzimekis, Theodoros; Panagiotou, Apostolos; Saoulidou, Niki; Evangelou, Ioannis; Foudas, Costas; Kokkas, Panagiotis; Manthos, Nikolaos; Papadopoulos, Ioannis; Bencze, Gyorgy; Hajdu, Csaba; Hidas, Pàl; Horvath, Dezso; Sikler, Ferenc; Veszpremi, Viktor; Vesztergombi, Gyorgy; Zsigmond, Anna Julia; Beni, Noemi; Czellar, Sandor; Molnar, Jozsef; Palinkas, Jozsef; Szillasi, Zoltan; Karancsi, János; Raics, Peter; Trocsanyi, Zoltan Laszlo; Ujvari, Balazs; Beri, Suman Bala; Bhatnagar, Vipin; Dhingra, Nitish; Gupta, Ruchi; Kaur, Manjit; Mehta, Manuk Zubin; Mittal, Monika; Nishu, Nishu; Saini, Lovedeep Kaur; Sharma, Archana; Singh, Jasbir; Kumar, Ashok; Kumar, Arun; Ahuja, Sudha; Bhardwaj, Ashutosh; Choudhary, Brajesh C; Malhotra, Shivali; Naimuddin, Md; Ranjan, Kirti; Saxena, Pooja; Sharma, Varun; Shivpuri, Ram Krishen; Banerjee, Sunanda; Bhattacharya, Satyaki; Chatterjee, Kalyanmoy; Dutta, Suchandra; Gomber, Bhawna; Jain, Sandhya; Jain, Shilpi; Khurana, Raman; Modak, Atanu; Mukherjee, Swagata; Roy, Debarati; Sarkar, Subir; Sharan, Manoj; Abdulsalam, Abdulla; Dutta, Dipanwita; Kailas, Swaminathan; Kumar, Vineet; Mohanty, Ajit Kumar; Pant, Lalit Mohan; Shukla, Prashant; Aziz, Tariq; Chatterjee, Rajdeep Mohan; Ganguly, Sanmay; Guchait, Monoranjan; Gurtu, Atul; Maity, Manas; Majumder, Gobinda; Mazumdar, Kajari; Mohanty, Gagan Bihari; Parida, Bibhuti; Sudhakar, Katta; Wickramage, Nadeesha; Banerjee, Sudeshna; Dugad, Shashikant; Arfaei, Hessamaddin; Bakhshiansohi, Hamed; Etesami, Seyed Mohsen; Fahim, Ali; Hashemi, Majid; Hesari, Hoda; Jafari, Abideh; Khakzad, Mohsen; Mohammadi Najafabadi, Mojtaba; Paktinat Mehdiabadi, Saeid; Safarzadeh, Batool; Zeinali, Maryam; Abbrescia, Marcello; Barbone, Lucia; Calabria, Cesare; Chhibra, Simranjit Singh; Colaleo, Anna; Creanza, Donato; De Filippis, Nicola; De Palma, Mauro; Fiore, Luigi; Iaselli, Giuseppe; Maggi, Giorgio; Maggi, Marcello; Marangelli, Bartolomeo; My, Salvatore; Nuzzo, Salvatore; Pacifico, Nicola; Pompili, Alexis; Pugliese, Gabriella; Selvaggi, Giovanna; Silvestris, Lucia; Singh, Gurpreet; Venditti, Rosamaria; Verwilligen, Piet; Zito, Giuseppe; Abbiendi, Giovanni; Benvenuti, Alberto; Bonacorsi, Daniele; Braibant-Giacomelli, Sylvie; Brigliadori, Luca; Capiluppi, Paolo; Castro, Andrea; Cavallo, Francesca Romana; Cuffiani, Marco; Dallavalle, Gaetano-Marco; Fabbri, Fabrizio; Fanfani, Alessandra; Fasanella, Daniele; Giacomelli, Paolo; Grandi, Claudio; Guiducci, Luigi; Marcellini, Stefano; Masetti, Gianni; Meneghelli, Marco; Montanari, Alessandro; Navarria, Francesco; Odorici, Fabrizio; Perrotta, Andrea; Primavera, Federica; Rossi, Antonio; Rovelli, Tiziano; Siroli, Gian Piero; Tosi, Nicolò; Travaglini, Riccardo; Albergo, Sebastiano; Cappello, Gigi; Chiorboli, Massimiliano; Costa, Salvatore; Potenza, Renato; Tricomi, Alessia; Tuve, Cristina; Barbagli, Giuseppe; Ciulli, Vitaliano; Civinini, Carlo; D'Alessandro, Raffaello; Focardi, Ettore; Frosali, Simone; Gallo, Elisabetta; Gonzi, Sandro; Meschini, Marco; Paoletti, Simone; Sguazzoni, Giacomo; Tropiano, Antonio; Benussi, Luigi; Bianco, Stefano; Colafranceschi, Stefano; Fabbri, Franco; Piccolo, Davide; Fabbricatore, Pasquale; Musenich, Riccardo; Tosi, Silvano; Benaglia, Andrea; De Guio, Federico; Di Matteo, Leonardo; Fiorendi, Sara; Gennai, Simone; Ghezzi, Alessio; Lucchini, Marco Toliman; Malvezzi, Sandra; Manzoni, Riccardo Andrea; Martelli, Arabella; Massironi, Andrea; Menasce, Dario; Moroni, Luigi; Paganoni, Marco; Pedrini, Daniele; Ragazzi, Stefano; Redaelli, Nicola; Tabarelli de Fatis, Tommaso; Buontempo, Salvatore; Cavallo, Nicola; De Cosa, Annapaola; Dogangun, Oktay; Fabozzi, Francesco; Iorio, Alberto Orso Maria; Lista, Luca; Meola, Sabino; Merola, Mario; Paolucci, Pierluigi; Azzi, Patrizia; Bacchetta, Nicola; Branca, Antonio; Carlin, Roberto; Checchia, Paolo; Dorigo, Tommaso; Gasparini, Fabrizio; Gasparini, Ugo; Gozzelino, Andrea; Kanishchev, Konstantin; Lacaprara, Stefano; Lazzizzera, Ignazio; Margoni, Martino; Meneguzzo, Anna Teresa; Pazzini, Jacopo; Pozzobon, Nicola; Ronchese, Paolo; Sgaravatto, Massimo; Simonetto, Franco; Torassa, Ezio; Tosi, Mia; Vanini, Sara; Zotto, Pierluigi; Zucchetta, Alberto; Zumerle, Gianni; Gabusi, Michele; Ratti, Sergio P; Riccardi, Cristina; Torre, Paola; Vitulo, Paolo; Biasini, Maurizio; Bilei, Gian Mario; Fanò, Livio; Lariccia, Paolo; Mantovani, Giancarlo; Menichelli, Mauro; Nappi, Aniello; Romeo, Francesco; Saha, Anirban; Santocchia, Attilio; Spiezia, Aniello; Taroni, Silvia; Azzurri, Paolo; Bagliesi, Giuseppe; Bernardini, Jacopo; Boccali, Tommaso; Broccolo, Giuseppe; Castaldi, Rino; D'Agnolo, Raffaele Tito; Dell'Orso, Roberto; Fiori, Francesco; Foà, Lorenzo; Giassi, Alessandro; Kraan, Aafke; Ligabue, Franco; Lomtadze, Teimuraz; Martini, Luca; Messineo, Alberto; Palla, Fabrizio; Rizzi, Andrea; Serban, Alin Titus; Spagnolo, Paolo; Squillacioti, Paola; Tenchini, Roberto; Tonelli, Guido; Venturi, Andrea; Verdini, Piero Giorgio; Barone, Luciano; Cavallari, Francesca; Del Re, Daniele; Diemoz, Marcella; Fanelli, Cristiano; Grassi, Marco; Longo, Egidio; Meridiani, Paolo; Micheli, Francesco; Nourbakhsh, Shervin; Organtini, Giovanni; Paramatti, Riccardo; Rahatlou, Shahram; Soffi, Livia; Amapane, Nicola; Arcidiacono, Roberta; Argiro, Stefano; Arneodo, Michele; Biino, Cristina; Cartiglia, Nicolo; Casasso, Stefano; Costa, Marco; Demaria, Natale; Mariotti, Chiara; Maselli, Silvia; Migliore, Ernesto; Monaco, Vincenzo; Musich, Marco; Obertino, Maria Margherita; Pastrone, Nadia; Pelliccioni, Mario; Potenza, Alberto; Romero, Alessandra; Ruspa, Marta; Sacchi, Roberto; Solano, Ada; Staiano, Amedeo; Belforte, Stefano; Candelise, Vieri; Casarsa, Massimo; Cossutti, Fabio; Della Ricca, Giuseppe; Gobbo, Benigno; Marone, Matteo; Montanino, Damiana; Penzo, Aldo; Schizzi, Andrea; Kim, Tae Yeon; Nam, Soon-Kwon; Chang, Sunghyun; Kim, Dong Hee; Kim, Gui Nyun; Kong, Dae Jung; Park, Hyangkyu; Son, Dong-Chul; Kim, Jae Yool; Kim, Zero Jaeho; Song, Sanghyeon; Choi, Suyong; Gyun, Dooyeon; Hong, Byung-Sik; Jo, Mihee; Kim, Hyunchul; Kim, Tae Jeong; Lee, Kyong Sei; Moon, Dong Ho; Park, Sung Keun; Roh, Youn; Choi, Minkyoo; Kim, Ji Hyun; Park, Chawon; Park, Inkyu; Park, Sangnam; Ryu, Geonmo; Choi, Young-Il; Choi, Young Kyu; Goh, Junghwan; Kim, Min Suk; Kwon, Eunhyang; Lee, Byounghoon; Lee, Jongseok; Lee, Sungeun; Seo, Hyunkwan; Yu, Intae; Bilinskas, Mykolas Jurgis; Grigelionis, Ignas; Janulis, Mindaugas; Juodagalvis, Andrius; Castilla-Valdez, Heriberto; De La Cruz-Burelo, Eduard; Heredia-de La Cruz, Ivan; Lopez-Fernandez, Ricardo; Martínez-Ortega, Jorge; Sánchez Hernández, Alberto; Villasenor-Cendejas, Luis Manuel; Carrillo Moreno, Salvador; Vazquez Valencia, Fabiola; Salazar Ibarguen, Humberto Antonio; Casimiro Linares, Edgar; Morelos Pineda, Antonio; Reyes-Santos, Marco A; Krofcheck, David; Bell, Alan James; Butler, Philip H; Doesburg, Robert; Reucroft, Steve; Silverwood, Hamish; Ahmad, Muhammad; Asghar, Muhammad Irfan; Butt, Jamila; Hoorani, Hafeez R; Khalid, Shoaib; Khan, Wajid Ali; Khurshid, Taimoor; Qazi, Shamona; Shah, Mehar Ali; Shoaib, Muhammad; Bialkowska, Helena; Boimska, Bożena; Frueboes, Tomasz; Górski, Maciej; Kazana, Malgorzata; Nawrocki, Krzysztof; Romanowska-Rybinska, Katarzyna; Szleper, Michal; Wrochna, Grzegorz; Zalewski, Piotr; Brona, Grzegorz; Bunkowski, Karol; Cwiok, Mikolaj; Dominik, Wojciech; Doroba, Krzysztof; Kalinowski, Artur; Konecki, Marcin; Krolikowski, Jan; Misiura, Maciej; Wolszczak, Weronika; Almeida, Nuno; Bargassa, Pedrame; David Tinoco Mendes, Andre; Faccioli, Pietro; Ferreira Parracho, Pedro Guilherme; Gallinaro, Michele; Seixas, Joao; Varela, Joao; Vischia, Pietro; Bunin, Pavel; Golutvin, Igor; Gorbunov, Ilya; Kamenev, Alexey; Karjavin, Vladimir; Konoplyanikov, Viktor; Kozlov, Guennady; Lanev, Alexander; Malakhov, Alexander; Moisenz, Petr; Palichik, Vladimir; Perelygin, Victor; Shmatov, Sergey; Shulha, Siarhei; Smirnov, Vitaly; Volodko, Anton; Zarubin, Anatoli; Evstyukhin, Sergey; Golovtsov, Victor; Ivanov, Yury; Kim, Victor; Levchenko, Petr; Murzin, Victor; Oreshkin, Vadim; Smirnov, Igor; Sulimov, Valentin; Uvarov, Lev; Vavilov, Sergey; Vorobyev, Alexey; Vorobyev, Andrey; Andreev, Yuri; Dermenev, Alexander; Gninenko, Sergei; Golubev, Nikolai; Kirsanov, Mikhail; Krasnikov, Nikolai; Matveev, Viktor; Pashenkov, Anatoli; Tlisov, Danila; Toropin, Alexander; Epshteyn, Vladimir; Erofeeva, Maria; Gavrilov, Vladimir; Kossov, Mikhail; Lychkovskaya, Natalia; Popov, Vladimir; Safronov, Grigory; Semenov, Sergey; Shreyber, Irina; Stolin, Viatcheslav; Vlasov, Evgueni; Zhokin, Alexander; Andreev, Vladimir; Azarkin, Maksim; Dremin, Igor; Kirakosyan, Martin; Leonidov, Andrey; Mesyats, Gennady; Rusakov, Sergey V; Vinogradov, Alexey; Belyaev, Andrey; Boos, Edouard; Dubinin, Mikhail; Dudko, Lev; Ershov, Alexander; Gribushin, Andrey; Klyukhin, Vyacheslav; Kodolova, Olga; Lokhtin, Igor; Markina, Anastasia; Obraztsov, Stepan; Perfilov, Maxim; Petrushanko, Sergey; Popov, Andrey; Sarycheva, Ludmila; Savrin, Viktor; Snigirev, Alexander; Azhgirey, Igor; Bayshev, Igor; Bitioukov, Sergei; Grishin, Viatcheslav; Kachanov, Vassili; Konstantinov, Dmitri; Krychkine, Victor; Petrov, Vladimir; Ryutin, Roman; Sobol, Andrei; Tourtchanovitch, Leonid; Troshin, Sergey; Tyurin, Nikolay; Uzunian, Andrey; Volkov, Alexey; Adzic, Petar; Djordjevic, Milos; Ekmedzic, Marko; Krpic, Dragomir; Milosevic, Jovan; Aguilar-Benitez, Manuel; Alcaraz Maestre, Juan; Arce, Pedro; Battilana, Carlo; Calvo, Enrique; Cerrada, Marcos; Chamizo Llatas, Maria; Colino, Nicanor; De La Cruz, Begona; Delgado Peris, Antonio; Domínguez Vázquez, Daniel; Fernandez Bedoya, Cristina; Fernández Ramos, Juan Pablo; Ferrando, Antonio; Flix, Jose; Fouz, Maria Cruz; Garcia-Abia, Pablo; Gonzalez Lopez, Oscar; Goy Lopez, Silvia; Hernandez, Jose M; Josa, Maria Isabel; Merino, Gonzalo; Puerta Pelayo, Jesus; Quintario Olmeda, Adrián; Redondo, Ignacio; Romero, Luciano; Santaolalla, Javier; Senghi Soares, Mara; Willmott, Carlos; Albajar, Carmen; Codispoti, Giuseppe; de Trocóniz, Jorge F; Brun, Hugues; Cuevas, Javier; Fernandez Menendez, Javier; Folgueras, Santiago; Gonzalez Caballero, Isidro; Lloret Iglesias, Lara; Piedra Gomez, Jonatan; Brochero Cifuentes, Javier Andres; Cabrillo, Iban Jose; Calderon, Alicia; Chuang, Shan-Huei; Duarte Campderros, Jordi; Felcini, Marta; Fernandez, Marcos; Gomez, Gervasio; Gonzalez Sanchez, Javier; Graziano, Alberto; Jorda, Clara; Lopez Virto, Amparo; Marco, Jesus; Marco, Rafael; Martinez Rivero, Celso; Matorras, Francisco; Munoz Sanchez, Francisca Javiela; Rodrigo, Teresa; Rodríguez-Marrero, Ana Yaiza; Ruiz-Jimeno, Alberto; Scodellaro, Luca; Vila, Ivan; Vilar Cortabitarte, Rocio; Abbaneo, Duccio; Auffray, Etiennette; Auzinger, Georg; Bachtis, Michail; Baillon, Paul; Ball, Austin; Barney, David; Benitez, Jose F; Bernet, Colin; Bianchi, Giovanni; Bloch, Philippe; Bocci, Andrea; Bonato, Alessio; Botta, Cristina; Breuker, Horst; Camporesi, Tiziano; Cerminara, Gianluca; Christiansen, Tim; Coarasa Perez, Jose Antonio; D'Enterria, David; Dabrowski, Anne; De Roeck, Albert; De Visscher, Simon; Di Guida, Salvatore; Dobson, Marc; Dupont-Sagorin, Niels; Elliott-Peisert, Anna; Frisch, Benjamin; Funk, Wolfgang; Georgiou, Georgios; Giffels, Manuel; Gigi, Dominique; Gill, Karl; 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Klukas, Jeffrey; Lanaro, Armando; Lazaridis, Christos; Loveless, Richard; Mohapatra, Ajit; Mozer, Matthias Ulrich; Ojalvo, Isabel; Palmonari, Francesco; Pierro, Giuseppe Antonio; Ross, Ian; Savin, Alexander; Smith, Wesley H; Swanson, Joshua

