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Sample records for blowby

  1. Non-intrusive method of measuring PCV blowby constituents

    Energy Technology Data Exchange (ETDEWEB)

    Crane, M.E.; Ariga, S.; Boulard, R.; Lindamood, B.

    1994-10-01

    A technique is presented that has been successfully demonstrated to non-intrusively and quickly sample gases typically found in PCV systems. Color Detection Tubes (CDTs) were used with a simple sampling arrangement to monitor CO{sub 2}, NO{sub x}, O{sub 2}, and H{sub 2}O(g) at the closure line, crankcase, and PCV line. Measurements were accurate and could be made instantaneously. Short Path Thermal Desorbtion Tubes (SPTDTs) were used at the same engine locations for the characterization of fuel- and oil-derived hydrocarbon (HC) fractions and required only 50 cc samples. High engine loads caused pushover of blowby vapors as indicated by increased concentrations of CO{sub 2}, NO{sub x}, H{sub 2}O(g), and fuel HCs in the engines` fresh air inlets during WOT operation. Peak concentrations of blowby vapors were measured in the crankcase under no load and part throttle conditions. Oxygen concentrations always opposed the trends of CO{sub 2}, NO{sub x}, and H{sub 2}O(g). SPTDT data revealed that the PCV system consumes approximately 100-200 times more fuel vapors than oil vapors, on a mass basis; however, PCV-derived oil consumption represented almost 12 percent of total engine oil consumption under no load conditions. 8 refs., 17 figs.

  2. Influence of discharge parameters on blow-by in a coaxial plasma gun%放电参数对同轴枪中等离子体团的分离的影响

    Institute of Scientific and Technical Information of China (English)

    张俊龙; 杨亮; 闫慧杰; 滑跃; 任春生

    2015-01-01

    同轴枪中的等离子体团的分离现象主要是由同轴枪内磁场的梯度造成的电流层倾斜而引起的一个增强反馈过程导致的,这种分离现象越来越成为限制同轴枪有效使用的一个不利因素。在实验上研究放电参数对等离子体团的分离的影响,对理论研究和实际应用都具有重要意义。在实验中发现,利用光电倍增管可以直接观察到等离子体团的分离程度,由此可以研究放电参数对等离子体团的分离的影响。本实验主要研究电容充电电压、电容、放电气压这三个参数对分离现象的影响。实验发现,分离程度随着电容以及其充电电压的增大而增强,随着气压的增大而减弱。实验结果基于雪犁模型进行分析,电容以及电容充电电压的增大使放电电流增强使磁场梯度增大而导致电流层的倾斜程度增加,而使等离子体团的分离程度变严重,相反,气压的增加使需要加速更多粒子而导致电流层的倾斜程度减弱,而使等离子体团分离程度减弱。分析认为,通过控制在加速过程中影响电流层倾斜程度的因素可控制共轴枪中等离子体团的分离程度。%The blow-by which occurs in a coaxial plasma gun is the result of reinforcing feedback caused by the gradient of magnetic field and the component of axial current due to the canting of current sheath. The blow-by has become a serious negative effect which limits the effective use of the coaxial plasma gun, so it is necessary to study by experiment the parameters that influence the degree of blow-by. This will not only contribute to the study of the theory and mode about blow-by but also give advices to the weakening or eliminating blow-by by choosing suitable parameters in engineering field. The degree of blow-by can be observed directly by photomultiplier, and the influence of voltage of capacitance, capacitance, and the pressure of gas on blow-by have

  3. The Liquid Sustainer Build-up Time Impact on the Emptying Spacecraft Fuel Tank in Free Orbiting Conditions

    Directory of Open Access Journals (Sweden)

    V. B. Sapozhnikov

    2015-01-01

    Full Text Available Trouble-free operation of liquid rocket engines (LRE depends, among other factors, on the nonstop supply of liquid rocket fuel components in the fuel tank feed line with continuous flow.This condition becomes especially relevant for the aerial vehicles (AV in orbital (suborbital environment. With a little filled fuel tanks discontinuity of flow may occur because of pressurizing gas blow-by in the feed line as a result of the funnel generation (with or without vortex formation and so-called phenomenon of dynamic failure of the interface "liquid-gas”.The paper presents a mathematical model of the process of emptying tank initially a little filled and having a reduced level of the gravity acceleration. Using the developed mathematical model a parametric study has been conducted to find how stabilization rate of liquid flow effects on the volume of drained liquid. The computational experiment defines gas blow-by points in the feed line and propellant residuals, depending on the flow rate, physical properties of the fuel components, residual value of the acceleration, and diameter of the feed line.As a result, an effect is discovered that previously has been never mentioned in publications on research of the emptying processes of the aircraft fuel tanks, namely: with abrupt bootstrap of the flow rate a blow-by of gas occurs at the initial stage of emptying tank. In this case, to ensure LRE trouble-free operation there is a need in a special inner-tank device to prevent premature blow-by of pressurizing gas in the tank feed line.

  4. Reciprocating Compressor 1D Thermofluid Dynamic Simulation: Problems and Comparison with Experimental Data

    Directory of Open Access Journals (Sweden)

    A. Gimelli

    2012-01-01

    Full Text Available The authors here extend a 0D-1D thermofluid dynamic simulation approach to describe the phenomena internal to the volumetric machines, reproducing pressure waves’ propagation in the ducts. This paper reports the first analysis of these phenomena in a reciprocating compressor. The first part presents a detailed experimental analysis of an open-type reciprocating compressor equipped with internal sensors. The second part describes a 0D-1D thermofluid dynamic simulation of the compressor. Comparison of computed and measured values of discharge mass flow rate shows a good agreement between results for compression ratio <5. Then, to improve the model fitting at higher pressures, a new scheme has been developed to predict the blow-by through the ring pack volumes. This model is based on a series of volumes and links which simulate the rings’ motions inside the grooves, while the ring dynamics are imposed using data from the literature about blow-by in internal combustion engines. The validation is obtained comparing experimental and computing data of the two cylinder engine blowby. After the validation, a new comparison of mass flow rate on the compressor shows a better fitting of the curves at higher compression ratio.

