WorldWideScience

Sample records for baffles

  1. Baffle construction notes

    DEFF Research Database (Denmark)

    Jørgensen, John Leif

    1998-01-01

    The design process for multi-stage high performance straylight suppression baffles for star trackers are described. Furthermore details for manufacturing are given......The design process for multi-stage high performance straylight suppression baffles for star trackers are described. Furthermore details for manufacturing are given...

  2. Scandinavian baffle boiler design revisited

    OpenAIRE

    Stepanov Borivoj Lj.; Pešenjanski Ivan K.; Spasojević Momčilo Đ.

    2015-01-01

    The aim of this paper is to examine whether the use of baffles in a combustion chamber, one of the well-known low-cost methods for the boiler performance improvement, can be enhanced. Modern day tools like computational fluid dynamics were not present at the time when these measures were invented, developed and successfully applied. The objective of this study is to determine the influence of location and length of a baffle in a furnace, for different mass ...

  3. Modelling of baffled stirred tanks

    Energy Technology Data Exchange (ETDEWEB)

    Ahlstedt, H.; Lahtinen, M. [Tampere Univ. of Technology (Finland). Energy and Process Engineering

    1996-12-31

    The three-dimensional flow field of a baffled stirred tank has been calculated using four different turbulence models. The tank is driven by a Rushton-type impeller. The boundary condition for the impeller region has been given as a source term or by calculating the impeller using the sliding mesh technique. Calculated values have been compared with measured data. (author)

  4. Mixed convection in a baffled grooved channel

    Indian Academy of Sciences (India)

    Aayush K Sharma; Pallab S Mahapatra; Nirmal K Manna; Koushik Ghosh

    2015-05-01

    In the present numerical work, flow structure and heat transfer characteristics are investigated in a baffled grooved channel, differentially heated from the sides. The baffle is placed vertically downward from the top wall of grooved channel geometry, with the motive of diverting outside forced flow towards the inside of the square cavity. In-house CFD code based on finite volume method has been used to solve the 2D equations of continuity, momentum and energy. The effect of change in baffle position and height is investigated in the range of Richardson numbers 0.1 to 10. For the present study, external flow from both left and right of the grooved channel are considered. A remarkable enhancement of heat transfer is observed in presence of baffle. The study has also pointed out that for optimal performance, the position and height of the baffle need to be adjusted depending on the direction of external flow.

  5. Simulasi Performansi Heat Exchanger Type Shell And Tube Dengan Double Segmental Baffle Terhadap Helical Baffle

    OpenAIRE

    Anggareza Adhitiya; Djatmiko Ichsani

    2013-01-01

    Pada heat exchanger type shell and tube, selain pengunaan baffle yang bertujuan untuk mengarahkan aliran pada sisi shell juga bertujuan untuk meningkatkan laju perpindahan panas yang terjadi antara fluida kerja dengan cara menimbulkan olakan aliran di sisi shell. Olakan –olakan ini nantinya yang akan mempengaruhi besarnya perpindahan panas dalam sisi shell. Pada kondisi standart baffle yang digunakan pada tugas akhir ini adalah jenis double segmental. Double segmental baffle mempunyai tingkat...

  6. Comparison of heat transfer performances of helix baffled heat exchangers with different baffle configurations

    Institute of Scientific and Technical Information of China (English)

    Cong Dong; Yaping Chen; Jiafeng Wu

    2015-01-01

    Numerical simulations were performed on flow and heat transfer performances of heat exchangers having six helical baffles of different baffle shapes and assembly configurations, i.e., two trisection baffle schemes, two quadrant baffle schemes, and two continuous helical baffle schemes. The temperature contour or the pressure contour and velocity contour plots with superimposed velocity vectors on meridian, transverse and unfolded concentric hexagonal slices are presented to obtain a full angular view. For the six helix baffled heat exchangers, the different patterns of the single vortex secondary flow and the shortcut leakage flow were depicted as wel as the heat transfer properties were compared. The results show that the optimum scheme among the six configurations is a circumferential overlap trisection helix baffled heat exchanger with a baffle incline angle of 20° (20°TCO) scheme with an anti-shortcut baffle structure, which exhibits the second highest pressure dropΔpo, the highest overal heat transfer coefficient K, shel-side heat transfer coefficient ho and shel-side average comprehensive index ho/Δpo.

  7. Simulasi Performansi Heat Exchanger Type Shell And Tube Dengan Double Segmental Baffle Terhadap Helical Baffle

    Directory of Open Access Journals (Sweden)

    Anggareza Adhitiya

    2013-12-01

    Full Text Available Pada heat exchanger type shell and tube, selain pengunaan baffle yang bertujuan untuk mengarahkan aliran pada sisi shell juga bertujuan untuk meningkatkan laju perpindahan panas yang terjadi antara fluida kerja dengan cara menimbulkan olakan aliran di sisi shell. Olakan –olakan ini nantinya yang akan mempengaruhi besarnya perpindahan panas dalam sisi shell. Pada kondisi standart baffle yang digunakan pada tugas akhir ini adalah jenis double segmental. Double segmental baffle mempunyai tingkat pressure drop yang cukup besar. sehingga perlu di ganti dengan baffle jenis helical yang mempunyai pressure drop yang lebih kecil. Untuk mengetahui performansi heat exchanger maka perlu adanya penelitian lebih lanjut simulasi numerik pada baffle heat exchanger type shell and tube. agar didapat pengaruh jenis baffle yang di gunakan terhadap karakteristik aliran dan perpindahan panas dari suatu heat exchanger type shell and tube. Tugas Akhir ini menggunakan program GAMBIT 2.4.6 untuk penggambaran geometri secara tiga dimensi dan program FLUENT 6.3.26 untuk mensimulasi aliran yang terjadi di dalam shell and tube heat exchanger. Pada software FLUENT 6.3.26 digunakan permodelan 3D Steady Flow dengan  memilih k – Epsilon RNG sebagai turbulence modeling serta mengaktifkan persamaan energy. Penelitian dilakukan dengan menggunakan dua variasi heat exchanger dengan jenis baffle yang berbeda .Heat exchanger type shell and tube dengan jenis double segmental baffle mempunyai nilai koefisien konveksi rata-rata = 218.408 w/m2.K. Sedangkan untuk helical baffle sebesar = 171.122 w/m2.K. Temperature outflow pada heat exchanger type shell and tube dengan jenis double segmental baffle = 306.7450K. Di ikuti dengan pressure drop sebesar = 2100 pascal Sedangkan untuk helical baffle mempunyai temperatur outflow sebesar = 307.0220K dengan pressure drop sebesar = 500 pascal.