2013-05-17

Invariant mass spectra for jets reconstructed using the anti-kt and Cambridge-Aachen algorithms are studied for different jet "grooming" techniques in data corresponding to an integrated luminosity of 5 inverse femtobarns, recorded with the CMS detector in proton-proton collisions at the LHC at a center-of-mass energy of 7 TeV. Leading-order QCD predictions for inclusive dijet and W/Z+jet production combined with parton-shower Monte Carlo models are found to agree overall with the data, and the agreement improves with the implementation of jet grooming methods used to distinguish merged jets of large transverse momentum from softer QCD gluon radiation.

Metal impurity transport control in JET H-mode plasmas with central ion cyclotron radiofrequency power injection

DEFF Research Database (Denmark)

Valisa, M.; Carraro, L.; Predebon, I.

2011-01-01

The scan of ion cyclotron resonant heating (ICRH) power has been used to systematically study the pump out effect of central electron heating on impurities such as Ni and Mo in H-mode low collisionality discharges in JET. The transport parameters of Ni and Mo have been measured by introducing...

Dynamics of Magnetized Plasma Jets and Bubbles Launched into a Background Magnetized Plasma

Science.gov (United States)

Wallace, B.; Zhang, Y.; Fisher, D. M.; Gilmore, M.

2016-10-01

The propagation of dense magnetized plasma, either collimated with mainly azimuthal B-field (jet) or toroidal with closed B-field (bubble), in a background plasma occurs in a number of solar and astrophysical cases. Such cases include coronal mass ejections moving in the background solar wind and extragalactic radio lobes expanding into the extragalactic medium. Understanding the detailed MHD behavior is crucial for correctly modeling these events. In order to further the understanding of such systems, we are investigating the injection of dense magnetized jets and bubbles into a lower density background magnetized plasma using a coaxial plasma gun and a background helicon or cathode plasma. In both jet and bubble cases, the MHD dynamics are found to be very different when launched into background plasma or magnetic field, as compared to vacuum. In the jet case, it is found that the inherent kink instability is stabilized by velocity shear developed due to added magnetic tension from the background field. In the bubble case, rather than directly relaxing to a minimum energy Taylor state (spheromak) as in vacuum, there is an expansion asymmetry and the bubble becomes Rayleigh-Taylor unstable on one side. Recent results will be presented. Work supported by the Army Research Office Award No. W911NF1510480.

Effects of Wall-Normal and Angular Momentum Injections in Airfoil Separation Control

Science.gov (United States)

Munday, Phillip M.; Taira, Kunihiko

2018-05-01

The objective of this computational study is to quantify the influence of wall-normal and angular momentum injections in suppressing laminar flow separation over a canonical airfoil. Open-loop control of fully separated, incompressible flow over a NACA 0012 airfoil at $\\alpha = 9^\\circ$ and $Re = 23,000$ is examined with large-eddy simulations. This study independently introduces wall-normal momentum and angular momentum into the separated flow using swirling jets through model boundary conditions. The response of the flow field and the surface vorticity fluxes to various combinations of actuation inputs are examined in detail. It is observed that the addition of angular momentum input to wall-normal momentum injection enhances the suppression of flow separation. Lift enhancement and suppression of separation with the wall-normal and angular momentum inputs are characterized by modifying the standard definition of the coefficient of momentum. The effect of angular momentum is incorporated into the modified coefficient of momentum by introducing a characteristic swirling jet velocity based on the non-dimensional swirl number. With this single modified coefficient of momentum, we are able to categorize each controlled flow into separated, transitional, and attached flows.

Large-Eddy Simulation (LES of Spray Transients: Start and End of Injection Phenomena

Directory of Open Access Journals (Sweden)

Battistoni Michele

2016-01-01

Full Text Available This work reports investigations on Diesel spray transients, accounting for internal nozzle flow and needle motion, and demonstrates how seamless calculations of internal flow and external jet can be accomplished in a Large-Eddy Simulation (LES framework using an Eulerian mixture model. Sub-grid stresses are modeled with the Dynamic Structure (DS model, a non-viscosity based one-equation LES model. Two problems are studied with high level of spatial and temporal resolution. The first one concerns an End-Of-Injection (EOI case where gas ingestion, cavitation, and dribble formation are resolved. The second case is a Start-Of-Injection (SOI simulation that aims at analyzing the effect of residual gas trapped inside the injector sac on spray penetration and rate of fuel injection. Simulation results are compared against experiments carried out at Argonne National Laboratory (ANL using synchrotron X-ray. A mesh sensitivity analysis is conducted to assess the quality of the LES approach by evaluating the resolved turbulent kinetic energy budget and comparing the outcomes with a length-scale resolution index. LES of both EOI and SOI processes have been carried out on a single hole Diesel injector, providing insights in to the physics of the processes, with internal and external flow details, and linking the phenomena at the end of an injection event to those at the start of a new injection. Concerning the EOI, the model predicts ligament formation and gas ingestion, as observed experimentally, and the amount of residual gas in the nozzle sac matches with the available data. The fast dynamics of the process is described in detail. The simulation provides unique insights into the physics at the EOI. Similarly, the SOI simulation shows how gas is ejected first, and liquid fuel starts being injected with a delay. The simulation starts from a very low needle lift and is able to predict the actual Rate-Of-Injection (ROI and jet penetration, based only on the

High Fidelity Simulation of Transcritical Liquid Jet in Crossflow

Science.gov (United States)

Li, Xiaoyi; Soteriou, Marios

2017-11-01

Transcritical injection of liquid fuel occurs in many practical applications such as diesel, rocket and gas turbine engines. In these applications, the liquid fuel, with a supercritical pressure and a subcritical temperature, is introduced into an environment where both the pressure and temperature exceeds the critical point of the fuel. The convoluted physics of the transition from subcritical to supercritical conditions poses great challenges for both experimental and numerical investigations. In this work, numerical simulation of a binary system of a subcritical liquid injecting into a supercritical gaseous crossflow is performed. The spatially varying fluid thermodynamic and transport properties are evaluated using established cubic equation of state and extended corresponding state principles with established mixing rules. To efficiently account for the large spatial gradients in property variations, an adaptive mesh refinement technique is employed. The transcritical simulation results are compared with the predictions from the traditional subcritical jet atomization simulations.

The improvement of the heat transfer model for sodium-water reaction jet code

International Nuclear Information System (INIS)

Hashiguchi, Yoshirou; Yamamoto, Hajime; Kamoshida, Norio; Murata, Shuuichi

2001-02-01

For confirming the reasonable DBL (Design Base Leak) on steam generator (SG), it is necessary to evaluate phenomena of sodium-water reaction (SWR) in an actual steam generator realistically. The improvement of a heat transfer model on sodium-water reaction (SWR) jet code (LEAP-JET ver.1.40) and application analysis to the water injection tests for confirmation of propriety for the code were performed. On the improvement of the code, the heat transfer model between a inside fluid and a tube wall was introduced instead of the prior model which was heat capacity model including both heat capacity of the tube wall and inside fluid. And it was considered that the fluid of inside the heat exchange tube was able to treat as water or sodium and typical heat transfer equations used in SG design were also introduced in the new heat transfer model. Further additional work was carried out in order to improve the stability of the calculation for long calculation time. The test calculation using the improved code (LEAP-JET ver.1.50) were carried out with conditions of the SWAT-IR·Run-HT-2 test. It was confirmed that the SWR jet behavior on the result and the influence to the result of the heat transfer model were reasonable. And also on the improved code (LEAP-JET ver.1.50), user's manual was revised with additional I/O manual and explanation of the heat transfer model and new variable name. (author)

Innovative diagnostics for ITER physics addressed in JET

Energy Technology Data Exchange (ETDEWEB)

Murari, A; Alfier, A; Pasqualotto, R [Associazione EURATOM-ENEA per la Fusione, Consorzio RFX, 4-35127 Padova (Italy); Edlington, T; Andrew, Y; Arnoux, G; Beurskens, M; Coad, P; Kempenaars, M; Kiptily, V; Meigs, A [Euratom/UKAEA Fusion Association, Culham Science Centre, Abingdon, Oxon, OX14 3DB (United Kingdom); Alonso, A; Hidalgo, C [Asociacion EURATOM-CIEMAT para Fusion, CIEMAT, Madrid (Spain); Crombe, C [Department of Applied Physics, Ghent University, Rozier 44, 900 Gent (Belgium); Gauthier, E; Giroud, C; Hong, S; Loarer, T [Association EURATOM-CEA, CEA Cadarache, 13108 Saint-Paul-lez-Durance (France); Tala, T [Association EURATOM-Tekes, VTT, PO Box 1000, FIN-02044 VTT (Finland)

2008-12-15

In recent years, JET diagnostic capability has been significantly improved to widen the range of physical phenomena that can be studied and thus contribute to the understanding of some ITER relevant issues. The most significant results reported in this paper refer to the plasma wall interactions, the interplay between core and edge physics and fast particles. A synergy between new infrared cameras, visible cameras and spectroscopy diagnostics has allowed investigating a series of new aspects of the plasma wall interactions. The power loads on the plasma facing components of JET main chambers have been assessed at steady state and during transient events like ELMs and disruptions. Evidence of filaments in the edge region of the plasma has been collected with a new fast visible camera and high resolution Thomson scattering. The physics of detached plasmas and some new aspects of dust formation have also been devoted particular attention. The influence of the edge plasma on the core has been investigated with upgraded active spectroscopy, providing new information on momentum transport and the effects of impurity injection on ELMs and ITBs and their interdependence. Given the fact that JET is the only machine with a plasma volume big enough to confine the alphas, a coherent programme of diagnostic developments for the energetic particles has been undertaken. With upgraded {gamma}-ray spectroscopy and a new scintillator probe, it is now possible to study both the redistribution and the losses of the fast particles in various plasma conditions.