  5. Rail accelerators for space transportation: An experimental investigation

    Science.gov (United States)

    Zana, L. M.; Kerslake, W. R.; Sturman, J. L.

    1986-01-01

    An experimental program was conducted at the Lewis Research Center with the objective of investigating the technical feasibility of rail accelerators for propulsion applications. Single-stage, plasma driven rail accelerators of small (4 by 6 mm) and medium (12.5 by 12.5 mm) bores were tested at peak accelerating currents of 50 to 450 kA. Streak-camera photography was used to provide a qualitative description of plasma armature acceleration. The effects of plasma blowby and varying bore pressure on the behavior of plasma armatures were studied.

  6. The projectile-wall interface in rail launchers

    Science.gov (United States)

    Thio, Y. C.; Huerta, M. A.; Boynton, G. C.; Tidman, D. A.; Wang, S. Y.; Winsor, N. K.

    1993-01-01

    At sufficiently high velocity, an energetic gaseous interface is formed between the projectile and the gun wall. We analyze the flow in this interface in the regime of moderately high velocity. The effect of this gaseous interface is to push the gun wall radially outward and shrink the projectile radially inward. Our studies show that significant plasma blow-by can be expected in most experimental railguns in which organic polymers are used as insulators. Since plasma leakage may result in the reduction of propulsion pressure and possibly induce the separation of the primary, the results point to the importance of having sufficiently stiff barrels and structurally stiff but 'ballistically compliant' projectile designs.

  7. Air/oil separator with minimal space requirements in the crankcase venting system; Oelnebelabscheidung in der Kurbelgehaeuseentlueftung auf engstem Raum

    Energy Technology Data Exchange (ETDEWEB)

    Bastias, P. [Dana Sealing and Plastics Products Design Center, Paris, TN (United States); Brueckle, T.; Grafl, D.; Sattler-Laegel, T.; Spaeth, B. [Reinz-Dichtungs-GmbH, Neu-Ulm (Germany); Caloghero, D. [Victor Reinz Mercosur (VRM), Gravatai (Brazil)

    2005-12-01

    An important function for crankcase venting is the separation of oil mist from the blow-by gas. In this area, engine builders place widely varying demands on their development suppliers. Not only must air/oil separator systems be highly efficient, robust, functionally reliable, flexible and compact, they must also be cost-effective. Reinz-Dichtungs-GmbH, a Dana Corporation company, set up a global development team to take on the challenge. The result is one of today's smallest and at the same time most efficient air/oil separator systems - the Multitwister. (orig.)

  8. Mathematical model of the Beta Rand Cam{trademark} engine vane seals

    Energy Technology Data Exchange (ETDEWEB)

    Braden, C.H.; Thompson, G.J.; Smith, J.E.; Mucino, V.H. [West Virginia Univ., Morgantown, WV (United States)

    1996-12-31

    A mathematical model of the vane sealing mechanism is presented to determine how the loading on the seals will affect the performance of the Rand Cam{trademark} engine. Within the Rand Cam{trademark} engine, sacrificial linear seals in the vane are used as the main sealing mechanism to prevent blowby from one chamber to the next. Throughout this investigation a kinetostatic analysis, based upon Yamamoto`s Wankel apex seal analysis, is extended into three dimensions. The input data to the model can be varied to study the effects of seal dimensions, seal material, seal dynamics, and friction.

  9. Military Adaptation of Commercial Items: Laboratory Evaluation of the Code E-436 Engine

    Science.gov (United States)

    1984-02-01

    Coolant, engine outlet 120-250 + 2 (13) Combustion air at meter ( Meriam 30-160 ± 2 flow meter) (14) Cooling water, tower inlet * 35-100 (15) Cooling...2) Air, before turbo (in.H 2 0)-S 0 to -25 ± 1 (3) Air, after turbo (in. hg) 0 to +60 +.2 (4) Air across Meriam flow meter 0 to -28 +.1 (in. H 20) (5...meter for measuring engine blowby. (8) Temperature reference bath (Maintain at 2000 F). (9) Meriam air flow meter. e. The folloing monitors vill be

  10. Interring Gas Dynamic Analysis of Piston in a Diesel Engine considering the Thermal Effect

    Directory of Open Access Journals (Sweden)

    Wanyou Li

    2015-01-01

    Full Text Available Understanding the interaction between ring dynamics and gas transport in ring pack systems is crucial and needs to be imperatively studied. The present work features detailed interring gas dynamics of piston ring pack behavior in internal combustion engines. The model is developed for a ring pack with four rings. The dynamics of ring pack are simulated. Due to the fact that small changes in geometry of the grooves and lands would have a significant impact on the interring gas dynamics, the thermal deformation of piston has been considered during the ring pack motion analysis in this study. In order to get the temperature distribution of piston head more quickly and accurately, an efficient method utilizing the concept of inverse heat conduction is presented. Moreover, a sensitive analysis based on the analysis of partial regression coefficients is presented to investigate the effect of groove parameters on blowby.