  8. Numerical investigation on baffle configuration improvement of the heat exchanger with helical baffles

    International Nuclear Information System (INIS)

    Highlights: • Fluid flow and heat transfer was numerically investigated in STHXsHB. • Ladder-type fold baffle was proposed to block triangle leakage zones. • The shell-side tangential velocity and radial velocity increase significantly. • The optimum configuration of ladder-type fold baffle was obtained. • The comprehensive performance of the improved heat exchanger is enhanced. - Abstract: An improved structure of ladder-type fold baffle is proposed to block the triangular leakage zones in original heat exchangers with helical baffles. The numerical results showed that the shell-side tangential velocity and radial velocity in improved heat exchanger increase significantly and the shell-side fluid becomes approximately continuous spiral flow. And the configuration of ladder-type fold baffles was optimized. The numerical results showed that the shell-side heat transfer coefficient of the improved heat exchanger increases by 82.8–86.1%, when the folding ratio φ is 0.3, the baffle height ω is 60%, and the folding angle α is 37°. The associated pumping power penalty is about 21–549 W due to the increased shell-side pressure drop. The thermal performance factor TEF enhances by 28.4–30.7%, which demonstrates that the ladder-type fold baffle effectively improves the heat transfer performance of heat exchangers with helical baffles. The results of this paper are of great significance in the optimal design of heat exchanger

  9. A directional spotlight baffle for control cabins

    Science.gov (United States)

    Anderson, K. W.; Clark, B. A. J.

    1980-10-01

    Direct overhead lighting in control cabins frequently gives rise to unwanted bright images of the luminaries in the windows and these images may degrade the cabin operator's view of the external world. A directional baffle incorporating light traps which allow a high ratio of wanted to unwanted illumination from a specific conventional spotlamp is described. In practical tests, images from the spotlamp baffle combination were practically inconspicuous both in day and night conditions. A general method of design is described for extension of the principle to other types of spotlamps.

  10. PENGARUH PENGGUNAAN BAFFLE PADA SHELL-AND-TUBE HEAT EXCHANGER

    OpenAIRE

    Ekadewi Anggraini Handoyo

    2001-01-01

    Shell-and-tube heat exchanger is a device commonly used to transfer heat. To enhance the heat transfer occurred and to support the tubes inside the shell, baffles are installed. Better heat transfer is obviously expected in a heat exchanger. A research is done to find out the effect of baffle used toward the effectiveness and pressure drop in heat exchanger. The result is that the effectiveness increases when the baffles are installed. Effectiveness increases as the spacing between the baffle...

  11. Microsatellite Star Tracker Baffles: Validation and Testing

    OpenAIRE

    Marciniak, Martin; Enright, John; Sinclair, Doug; Dzamba, Tom

    2013-01-01

    In this paper, we examine the challenges of ground-based stray light testing from a microsatellite perspective. We consider some of the historical approaches to simulation and laboratory testing and propose strategies for ground validation that require only modest investment in test facilities. The star tracker or instrument is characterized in the lab without any baffle, using a novel technique to subtract out reflections internal to the test chamber. From the resulting data a simulation ele...

  12. Velocity Profiles between Two Baffles in a Horizontal Circular Tube

    Institute of Scientific and Technical Information of China (English)

    Tae-Hyun Chang; Hae-Soo Lee; Keon-Je Oh; Doeg Hee Doh; Chang-Hoan Lee

    2014-01-01

    The shell and tube heat exchanger is an essential part of a power plant for recovering heat transfer between the feed water of a boiler and the wasted heat.The baffles are also an important element inside the heat exchanger.Internal materials influence the flow pattern in the bed.The influence of baffles in the velocity profiles was observed using a three-dimensional particle image velocimetry around baffles in a horizontal circular tube.The velocity of the particles was measured before the baffle and between them in the test tube.Results show that the flows near the front baffle flow were parallel to the vertical wall,and then concentrate on the upper opening of the front baffle.The flows circulate in the front and rear baffles.These flow profiles are related to the Reynolds number (Re) or the flow intensity.The velocity profiles at lower Re number showed a complicated mixing,concentrating on the lower opening of the rear baffle as front wall.Swirling flow was employed in this study,which was produced using tangential velocities at the inlet.At the entrance of the front baffle,the velocity vector profiles with swirl were much different from that without swirl.However,velocities between two baffles are not much different from those without swirl.

  13. Velocity profiles between two baffles in a horizontal circular tube

    Science.gov (United States)

    Chang, Tae-Hyun; Lee, Hae-Soo; Oh, Keon-Je; Doh, Doeg Hee; Lee, Chang-Hoan

    2014-12-01

    The shell and tube heat exchanger is an essential part of a power plant for recovering heat transfer between the feed water of a boiler and the wasted heat. The baffles are also an important element inside the heat exchanger. Internal materials influence the flow pattern in the bed. The influence of baffles in the velocity profiles was observed using a three-dimensional particle image velocimetry around baffles in a horizontal circular tube. The velocity of the particles was measured before the baffle and between them in the test tube. Results show that the flows near the front baffle flow were parallel to the vertical wall, and then concentrate on the upper opening of the front baffle. The flows circulate in the front and rear baffles. These flow profiles are related to the Reynolds number (Re) or the flow intensity. The velocity profiles at lower Re number showed a complicated mixing, concentrating on the lower opening of the rear baffle as front wall. Swirling flow was employed in this study, which was produced using tangential velocities at the inlet. At the entrance of the front baffle, the velocity vector profiles with swirl were much different from that without swirl. However, velocities between two baffles are not much different from those without swirl.

  14. BaffleText: a Human Interactive Proof

    Science.gov (United States)

    Chew, Monica; Baird, Henry S.