Numerical assessment of pulsating water jet in the conical diffusers

Science.gov (United States)

Tanasa, Constantin; Ciocan, Tiberiu; Muntean, Sebastian

2017-11-01

The hydraulic fluctuations associated with partial load operating conditions of Francis turbines are often periodic and characterized by the presence of a vortex rope. Two types of pressure fluctuations associated with the draft tube surge are identified in the literature. The first is an asynchronous (rotating) pressure fluctuation due to the precession of the helical vortex around the axis of the draft tube. The second type of fluctuation is a synchronous (plunging) fluctuation. The plunging fluctuations correspond to the flow field oscillations in the whole hydraulic passage, and are generally propagated overall in the hydraulic system. The paper introduced a new control method, which consists in injecting a pulsating axial water jet along to the draft tube axis. Nevertheless, the great calling of this control method is to mitigate the vortex rope effects targeting the vortex sheet and corresponding plunging component. In this paper, is presented our 3D numerical investigations with and without pulsating axial water jet control method in order to evaluate the concept.

Jet inclusive cross sections

International Nuclear Information System (INIS)

Del Duca, V.

1992-11-01

Minijet production in jet inclusive cross sections at hadron colliders, with large rapidity intervals between the tagged jets, is evaluated by using the BFKL pomeron. We describe the jet inclusive cross section for an arbitrary number of tagged jets, and show that it behaves like a system of coupled pomerons

Turbulent buoyant jets and plumes

CERN Document Server

Rodi, Wolfgang

The Science & Applications of Heat and Mass Transfer: Reports, Reviews, & Computer Programs, Volume 6: Turbulent Buoyant Jets and Plumes focuses on the formation, properties, characteristics, and reactions of turbulent jets and plumes. The selection first offers information on the mechanics of turbulent buoyant jets and plumes and turbulent buoyant jets in shallow fluid layers. Discussions focus on submerged buoyant jets into shallow fluid, horizontal surface or interface jets into shallow layers, fundamental considerations, and turbulent buoyant jets (forced plumes). The manuscript then exami

A FLUX ROPE ERUPTION TRIGGERED BY JETS

International Nuclear Information System (INIS)

Guo Juan; Zhang Hongqi; Deng Yuanyong; Lin Jiaben; Su Jiangtao; Liu Yu

2010-01-01

We present an observation of a filament eruption caused by recurrent chromospheric plasma injections (surges/jets) on 2006 July 6. The filament eruption was associated with an M2.5 two-ribbon flare and a coronal mass ejection (CME). There was a light bridge in the umbra of the main sunspot of NOAA 10898; one end of the filament was terminated at the region close to the light bridge, and recurrent surges were observed to be ejected from the light bridge. The surges occurred intermittently for about 8 hr before the filament eruption, and finally a clear jet was found at the light bridge to trigger the filament eruption. We analyzed the evolutions of the relative darkness of the filament and the loaded mass by the continuous surges quantitatively. It was found that as the occurrence of the surges, the relative darkness of the filament body continued growing for about 3-4 hr, reached its maximum, and kept stable for more than 2 hr until it erupted. If suppose 50% of the ejected mass by the surges could be trapped by the filament channel, then the total loaded mass into the filament channelwill be about 0.57x10 16 g with a momentum of 0.57x10 22 g cm s -1 by 08:08 UT, which is a non-negligible effect on the stability of the filament. Based on the observations, we present a model showing the important role that recurrent chromospheric mass injection play in the evolution and eruption of a flux rope. Our study confirms that the surge activities can efficiently supply the necessary material for some filament formation. Furthermore, our study indicates that the continuous mass with momentum loaded by the surge activities to the filament channel could make the filament unstable and cause it to erupt.

Technological Innovations of Carbon Dioxide Injection in EAF-LF Steelmaking

Science.gov (United States)

Wei, Guangsheng; Zhu, Rong; Wu, Xuetao; Dong, Kai; Yang, Lingzhi; Liu, Runzao

2018-06-01

In this study, the recent innovations and improvements in carbon dioxide (CO2) injection technologies for electric arc furnace (EAF)-ladle furnace (LF) steelmaking processes have been reviewed. The utilization of CO2 in the EAF-LF steelmaking process resulted in improved efficiency, purity and environmental impact. For example, coherent jets with CO2 and O2 mixed injection can reduce the amount of iron loss and dust generation, and submerged O2 and powder injection with CO2 in an EAF can increase the production efficiency and improve the dephosphorization and denitrification characteristics. Additionally, bottom-blowing CO2 in an EAF can strengthen molten bath stirring and improve nitrogen removal, while bottom-blowing CO2 in a LF can increase the rate of desulfurization and improve the removal of inclusions. Based on these innovations, a prospective process for the cyclic utilization of CO2 in the EAF-LF steelmaking process is introduced that is effective in mitigating greenhouse gas emissions from the steelmaking shop.

Technological Innovations of Carbon Dioxide Injection in EAF-LF Steelmaking

Science.gov (United States)

Wei, Guangsheng; Zhu, Rong; Wu, Xuetao; Dong, Kai; Yang, Lingzhi; Liu, Runzao

2018-03-01

In this study, the recent innovations and improvements in carbon dioxide (CO2) injection technologies for electric arc furnace (EAF)-ladle furnace (LF) steelmaking processes have been reviewed. The utilization of CO2 in the EAF-LF steelmaking process resulted in improved efficiency, purity and environmental impact. For example, coherent jets with CO2 and O2 mixed injection can reduce the amount of iron loss and dust generation, and submerged O2 and powder injection with CO2 in an EAF can increase the production efficiency and improve the dephosphorization and denitrification characteristics. Additionally, bottom-blowing CO2 in an EAF can strengthen molten bath stirring and improve nitrogen removal, while bottom-blowing CO2 in a LF can increase the rate of desulfurization and improve the removal of inclusions. Based on these innovations, a prospective process for the cyclic utilization of CO2 in the EAF-LF steelmaking process is introduced that is effective in mitigating greenhouse gas emissions from the steelmaking shop.

VLBA AND CHANDRA OBSERVATIONS OF JETS IN FRI RADIO GALAXIES: CONSTRAINTS ON JET EVOLUTION

International Nuclear Information System (INIS)

Kharb, P.; O'Dea, C. P.; Tilak, A.; Baum, S. A.; Haynes, E.; Noel-Storr, J.; Fallon, C.; Christiansen, K.

2012-01-01

We present here the results from new Very Long Baseline Array (VLBA) observations at 1.6 and 5 GHz of 19 galaxies of a complete sample of 21 Uppasala General Catalog (UGC) Fanaroff-Riley type I (FRI) radio galaxies. New Chandra data of two sources, viz., UGC 00408 and UGC 08433, are combined with the Chandra archival data of 13 sources. The 5 GHz observations of 10 'core-jet' sources are polarization-sensitive, while the 1.6 GHz observations constitute second-epoch total intensity observations of nine 'core-only' sources. Polarized emission is detected in the jets of seven sources at 5 GHz, but the cores are essentially unpolarized, except in M87. Polarization is detected at the jet edges in several sources, and the inferred magnetic field is primarily aligned with the jet direction. This could be indicative of magnetic field 'shearing' due to jet-medium interaction, or the presence of helical magnetic fields. The jet peak intensity I ν falls with distance d from the core, following the relation, I ν ∝d a , where a is typically ∼ – 1.5. Assuming that adiabatic expansion losses are primarily responsible for the jet intensity 'dimming,' two limiting cases are considered: (1) the jet has a constant speed on parsec scales and is expanding gradually such that the jet radius r∝d 0 .4 ; this expansion is, however, unobservable in the laterally unresolved jets at 5 GHz, and (2) the jet is cylindrical and is accelerating on parsec scales. Accelerating parsec-scale jets are consistent with the phenomenon of 'magnetic driving' in Poynting-flux-dominated jets. While slow jet expansion as predicted by case (1) is indeed observed in a few sources from the literature that are resolved laterally, on scales of tens or hundreds of parsecs, case (2) cannot be ruled out in the present data, provided the jets become conical on scales larger than those probed by VLBA. Chandra observations of 15 UGC FRIs detect X-ray jets in 9 of them. The high frequency of occurrence of X

A theoretical study of mixing downstream of transverse injection into a supersonic boundary layer

Science.gov (United States)

Baker, A. J.; Zelazny, S. W.

1972-01-01

A theoretical and analytical study was made of mixing downstream of transverse hydrogen injection, from single and multiple orifices, into a Mach 4 air boundary layer over a flat plate. Numerical solutions to the governing three-dimensional, elliptic boundary layer equations were obtained using a general purpose computer program. Founded upon a finite element solution algorithm. A prototype three-dimensional turbulent transport model was developed using mixing length theory in the wall region and the mass defect concept in the outer region. Excellent agreement between the computed flow field and experimental data for a jet/freestream dynamic pressure ratio of unity was obtained in the centerplane region of the single-jet configuration. Poorer agreement off centerplane suggests an inadequacy of the extrapolated two-dimensional turbulence model. Considerable improvement in off-centerplane computational agreement occured for a multi-jet configuration, using the same turbulent transport model.

Numerical Simulation and Experimental Investigation of Multi-function Micro-plasma Jet and Alumina Particle Behaviour

Directory of Open Access Journals (Sweden)

Liu Gu

2016-01-01

Full Text Available Turbulent flow in multi-function micro-plasma spray, as well as the trajectories and state-changing course of alumina particles in the plasma jet were simulated. The distribution of temperature and velocity of the plasma jet and in-flight alumina particles is discussed. Calculations show that particles are heated and accelerated sufficiently by the plasma flame due to a longer travel time than that of external injection system, therefore, possess higher temperature and velocity. Alumina particles temperature and velocity increase rapidly along the jet axis at the initial stage, but then decrease gradually. The velocity and surface temperature of in-flight alumina particles are measured by Spray Watch-2i system. The velocity and surface temperature of alumina particles measured agree well with the simulation results, confirming that the simulation model is suitable for the prediction of the turbulent flow and the particle characteristics, which also reveals the superiority of the plasma spray gun in this multi-function micro-plasma spraying system.

3D printing of gas jet nozzles for laser-plasma accelerators

Energy Technology Data Exchange (ETDEWEB)

Döpp, A.; Guillaume, E.; Thaury, C.; Gautier, J.; Ta Phuoc, K.; Malka, V. [LOA, ENSTA ParisTech, CNRS, École Polytechnique, Université Paris-Saclay, 828 Boulevard des Maréchaux, 91762 Palaiseau Cedex (France)

2016-07-15

Recent results on laser wakefield acceleration in tailored plasma channels have underlined the importance of controlling the density profile of the gas target. In particular, it was reported that the appropriate density tailoring can result in improved injection, acceleration, and collimation of laser-accelerated electron beams. To achieve such profiles, innovative target designs are required. For this purpose, we have reviewed the usage of additive layer manufacturing, commonly known as 3D printing, in order to produce gas jet nozzles. Notably we have compared the performance of two industry standard techniques, namely, selective laser sintering (SLS) and stereolithography (SLA). Furthermore we have used the common fused deposition modeling to reproduce basic gas jet designs and used SLA and SLS for more sophisticated nozzle designs. The nozzles are characterized interferometrically and used for electron acceleration experiments with the SALLE JAUNE terawatt laser at Laboratoire d’Optique Appliquée.