  11. Heat insulation of combustion chamber walls - A measure to decrease the fuel consumption of I. C. engines

    Energy Technology Data Exchange (ETDEWEB)

    Woschni, G.; Spindler, W.; Kolesa, K.

    1987-01-01

    Experimental investigations were made with a single-cylinder direct-injection Diesel engine with heat-insulated piston. The most important result is an inferior economy compared with the not insulated aluminum-piston engine. It was found that this phenomenon is not caused by neither a changed combustion process nor increased blowby nor different friction losses, but rather by a drastic increase of the heat transfer coefficient during the first part of combustion with increasing surface temperature. This is taken into account in a modified equation for the heat transfer coefficient. Cycle-simulations using this modified equation show that there is neither a gain in fuel economy of naturally aspirated nor of turbocharged nor of turbocompound Diesel engines with ''heat insulated'' combustion chamber walls.

  12. Effect of the trapped mass and its composition on the heat transfer in the compression cycle of a reciprocating engine

    Energy Technology Data Exchange (ETDEWEB)

    Armas, Octavio; Rodriguez, Jose [Departamento de Mecanica Aplicada e Ingenieria de Proyectos, Escuela Tecnica Superior de Ingenieros Industriales, Universidad de Castilla-La Mancha, Ave. Camilo Jose Cela, s/n. Ciudad Real 13071 (Spain); Payri, Francisco; Martin, Jaime [Departamento de Maquinas y Motores Termicos, Escuela Tecnica Superior de Ingenieros Industriales, Universidad Politecnica de Valencia, Avda. de los Naranjos, s/n. 46022 Valencia (Spain); Agudelo, John R. [Grupo Ciencia y Tecnologia del Gas y Uso Racional de la Energia, Universidad de Antioquia, Medellin (Colombia)

    2005-12-01

    The use of the polytropic coefficient calculation during the compression process in the thermodynamic cycle of a reciprocating internal combustion engine is an interesting tool to minimize errors in the synchronization of pressure and volume signals, and to determine heat flux transferred to the cylinder walls. The accuracy of this calculation depends on the instantaneous values for pressure, volume, trapped mass and its composition, as well as on their variations. In this work the effect of the errors in blow-by, trapped mass and its composition have been studied in detail, specially the effect of errors in the composition estimation, owing to the use of exhaust gas recirculation in typical diesel engines. (author)

  13. Cross-field plasma injection into mirror geometry

    Science.gov (United States)

    Uzun-Kaymak, I. U.; Messer, S.; Bomgardner, R.; Case, A.; Clary, R.; Ellis, R.; Elton, R.; Teodorescu, C.; Witherspoon, F. D.; Young, W.

    2009-09-01

    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 µg, velocities up to 90 km s-1 and plasma density in the high 1014 cm-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.

  14. Dense Plasma Injection Experiment at MCX

    Science.gov (United States)

    Uzun-Kaymak, I.; Messer, S.; Bomgardner, R.; Case, A.; Clary, R.; Ellis, R.; Elton, R.; Hassam, A.; Teodorescu, C.; Witherspoon, D.; Young, W.

    2009-09-01

    We present preliminary results of the High Density Plasma Injection Experiment at the Maryland Centrifugal Experiment (MCX). HyperV Technologies Corp. has designed, built, and installed a prototype coaxial gun to drive rotation in MCX. This gun has been designed to avoid the blow-by instability via a combination of electrode shaping and a tailored plasma armature. An array of diagnostics indicates the gun is capable of plasma jets with a mass of 160 μg at 70 km/s with an average plasma density above 1015 cm-3. Preliminary measurements are underway at MCX to understand the penetration of the plasma jet through the MCX magnetic field and the momentum transfer from the jet to the MCX plasma. Data will be presented for a wide range of MCX field parameters, and the prospects for future injection experiments will be evaluated.

  15. Computational Modelling of Piston Ring Dynamics in 3D

    Directory of Open Access Journals (Sweden)

    Dlugoš Jozef

    2014-12-01

    Full Text Available Advanced computational models of a piston assembly based on the level of virtual prototypes require a detailed description of piston ring behaviour. Considering these requirements, the piston rings operate in regimes that cannot, in general, be simplified into an axisymmetric model. The piston and the cylinder liner do not have a perfect round shape, mainly due to machining tolerances and external thermo-mechanical loads. If the ring cannot follow the liner deformations, a local loss of contact occurs resulting in blow-by and increased consumption of lubricant oil in the engine. Current computational models are unable to implement such effects. The paper focuses on the development of a flexible 3D piston ring model based on the Timoshenko beam theory using the multibody system (MBS. The MBS model is compared to the finite element method (FEM solution.

  16. Problems in the wellbore integrity of a shale gas horizontal well and corresponding countermeasures

    Directory of Open Access Journals (Sweden)

    Zhonglan Tian

    2015-12-01

    Full Text Available In the Changning–Weiyuan national shale gas demonstration area, SW Sichuan Basin, the wellbore integrity damage occurs in some shale gas wells and has direct effect on the gas production rate of single shale gas horizontal well. After statistics analysis was performed on the problems related with wellbore integrity, such as casing damage, casing running difficulty and cement sheath blow-by, the multi-factor coupling casing stress calculation and evaluation mode laws established. Then study was conducted on the influential mechanism of multi-factor coupling (temperature effect, casing bending and axial pressure on casing damage. The shale slip mechanism and its relationship with casing sheared formation were analyzed by using the Mohr–Coulomb criterion. Inversion analysis was performed on the main controlling factors of casing friction by using the developed casing hook load prediction and friction analysis software. And finally, based on the characteristics of shale gas horizontal wells, wellbore integrity control measures were proposed in terms of design and construction process, so as to improve the drilling quality (DQ. More specifically, shale gas well casing design calculation method and check standard were modified, well structure and full bore hole trajectory design were optimized, drilling quality was improved, cement properties were optimized and cement sealing integrity during fracturing process was checked. These research findings are significant in the design and management of future shale gas borehole integrity.