    2003-01-01

    Internet services designed for human use are being abused by programs. We present a defense against such attacks in the form of a CAPTCHA (Completely Automatic Public Turing test to tell Computers and Humans Apart) that exploits the difference in ability between humans and machines in reading images of text. CAPTCHAs are a special case of 'human interactive proofs,' a broad class of security protocols that allow people to identify themselves over networks as members of given groups. We point out vulnerabilities of reading-based CAPTCHAs to dictionary and computer-vision attacks. We also draw on the literature on the psychophysics of human reading, which suggests fresh defenses available to CAPTCHAs. Motivated by these considerations, we propose BaffleText, a CAPTCHA which uses non-English pronounceable words to defend against dictionary attacks, and Gestalt-motivated image-masking degradations to defend against image restoration attacks. Experiments on human subjects confirm the human legibility and user acceptance of BaffleText images. We have found an image-complexity measure that correlates well with user acceptance and assists in engineering the generation of challenges to fit the ability gap. Recent computer-vision attacks, run independently by Mori and Jitendra, suggest that BaffleText is stronger than two existing CAPTCHAs.

  15. Numerical Study on Improved Baffle in Compact Test Separator

    OpenAIRE

    Yanhai Wei; Xinran Wang; Limin He; Shenghua Jiao; Guoqiang Zhang; Hao Cheng; Yujiang Li; Tao Li

    2014-01-01

    The aim of this paper is to design two improved baffles to solve the injection problem caused by traditional baffle in compact test separator and use FLUENT software to study their effects on separator pressure loss and separation efficiency. The result shows: that anti-injection baffle can make compact test separator with a high separation efficiency with a relatively low pressure loss. Also, the diameter of anti-injection plate which makes the compact test separator at its highest separatio...

  16. PENGARUH PENGGUNAAN BAFFLE PADA SHELL-AND-TUBE HEAT EXCHANGER

    Directory of Open Access Journals (Sweden)

    Ekadewi Anggraini Handoyo

    2001-01-01

    Full Text Available Shell-and-tube heat exchanger is a device commonly used to transfer heat. To enhance the heat transfer occurred and to support the tubes inside the shell, baffles are installed. Better heat transfer is obviously expected in a heat exchanger. A research is done to find out the effect of baffle used toward the effectiveness and pressure drop in heat exchanger. The result is that the effectiveness increases when the baffles are installed. Effectiveness increases as the spacing between the baffles is smaller until certain spacing, and then it decreases. Abstract in Bahasa Indonesia : Shell-and-tube heat exchanger merupakan jenis alat penukar panas yang banyak digunakan. Untuk membuat perpindahan panas lebih baik dan untuk menyangga tube yang ada di dalam shell, maka sering dipasang baffle. Perpindahan panas yang lebih baik sangat diharapkan dalam suatu heat exchanger. Penelitian dilakukan untuk mengetahui pengaruh penggunaan baffle terhadap efektifitas dan penurunan tekanan dalam heat exchanger. Dari hasil penelitian didapat bahwa efektifitas meningkat dengan dipasangnya baffle. Efektifitas meningkat seiring dengan mengecilnya jarak antar baffle hingga suatu jarak tertentu, kemudian menurun. Kata kunci: penukar kalor, baffle, efektifitas.

  17. Hydraulic optimization of membrane bioreactor via baffle modification using computational fluid dynamics.

    Science.gov (United States)

    Yan, Xiaoxu; Xiao, Kang; Liang, Shuai; Lei, Ting; Liang, Peng; Xue, Tao; Yu, Kaichang; Guan, Jing; Huang, Xia

    2014-11-01

    Baffles are a key component of an airlift membrane bioreactor (MBR), which could enhance membrane surface shear for fouling control. In order to obtain an optimal hydraulic condition of the reactor, the effects of baffle location and size were systematically explored in this study. Computational fluid dynamics (CFD) was used to investigate the hydrodynamics in a bench-scale airlift flat sheet MBR with various baffle locations and sizes. Validated simulation results showed that side baffles were more effective in elevating membrane surface shear than front baffles. The maximum average shear stress was achieved by adjusting baffle size when both front and side baffles were installed. With the optimized baffle configuration, the shear stress was 10-30% higher than that without baffles at a same aeration intensity (specific air demand per membrane area in the range of 0-0.45m(3)m(-2)h(-1)). The effectiveness of baffles was particularly prominent at lower aeration intensities. PMID:25465790

  18. The eROSITA x-ray baffle

    Science.gov (United States)

    Friedrich, Peter; Rohé, C.; Gaida, R.; Hartwig, J.; Soller, F.; Bräuninger, H.; Budau, B.; Burkert, W.; Burwitz, V.; Eder, J.; Hartner, G.; Menz, B.; Predehl, P.

    2014-07-01

    The X-ray baffle is an important part of the eROSITA mirror assembly as it reduces the stray light caused by single reflections at the Wolter 1 Mirrors by more than 90%. The stray light problem and possible solutions were analyzed by ray-tracing resulting in a trade-off between effective stray light protection and avoidance of vignetting. Possible design alternatives were considered and the influences of manufacturing tolerances were studied. Other than for XMM, the eROSITA X-ray baffle could not be realized as sieve plates; instead a system of co-aligned "baffle rings" was mounted onto each of the mirror modules. The mechanical design is based on concentric Invar foils fixed by an own spider. The complete X-ray baffles were finally mounted to the mirror module while the alignment was controlled by optical means.

  19. A thermally baffled device for highly stabilized convective PCR

    OpenAIRE

    Chang, Hsiao-Fen Grace; Tsai, Yun-Long; Tsai, Chuan-Fu; Lin, Ching-Ko; Lee, Pei-Yu; Teng, Ping-Hua; Su, Chen; Jeng, Chien-Chung

    2012-01-01

    Rayleigh-Bénard convective PCR is a simple and effective design for amplification of DNA. Convective PCR is, however, extremely sensitive to environmental temperature fluctuations, especially when using small- diameter test tubes. Therefore, this method is inherently unstable with limited applications. Here, we present a convective PCR device that has been modified by adding thermal baffles. With this thermally baffled device the influence from fluctuations in environmental temperature were s...