First neutron spectroscopy measurements with a pixelated diamond detector at JET

Energy Technology Data Exchange (ETDEWEB)

Muraro, A., E-mail: muraro@ifp.cnr.it; Giacomelli, L.; Grosso, G.; Tardocchi, M. [Istituto di Fisica del Plasma “P. Caldirola,” CNR, Milano (Italy); Nocente, M.; Rebai, M.; Rigamonti, D.; Gorini, G. [Istituto di Fisica del Plasma “P. Caldirola,” CNR, Milano (Italy); University of Milano Bicocca, Piazza della Scienza 3, 20126 Milano (Italy); Belli, F. [Centro Ricerca ENEA-Frascati, Via E.Fermi 45, Frascati, Rome (Italy); Calvani, P.; Girolami, M.; Trucchi, D. M. [CNR—Istituto di Struttura della Materia (ISM), Via Salaria km 29.300, 00015 Monterotondo Scalo, Rome (Italy); Figueiredo, J. [Instituto de Plasmas e Fusão Nuclear, Instituto Superior Técnico, Universidade de Lisboa, Lisbon (Portugal); EUROfusion Programme Management Unit, Culham Science Centre, Abingdon (United Kingdom); Murari, A. [Culham Centre for Fusion Energy, Culham (United Kingdom); Consorzio RFX (CNR, ENEA, INFN, Università di Padova, Acciaierie Venete SpA), Padova (Italy); Popovichev, S. [Instituto de Plasmas e Fusão Nuclear, Instituto Superior Técnico, Universidade de Lisboa, Lisbon (Portugal); Collaboration: EUROfusion Consortium, JET, Culham Science Centre, Abingdon OX14 3DB (United Kingdom)

2016-11-15

A prototype Single crystal Diamond Detector (SDD) was installed at the Joint European Torus (JET) in 2013 along an oblique line of sight and demonstrated the possibility to carry out neutron spectroscopy measurements with good energy resolution and detector stability in discharges heated by neutral beam injection and radio-frequency waves. Starting from these positive results, within the Vertical Neutron Spectrometer project of the Joint European Torus, we have developed a pixelated instrument consisting of a matrix of 12 independent SDDs, called the Diamond Vertical Neutron Spectrometer (DVNS), which boosts the detection efficiency of a single SDD by an order of magnitude. In this paper we describe the main features of the DVNS, including the detector design, energy resolution, and data acquisition system for on-line processing. Preliminary spectroscopy measurements of 2.5 MeV neutrons from the present deuterium plasma at JET are finally presented.

Determining How Magnetic Helicity Injection Really Works

International Nuclear Information System (INIS)

Paul M Bellan

2001-01-01

OAK-B135 The goal of the Caltech program is to determine how helicity injection works by investigating the actual dynamics and topological evolution associated with magnetic relaxation. A new coaxial helicity injection source has been constructed and brought into operation. The key feature of this source is that it has maximum geometric simplicity. Besides being important for fusion research, this work also has astrophysical implications. Photos obtained using high-speed cameras show a clear sequence of events in the formation process. In particular, they show initial merging/reconnection processes, jet-like expansion, kinking, and separation of the plasma from the source. Various diagnostics have been developed, including laser induced fluorescence and soft x-ray detection using high speed diodes. Gas valves have been improved and a patent disclosure relating to puffed gas valves has been filed. Presentations on this work have been given in the form of invited talks at several university physics departments that were previously unfamiliar with laboratory plasma experiments

Jet substructure in ATLAS

CERN Document Server

Miller, David W

2011-01-01

Measurements are presented of the jet invariant mass and substructure in proton-proton collisions at $\\sqrt{s} = 7$ TeV with the ATLAS detector using an integrated luminosity of 37 pb$^{-1}$. These results exercise the tools for distinguishing the signatures of new boosted massive particles in the hadronic final state. Two "fat" jet algorithms are used, along with the filtering jet grooming technique that was pioneered in ATLAS. New jet substructure observables are compared for the first time to data at the LHC. Finally, a sample of candidate boosted top quark events collected in the 2010 data is analyzed in detail for the jet substructure properties of hadronic "top-jets" in the final state. These measurements demonstrate not only our excellent understanding of QCD in a new energy regime but open the path to using complex jet substructure observables in the search for new physics.

Overview of the JET Neutral Beam Enhancement Project

International Nuclear Information System (INIS)

Ciric, D.

2006-01-01

Three objectives of the JET Neutral Beam Enhancement (NBE) are a) to increase the NB power delivered to JET from 25 MW to >34 MW; b) to extend the beam pulse duration from 10 to 20 seconds and c) to improve availability and reliability of the JET NB system. The project is based on the upgrade of the two existing JET neutral injectors, each equipped with eight positive ion neutral injectors (PINIs). The main increase of the NB power will come from the rearrangement of the ion source permanent magnets from the present supercusp to pure chequerboard configuration, thus eliminating the magnetic filter used to limit primary electrons reaching the extraction region. This modification considerably increases the fraction of molecular ions, which leads to higher neutralisation efficiency. Further increase in the injected neutral beam power will result from higher beam transmission, the consequence of high uniformity and superior properties of the beams extracted from chequerboard ion sources. Finally, the maximum extracted deuterium ion current will be increased from the present ∼ 55 A to ∼ 65 A. This will be accomplished by the minor modification of the extraction aperture diameter and the accelerator gap. All PINIs will be operated at the same acceleration voltage (125 kV). The increase of the beam pulse length from 10 to 20 seconds requires modification or replacement of inter-pulse water cooled beamline components. The most challenging among these tasks is the replacement the duct liner, which protects the vessel from re-ionised beam power at the beam entry into the torus. It will be replaced with an actively cooled liner based on proven hypervapotron technology. To improve the overall reliability of the JET neutral beam system and to allow extraction of 65 A of deuterium ion current, eight existing 80 kV/60 A high voltage power supplies (HVPS) will be replaced with four new 130 kV/130 A units. This means that, after the completion of the NBE project, 75% of the JET

Jet Substructure Without Trees

Energy Technology Data Exchange (ETDEWEB)

Jankowiak, Martin; Larkoski, Andrew J.; /SLAC /Stanford U., ITP

2011-08-19

We present an alternative approach to identifying and characterizing jet substructure. An angular correlation function is introduced that can be used to extract angular and mass scales within a jet without reference to a clustering algorithm. This procedure gives rise to a number of useful jet observables. As an application, we construct a top quark tagging algorithm that is competitive with existing methods. In preparation for the LHC, the past several years have seen extensive work on various aspects of collider searches. With the excellent resolution of the ATLAS and CMS detectors as a catalyst, one area that has undergone significant development is jet substructure physics. The use of jet substructure techniques, which probe the fine-grained details of how energy is distributed in jets, has two broad goals. First, measuring more than just the bulk properties of jets allows for additional probes of QCD. For example, jet substructure measurements can be compared against precision perturbative QCD calculations or used to tune Monte Carlo event generators. Second, jet substructure allows for additional handles in event discrimination. These handles could play an important role at the LHC in discriminating between signal and background events in a wide variety of particle searches. For example, Monte Carlo studies indicate that jet substructure techniques allow for efficient reconstruction of boosted heavy objects such as the W{sup {+-}} and Z{sup 0} gauge bosons, the top quark, and the Higgs boson.

Design and preliminary characterization of a miniature pulsed RF APGD torch with downstream injection of the source of reactive species

International Nuclear Information System (INIS)

Leveille, V; Coulombe, S

2005-01-01

The design of a miniature low-power atmospheric pressure glow discharge torch (APGD-t) and the results of its preliminary electrical and spectroscopic characterization are presented. A capacitively-coupled pulsed RF (13.56 MHz) helium plasma jet is formed in a converging confinement tube and O 2 is injected downstream in the plasma afterglow region through a capillary electrode. With 1 SLM He, the APGD-t produced a non-thermal plasma jet of 500 μm-diameter and ∼2.5 mm-long at power levels ranging from 1 to 5 W. At ∼1 W, the gas temperature and He excitation temperature near the nozzle exit were ∼50 0 C and slightly below 2000 K, respectively. The breakdown voltage in 1 SLM He is approximately 220 V pk-to-0 . Careful electric probe measurements and circuit analysis revealed the strong effect of the voltage probe on the total load impedance. The injection of 10 SCCM O 2 through the capillary electrode led to the transport of atomic O further downstream in the plasma jet and to a slight increase of the He excitation temperature without significant effects on the electrical properties and jet length. Alternatively, the addition of an equivalent amount of O 2 (1 v/v%) to the plasma-forming gas affected the electrical properties slightly, but led to a drastic contraction of the plasma jet. The atomic oxygen production and transport conditions provided by the APGD-t are promising for precise bio-applications such as the treatment of skin tissues and cells

Magnetosheath jets: MMS observations of internal structures and jet interactions with ambient plasma

Science.gov (United States)

Plaschke, F.; Karlsson, T.; Hietala, H.; Archer, M. O.; Voros, Z.; Nakamura, R.; Magnes, W.; Baumjohann, W.; Torbert, R. B.; Russell, C. T.; Giles, B. L.

2017-12-01

The dayside magnetosheath downstream of the quasi-parallel bow shock is commonly permeated by high-speed jets. Under low IMF cone angle conditions, large scale jets alone (with cross-sectional diameters of over 2 Earth radii) have been found to impact the subsolar magnetopause once every 6 minutes - smaller scale jets occurring much more frequently. The consequences of jet impacts on the magnetopause can be significant: they may trigger local reconnection and waves, alter radiation belt electron drift paths, disturb the geomagnetic field, and potentially generate diffuse throat aurora at the dayside ionosphere. Although some basic statistical properties of jets are well-established, their internal structure and interactions with the surrounding magnetosheath plasma are rather unknown. We present Magnetospheric Multiscale (MMS) observations which reveal a rich jet-internal structure of high-amplitude plasma moment and magnetic field variations and associated currents. These variations/structures are generally found to be in thermal and magnetic pressure balance; they mostly (but not always) convect with the plasma flow. Small velocity differences between plasma and structures are revealed via four-spacecraft timing analysis. Inside a jet core region, where the plasma velocity maximizes, structures are found to propagate forward (i.e., with the jet), whereas backward propagation is found outside that core region. Although super-magnetosonic flows are detected by MMS in the spacecraft frame of reference, no fast shock is seen as the jet plasma is sub-magnetosonic with respect to the ambient magnetosheath plasma. Instead, the fast jet plasma pushes ambient magnetosheath plasma ahead of the jet out of the way, possibly generating anomalous sunward flows in the vicinity, and modifies the magnetic field aligning it with the direction of jet propagation.

Deformations of free jets

Science.gov (United States)

Paruchuri, Srinivas

This thesis studies three different problems. First we demonstrate that a flowing liquid jet can be controllably split into two separate subfilaments through the applications of a sufficiently strong tangential stress to the surface of the jet. In contrast, normal stresses can never split a liquid jet. We apply these results to observations of uncontrolled splitting of jets in electric fields. The experimental realization of controllable jet splitting would provide an entirely novel route for producing small polymeric fibers. In the second chapter we present an analytical model for the bending of liquid jets and sheets from temperature gradients, as recently observed by Chwalek et al. [Phys. Fluids, 14, L37 (2002)]. The bending arises from a local couple caused by Marangoni forces. The dependence of the bending angle on experimental parameters is presented, in qualitative agreement with reported experiments. The methodology gives a simple framework for understanding the mechanisms for jet and sheet bending. In chapter 4 we address the discrepancy between hydrodynamic theory of liquid jets, and the snap-off of narrow liquid jets observed in molecular dynamics (MD) simulations [23]. This has been previously attributed to the significant role of thermal fluctuations in nanofluidic systems. We argue that hydrodynamic description of such systems should include corrections to the Laplace pressure which result from the failure of the sharp interface assumption when the jet diameter becomes small enough. We show that this effect can in principle give rise to jet shapes similar to those observed in MD simulations, even when thermal fluctuations are completely neglected. Finally we summarize an algorithm developed to simulate droplet impact on a smooth surface.

Effects of sawtooth crashes on beam ions and fusion product tritons in JET

Energy Technology Data Exchange (ETDEWEB)

Marcus, F.B.; Hone, M.A.; Jarvis, O.N.; Loughlin, M.J.; Sadler, G. [Commission of the European Communities, Abingdon (United Kingdom). JET Joint Undertaking; Adams, J.M.; Bond, D.S.; Watkins, N. [AEA Technology, Harwell (United Kingdom); Howarth, P.J.A. [Birmingham Univ. (United Kingdom)

1994-12-31

The objective of this study is to examine the effect of a sawtooth crash on the radial distribution of the slowing down fusion product tritons and on beam ions. The JET neutron emission profile monitor was used to measure the 2.5 MeV and 14 MeV neutron emission line-integrals before and after sawtooth crashes in the Joint European Torus (JET). In deuterium discharges, the 14 MeV neutron production was wholly attributable to burnup of the 1 MeV fusion product tritons from d-d fusion. It has been known for many years that the global emission of 14 MeV neutrons is not affected by sawtooth crashes. Examination of the data obtained with the profile monitor shows that the local emissivity of 14 MeV neutrons, and hence of the profile of thermalizing tritons, is only weakly affected by crashes in the discharges studied. This is in contradiction with the apparent behaviour of injected beam ions as deduced from a study of the considerable changes in local emissivity of the 2.5 MeV neutrons. Nevertheless, the behaviour of the fusion product tritons is consistent with the scaling of the beam injected deuterium. (author) 1 ref., 6 figs.