  17. Contoured-gap coaxial guns for imploding plasma liner experiments

    Science.gov (United States)

    Witherspoon, F. D.; Case, A.; Brockington, S.; Cassibry, J. T.; Hsu, S. C.

    2014-10-01

    Arrays of supersonic, high momentum flux plasma jets can be used as standoff compression drivers for generating spherically imploding plasma liners for driving magneto-inertial fusion, hence the name plasma-jet-driven MIF (PJMIF). HyperV developed linear plasma jets for the Plasma Liner Experiment (PLX) at LANL where two guns were successfully tested. Further development at HyperV resulted in achieving the PLX goal of 8000 μg at 50 km/s. Prior work on contoured-gap coaxial guns demonstrated an approach to control the blowby instability and achieved substantial performance improvements. For future plasma liner experiments we propose to use contoured-gap coaxial guns with small Minirailgun injectors. We will describe such a gun for a 60-gun plasma liner experiment. Discussion topics will include impurity control, plasma jet symmetry and topology (esp. related to uniformity and compactness), velocity capability, and techniques planned for achieving gun efficiency of >50% using tailored impedance matched pulse forming networks. Mach2 and UAH SPH code simulations will be included. Work supported by US DOE DE-FG02-05ER54810.

  18. High Current Systems for HyperV and PLX Plasma Railguns

    Science.gov (United States)

    Brockington, Samuel; Case, Andrew; Messer, Sarah; Bomgardner, Richard; Wu, Linchun; Elton, Raymond; Witherspoon, F. Douglas

    2010-11-01

    HyperV has been developing coaxial pulsed, plasma railgun accelerators for PLX and other high momentum plasma experiments. The full scale HyperV coaxial gun accelerates plasma armatures using a contoured electrode gap designed to mitigate the blow-by instability. Previous experiments with the full scale gun successfully formed and accelerated annular plasma armatures, but were limited to currents of up to only ˜400 kA. In order to increase full scale gun performance to the design goal of 200 μg at 200 km/s, the pulse forming networks required upgrading to support currents up to ˜1 MA. A high voltage, high current field-effect sparkgap switch and low inductance transmission line were designed and constructed to handle the increased current pulse. We will describe these systems and present initial test data from high current operation of the full-scale coax gun along with plans for future testing. Similar high current accelerator banks, switches, and TM lines will also be required to power PLX railguns which are planned to operate at 8000 μg at 50 km/s. The design of that experiment may require the capacitor banks to be located as much as 10 feet from the gun. We discuss the available options for low inductance connections for these systems.

  19. Engineering design of the PLX- α coaxial gun

    Science.gov (United States)

    Cruz, Edward; Brockington, Samuel; Case, Andrew; Luna, Marco; Witherspoon, Douglas; Langendorf, Samuel

    2016-10-01

    We describe the engineering and technical aspects of the coaxial gun designed for the 60-gun scaling study of spherically imploding plasma liners as a standoff driver for plasma-jet-driven magneto-inertial fusion. Each coaxial gun incorporates a fast, dense gas injection and triggering system, a compact low-weight pfn with integral sparkgap switching, and a contoured gap designed to suppress the blow-by instability. Alpha1 and Alpha2 guns are compared, with emphasis on the improvements on Alpha2, which include a faster more robust gas valve, an improved electrode contour, a custom 600- μF, 5-kV pfn, and a set of six inline sparkgap switches operated in parallel. The switch and pfn configurations are mounted directly to the back of the gun, and are designed to reduce inductance, cost, and complexity, maximize efficiency and system reliability, and ensure symmetric current flow. We will provide a detailed overview of the design choices made for the PLX- α coaxial gun. This work supported by the ARPA-E ALPHA Program.

  20. Coaxial-gun design and testing for the PLX- α Project

    Science.gov (United States)

    Witherspoon, F. Douglas; Brockington, Samuel; Case, Andrew; Cruz, Edward; Luna, Marco; Langendorf, Samuel

    2016-10-01

    We describe the Alpha coaxial gun designed for a 60-gun scaling study of spherically imploding plasma liners as a standoff driver for plasma-jet-driven magneto-inertial fusion (PJMIF). The guns operate over a range of parameters: 0.5-5.0 mg of Ar, Ne, N2, Kr, and Xe; 20-60 km/s; 2 × 1016 cm-3 muzzle density; and up to 7.5 kJ stored energy per gun. Each coaxial gun incorporates a fast dense gas injection and triggering system, a compact low-weight pfn with integral sparkgap switching, and a contoured gap designed to suppress the blow-by instability. The latest design iteration incorporates a faster more robust gas valve, an improved electrode contour, a custom 600- μF, 5-kV pfn, and six inline sparkgap switches operated in parallel. The switch and pfn are mounted directly to the back of the gun and are designed to reduce inductance, cost, and complexity, maximize efficiency and system reliability, and ensure symmetric current flow. We provide a brief overview of the design choices, the projected performance over the parameter ranges mentioned above, and experimental results from testing of the PLX- α coaxial gun. This work supported by the ARPA-E ALPHA Program.

  1. 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.