  20. Influence of baffle configurations on flow and heat transfer characteristics of trisection helical baffle heat exchangers

    International Nuclear Information System (INIS)

    Highlights: • Nephograms with velocity-vector superimposed are proposed on special slices. • Single vortex secondary flow and shortcut leakage patterns are clearly depicted. • Local heat transfer coefficient field and average value on tubes are presented. • Circumferential overlap scheme performs best over other schemes. - Abstract: Numerical simulation of flow and heat transfer characteristics in four trisection helical baffle heat exchangers with equilateral triangle tube layouts was conducted. The heat exchangers have the same helical pitch but four different baffle shapes or connections, i.e., a circumferential overlap (CO) scheme, an end-to-end (EE) scheme, a blocked V-notches (BV) scheme, and a middle axial overlap (MO) scheme. The single vortex secondary flow in each helical cycle and the leakage flow patterns in the V-notches of the adjacent baffles of these schemes are clearly depicted on the meridian slices and unfolded hexagon slices. The results for nine tubes in a 60° sector and four tube layers reveal that the local heat transfer coefficient of the center tube is much higher than that of the other tubes for all the schemes. The results show that the CO scheme has the highest shell-side heat transfer coefficient and comprehensive indexes, the BV scheme has the highest pressure drop and the worst comprehensive indexes, and the MO scheme has the lowest values of both shell-side heat transfer coefficient and pressure drop and the second highest comprehensive indexes. The average values of comprehensive index ho/Δpo of CO scheme in the calculated range is respectively 16.5%, 27.3% and 13.5% higher than that of the EE, BV and MO schemes

  1. Stress evaluation of baffle former bolt for IASCC failure prediction

    International Nuclear Information System (INIS)

    Baffle structure in PWRs Reactor is quite important assembly for the core safety, and Baffle Former Bolts (BFBs) are fastener members for maintaining Baffle structure. It has been reported worldwide that some of BFBs were cracked due to IASCC (Irradiation Assisted Stress Corrosion Cracking) because BFBs are located at core region under severe environments, high neutron flux, high temperature and high stress. According to the material studies of IASCC on austenitic stainless steel, a crack initiation of IASCC is strongly related with the stress and the neutron fluence. For this reason, it is very important for IASCC failure prediction to simulate the stress of BFBs. However, the stress of BFBs are considered to be influenced by several factors and to be changed complexly as operational time increases, by irradiation creep of Bolt itself, swelling of Baffle structure, and so on. Therefore, it is difficult to estimate the stress histories of BFBs (Bolt stress as a function of operational time) precisely. Then, the author has developed the calculation method of the stress histories of BFBs considering irradiation effects (swelling and irradiation creep). In this method, the stress histories of BFBs are calculated by combining two kinds of FE models, Global model (modeled whole Baffle structure which consists of Baffle plates, Former plates and Core Barrel) and Local model (modeled around BFB finely). The whole Baffle structure deformation changes as a function of heat, swelling and irradiated creep are calculated by Global model, and the stress histories of BFBs are calculated by Local model using the outputs (deformations on driving nodes) of Global model. In the FE analysis of Local model, the stress of BFBs are calculated considering irradiation effects and elastic-plastic characteristics depending on neutron fluence, so this method enables to calculate precisely the stress of extreme small area of BFBs surface. This paper shows the outline of the calculation method

  2. Enhancing mixing of particles by baffles in a rotating drum mixer

    Institute of Scientific and Technical Information of China (English)

    Maoqiang Jiang; Yongzhi Zhao; Gesi Liu; Jinyang Zheng

    2011-01-01

    Baffles with shape of “-” (single baffle), “+” (cross-baffles with four arms) and (baffles with 6 arms)are used to enhance the mixing of particles in a rotating drum mixer. A micro-dynamics study of mixing and segregation of a bi-disperse system of two particle sizes in the rotating drum with these three kinds of baffles is carried out using the discrete element method (DEM). The effect of the baffles on mixing, and the mechanisms of mixing enhancement by the baffles are discussed and analyzed. Simulation results show that in an unbaffled drum mixer, particle convection, particle diffusion, and size segregation of bidisperse particles, all play important roles in the mixing process; whereas size segregation will be largely restrained when the drum mixer has a baffle, regardless of its shape, and the degree of mixing is higher than that in an unbaffled drum mixer. The different mixing characteristics for “-” shaped baffle, “+” baffle,and baffle are revealed by the simulation results. For “+” or “*” style baffles, there is an optimal size of baffles for the mixing of particles, and the optimal mixing efficiency is higher than that for “-” baffle.

  3. Telescope baffle performance for Lyman Far Ultraviolet Spectrographic Explorer

    Science.gov (United States)

    Morbey, Christopher; Hutchings, J. B.

    1993-07-01

    The Lyman Far Ultraviolet Spectrographic Explorer telescope is a Wolter type II glancing incidence design with an aperture of 64 cm. Because the spacecraft is required to guide on stars fainter than m(v) = 16, a visible light baffle is necessary to protect the FOV from the stray light that results from out-of-field bright sources. Such a baffle system is described here. Total point-source transmittances are computed for incident beams in the range 0-70 deg. Estimates for background brightness on the detector are made for the contribution from direct sunlight and earthshine. Scattering from the black surfaces of the baffle, the vanes, and diffraction at the structure's edges are taken into consideration.

  4. Anaerobic wastewater treatment using anaerobic baffled bioreactor: a review

    Science.gov (United States)

    Hassan, Siti; Dahlan, Irvan

    2013-09-01

    Anaerobic wastewater treatment is receiving renewed interest because it offers a means to treat wastewater with lower energy investment. Because the microorganisms involved grow more slowly, such systems require clever design so that the microbes have sufficient time with the substrate to complete treatment without requiring enormous reactor volumes. The anaerobic baffled reactor has inherent advantages over single compartment reactors due to its circulation pattern that approaches a plug flow reactor. The physical configuration of the anaerobic baffled reactor enables significant modifications to be made; resulting in a reactor which is proficient of treating complex wastewaters which presently require only one unit, ultimately significant reducing capital costs. This paper also concerns about mechanism, kinetic and hydrodynamic studies of anaerobic digestion for future application of the anaerobic baffled reactor for wastewater treatment.