Disruption mitigation with high-pressure helium gas injection on EAST tokamak

Science.gov (United States)

Chen, D. L.; Shen, B.; Granetz, R. S.; Qian, J. P.; Zhuang, H. D.; Zeng, L.; Duan, Y.; Shi, T.; Wang, H.; Sun, Y.; Xiao, B. J.

2018-03-01

High pressure noble gas injection is a promising technique to mitigate the effect of disruptions in tokamaks. In this paper, results of mitigation experiments with low-Z massive gas injection (helium) on the EAST tokamak are reported. A fast valve has been developed and successfully implemented on EAST, with valve response time  ⩽150 μs, capable of injecting up to 7 × 1022 particles, corresponding to 300 times the plasma inventory. Different amounts of helium gas were injected into stable plasmas in the preliminary experiments. It is seen that a small amount of helium gas (N_He≃ N_plasma ) can not terminate a discharge, but can trigger MHD activity. Injection of 40 times the plasma inventory impurity (N_He≃ 40× N_plasma ) can effectively radiate away part of the thermal energy and make the electron density increase rapidly. The mitigation result is that the current quench time and vertical displacement can both be reduced significantly, without resulting in significantly higher loop voltage. This also reduces the risk of runaway electron generation. As the amount of injected impurity gas increases, the gas penetration time decreases slowly and asymptotes to (˜7 ms). In addition, the impurity gas jet has also been injected into VDEs, which are more challenging to mitigate that stable plasmas.

Structure of pulsed plasma jets

International Nuclear Information System (INIS)

Cavolowsky, J.A.

1987-01-01

A pulsed plasma jet is a turbulent, inhomogeneous fluid mechanical discharge capable of initiating and enhancing combustion. Having shown the ability to ignite lean fuel mixtures, it now offers the potential for real-time control of combustion processes. This study explored the fluid-mechanical and chemical properties of such jets. The fluid-mechanical structure of the jet was examined using two optical diagnostic techniques. Self-light streak photography provided information on the motion of luminous gas particles in its core. It revealed that plasma jets behave either totally subsonic or embody a supersonic core. The turbulent, thermal evolution of the jet was explored using high-speed-laser schlieren cinematography. By examining plasma jet generators with both opaque and transparent plasma cavities, detailed information on plasma formation and jet structure, beginning with the electric arc discharge in the cavity, was obtained. These records revealed the production of thermal stratifications in the cavity that could account for the plasma particles in the jet core. After the electrical discharges ceased, the turbulent jet behaved as a self-similar plume. Molecular-beam mass spectrometry was used to determine temperature and species concentration in the jet. Both non-combustible and combustible jets were studied

Computational and experimental study of the effect of mass transfer on liquid jet break-up

Science.gov (United States)

Schetz, J. A.; Situ, M.

1983-06-01

A computational method has been developed to predict the effect of mass transfer on liquid jet break-up in coaxial, low velocity gas streams. Two conditions, both with and without the effect of mass transfer on the jet break-up, are calculated, and compared with experimental results and the classical linear theory. Methanol and water were used as the injectants. The numerical solution can predict the instantaneous shape of the jet surface and the break-up time, and it is very close to the experimental results. The numerical solutions and the experimental results both indicate that the wave number of the maximum instability is about 6.9, higher than 4.51 which was predicted by Rayleigh's linear theory. The experimental results and numerical solution show that the growth of the amplitude of the trough is faster than the growth of the amplitude of the crest, especially for a rapidly vaporizing jet. The numerical solutions show that for the small rates of evaporation, the effect of the mass transfer on the interface has a stabilizing effect near the wave number for maximum instability. Inversely, it has a destabilizing effect far from the wave number for maximum instability. For rapid evaporation, the effect of the mass transfer always has a destabilizing effect and decreases the break-up time of the jet.

Jets and QCD

International Nuclear Information System (INIS)

Ali, A.; Kramer, G.

2010-12-01

The observation of quark and gluon jets has played a crucial role in establishing Quantum Chromodynamics [QCD] as the theory of the strong interactions within the Standard Model of particle physics. The jets, narrowly collimated bundles of hadrons, reflect configurations of quarks and gluons at short distances. Thus, by analysing energy and angular distributions of the jets experimentally, the properties of the basic constituents of matter and the strong forces acting between them can be explored. In this review we summarise the properties of quark and gluon jets and the impact of their observation on Quantum Chromodynamics, primarily the discovery of the gluons as the carriers of the strong force. Focusing on these basic points, jets in e + e - collisions will be in the foreground of the discussion. In addition we will delineate the role of jets as tools for exploring other particle aspects in ep and pp/p anti p collisions - quark and gluon densities in protons, measurements of the QCD coupling, fundamental 2-2 quark/gluon scattering processes, but also the impact of jet decays of top quarks, and W ± ,Z bosons on the electroweak sector. The presentation to a large extent is formulated in a non-technical language with the intent to recall the significant steps historically and convey the significance of this field also to communities beyond high energy physics. (orig.)

Jets and QCD

Energy Technology Data Exchange (ETDEWEB)

Ali, A. [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany); Kramer, G. [Hamburg Univ. (Germany). II. Inst. fuer Theoretische Physik

2010-12-15

The observation of quark and gluon jets has played a crucial role in establishing Quantum Chromodynamics [QCD] as the theory of the strong interactions within the Standard Model of particle physics. The jets, narrowly collimated bundles of hadrons, reflect configurations of quarks and gluons at short distances. Thus, by analysing energy and angular distributions of the jets experimentally, the properties of the basic constituents of matter and the strong forces acting between them can be explored. In this review we summarise the properties of quark and gluon jets and the impact of their observation on Quantum Chromodynamics, primarily the discovery of the gluons as the carriers of the strong force. Focusing on these basic points, jets in e{sup +}e{sup -} collisions will be in the foreground of the discussion. In addition we will delineate the role of jets as tools for exploring other particle aspects in ep and pp/p anti p collisions - quark and gluon densities in protons, measurements of the QCD coupling, fundamental 2-2 quark/gluon scattering processes, but also the impact of jet decays of top quarks, and W{sup {+-}},Z bosons on the electroweak sector. The presentation to a large extent is formulated in a non-technical language with the intent to recall the significant steps historically and convey the significance of this field also to communities beyond high energy physics. (orig.)

Predictive modelling of the impact of argon injection on H-mode plasmas in JET with the RITM code

International Nuclear Information System (INIS)

Unterberg, B; Kalupin, D; Tokar', M Z; Corrigan, G; Dumortier, P; Huber, A; Jachmich, S; Kempenaars, M; Kreter, A; Messiaen, A M; Monier-Garbet, P; Ongena, J; Puiatti, M E; Valisa, M; Hellermann, M von

2004-01-01

Self-consistent modelling of energy and particle transport of the plasma background and impurities has been performed with the code RITM for argon seeded high density H-mode plasmas in JET. The code can reproduce both the profiles in the plasma core and the structure of the edge pedestal. The impact of argon on core transport is found to be small; in particular, no significant change in confinement is observed in both experimental and modelling results. The same transport model, which has been used to reproduce density peaking in the radiative improved mode in TEXTOR, reveals a flat density profile in Ar seeded JET H-mode plasmas in agreement with the experimental observations. This behaviour is attributed to the rather flat profile of the safety factor in the bulk of H-mode discharges

NUMERICAL SIMULATIONS OF RADIATIVE MAGNETIZED HERBIG–HARO JETS: THE INFLUENCE OF PRE-IONIZATION FROM X-RAYS ON EMISSION LINES

International Nuclear Information System (INIS)

Teşileanu, O.; Mignone, A.; Massaglia, S.; Bacciotti, F.

2012-01-01

We investigate supersonic, axisymmetric magnetohydrodynamic jets with a time-dependent injection velocity by numerical simulations with the PLUTO code. Using a comprehensive set of parameters, we explore different jet configurations in the attempt to construct models that can be directly compared to observational data of microjets. In particular, we focus our attention on the emitting properties of traveling knots and construct, at the same time, accurate line intensity ratios and surface brightness maps. Direct comparison of the resulting brightness and line intensity ratios distributions with observational data of microjets shows that a closer match can be obtained only when the jet material is pre-ionized to some degree. A very likely source for a pre-ionized medium is photoionization by X-ray flux coming from the central object.

Study Of Boosted W-Jets And Higgs-Jets With the SiFCC Detector

Energy Technology Data Exchange (ETDEWEB)

Yu, Shin-Shan [Taiwan, Natl. Central U.; Chekanov, Sergei [Argonne; Gray, Lindsey [Fermilab; Kotwal, Ashutosh [Duke U.; Sen, Sourav [Duke U.; Tran, Nhan Viet [Fermilab

2016-11-04

We study the detector performance in the reconstruction of hadronically-decaying W bosons and Higgs bosons at very high energy proton colliders using a full GEANT4 simulation of the SiFCC detector. The W and Higgs bosons carry transverse momentum in the multi-TeV range, which results in collimated decay products that are reconstructed as a single jet. We present a measurement of the energy response and resolution of boosted W-jets and Higgs-jets and show the separation of two sub-jets within the boosted boson jet.

Inclusive jet cross sections and jet shapes at CDF

International Nuclear Information System (INIS)

Wainer, N.

1991-09-01

The inclusive jet cross section and jet shapes at √s = 1.8 TeV have been measured by CDF at the Fermilab Tevatron Collider. results are compared to recent next-to-leading order QCD calculations, which predict variation of the cross section with cone size, as well as variation of the jet shape with energy. A lower limit on the parameter Λ c , which characterize a contact interaction associated with quark sub-structure is determined to be 1400 GeV at the 95% confidence level. 3 refs., 4 figs

Numerical simulation of boron injection in a BWR

Energy Technology Data Exchange (ETDEWEB)

Tinoco, Hernan, E-mail: htb@forsmark.vattenfall.s [Forsmarks Kraftgrupp AB, SE-742 03 Osthammar (Sweden); Buchwald, Przemyslaw [Reactor Technology, Royal Institute of Technology, SE-100 44 Stockholm (Sweden); Frid, Wiktor, E-mail: wiktor@reactor.sci.kth.s [Reactor Technology, Royal Institute of Technology, SE-100 44 Stockholm (Sweden)

2010-02-15

The present study constitutes a first step to understand the process of boron injection, transport and mixing in a BWR. It consists of transient CFD simulations of boron injection in a model of the downcomer of Forsmark's Unit 3 containing about 6 million elements. The two cases studied are unintentional start of boron injection under normal operation and loss of offsite power with partial ATWS leaving 10% of the core power uncontrolled. The flow conditions of the second case are defined by means of an analysis with RELAP5, assuming boron injection start directly after the first ECCS injection. Recent publications show that meaningful conservative results may be obtained for boron or thermal mixing in PWRs with grids as coarse as that utilized here, provided that higher order discretization schemes are used to minimize numerical diffusion. The obtained results indicate an apparently strong influence of the scenario in the behavior of the injection process. The normal operation simulation shows that virtually all boron solution flows down to the Main Recirculation Pump inlet located directly below the boron inlet nozzle. The loss of offsite power simulation shows initially a spread of the boron solution over the entire sectional area of the lower part of the downcomer filled with colder water. This remaining effect of the ECCS injection lasts until all this water has left the downcomer. Above this region, the boron injection jet develops in a vertical streak, eventually resembling the injection of the normal operation scenario. Due to the initial spread, this boron injection will probably cause larger temporal and spatial concentration variations in the core. In both cases, these variations may cause reactivity transients and fuel damage due to local power escalation. To settle this issue, an analysis using an extended model containing the downcomer, the MRPs and the Lower Plenum will be carried out. Also, the simulation time will be extended to a scale of

Numerical simulation of boron injection in a BWR

International Nuclear Information System (INIS)