  2. Deep procedural sedation by a sedationist team for outpatient pediatric renal biopsies.

    Science.gov (United States)

    Kamat, Pradip P; Ayestaran, Frank W; Gillespie, Scott E; Sanders, Rebecca D; Greenbaum, Larry A; Simon, Harold K; Stockwell, Jana A

    2016-05-01

    To date, no study has analyzed the use of deep PS for pediatric renal biopsies by a dedicated sedation team in an outpatient setting. Retrospective analysis of renal biopsies performed at CHOA from 2009 to 2013. Patient demographics, procedure success, and sedation-related events were analyzed. Logistic regression techniques were applied to identify characteristics associated with procedure safety and success. A total of 174 biopsies from 136 patients, aged 2-21 yr, were reviewed. Of the 174 biopsies, 63 of 174 (36%) were from native, and 111 of 174 (64%) were from transplanted kidneys, respectively. No deaths, allograft losses, or unanticipated hospital admissions occurred. The most commonly utilized interventions during sedation were blow-by oxygen (29.9%) and CPAP (12.1%). Children receiving the combination of F + P had significantly higher biopsy success rates vs. other drug combinations (96.1% vs. 79%; p = 0.014). There was no difference in complication rates regardless of drug combination or biopsy type (transplanted vs. native). The combination of F + P yields a high procedural success rate for outpatient native and transplanted kidney biopsies. We identified a number of sedation-related events that can be easily managed by a well-trained sedationist team.

  3. The HyperV Full-Scale Contoured-Gap Coaxial Plasma Railgun

    Science.gov (United States)

    Brockington, Samuel; Case, Andrew; Messer, Sarah; Bomgardner, Richard; Elton, Raymond; Wu, Linchun; Witherspoon, F. Douglas

    2009-11-01

    HyperV has been developing pulsed plasma injected coaxial railguns with a contoured gap profile designed to mitigate the blowby instability. Previous work using half-scale guns has been successful in launching 150 μg plasmas at 90 km/s [1]. In order to meet the original goal of 200 μg at 200 km/s the full-scale coaxial plasma gun has been constructed, and initial testing is beginning. This new plasma gun consists of two machined aluminum electrodes and a UHMW polyethylene breech insulator. The gun is breech fed by 64 ablative polyethylene capillary discharge units identical to the half-scale gun units. Maximum accelerator energy storage has also been increased 50%. Refractory coatings may be necessary to allow full current (˜800 kA) operation. The outer electrode includes 24 small diagnostic ports for optical and magnetic probe access to the plasma inside the gun to allow direct measurement of the plasma armature dynamics. Initial test data from the full-scale coax gun will be presented along with plans for future testing. Work supported by the U.S. DOE Office of Fusion Energy Sciences.[4pt] [1] F. D. Witherspoon, A. Case, S. Messer, R. Bomgardner, M. Phillips, S. Brockington, R. Elton, ``Contoured Gap Coaxial Plasma Gun with Injected Plasma Armature'' Rev. Sci. Instr. submitted (2009)

  4. Experiments on Plasma Injection into a Centrifugally Confined System

    Science.gov (United States)

    Messer, S.; Bomgardner, R.; Brockington, S.; Case, A.; Witherspoon, F. D.; Uzun-Kaymak, I.; Elton, R.; Young, W.; Teodorescu, C.; Morales, C. H.; Ellis, R. F.

    2009-11-01

    We describe the cross-field injection of plasma into a centrifugally-confined system. Two different types of plasma railgun have been installed on the Maryland Centrifugal Experiment (MCX) in an attempt to drive that plasma's rotation. The initial gun was a coaxial device designed to mitigate the blowby instability. The second one was a MiniRailgun with a rectangular bore oriented so that the MCX magnetic field augments the railgun's internal magnetic field. Tests at HyperV indicate this MiniRailgun reaches much higher densities than the original gun, although muzzle velocity is slightly reduced. We discuss the impact of these guns on MCX for various conditions. Initial results show that even for a 2 kG field, firing the MiniRailgun modifies oscillations of the MCX diamagnetic loops and can impact the core current and voltage. The gun also has a noticeable impact on MCX microwave emissions. These observations suggest plasma enters the MCX system. We also compare diagnostic data collected separately from MCX for these and other guns, focussing primarily on magnetic measurements.

  5. 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 μg of plasma with density above 1017 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.

  6. Estimation of trapped mass by in-cylinder pressure resonance in HCCI engines

    Science.gov (United States)

    Luján, José Manuel; Guardiola, Carlos; Pla, Benjamín; Bares, Pau

    2016-01-01

    High pressure gradients at homogeneous charge compression ignition (HCCI) engines heavily excite the pressure resonance. The pressure resonant frequency depends on speed of sound in the cylinder, and thus on the bulk gas temperature. Present paper profits this relation estimating the trapped mass inside the cylinder. In contrast to other estimation methods in the literature, the presented method is based on the trace of the in-cylinder pressure during the cycle; therefore, it permits a cycle-to-cycle mass estimation, and avoids errors associated with other assumptions, such as heat transfer during compression or initial temperature of the in-cylinder gases. The proposed strategy only needs the pressure signal, a volume estimation and a composition assumption to obtain several trapped mass estimates during one cycle. These estimates can be later combined for providing an error estimate of the measurement, with the assumption of negligible blow-by. The method is demonstrated in two HCCI engines of different size, showing good performance in steady operation and presenting great potential to control transient operation.