  5. The baffle aperture region of an ion thruster

    International Nuclear Information System (INIS)

    During the period of this research project, electron bombardment ion thrusters have passed from an advanced state of development to highly successful flight demonstrations (e.g. Deep Space 1). Such advances made by NASA have been quickly followed in the commercial sector (e.g. NSSK of communications satellites). In the next few years, these early successes will be followed by many new electric propulsion missions, planned by the world's space agencies and commercial space organisations. These early successes will spawn more ambitious and demanding missions, necessitating thrusters of different power demands, thrusts and sizes. Scaling of the UK series of electron bombardment ion thrusters has previously been carried out by semi- empirical scaling laws. These scaling laws have worked well within a certain range of thruster sizes with some iterative redesign necessary to produce acceptable efficiencies. However, when scaling beyond the ranges of the T5, T6 and UK25, the current scaling laws cannot be used due to the conflicting requirements of magnetic field strength in the discharge chamber and baffle aperture region. The baffle aperture region contains a plasma double layer that accelerates primary electrons into the discharge chamber and thus controls ionisation in the ion thruster. Previously, the baffle aperture region was poorly understood. An extensive and unique experimental investigation of the plasma properties around this critical baffle aperture region has been carried out using Langmuir probes. The externally applied magnetic field has been mapped and the Langmuir probe results have been validated using emissive probes. Results are presented on both argon and xenon propellant and high- resolution maps of an extensive range of plasma properties are plotted over a continuous area from the coupling plasma, through the baffle aperture and into the discharge plasma. Maps were taken over a unique and wide range of thruster operating conditions in which all

  6. Seismic Analysis of a Liquid Storage Tank with a Baffle

    Science.gov (United States)

    Gedikli, A.; Ergüven, M. E.

    1999-05-01

    The effects of a rigid baffle on the seismic response of liquid in a rigid cylindrical tank are presented. A baffle is an additional structural element which supplies a kind of passive control on the effects of earthquake motion. Fluid motion is assumed to be irrotational, incompressible and inviscid. The method of superposition of modes has been implemented to compute the seismic response. The boundary element method is used to evaluate the natural modes of liquid in a cylindrical tank. Linearized free surface conditions have been taken into consideration.

  7. Modal radiation patterns of baffled circular plates and membranes

    DEFF Research Database (Denmark)

    Christiansen, Thomas Lehrmann; Hansen, Ole; Thomsen, Erik Vilain;

    2014-01-01

    The far field velocity potential and radiation pattern of baffled circular plates and membranes are found analytically using the full set of modal velocity profiles derived from the corresponding equation of motion. The derivation is valid for a plate or membrane subjected to an external excitation...... circular radiator....

  8. Shock-induced turbulent flow in baffle systems

    Energy Technology Data Exchange (ETDEWEB)

    Kuhl, A.L. [Lawrence Livermore National Lab., CA (United States); Reichenbach, H. [Fraunhofer-Institut fuer Kurzzeitdynamik - Ernst-Mach-Institut (EMI), Freiburg im Breisgau (Germany)

    1993-07-01

    Experiments are described on shock propagation through 2-D aligned and staggered baffle systems. Flow visualization was provided by shadow and schlieren photography, recorded by the Cranz-Schardin camera. Also single-frame, infinite-fringe, color interferograms were used. Intuition suggests that this is a rather simple 2-D shock diffraction problem. However, flow visualization reveals that the flow rapidly evolved into a complex 3-D turbulent mixing problem. Mushroom-shaped mixing regions blocked the flow into the next baffle orifice. Thus energy was transferred from the directed kinetic energy (induced by the shock) to rotational energy of turbulent mixing, and then dissipated by molecular effects. These processes dramatically dissipate the strength of the shock wave. The experiments provide an excellent test case that could be used to assess the accuracy of computer code calculations of such problems.

  9. Optimized baffle and aperture placement in neutral beamlines

    Science.gov (United States)

    Stone, R.; Duffy, T.; Vetrovec, J.

    1983-11-01

    Most neutral beamlines contain an iron-core ion-bending magnet that requires shielding between the end of the neutralizer and this magnet. This shielding allows the gas pressure to drop prior to the beam entering the magnet and therefore reduces beam losses in this drift region. The beam losses are reduced even further by eliminating the iron-core magnet and the magnetic shielding altogether. The required bending field is supplied by current coils without the iron poles. In addition, placement of the baffles and apertures affects the cold gas entering the plasma region and the losses in the neutral beam due to re-ionization. The placement of the baffles which, determine the amount of pumping in each chamber, and the apertures, which determine the beam loss were varied. A baffler/aperture configuration is for either minimum cold gas into the plasma region or minimum beam losses, but not both.

  10. Solidification Using a Baffle in Sealed Ampoules (SUBSA)

    Science.gov (United States)

    Marin, C.; Ostrogorsky, A. G.; Volz, M.; Luz, P.; Jeter, L.; Spivey, R.; Burton, H.; Smith, G.; Knowles, T. R.; Bonner, W. A.

    2003-01-01

    Solidification Using a Baffle in Sealed Ampoules (SUBSA) will be the first materials science experiment conducted in the Microgravity Science Glovebox (MSG) Facility at the International Space Station (ISS) Alpha. The launch is schedule for May 31, 2002. Using the specially developed furnace, 10 Te and Zn-doped single crystals of InSb will be directionally solidified in microgravity. A key goal of the SUBSA investigation is to (i) clarify the origin of the melt motion in space laboratories and (ii) to reduce the magnitude of the melt motion to the point that it does not interfere with the transport phenomena. These goals will be accomplished through a special ampoule and furnace design. A disk-shaped baffle, positioned close to the freezing front, is used to reduce melt motion. Furthermore, the solidification will be visualized by using a transparent furnace, with a video camera, continuously sending images to the earth. This allows detection of bubbles and melt de-wetting that could cause surface tension driven convection. In preparation for the space experiments, 30 ground-based experiments were conducted. The results of ground based tests and numerical modeling will be presented. Based on numerical modeling, 12 mm 1D silica ampoules were selected. The small diameter ampoule favors closer placement of the baffle to the interface, without excessive radial segregation caused by forced convection while providing more damping of natural convection. The parts in the silica ampoule include 2 carbon springs made by Energy Science Laboratories, Inc., a pyrocarbon-coated graphite cylinder, pyrocarbon-coated graphite a baffle with the shaft and the InSb charge with the seed crystal grown by W.A. Bonner of Crystallod Inc.

  11. Baffled Circular Loudspeaker Array With Broadband High Directivity

    OpenAIRE

    Kolundzija, Mihailo; Faller, Christof; Vetterli, Martin

    2010-01-01

    Super-directional loudspeaker arrays can be used to achieve high directivity in a limited low-frequency range. As opposed to microphone arrays, the distance between the loudspeakers has to be relatively large, resulting in aliasing starting at relatively low frequencies. On the other hand, mounting a loudspeaker on a rigid baffle (e.g., a rigid cylinder or sphere) increases its directivity with frequency. Using super-directional array techniques at low frequencies and leveraging loudspeakers'...