Tinoco, Hernan; Buchwald, Przemyslaw; Frid, Wiktor

2010-01-01

The present study constitutes a first step to understand the process of boron injection, transport and mixing in a BWR. It consists of transient CFD simulations of boron injection in a model of the downcomer of Forsmark's Unit 3 containing about 6 million elements. The two cases studied are unintentional start of boron injection under normal operation and loss of offsite power with partial ATWS leaving 10% of the core power uncontrolled. The flow conditions of the second case are defined by means of an analysis with RELAP5, assuming boron injection start directly after the first ECCS injection. Recent publications show that meaningful conservative results may be obtained for boron or thermal mixing in PWRs with grids as coarse as that utilized here, provided that higher order discretization schemes are used to minimize numerical diffusion. The obtained results indicate an apparently strong influence of the scenario in the behavior of the injection process. The normal operation simulation shows that virtually all boron solution flows down to the Main Recirculation Pump inlet located directly below the boron inlet nozzle. The loss of offsite power simulation shows initially a spread of the boron solution over the entire sectional area of the lower part of the downcomer filled with colder water. This remaining effect of the ECCS injection lasts until all this water has left the downcomer. Above this region, the boron injection jet develops in a vertical streak, eventually resembling the injection of the normal operation scenario. Due to the initial spread, this boron injection will probably cause larger temporal and spatial concentration variations in the core. In both cases, these variations may cause reactivity transients and fuel damage due to local power escalation. To settle this issue, an analysis using an extended model containing the downcomer, the MRPs and the Lower Plenum will be carried out. Also, the simulation time will be extended to a scale of several

The hydrogen laminar jet

Energy Technology Data Exchange (ETDEWEB)

Sanchez-Sanz, M. [Departamento de Motopropulsion y Termofluidomecanica, ETSI Aeronauticos, Universidad Politecnica de Madrid, 28040 Madrid (Spain); Rosales, M. [Department Ingenieria Termica y de Fluidos, Universidad Carlos III de Madrid, 28911, Leganes (Spain); Instituto de Innovacion en Mineria y Metalurgia, Avenida del Valle 738, Santiago (Chile); Sanchez, A.L. [Department Ingenieria Termica y de Fluidos, Universidad Carlos III de Madrid, 28911, Leganes (Spain)

2010-04-15

Numerical and asymptotic methods are used to investigate the structure of the hydrogen jet discharging into a quiescent air atmosphere. The analysis accounts in particular for the variation of the density and transport properties with composition. The Reynolds number of the flow R{sub j}, based on the initial jet radius a, the density {rho}{sub j} and viscosity {mu}{sub j} of the jet and the characteristic jet velocity u{sub j}, is assumed to take moderately large values, so that the jet remains slender and stable, and can be correspondingly described by numerical integration of the continuity, momentum and species conservation equations written in the boundary-layer approximation. The solution for the velocity and composition in the jet development region of planar and round jets, corresponding to streamwise distances of order R{sub j}a, is computed numerically, along with the solutions that emerge both in the near field and in the far field. The small value of the hydrogen-to-air molecular weight ratio is used to simplify the solution by considering the asymptotic limit of vanishing jet density. The development provides at leading-order explicit analytical expressions for the far-field velocity and hydrogen mass fraction that describe accurately the hydrogen jet near the axis. The information provided can be useful in particular to characterize hydrogen discharge processes from holes and cracks. (author)

The influence of nitrogen entrainment on argon plasmas created by the 'Torche à Injection Axiale' (TIA)

NARCIS (Netherlands)

Jonkers, J.; Hartgers, A.; Selen, L.J.M.; Mullen, van der J.J.A.M.; Schram, D.C.

1999-01-01

When a plasma is sustained in the open air, nitrogen will diffuse into the plasma. Especially for plasmas sustained by the `Torche à Injection Axiale' (TIA) this appears to be the case, since this turbulent jet draws gases from the surroundings. In the argon plasma the entrained nitrogen is probably

Jet quenching at ALICE

International Nuclear Information System (INIS)

Bianchi, Nicola

2007-01-01

RHIC results on leading hadron suppression indicate that the jets produced in hard processes are strongly quenched by the dense medium created in heavy ion collisions. Most of the energy lost by the leading parton remains within the jet cone, but several questions on the medium modification of the jet structure have not been addressed. These include the longitudinal and transverse structures of the quenched jet, the associated radiation observables, and the dependence on the parton flavor. These topics will be studied by ALICE thanks to both the robustness of its tracking and the charged particle identification system. Large medium effects are expected in both the low pt and in the high pt regions. To make ALICE better suited for jet physics, the performances on high p t particles and jets can be significantly improved by completing the present set-up with a large Electromagnetic Calorimeter (EmCal). This will significantly improve the resolution on the jet energy and on the particle composition (with the detection of both charged and neutral particles). It will also allow to calibrate the jet energy by measuring the high energy photon emitted in the opposite direction. EmCal will be used to trigger on the jet energy itself, thus allowing a significant improvement of the statistics achievable for jets of high energy. Finally, due too both the γ/π 0 and the electron/hadron discrimination, EmCal will enhance the ALICE capabilities at high p t for direct photons and heavy quarks measurements

Spray and atomization of diesel fuel and its alternatives from a single-hole injector using a common rail fuel injection system

KAUST Repository

Chen, PinChia

2013-01-01

Fuel spray and atomization characteristics play an important role in the performance of internal combustion engines. As the reserves of petroleum fuel are expected to be depleted within a few decades, finding alternative fuels that are economically viable and sustainable to replace the petroleum fuel has attracted much research attention. In this work, the spray and atomization characteristics were investigated for commercial No. 2 diesel fuel, biodiesel (FAME) derived from waste cooking oil (B100), 20% biodiesel blended diesel fuel (B20), renewable diesel fuel produced in house, and civil aircraft jet fuel (Jet-A). Droplet diameters and particle size distributions were measured by a laser diffraction particle analyzing system and the spray tip penetrations and cone angles were acquired using a high speed imaging technique. All experiments were conducted by employing a common-rail high-pressure fuel injection system with a single-hole nozzle under room temperature and pressure. The experimental results showed that biodiesel and jet fuel had different features compared with diesel. Longer spray tip penetration and larger droplet diameters were observed for B100. The smaller droplet size of the Jet-A were believed to be caused by its relatively lower viscosity and surface tension. B20 showed similar characteristics to diesel but with slightly larger droplet sizes and shorter tip penetration. Renewable diesel fuel showed closer droplet size and spray penetration to Jet-A with both smaller than diesel. As a result, optimizing the trade-off between spray volume and droplet size for different fuels remains a great challenge. However, high-pressure injection helps to optimize the trade-off of spray volume and droplet sizes. Furthermore, it was observed that the smallest droplets were within a region near the injector nozzle tip and grew larger along the axial and radial direction. The variation of droplet diameters became smaller with increasing injection pressure. �

Jet physics in ALICE

International Nuclear Information System (INIS)

Loizides, C.A.

2005-01-01

The ALICE experiment is one of the experiments currently prepared for the Large Hadron Collider (LHC) at CERN, Geneva, starting operation end of 2007. ALICE is dedicated to the research on nucleus-nucleus collisions at ultra-relativistic energies, which addresses the properties of strongly interacting matter under varying conditions of high density and temperature. The conditions provided at the LHC allow significant qualitative improvement with respect to previous studies. In particular, energetic probes, light quarks and gluons, will be abundantly produced. These probes might be identified by their fragmentation into correlated particles, so called jets, of high enough energy to allow full reconstruction of jet properties; even in the underlying heavy-ion environment. Understanding the dependence of high-energy jet production and fragmentation influenced by the dense medium created in the collision region is an open field of active research. Generally, one expects energy loss of the probes due to medium-induced gluon radiation. It is suggested that hadronization products of these, rather soft gluons may be contained within the jet emission cone, resulting in a modification of the characteristic jet fragmentation, as observed via longitudinal and transverse momentum distributions with respect to the direction of the initial parton, as well as of the multiplicity distributions arising from the jet fragmentation. Particle momenta parallel to the jet axis are softened (jet quenching), while transverse to it increased (transverse heating). The present thesis studies the capabilities of the ALICE detectors to measure these jets and quantifies obtainable rates and the quality of jet reconstruction, in both proton-proton and lead-lead collisions at the LHC. In particular, it is addressed whether modification of the jet fragmentation can be detected within the high-particle-multiplicity environment of central lead-lead collisions. (orig.)

OBSERVATIONS OF A SERIES OF FLARES AND ASSOCIATED JET-LIKE ERUPTIONS DRIVEN BY THE EMERGENCE OF TWISTED MAGNETIC FIELDS

Energy Technology Data Exchange (ETDEWEB)

Lim, Eun-Kyung; Yurchyshyn, Vasyl; Kim, Sujin; Cho, Kyung-Suk; Kumar, Pankaj; Kim, Yeon-Han [Korea Astronomy and Space Science Institute, 776 Daedeokdae-ro, Yuseong-gu, Daejeon 305-348 (Korea, Republic of); Park, Sung-Hong [Institute for Astronomy, Astrophysics, Space Applications and Remote Sensing (IAASARS), National Observatory of Athens, Penteli 15236 (Greece); Chae, Jongchul; Yang, Heesu; Cho, Kyuhyoun; Song, Donguk, E-mail: eklim@kasi.re.kr [Astronomy Program, Department of Physics and Astronomy, Seoul National University, Seoul 151-747 (Korea, Republic of)

2016-01-20

We studied temporal changes of morphological and magnetic properties of a succession of four confined flares followed by an eruptive flare using the high-resolution New Solar Telescope (NST) operating at the Big Bear Solar Observatory (BBSO) and Helioseismic and Magnetic Imager (HMI) magnetograms and Atmospheric Image Assembly (AIA) EUV images provided by the Solar Dynamics Observatory (SDO). From the NST/Hα and the SDO/AIA 304 Å observations we found that each flare developed a jet structure that evolved in a manner similar to evolution of the blowout jet: (1) an inverted-Y-shaped jet appeared and drifted away from its initial position; (2) jets formed a curtain-like structure that consisted of many fine threads accompanied by subsequent brightenings near the footpoints of the fine threads; and finally, (3) the jet showed a twisted structure visible near the flare maximum. Analysis of the HMI data showed that both the negative magnetic flux and the magnetic helicity have been gradually increasing in the positive-polarity region, indicating the continuous injection of magnetic twist before and during the series of flares. Based on these results, we suggest that the continuous emergence of twisted magnetic flux played an important role in producing successive flares and developing a series of blowout jets.

ERRATIC JET WOBBLING IN THE BL LACERTAE OBJECT OJ287 REVEALED BY SIXTEEN YEARS OF 7 mm VLBA OBSERVATIONS

Energy Technology Data Exchange (ETDEWEB)

Agudo, Ivan; Gomez, Jose L. [Instituto de Astrofisica de Andalucia, CSIC, Apartado 3004, 18080 Granada (Spain); Marscher, Alan P.; Jorstad, Svetlana G. [Institute for Astrophysical Research, Boston University, 725 Commonwealth Avenue, Boston, MA 02215 (United States); Perucho, Manel [Departament d' Astronomia i Astrofisica, Universitat de Valencia, Dr. Moliner 50, E-46100 Burjassot, Valencia (Spain); Piner, B. Glenn [Department of Physics and Astronomy, Whittier College, 13406 East Philadelphia Street, Whittier, CA 90608 (United States); Rioja, Maria [Observatorio Astronomico Nacional, Apdo. 112, E-28803 Alcala de Henares, Madrid (Spain); Dodson, Richard, E-mail: iagudo@iaa.es [ICRAR/University of Western Australia, 35 Stirling Highway, Crawley, WA 6009 (Australia)

2012-03-01

We present the results from an ultra-high-resolution 7 mm Very Long Baseline Array study of the relativistic jet in the BL Lacertae object OJ287 from 1995 to 2011 containing 136 total intensity images. Analysis of the image sequence reveals a sharp jet-position-angle swing by >100 Degree-Sign during [2004,2006], as viewed in the plane of the sky, which we interpret as the crossing of the jet from one side of the line of sight to the other during a softer- and longer-term swing of the inner jet. Modulating such long-term swing, our images also show for the first time a prominent erratic wobbling behavior of the innermost {approx}0.4 mas of the jet with fluctuations in position angle of up to {approx}40 Degree-Sign over timescales {approx}2 yr. This is accompanied by highly superluminal motions along non-radial trajectories, which reflect the remarkable non-ballistic nature of the jet plasma on these scales. The erratic nature and short timescales of the observed behavior rule out scenarios such as binary black hole systems, accretion disk precession, and interaction with the ambient medium as possible origins of the phenomenon on the scales probed by our observations, although such processes may cause longer-term modulation of the jet direction. We propose that variable asymmetric injection of the jet flow, perhaps related to turbulence in the accretion disk, coupled with hydrodynamic instabilities leads to the non-ballistic dynamics that causes the observed non-periodic changes in the direction of the inner jet.