  7. Low-Engine-Friction Technology for Advanced Natural-Gas Reciprocating Engines

    Energy Technology Data Exchange (ETDEWEB)

    Victor Wong; Tian Tian; G. Smedley; L. Moughon; Rosalind Takata; J. Jocsak

    2006-11-30

    This program aims at improving the efficiency of advanced natural-gas reciprocating engines (ANGRE) by reducing piston and piston ring assembly friction without major adverse effects on engine performance, such as increased oil consumption and wear. An iterative process of simulation, experimentation and analysis has been followed towards achieving the goal of demonstrating a complete optimized low-friction engine system. In this program, a detailed set of piston and piston-ring dynamic and friction models have been adapted and applied that illustrate the fundamental relationships among mechanical, surface/material and lubricant design parameters and friction losses. Demonstration of low-friction ring-pack designs in the Waukesha VGF 18GL engine confirmed ring-pack friction reduction of 30-40%, which translates to total engine FEMP (friction mean effective pressure) reduction of 7-10% from the baseline configuration without significantly increasing oil consumption or blow-by flow. The study on surface textures, including roughness characteristics, cross hatch patterns, dimples and grooves have shown that even relatively small-scale changes can have a large effect on ring/liner friction, in some cases reducing FMEP by as much as 30% from a smooth surface case. The measured FMEP reductions were in good agreement with the model predictions. The combined analysis of lubricant and surface design indicates that low-viscosity lubricants can be very effective in reducing friction, subject to component wear for extremely thin oils, which can be mitigated with further lubricant formulation and/or engineered surfaces. Hence a combined approach of lubricant design and appropriate wear reduction offers improved potential for minimum engine friction loss. Testing of low-friction lubricants showed that total engine FMEP reduced by up to {approx}16.5% from the commercial reference oil without significantly increasing oil consumption or blow-by flow. Piston friction studies

  8. Intravenous midazolam sedation in pediatric diagnostic upper digestive endoscopy. A prospective study in a general hospital.

    Science.gov (United States)

    Verhage, Jan; Mulder, Chris J J; Willekens, Frans L A

    2003-12-01

    The positive role of benzodiazepines (Midazolam) in conscious sedation in pediatric patients is widely known. However, problems concerning the role of sedation in diagnostic upper endoscopy are a matter for debate as little is known about dosage and timing. We prospectively evaluated the efficacy, safety and optimal intravenous sedation dosage of midazolam in 257 consecutive patients, aged 2 months to 18 years old, who underwent upper endoscopy of the gastrointestinal tract. The initial midazolam dosage was 0.2 mg/kg Bw (Body weight) i.v. for 1 minute and, if necessary, another 0.1 mg/kg Bw was administered 5 minutes later. If sedation was sufficient, the procedure would be started 4-5 minutes later; if not, another 0.1 - 0.2 mg/kg Bw would be administered. All procedures were performed by a pediatrician together with a gastroenterologist. No serious complications occurred in any of the procedures. Oxygen saturation (OS) was maintained at over 90%, if necessary with blowby oxygen. Flumazenil was administered to 7 children (OS < 90%). Endoscopy could not be completed in 1 child. All endoscopies were completed within 10 minutes. No unexpected hospital admissions were necessary. The mean midazolam dosage was 0.4 mg/kg Bw in patients up to 6 years, for the over 6 years-olds the mean dosage was decreased to 0,2 mg/kg Bw. Particular attention was paid to the importance of informing patients before the procedure. Endoscopic diagnostic procedures can be performed safely and effectively in children with intravenous sedation in a well equipped pediatric endoscopy unit.

  9. The influence of lubricant degradation on the wear of the tribo systems in an internal combustion engine; Der Einfluss der Oelalterung auf das Verschleissverhalten der Tribosysteme im Verbrennungsmotor

    Energy Technology Data Exchange (ETDEWEB)

    Schwarze, H.; Brouwer, L.; Wolf, M. [Technische Univ. Clausthal-Zellerfeld (Germany). Inst. fuer Tribologie und Energiewandlungsmaschinen; Knoll, G.; Schlerege, F. [Kassel Univ. (Germany). Inst. fuer Maschinenelemente und Konstruktionstechnik; Kopnarski, M.; Emrich, S. [IFOS Inst. fuer Oberflaechen- und Schichtanalytik GmbH, Kaiserslautern (Germany)

    2007-07-01

    For a distinct extension of oil change intervals an improved knowledge of the influence of deteriorated lubricants on the wear properties of the engine's tribo systems is necessary. In test runs with a modern 1.8 l direct injection Otto engine the impact of the input of contaminants into the oil was studied by means of on line wear measurements, surface analyses and computer simulation. Two different test cycles and a modification of the blow-by system were utilized for a variation of the mechanical and chemical stress to the oil. The crucial oil contamination takes place at low temperature conditions. In a certain temperature range a water/oil-emulsion is formed from oil dust and blow by gas, which decomposes to a water phase and an oil phase at colder surfaces in the engine. The water phases show strongly corrosive properties. The chemical deterioration of oil from the emulsion is significantly increased as compared to the bulk oil. Only after a short run time these changes in the lubricant caused increased rates of wear as compared to reference experiments, in which the oil temperature was always kept above the critical temperature range. Decreasing the input of contaminants by limiting the circulation of blow by gas in the engine and removing it at its place of formation resulted in a delayed and reduced increase of the rate of wear. In the surfaces of the tribo contacts phosphorus, zinc, and sulphur could be identified indicating the formation of wear protection layers. Whereas under high temperature conditions these layers are conserved during the entire test run, they could not be detected in low temperature runs for most of the tribo systems. There is some evidence that wear protection layers may tolerate unfavourable oil condition before irreversible damages occur. Computer simulations utilizing flow factors deducted from real surfaces of components taken from the test runs clearly indicate that under low temperature conditions wear produces grooves

  10. LOW-ENGINE-FRICTION TECHNOLOGY FOR ADVANCED NATURAL-GAS RECIPROCATING ENGINES

    Energy Technology Data Exchange (ETDEWEB)