  12. Effects of temperature variations on the performance of a space imaging system baffle

    Science.gov (United States)

    Haghshenas, Javad; Mohasel Afshari, Behzad

    2015-09-01

    All the star trackers must be composed of a baffle system to removes stray lights intensity. The baffle is designed to mount in front of the optical system. The performance of a star tracker is often limited by the stray light level on the detector. According to the space conditions, the baffle may deflect due to the temperature variation during the mission. Sun heat flux imposed to the baffle from one side and heat radiates from baffle to the space in all sides. In our case, the baffle is fixed to the satellite structure by four titanium screw. A finite element model has been used to modeling the baffle and temperature distribution and deflection is obtained in worst cold and hot conditions. Results show that in the worst cold condition, baffle is deflected symmetrically whereas in hot case, deflection is not symmetric and the side exposed to the sun light is elongated. Using ray tracing methods along with Monte Carlo algorithm, the baffle efficiency is obtained and compared for both cases. Results show that baffle deflections are not so extreme to force us to cover it with the MLI.

  13. Optimized baffle and aperture placement in neutral beamlines

    International Nuclear Information System (INIS)

    Most neutral beamlines contain an iron-core ion-bending magnet that requires shielding between the end of the neutralizer and this magnet. This shielding allows the gas pressure to drop prior to the beam entering the magnet and therefore reduces beam losses in this drift region. We have found that the beam losses can be reduced even further by eliminating the iron-core magnet and the magnetic shielding altogether. The required bending field can be supplied by current coils without the iron poles. In addition, placement of the baffles and apertures can affect the cold gas entering the plasma region and the losses in the neutral beam due to re-ionization. In our study we varied the placement of the baffles, which determine the amount of pumping in each chamber, and the apertures, which determine the beam loss. Our results indicate that a baffle/aperture configuration can be set for either minimum cold gas into the plasma region or minimum beam losses, but not both

  14. Fano line shapes in the branch-baffle system

    Science.gov (United States)

    Gou, Bo; Zhao, Yufang; Duan, Gaoyan; Wang, Lulu; Chen, Zhao; Cui, Runa; Zhang, Yong; Yu, Li

    2014-12-01

    A compact branch-baffle system, consisting of a branch resonator and a baffle in the metal-dielectric-metal waveguide (MDM), is proposed. A novel and efficient circuit model is developed to present the mechanisms of the plasmonic system. The model predicts two sharp asymmetric Fano line shapes, which are caused by the interactions between the branch resonator and the constructed branch-baffle resonator, exhibiting good agreement with the finite-element simulation results. The peaks of the two Fano line shapes are investigated by the relative phase method and demonstrated referring to the field distributions. The physical mechanisms of the remaining three resonances in the transmission spectrum are also carefully studied. From the analysis, the five resonances can all be precisely calculated and designed in theory. Considering the compact structure, multiple Fano resonances may be adjusted in different ways. Also, the transmittance of the Fano resonances is highly efficient (0.8). The proposed structure can have important applications in high-resolution and high-sensitivity nano-plasmonic devices.

  15. Abatement of an aircraft exhaust plume using aerodynamic baffles.

    Science.gov (United States)

    Bennett, Michael; Christie, Simon M; Graham, Angus; Garry, Kevin P; Velikov, Stefan; Poll, D Ian; Smith, Malcolm G; Mead, M Iqbal; Popoola, Olalekan A M; Stewart, Gregor B; Jones, Roderic L

    2013-03-01

    The exhaust jet from a departing commercial aircraft will eventually rise buoyantly away from the ground; given the high thrust/power (i.e., momentum/buoyancy) ratio of modern aero-engines, however, this is a slow process, perhaps requiring ∼ 1 min or more. Supported by theoretical and wind tunnel modeling, we have experimented with an array of aerodynamic baffles on the surface behind a set of turbofan engines of 124 kN thrust. Lidar and point sampler measurements show that, as long as the intervention takes place within the zone where the Coanda effect holds the jet to the surface (i.e., within about 70 m in this case), then quite modest surface-mounted baffles can rapidly lift the jet away from the ground. This is of potential benefit in abating both surface concentrations and jet blast downstream. There is also some modest acoustic benefit. By distributing the aerodynamic lift and drag across an array of baffles, each need only be a fraction of the height of a single blast fence. PMID:23343109

  16. Installation of center disk baffle into Madison Dynamo Experiment vessel

    Science.gov (United States)

    Clark, M. M.; Nornberg, M. D.; Taylor, N. Z.; Wallace, J. P.; Forest, C. B.

    2013-10-01

    The Madison Dynamo Experiment (MDE) comprises a 1 m diameter spherical chamber that contains a turbulent flow of liquid sodium driven by two counter rotating impellers. One of the goals of the MDE is to observe a magnetic field grow at the expense of kinetic energy in the liquid sodium flow. It has been found that turbulence in the MDE plays a significant and solely detrimental role in the generation of magnetic fields. The installation of an equatorial baffle and the three rotatable vanes in each hemisphere resulted in a reduction of large scale eddies in the flow and enhanced field generation. However, no self-excited field was observed. This Poster will present recent modifications made to the experiment consisting of installing a copper disk baffle in the center of the spherical vessel. The design and installation of the structure will be illustrated and discussed. Results from before and after the center disk baffle installation will be shown. Supported by NSF and DoE.

  17. Relay telescope including baffle, and high power laser amplifier utilizing the same

    Science.gov (United States)

    Dane, C. Brent; Hackel, Lloyd; Harris, Fritz B.

    2006-09-19

    A laser system includes an optical path having an intracavity relay telescope with a telescope focal point for imaging an output of the gain medium between an image location at or near the gain medium and an image location at or near an output coupler for the laser system. A kinematic mount is provided within a vacuum chamber, and adapted to secure beam baffles near the telescope focal point. An access port on the vacuum chamber is adapted for allowing insertion and removal of the beam baffles. A first baffle formed using an alignment pinhole aperture is used during alignment of the laser system. A second tapered baffle replaces the alignment aperture during operation and acts as a far-field baffle in which off angle beams strike the baffle a grazing angle of incidence, reducing fluence levels at the impact areas.