The semi-inclusive jet function in SCET and small radius resummation for inclusive jet production

International Nuclear Information System (INIS)

Kang, Zhong-Bo; Ringer, Felix; Vitev, Ivan

2016-01-01

We introduce a new kind of jet function: the semi-inclusive jet function J_i(z,ω_J,μ), which describes how a parton i is transformed into a jet with a jet radius R and energy fraction z=ω_J/ω, with ω_J and ω being the large light-cone momentum component of the jet and the corresponding parton i that initiates the jet, respectively. Within the framework of Soft Collinear Effective Theory (SCET) we calculate both J_q(z,ω_J,μ) and J_g(z,ω_J,μ) to the next-to-leading order (NLO) for cone and anti-k_T algorithms. We demonstrate that the renormalization group (RG) equations for J_i(z,ω_J,μ) follow exactly the usual DGLAP evolution, which can be used to perform the ln R resummation for inclusive jet cross sections with a small jet radius R. We clarify the difference between our RG equations for J_i(z,ω_J,μ) and those for the so-called unmeasured jet functions J_i(ω_J,μ), widely used in SCET for exclusive jet production. Finally, we present applications of the new semi-inclusive jet functions to inclusive jet production in e"+e"− and pp collisions. We demonstrate that single inclusive jet production in these collisions shares the same short-distance hard functions as single inclusive hadron production, with only the fragmentation functions D_i"h(z,μ) replaced by J_i(z,ω_J,μ). This can facilitate more efficient higher-order analytical computations of jet cross sections. We further match our ln R resummation at both LL_R and NLL_R to fixed NLO results and present the phenomenological implications for single inclusive jet production at the LHC.

Study of Aerosols capture process in pool for injections Gaseous Jets at High Speeds: Enhancements SPARC90

International Nuclear Information System (INIS)

Berna, C.; Escriva, A.; Munoz-Cobo, J. L.; Herranz, L. E.

2012-01-01

Code The different expressions found in the literature have been analyzed in a modified version of the code SPARC90, those considered most appropriate. are compared in terms of decontamination factors, the results obtained using the original and modified (SPARC90-Jet) for SGTR accident conditions SPARC code.

Experimental studies of unbiased gluon jets from $e^{+}e^{-}$ annihilations using the jet boost algorithm

CERN Document Server

Abbiendi, G.; Akesson, P.F.; Alexander, G.; Allison, John; Amaral, P.; Anagnostou, G.; Anderson, K.J.; Arcelli, S.; Asai, S.; Axen, D.; Azuelos, G.; Bailey, I.; Barberio, E.; Barlow, R.J.; Batley, R.J.; Bechtle, P.; Behnke, T.; Bell, Kenneth Watson; Bell, P.J.; Bella, G.; Bellerive, A.; Benelli, G.; Bethke, S.; Biebel, O.; Boeriu, O.; Bock, P.; Boutemeur, M.; Braibant, S.; Brigliadori, L.; Brown, Robert M.; Buesser, K.; Burckhart, H.J.; Campana, S.; Carnegie, R.K.; Caron, B.; Carter, A.A.; Carter, J.R.; Chang, C.Y.; Charlton, David G.; Csilling, A.; Cuffiani, M.; Dado, S.; De Roeck, A.; De Wolf, E.A.; Desch, K.; Dienes, B.; Donkers, M.; Dubbert, J.; Duchovni, E.; Duckeck, G.; Duerdoth, I.P.; Etzion, E.; Fabbri, F.; Feld, L.; Ferrari, P.; Fiedler, F.; Fleck, I.; Ford, M.; Frey, A.; Furtjes, A.; Gagnon, P.; Gary, John William; Gaycken, G.; Geich-Gimbel, C.; Giacomelli, G.; Giacomelli, P.; Giunta, Marina; Goldberg, J.; Gross, E.; Grunhaus, J.; Gruwe, M.; Gunther, P.O.; Gupta, A.; Hajdu, C.; Hamann, M.; Hanson, G.G.; Harder, K.; Harel, A.; Harin-Dirac, M.; Hauschild, M.; Hawkes, C.M.; Hawkings, R.; Hemingway, R.J.; Hensel, C.; Herten, G.; Heuer, R.D.; Hill, J.C.; Hoffman, Kara Dion; Horvath, D.; Igo-Kemenes, P.; Ishii, K.; Jeremie, H.; Jovanovic, P.; Junk, T.R.; Kanaya, N.; Kanzaki, J.; Karapetian, G.; Karlen, D.; Kawagoe, K.; Kawamoto, T.; Keeler, R.K.; Kellogg, R.G.; Kennedy, B.W.; Kim, D.H.; Klein, K.; Klier, A.; Kluth, S.; Kobayashi, T.; Kobel, M.; Komamiya, S.; Kormos, Laura L.; Kramer, T.; Krieger, P.; von Krogh, J.; Kruger, K.; Kuhl, T.; Kupper, M.; Lafferty, G.D.; Landsman, H.; Lanske, D.; Layter, J.G.; Leins, A.; Lellouch, D.; Letts, J.; Levinson, L.; Lillich, J.; Lloyd, S.L.; Loebinger, F.K.; Lu, J.; Ludwig, J.; Macpherson, A.; Mader, W.; Marcellini, S.; Martin, A.J.; Masetti, G.; Mashimo, T.; Mattig, Peter; McDonald, W.J.; McKenna, J.; McMahon, T.J.; McPherson, R.A.; Meijers, F.; Menges, W.; Merritt, F.S.; Mes, H.; Michelini, A.; Mihara, S.; Mikenberg, G.; Miller, D.J.; Moed, S.; Mohr, W.; Mori, T.; Mutter, A.; Nagai, K.; Nakamura, I.; Nanjo, H.; Neal, H.A.; Nisius, R.; O'Neale, S.W.; Oh, A.; Okpara, A.; Oreglia, M.J.; Orito, S.; Pahl, C.; Pasztor, G.; Pater, J.R.; Patrick, G.N.; Pilcher, J.E.; Pinfold, J.; Plane, David E.; Poli, B.; Polok, J.; Pooth, O.; Przybycien, M.; Quadt, A.; Rabbertz, K.; Rembser, C.; Renkel, P.; Rick, H.; Roney, J.M.; Rosati, S.; Rozen, Y.; Runge, K.; Sachs, K.; Saeki, T.; Sarkisyan, E.K.G.; Schaile, A.D.; Schaile, O.; Scharff-Hansen, P.; Schieck, J.; Schoerner-Sadenius, Thomas; Schroder, Matthias; Schumacher, M.; Schwick, C.; Scott, W.G.; Seuster, R.; Shears, T.G.; Shen, B.C.; Sherwood, P.; Siroli, G.; Skuja, A.; Smith, A.M.; Sobie, R.; Soldner-Rembold, S.; Spano, F.; Stahl, A.; Stephens, K.; Strom, David M.; Strohmer, R.; Tarem, S.; Tasevsky, M.; Taylor, R.J.; Teuscher, R.; Thomson, M.A.; Torrence, E.; Toya, D.; Tran, P.; Trigger, I.; Trocsanyi, Z.; Tsur, E.; Turner-Watson, M.F.; Ueda, I.; Ujvari, B.; Vollmer, C.F.; Vannerem, P.; Vertesi, R.; Verzocchi, M.; Voss, H.; Vossebeld, J.; Waller, D.; Ward, C.P.; Ward, D.R.; Warsinsky, M.; Watkins, P.M.; Watson, A.T.; Watson, N.K.; Wells, P.S.; Wengler, T.; Wermes, N.; Wetterling, D.; Wilson, G.W.; Wilson, J.A.; Wolf, G.; Wyatt, T.R.; Yamashita, S.; Zer-Zion, D.; Zivkovic, Lidija

2004-01-01

We present the first experimental results based on the jet boost algorithm, a technique to select unbiased samples of gluon jets in e+e- annihilations, i.e. gluon jets free of biases introduced by event selection or jet finding criteria. Our results are derived from hadronic Z0 decays observed with the OPAL detector at the LEP e+e- collider at CERN. First, we test the boost algorithm through studies with Herwig Monte Carlo events and find that it provides accurate measurements of the charged particle multiplicity distributions of unbiased gluon jets for jet energies larger than about 5 GeV, and of the jet particle energy spectra (fragmentation functions) for jet energies larger than about 14 GeV. Second, we apply the boost algorithm to our data to derive unbiased measurements of the gluon jet multiplicity distribution for energies between about 5 and 18 GeV, and of the gluon jet fragmentation function at 14 and 18 GeV. In conjunction with our earlier results at 40 GeV, we then test QCD calculations for the en...

Radiation asymmetries during the thermal quench of massive gas injection disruptions in JET

Czech Academy of Sciences Publication Activity Database

Lehnen, M.; Gerasimov, S.N.; Jachmich, S.; Koslowski, H.R.; Kruezi, U.; Matthews, G.F.; Mlynář, Jan; Reux, C.; de Vries, P.C.

2015-01-01

Roč. 55, č. 12 (2015), s. 123027-123027 ISSN 0029-5515 Institutional support: RVO:61389021 Keywords : disruptions * disruption mitigation * heat loads * massive gas injection * radiation asymmetry Subject RIV: BL - Plasma and Gas Discharge Physics Impact factor: 4.040, year: 2015

Large Scale Behavior and Droplet Size Distributions in Crude Oil Jets and Plumes

Science.gov (United States)

Katz, Joseph; Murphy, David; Morra, David

2013-11-01

The 2010 Deepwater Horizon blowout introduced several million barrels of crude oil into the Gulf of Mexico. Injected initially as a turbulent jet containing crude oil and gas, the spill caused formation of a subsurface plume stretching for tens of miles. The behavior of such buoyant multiphase plumes depends on several factors, such as the oil droplet and bubble size distributions, current speed, and ambient stratification. While large droplets quickly rise to the surface, fine ones together with entrained seawater form intrusion layers. Many elements of the physics of droplet formation by an immiscible turbulent jet and their resulting size distribution have not been elucidated, but are known to be significantly influenced by the addition of dispersants, which vary the Weber Number by orders of magnitude. We present experimental high speed visualizations of turbulent jets of sweet petroleum crude oil (MC 252) premixed with Corexit 9500A dispersant at various dispersant to oil ratios. Observations were conducted in a 0.9 m × 0.9 m × 2.5 m towing tank, where large-scale behavior of the jet, both stationary and towed at various speeds to simulate cross-flow, have been recorded at high speed. Preliminary data on oil droplet size and spatial distributions were also measured using a videoscope and pulsed light sheet. Sponsored by Gulf of Mexico Research Initiative (GoMRI).

Jet Car Track Site

Data.gov (United States)

Federal Laboratory Consortium — Located in Lakehurst, New Jersey, the Jet Car Track Site supports jet cars with J57 engines and has a maximum jet car thrust of 42,000 pounds with a maximum speed of...

Combination of water-jet dissection and needle-knife as a hybrid knife simplifies endoscopic submucosal dissection.

Science.gov (United States)

Lingenfelder, Tobias; Fischer, Klaus; Sold, Moritz G; Post, Stefan; Enderle, Markus D; Kaehler, Georg F B A

2009-07-01

The safety and efficacy of endoscopic submucosal dissection (ESD) is very dependent on an effective injection beneath the submucosal lamina and on a controlled cutting technique. After our study group demonstrated the efficacy of the HydroJet in needleless submucosal injections under various physical conditions to create a submucosal fluid cushion (Selective tissue elevation by pressure = STEP technique), the next step was to develop a new instrument to combine the capabilities of an IT-Knife with a high-pressure water-jet in a single instrument. In this experimental study, we compared this new instrument with a standard ESD technique. Twelve gastric ESD were performed in six pigs under endotracheal anesthesia. Square areas measuring 4-cm x 4-cm were marked out on the anterior and posterior wall in the corpus-antrum transition region. The HybridKnife was used as an standard needle knife with insulated tip (i.e., the submucosal injection was performed with an injection needle and only the radiofrequency (RF) part of the HybridKnife was used for cutting (conventional technique)) or the HybridKnife was used in all the individual stages of the ESD, making use of the HybridKnife's combined functions (HybridKnife technique). The size of the resected specimens, the operating time, the frequency with which instruments were changed, the number of bleeding episodes, and the number of injuries to the gastric wall together with the subjective overall assessment of the intervention by the operating physician were recorded. The resected specimens were the same size, with average sizes of 16.96 cm(2) and 15.85 cm(2) resp (p = 0.8125). Bleeding episodes have been less frequent in the HybridKnife group (2.83 vs. 3.5; p = 0.5625). The standard knife caused more injuries to the lamina muscularis propria (0.17 vs. 1.33; p = 0.0313). The operating times had a tendency to be shorter with the HybridKnife technique (47.18 vs. 58.32 minute; p = 0.0313). The combination of a needle

Viscous hydrophilic injection matrices for serial crystallography

Directory of Open Access Journals (Sweden)