    Victor Wong; Tian Tian; Luke Moughon; Rosalind Takata; Jeffrey Jocsak

    2006-03-31

    This program aims at improving the efficiency of advanced natural-gas reciprocating engines (ANGRE) by reducing piston and piston ring assembly friction without major adverse effects on engine performance, such as increased oil consumption and wear. An iterative process of simulation, experimentation and analysis is being followed towards achieving the goal of demonstrating a complete optimized low-friction engine system. To date, a detailed set of piston and piston-ring dynamic and friction models have been developed and applied that illustrate the fundamental relationships among mechanical, surface/material and lubricant design parameters and friction losses. Demonstration of low-friction ring-pack designs in the Waukesha VGF 18GL engine confirmed total engine FEMP (friction mean effective pressure) reduction of 7-10% from the baseline configuration without significantly increasing oil consumption or blow-by flow. This represents a substantial (30-40%) reduction of the ringpack friction alone. The measured FMEP reductions were in good agreement with the model predictions. Further improvements via piston, lubricant, and surface designs offer additional opportunities. Tests of low-friction lubricants are in progress and preliminary results are very promising. The combined analysis of lubricant and surface design indicates that low-viscosity lubricants can be very effective in reducing friction, subject to component wear for extremely thin oils, which can be mitigated with further lubricant formulation and/or engineered surfaces. Hence a combined approach of lubricant design and appropriate wear reduction offers improved potential for minimum engine friction loss. Piston friction studies indicate that a flatter piston with a more flexible skirt, together with optimizing the waviness and film thickness on the piston skirt offer significant friction reduction. Combined with low-friction ring-pack, material and lubricant parameters, a total power cylinder friction

  11. Calage thermodynamique du point mort haut des moteurs à piston Thermodynamic Calibration of Top Dead Center in Piston Engines

    Directory of Open Access Journals (Sweden)

    Pinchon P.

    2006-11-01

    maximum pressure crank angle which is easy to identify. Based on theoretical thermodynamics analysis, this calibration method was validated by tests on different engines in which, in particular, variations were made in the volumetric ratio, volumetric efficiency and blow-by rate. The accuracy of the method is within about 1/10th of a degree of crankshaft rotation.

  12. Flex Fuel Optimized SI and HCCI Engine

    Energy Technology Data Exchange (ETDEWEB)

    Zhu, Guoming; Schock, Harold; Yang, Xiaojian; Huisjen, Andrew; Stuecken, Tom; Moran, Kevin; Zhen, Ron; Zhang, Shupeng

    2013-09-30

    the electrical variable valve timing (VVT) actuating system and satisfactory electrical VVT responses were obtained. Target engine control system was designed and fabricated at MSU for both single-cylinder optical and multi-cylinder metal engines. Finally, the developed control-oriented engine model was successfully implemented into the HIL simulation environment. The Chrysler 2.0L I4 DI engine was modified to fit the two-step vale with electrical variable valve timing actuating system. A used prototype engine was used as the base engine and the cylinder head was modified for the two-step valve with electrical VVT actuating system. Engine validation tests indicated that cylinder #3 has very high blow-by and it cannot be reduced with new pistons and rings. Due to the time constraint, it was decided to convert the four-cylinder engine into a single cylinder engine by blocking both intake and exhaust ports of the unused cylinders. The model-based combustion mode transition control algorithm was developed in the MSU HIL simulation environment and the Simulink based control strategy was implemented into the target engine controller. With both single-cylinder metal engine and control strategy ready, stable HCCI combustion was achived with COV of 2.1% Motoring tests were conducted to validate the actuator transient operations including valve lift, electrical variable valve timing, electronic throttle, multiple spark and injection controls. After the actuator operations were confirmed, 15-cycle smooth combustion mode transition from SI to HCCI combustion was achieved; and fast 8-cycle smooth combustion mode transition followed. With a fast electrical variable valve timing actuator, the number of engine cycles required for mode transition can be reduced down to five. It was also found that the combustion mode transition is sensitive to the charge air and engine coolant temperatures and regulating the corresponding temperatures to the target levels during the combustion mode

  13. Mécanisme de l'usure par polissage des cylindres de moteurs diesel Bore Polishing Wear Mechanism in Diesel Engine Cylinders

    Directory of Open Access Journals (Sweden)

    Fayard J. C.

    2006-11-01

    honing does not lead to the same phenomena as the ones observed when the liner is polished in situ in a running engine. In particular, ring wear as well as the flow rates of blowby gas are less than with a normal liner. The polishing-wear mechanism by two and three bodies soft abrasion is perfectly confirmed by micrographic exploration and by the microanalysis of polished surfaces.

  14. Flex Fuel Optimized SI and HCCI Engine

    Energy Technology Data Exchange (ETDEWEB)

    Zhu, Guoming; Schock, Harold; Yang, Xiaojian; Huisjen, Andrew; Stuecken, Tom; Moran, Kevin; Zhen, Ron; Zhang, Shupeng