  18. Thermoeconomic optimization of baffle spacing for shell and tube heat exchangers

    International Nuclear Information System (INIS)

    Despite the importance of thermoeconomic analysis in shell and tube heat exchanger design, the determination of the optimum baffle spacing by using the thermoeconomic analysis is usually neglected. On the other hand, baffle spacing is one of the most important parameters used in the design of shell and tube heat exchangers, and there is no precise criterion for the determination of baffle spacing in the literature. In this study, thermoeconomic analysis is used to determine the optimum baffle spacing, accompanied by an example of such an optimization of baffle spacing for a shell and tube heat exchanger. The results of this example are then used to demonstrate how the optimum ratio of baffle spacing to shell diameter is determined precisely and affected by the varying values of the geometrical parameters. Finally, the results are compared to those obtained by classical approaches

  19. NUMERICAL SIMULATION OF FLUID FLOW BEHAVIOUR ON SCALE UP OF OSCILLATORY BAFFLED COLUMN

    OpenAIRE

    WAH KENG SERN; MOHD SOBRI TAKRIFF; SITI KARTOM KAMARUDIN; MEOR ZAINAL MEOR TALIB; NURUL HASAN

    2012-01-01

    The fluid dynamics of oscillatory flow in a baffled column of 145 mm diameter was investigated numerically in this work. This numerical simulation was carried out by a 2D laminar unsteady solver using CFD package Fluent® 6.3. From the simulation, data on surface velocity were collected and velocity ratio was calculated to determine the intensity of mixing which were the main operating parameters in oscillatory flow in a baffled column. The suitable operating parameters of oscillatory baffled ...

  20. Dynamic Effect of Discharge Flow of a Rushton Turbine Impeller on a Radial Baffle

    OpenAIRE

    J. Kratěna; I. Fořt; O. Brůha

    2001-01-01

    This paper presents an analysis of the mutual dynamic relation between the impeller discharge flow of a standard Rushton turbine impeller and a standard radial baffle at the wall of a cylindrical mixing vessel under turbulent regime of flow of an agitated liquid. A portion of the torsional moment of the baffle corresponding to the region of the force interaction of the impeller discharge stream and the baffle is calculated under the assumption of constant angular momentum in the flow region b...

  1. Particle contamination from Martin Optical Black. [in design of barrel baffle of Infrared Astronomical Satellite

    Science.gov (United States)

    Young, P. J.; Noll, R.; Andreozzi, L.; Hope, J.

    1981-01-01

    The design of the barrel baffle of the Infrared Astronomical Satellite (IRAS) Optical Subsystem to minimize production of particulate contamination is described. The configuration of the 50-inch long, 28.5-inch diameter baffle required pop-rivet assembly after coating with Martin Optical Black for stray light suppression. An experiment to determine the contamination produced at assembly led to the modification of the baffle construction to preclude such damage to the coated surfaces.

  2. ANALYSIS OF HELICAL BAFFLE HEAT EXCHANGER FOR OPTIMUM HELIX ANGLE THROUGH NUMERICAL SIMULATIONS

    OpenAIRE

    Roktutpal Borah; R.K Chitharthan

    2015-01-01

    Heat exchangers are very important heat & mass exchange apparatus in many industries like electric power generation, chemical industries, oil refining, etc. The most common heat exchangers used are shell-&-tube heat exchangers (STHXs). Among different kinds of baffles used in STHX, segmental baffles are most commonly used in conventional STHXs to support tubes & change fluid flow direction. But, conventional heat exchangers with segmental baffles in shell-side have some drawbacks ...

  3. Experimental investigation of shell-and-tube heat exchanger with a new type of baffles

    Science.gov (United States)

    Wang, Yingshuang; Liu, Zhichun; Huang, Suyi; Liu, Wei; Li, Weiwei

    2011-07-01

    A shell-and-tube heat exchanger with new type of baffles, is designed, fabricated and tested. The experimental investigation for the proposed model and the original segmental baffle heat exchanger are conducted. The operation performances of the two heat exchangers are also compared. The results suggest that, under the same conditions, the overall performance of the new model is 20-30% more efficient than that of the segmental baffle heat exchanger.

  4. Thermal design of retroreflective stray light fore-baffles for spaceborne optical systems

    Science.gov (United States)

    Schneider, Edward

    2001-03-01

    The use of stray light fore-baffles in space-borne optical systems solves the problem of protecting the optical system from unwanted radiation. However, this introduces the problem of adding a large area black cavity at the system entrance aperture, and this cavity will run hot due to capture of solar, planetary albedo, and planetary emission radiation. The optical system may need to be baffled by a cool shield to keep system absolute temperatures sufficiently low. Alternately, a reflecting baffle system can be used that retro-reflects the input environment radiation. This reduces absorbed heat loads by the baffle system and reduces system absolute temperature levels.

  5. EFFECT OF VERTICAL BAFFLES ON PARTICLE MIXING AND DRYING IN FLUIDIZED BEDS OF GROUP D PARTICLES

    Institute of Scientific and Technical Information of China (English)

    Chung Lim Law; Siti Masrinda Tasirin; Wan Ramli Wan Daud; Derek Geldart

    2003-01-01

    This study reports the effect of vertical baffles on the group D powder mixing and drying characteristics in a batch fluidized bed dryer. Results obtained in this study showed that operating the fluidized bed dryer with vertical baffles gave better particle mixing. This is due to the fact that the vertical baffles acted to limit the growth of small bubbles into large bubbles and the small bubbles caused more vigorous mixing in the bed of particles before finally erupting at the bed surface. Thus, insertion of vertical baffles is a useful way to process group D particles in a fluidized bed, especially when the fluidized bed is large.

  6. Further analysis of the effects of baffles on combustion instability. [computer techniques

    Science.gov (United States)

    Oberg, C. L.; Schuman, M. D.

    1975-01-01

    A computerized analytical model, developed to predict the effects of baffles on combustion instability, was modified in an effort to improve the ability to properly predict stability effects. The model was modified: (1) to replace a single spatially-averaged response factor by separate values for each baffle compartment; (2) to calculate the axial component of the acoustic energy flux, and (3) to permit analysis of traveling waves in a thin annular chamber. Allowance for separate average response factors in each baffle compartment was found to significantly affect the predicted results. With this modification, an optimum baffle length was predicted which gave maximum stability.