Gabriela Kovácsová

2017-07-01

Full Text Available Serial (femtosecond crystallography at synchrotron and X-ray free-electron laser (XFEL sources distributes the absorbed radiation dose over all crystals used for data collection and therefore allows measurement of radiation damage prone systems, including the use of microcrystals for room-temperature measurements. Serial crystallography relies on fast and efficient exchange of crystals upon X-ray exposure, which can be achieved using a variety of methods, including various injection techniques. The latter vary significantly in their flow rates – gas dynamic virtual nozzle based injectors provide very thin fast-flowing jets, whereas high-viscosity extrusion injectors produce much thicker streams with flow rates two to three orders of magnitude lower. High-viscosity extrusion results in much lower sample consumption, as its sample delivery speed is commensurate both with typical XFEL repetition rates and with data acquisition rates at synchrotron sources. An obvious viscous injection medium is lipidic cubic phase (LCP as it is used for in meso membrane protein crystallization. However, LCP has limited compatibility with many crystallization conditions. While a few other viscous media have been described in the literature, there is an ongoing need to identify additional injection media for crystal embedding. Critical attributes are reliable injection properties and a broad chemical compatibility to accommodate samples as heterogeneous and sensitive as protein crystals. Here, the use of two novel hydrogels as viscous injection matrices is described, namely sodium carboxymethyl cellulose and the thermo-reversible block polymer Pluronic F-127. Both are compatible with various crystallization conditions and yield acceptable X-ray background. The stability and velocity of the extruded stream were also analysed and the dependence of the stream velocity on the flow rate was measured. In contrast with previously characterized injection media, both new

Aircraft dual-shaft jet engine with indirect action fuel flow controller

Science.gov (United States)

Tudosie, Alexandru-Nicolae

2017-06-01

The paper deals with an aircraft single-jet engine's control system, based on a fuel flow controller. Considering the engine as controlled object and its thrust the most important operation effect, from the multitude of engine's parameters only its rotational speed n is measurable and proportional to its thrust, so engine's speed has become the most important controlled parameter. Engine's control system is based on fuel injection Qi dosage, while the output is engine's speed n. Based on embedded system's main parts' mathematical models, the author has described the system by its block diagram with transfer functions; furthermore, some Simulink-Matlab simulations are performed, concerning embedded system quality (its output parameters time behavior) and, meanwhile, some conclusions concerning engine's parameters mutual influences are revealed. Quantitative determinations are based on author's previous research results and contributions, as well as on existing models (taken from technical literature). The method can be extended for any multi-spool engine, single- or twin-jet.

Phenomenology of single-inclusive jet production with jet radius and threshold resummation

Science.gov (United States)

Liu, Xiaohui; Moch, Sven-Olaf; Ringer, Felix

2018-03-01

We perform a detailed study of inclusive jet production cross sections at the LHC and compare the QCD theory predictions based on the recently developed formalism for threshold and jet radius joint resummation at next-to-leading logarithmic accuracy to inclusive jet data collected by the CMS Collaboration at √{S }=7 and 13 TeV. We compute the cross sections at next-to-leading order in QCD with and without the joint resummation for different choices of jet radii R and observe that the joint resummation leads to crucial improvements in the description of the data. Comprehensive studies with different parton distribution functions demonstrate the necessity of considering the joint resummation in fits of those functions based on the LHC jet data.

Forward Jet Vertex Tagging: A new technique for the identification and rejection of forward pileup jets

CERN Document Server

The ATLAS collaboration

2015-01-01

The suppression of pileup forward jets is crucial for a variety of physics analyses at the LHC, ranging from VBF Higgs production to SUSY searches. A novel forward pileup tagging technique that exploits the correlation between central and forward jets originating from pileup interactions is presented. Tracking and vertex information in the central $\\eta$ region is used to indirectly tag and reject forward pileup jets that are back-to-back to central pileup jets. The pileup suppression power observed in Pythia8 simulated events increases with jet \\pt and ranges between a 30\\% and 60\\% pileup jet removal for 90\\% jet selection efficiency for jets between 20 and 50 GeV.

Fast ions and momentum transport in JET tokamak plasmas

International Nuclear Information System (INIS)

Salmi, A.

2012-01-01

Fast ions are an inseparable part of fusion plasmas. They can be generated using electromagnetic waves or injected into plasmas as neutrals to heat the bulk plasma and to drive toroidal rotation and current. In future power plants fusion born fast ions deliver the main heating into the plasma. Understanding and controlling the fast ions is of crucial importance for the operation of a power plant. Furthermore, fast ions provide ways to probe the properties of the thermal plasma and get insight of its confinement properties. In this thesis, numerical code packages are used and developed to simulate JET experiments for a range of physics issues related to fast ions. Namely, the clamping fast ion distribution at high energies with RF heating, fast ion ripple torque generation and the toroidal momentum transport properties using NBI modulation technique are investigated. Through a comparison of numerical simulations and the JET experimental data it is shown that the finite Larmor radius effects in ion cyclotron resonance heating are important and that they can prevent fast ion tail formation beyond certain energy. The identified mechanism could be used for tailoring the fast ion distribution in future experiments. Secondly, ASCOT simulations of NBI ions in a ripple field showed that most of the reduction of the toroidal rotation that has been observed in the JET enhanced ripple experiments could be attributed to fast ion ripple torque. Finally, fast ion torque calculations together with momentum transport analysis have led to the conclusion that momentum transport in not purely diffusive but that a convective component, which increases monotonically in radius, exists in a wide range of JET plasmas. Using parameter scans, the convective transport has been shown to be insensitive to collisionality and q-profile but to increase strongly against density gradient. (orig.)

Fast ions and momentum transport in JET tokamak plasmas

Energy Technology Data Exchange (ETDEWEB)

Salmi, A.

2012-07-01

Fast ions are an inseparable part of fusion plasmas. They can be generated using electromagnetic waves or injected into plasmas as neutrals to heat the bulk plasma and to drive toroidal rotation and current. In future power plants fusion born fast ions deliver the main heating into the plasma. Understanding and controlling the fast ions is of crucial importance for the operation of a power plant. Furthermore, fast ions provide ways to probe the properties of the thermal plasma and get insight of its confinement properties. In this thesis, numerical code packages are used and developed to simulate JET experiments for a range of physics issues related to fast ions. Namely, the clamping fast ion distribution at high energies with RF heating, fast ion ripple torque generation and the toroidal momentum transport properties using NBI modulation technique are investigated. Through a comparison of numerical simulations and the JET experimental data it is shown that the finite Larmor radius effects in ion cyclotron resonance heating are important and that they can prevent fast ion tail formation beyond certain energy. The identified mechanism could be used for tailoring the fast ion distribution in future experiments. Secondly, ASCOT simulations of NBI ions in a ripple field showed that most of the reduction of the toroidal rotation that has been observed in the JET enhanced ripple experiments could be attributed to fast ion ripple torque. Finally, fast ion torque calculations together with momentum transport analysis have led to the conclusion that momentum transport in not purely diffusive but that a convective component, which increases monotonically in radius, exists in a wide range of JET plasmas. Using parameter scans, the convective transport has been shown to be insensitive to collisionality and q-profile but to increase strongly against density gradient. (orig.)

The H-mode pedestal, ELMs and TF ripple effects in JT-60U/JET dimensionless identity experiments

International Nuclear Information System (INIS)

Saibene, G.; Oyama, N.; Loennroth, J.; Andrew, Y.; Luna, E. de la; Giroud, C.; Huysmans, G.T.A.; Kamada, Y.; Kempenaars, M.A.H.; Loarte, A.; Donald, D. Mc; Nave, M.M.F.; Meiggs, A.; Parail, V.; Sartori, R.; Sharapov, S.; Stober, J.; Suzuki, T.; Takechi, M.; Toi, K.; Urano, H.

2007-01-01

This paper summarizes results of dimensionless identity experiments in JT-60U and JET, aimed at the comparison of the H-mode pedestal and ELM behaviour in the two devices. Given their similar size, dimensionless matched plasmas are also similar in their dimensional parameters (in particular, the plasma minor radius a is the same in JET and JT-60U). Power and density scans were carried out at two values of I p , providing a q scan (q 95 = 3.1 and 5.1) with fixed (and matched) toroidal field. Contrary to initial expectations, a dimensionless match between the two devices was quite difficult to achieve. In general, p ped in JT-60U is lower than in JET and, at low q, the pedestal pressure of JT-60U with a Type I ELMy edge is matched in JET only in the Type III ELM regime. At q 95 = 5.1, a dimensionless match in ρ*, ν* and β p,ped is obtained with Type I ELMs, but only with low power JET H-modes. These results motivated a closer investigation of experimental conditions in the two devices, to identify possible 'hidden' physics that prevents obtaining a good match of pedestal values over a large range of plasmas parameters. Ripple-induced ion losses of the medium bore plasma used in JT-60U for the similarity experiments are identified as the main difference with JET. The magnitude of the JT-60U ripple losses is sufficient to induce counter-toroidal rotation in co-injected plasma. The influence of ripple losses was demonstrated at q 95 = 5.1: reducing ripple losses by ∼2 (from 4.3 to 1.9 MW) by replacing positive with negative neutral beam injection at approximately constant P in resulted in an increased p ped in JT-60U, providing a good match to full power JET H-modes. At the same time, the counter-toroidal rotation decreased. Physics mechanisms relating ripple losses to pedestal performance are not yet identified, and the possible role of velocity shear in the pedestal stability, as well as the possible influence of ripple on thermal ion transport are briefly

CYTOGENETIC STUDIES IN MICE TREATED WITH THE JET FUELS, JET-A AND JP-8

Science.gov (United States)

Cytogenetic studies in mice treated with the jet fuels, Jet-A and JP-8AbstractThe genotoxic potential of the jet fuels, Jet-A and JP-8, were examined in mice treated on the skin with a single dose of 240 ug/mouse. Peripheral blood smears were prepared at the start of the ...

Cold and hot model investigation of flow and mixing in a multi-jet flare

Energy Technology Data Exchange (ETDEWEB)

Pagot, P.R. [Petrobras Petroleo Brasileiro S.A., Rio de Janeiro (Brazil); Sobiesiak, A. [Windsor Univ., ON (Canada); Grandmaison, E.W. [Queen' s Univ., Kingston, ON (Canada). Centre for Advanced Gas Combustion Technology

2003-07-01

The oil and gas industry commonly disposes of hydrocarbon wastes by flaring. This study simulated several features of industrial offshore flares in a multi-jet burner. Cold and hot flow experiments were performed. Twenty-four nozzles mounted on radial arms originating from a central fuel plenum were used in the burner design. In an effort to improve the mixing and radiation characteristics of this type of burner, an examination of the effect of various mixing-altering devices on the nozzle exit ports was performed. Flow visualization studies of the cold and hot flow systems were presented, along with details concerning temperature, gas composition and radiation levels from the burner models. The complex flow pattern resulting when multiple jets are injected into a cross flow stream were demonstrated with the flow visualization studies from the cold model. The trajectory followed by the leading edge jet for the reference case and the ring attachments was higher but similar to the simple round jet in a cross flow. The precessing jets and the cone attachments were more strongly deflected by the cross flow with a higher degree of mixing between the jets in the nozzle region. For different firing rates, flow visualization, gas temperature, gas composition and radiative heat flux measurements were performed in the hot model studies. Flame trajectories, projected side view areas and volumes increased with firing rates for all nozzle configurations and the ring attachment flare had the smallest flame volume. The gas temperatures reached maximum values at close to 30 per cent of the flame length and the lowest gas temperature was observed for the flare model with precessing jets. For the reference case nozzle, nitrogen oxide (NOx) concentrations were in the 30 to 45 parts per million (ppm) range. The precessing jet model yielded NOx concentrations in the 22 to 24 ppm range, the lowest obtained. There was a linear dependence between the radiative heat flux from the flames

b-Jet Identification in CMS

CERN Document Server

AUTHOR|(CDS)2081921

2016-01-01

A large fraction of the CMS physics program relies on the identification of jets containing the decay of a B hadron (b jets). The b jets can be discriminated from jets produced by the hadronization of light quarks based on characteristic properties of B hadrons, such as the long lifetime or the presence of soft leptons produced during their decay.An overview of the large variety of b-tagging algorithms and the measurement of their performance with data collected in 2011 and 2012 are presented in this talk. A special focus lies on new methods of b-tagging in jet substructure.As the excluded mass regions for new physics beyond the Standard Model continue to increase, searches often focus on boosted final states characterized by particles with large transverse momenta. In the boosted regime the resulting decay products for hadronic decays of heavy particles tend to be collimated and can fall within a single jet, known as fat-jet. In this case, selections based on multiple jets cannot be applied and jet substruct...

Jet simulations and gamma-ray burst afterglow jet breaks

NARCIS (Netherlands)

van Eerten, H.J.; Meliani, Z.; Wijers, R.A.M.J.; Keppens, R.

2011-01-01

The conventional derivation of the gamma-ray burst afterglow jet break time uses only the blast wave fluid Lorentz factor and therefore leads to an achromatic break. We show that in general gamma-ray burst afterglow jet breaks are chromatic across the self-absorption break. Depending on

Jet simulations and gamma-ray burst afterglow jet breaks