    2013-09-30

    the electrical variable valve timing (VVT) actuating system and satisfactory electrical VVT responses were obtained. Target engine control system was designed and fabricated at MSU for both single-cylinder optical and multi-cylinder metal engines. Finally, the developed control-oriented engine model was successfully implemented into the HIL simulation environment. The Chrysler 2.0L I4 DI engine was modified to fit the two-step vale with electrical variable valve timing actuating system. A used prototype engine was used as the base engine and the cylinder head was modified for the two-step valve with electrical VVT actuating system. Engine validation tests indicated that cylinder #3 has very high blow-by and it cannot be reduced with new pistons and rings. Due to the time constraint, it was decided to convert the four-cylinder engine into a single cylinder engine by blocking both intake and exhaust ports of the unused cylinders. The model-based combustion mode transition control algorithm was developed in the MSU HIL simulation environment and the Simulink based control strategy was implemented into the target engine controller. With both single-cylinder metal engine and control strategy ready, stable HCCI combustion was achived with COV of 2.1% Motoring tests were conducted to validate the actuator transient operations including valve lift, electrical variable valve timing, electronic throttle, multiple spark and injection controls. After the actuator operations were confirmed, 15-cycle smooth combustion mode transition from SI to HCCI combustion was achieved; and fast 8-cycle smooth combustion mode transition followed. With a fast electrical variable valve timing actuator, the number of engine cycles required for mode transition can be reduced down to five. It was also found that the combustion mode transition is sensitive to the charge air and engine coolant temperatures and regulating the corresponding temperatures to the target levels during the combustion mode

  15. Formation of Imploding Plasma Liners for HEDP and MIF Application

    Energy Technology Data Exchange (ETDEWEB)

    Witherspoon, F. Douglas [HyperV Technologies Corp.; Case, Andrew [HyperV Technologies Corp.; Brockington, Samuel [HyperV Technologies Corp.y; Messer, Sarah [HyperV Technologies Corp.; Bomgardner, Richard [HyperV Technologies Corp.; Phillips, Mike [HyperV Technologies Corp.; Wu, Linchun [HyperV Technologies Corp.; Elton, Ray [University of Maryland

    2014-11-11

    /s for the Plasma Liner Experiment (PLX) at Los Alamos National Laboratory (LANL). Initial work used existing computational and analytical tools to develop and refine a specific plasma gun concept having a novel tapered coaxial electromagnetic accelerator contour with an array of symmetric ablative plasma injectors. The profile is designed to suppress the main barrier to success in coaxial guns, namely the blow-by instability in which the arc slips past and outruns the bulk of the plasma mass. Efforts to begin developing a set of annular non-ablative plasma injectors for the coaxial gun, in order to accelerate pure gases, resulted in development of linear parallel-plate MiniRailguns that turned out to work well as plasma guns in their own right and we subsequently chose them for an initial plasma liner experiment on the PLX facility at LANL. This choice was mainly driven by cost and schedule for that particular experiment, while longer term goals still projected use of coaxial guns for reactor-relevant applications for reasons of better symmetry, lower impurities, more compact plasma jet formation, and higher gun efficiency. Our efforts have focused mainly on 1) developing various plasma injection systems for both coax and linear railguns and ensuring they work reliably with the accelerator section, 2) developing a suite of plasma and gun diagnostics, 3) performing computational modeling to design and refine the plasma guns, 4) establishing a research facility dedicated to plasma gun development, and finally, 5) developing plasma guns and associated pulse power systems capable of achieving these goals and installing and testing the first two gun sets on the PLX facility at LANL. During the second funding cycle for this program, HyperV joined in a collaborative effort with LANL, the University of Alabama at Huntsville, and the University of New Mexico to perform a plasma liner experiment (PLX) to investigate the physics and technology of forming spherically imploding

  16. Formation of Imploding Plasma Liners for HEDP and MIF Application

    Energy Technology Data Exchange (ETDEWEB)

    Witherspoon, F. Douglas [HyperV Technologies Corp., Chantilly, VA (United States); Case, Andrew [HyperV Technologies Corp., Chantilly, VA (United States); Brockington, Samuel [HyperV Technologies Corp., Chantilly, VA (United States); Messer, Sarah [HyperV Technologies Corp., Chantilly, VA (United States); Bomgardner, Richard [HyperV Technologies Corp., Chantilly, VA (United States); Phillips, Mike [HyperV Technologies Corp., Chantilly, VA (United States); Wu, Linchun [HyperV Technologies Corp., Chantilly, VA (United States); Elton, Ray [Univ. of Maryland, College Park, MD (United States)

    2014-11-11

    /s for the Plasma Liner Experiment (PLX) at Los Alamos National Laboratory (LANL). Initial work used existing computational and analytical tools to develop and refine a specific plasma gun concept having a novel tapered coaxial electromagnetic accelerator contour with an array of symmetric ablative plasma injectors. The profile is designed to suppress the main barrier to success in coaxial guns, namely the blow-by instability in which the arc slips past and outruns the bulk of the plasma mass. Efforts to begin developing a set of annular non-ablative plasma injectors for the coaxial gun, in order to accelerate pure gases, resulted in development of linear parallel-plate MiniRailguns that turned out to work well as plasma guns in their own right and we subsequently chose them for an initial plasma liner experiment on the PLX facility at LANL. This choice was mainly driven by cost and schedule for that particular experiment, while longer term goals still projected use of coaxial guns for reactor-relevant applications for reasons of better symmetry, lower impurities, more compact plasma jet formation, and higher gun efficiency. Our efforts have focused mainly on 1) developing various plasma injection systems for both coax and linear railguns and ensuring they work reliably with the accelerator section, 2) developing a suite of plasma and gun diagnostics, 3) performing computational modeling to design and refine the plasma guns, 4) establishing a research facility dedicated to plasma gun development, and finally, 5) developing plasma guns and associated pulse power systems capable of achieving these goals and installing and testing the first two gun sets on the PLX facility at LANL. During the second funding cycle for this program, HyperV joined in a collaborative effort with LANL, the University of Alabama at Huntsville, and the University of New Mexico to perform a plasma liner experiment (PLX) to investigate the physics and technology of forming spherically imploding