  7. Improvement activities for the maintenance of Baffle Former Bolts

    International Nuclear Information System (INIS)

    Baffle Former Bolts (BFBs) in PWR nuclear plant have the possibility to be cracked due to Irradiation Assisted Stress Corrosion Cracking (IASCC). The maintenance guideline for BFBs had been established from Thermal and Nuclear Power Engineering Society in 2000, and BFBs have been maintained in accordance with this maintenance rules. Recently, the new edition of this guideline has been published in order to reflect latest IASCC data and more precise stress evaluation of BFB into maintenance rules. The summary of the revised contents and these improvement activities are introduced in this paper. (author)

  8. Mathematical Modelling of Cassava Wastewater Treatment Using Anaerobic Baffled Reactor

    OpenAIRE

    A.O. Ibeje

    2013-01-01

    The performance of an anaerobic baffled reactor (ABR) was evaluated in the treatment of cassava wastewater as a pollutant residue. An ABR divided in four equal volume compartments (total volume 4L) and operated at 35°C was used in cassava wastewater treatment. Feed tank chemical oxygen demand (COD) was varied from 2000 to 7000mg L-1. The objective of the study was to formulate an improved mathematical model to describe cassava wastewater treatment without taking into account its inhibition ch...

  9. Hydraulic jump basins with wedge-shaped baffles

    Institute of Scientific and Technical Information of China (English)

    Ashraf Fathy ELLAYN; Zhi-lin SUN

    2012-01-01

    This laboratory study deals with the hydraulic jump properties for an artificially roughened bed with wedge-shaped baffle blocks,The experiments were conducted for both smooth and rough beds with a Froude number in the range of 3.06≤F1≤10.95 and a relative bed roughness ranging 0.22≤KR≤1.4.The data from this study were compared with those of rectangular baffle blocks.New experimental formulae were developed for determining the sequent depth ratio and the hydraulic jump length in terms of the inflow Froude number and relative bed roughness.Bélangers jump equation of a rectangular channel was extended to account for the implications of the bed shear stress coefficient attributable to channel bed roughness.It was found that,in comparison with the smooth bed,the wedge-shaped bed roughness reduced the sequent depth of the hydraulic jump by approximately 16.5% to 30% and the hydraulic jump length by approximately 30% to 53%.

  10. Strategy and calculations for the design of baffles for Wolter Type II telescopes

    Science.gov (United States)

    Mangus, John D.

    Spaceflight, stellar pointing telescopes require baffle systems to define the field of view and protect this observational area from stray and scattered light. In the case of near normal incidence telescope systems, the problem consists in controlling the stray/scattered radiation reaching the image plane when circular plates, the primary and secondary mirrors, are the imaging elements. The case addressed in this paper is quite different in that it involves baffling two conical surfaces, i.e., the primary and secondary mirrors of a Wolter Type II telescope. A strategy is described for systematically moving through the telescope system and establishing criteria for placement of baffles. Calculations are given which determine the size and number of permitted baffles as a function of practical physical parameters. Clear options are given for the design of minimum baffle lengths to meet packaging constraints.

  11. Velocity profiles between two baffles in a shell and tube heat exchanger

    Science.gov (United States)

    Chang, Tae-Hyun; Lee, Chang-Hoan; Lee, Hae-Soo; Lee, Kwon-Soo

    2015-06-01

    Heat exchangers are extensively utilized for waste heat recovery, oil refining, chemical processing, and steam generation. In this study, velocity profiles are measured using a 3D particle image velocimetry (PIV) system betweentwo baffles in a shell and tube heat exchanger for parallel and counter flows. The PIV and computational fluid dynamics results show the occurrence of some strong vectors near the bottom. These vectors are assumed due to the clearance between the inner tubes and the front baffle. Therefore, the major parts of the vectors are moved out through the bottom opening of the rear baffle, and other vectors produce a large circle between the two baffles. Numerical simulations are conducted to investigate the effects of the baffle on the heat exchanger using the Fluent software. The k-ɛ turbulence model is employed to calculate the flows along the heat exchanger

  12. Appraising the performance of a baffled solar air heater with external recycle

    International Nuclear Information System (INIS)

    Highlights: • Thermal performance for a baffled solar air heater with external recycle is studied. • Applying external recycle boosts the energy efficiency of the air heater remarkably. • Applying fins and baffles under external recycle enhances energy efficiency. • Utilizing baffles at high recycle ratios and mass flow rates declines ηeff. • Utilizing only fins at high mass flow rates and recycle ratios is well-organized. - Abstract: This study aims at appraising the possibility of enhancing thermal performance of an upward-type single pass solar air heater by utilizing fins and baffles over the absorber plate as well as applying external recycle device simultaneously under various parametric conditions. The energy and effective efficiencies analysis is used as criteria to evaluate the performance. The investigation is carried out for three cases: simple absorber plate, absorber plate with fins and absorber plate with fins and baffles. The achieved results disclose that attaching both fins and baffles to the absorber plate under external recycling operation is an effective method to boost the energy efficiency notably. In contrast, the effective efficiency analysis reveals that attaching both fins and baffles at high mass flow rates and recycle ratios leads to considerable decline in effective efficiency. Parametric studies on variation of baffle parameters illustrate that increasing the baffles width as well as declining the distance between baffles under turbulent flow regime are not economically feasible owing to extremely increase of the pressure drop and required pump work. In a nutshell, it is found that utilizing only fins under external recycle application at high mass flow rates and recycle ratios is an attractive option

  13. Thermal analysis of the baffle structure of the Solar Space Telescope

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    The SST(Space Solar Telescope) is an astronomical telescope with a primary mirror of 1 m in diameter.It observes the sun with a small view field to ensure that its high spatial resolution imaging has 0.1″-0.15″ and high SNR(signal to noise ratio).Surrounding the small view field is still the sun,which is an intense source of both heat and stray light.The baffles(the main baffle,the aperture,and the outer baffle),which are used to eliminate the stray light,will change the thermal flux in the SST and will weaken the effect of the thermal control design.In this study,the compatibility analysis of the thermal effect of baffle structures in SST is performed.The GCF(Geometry Composing Function) and BRDF(Bidirectional Reflectance Distribution Function),which are two inherent related parameters in the compatibility analysis,are derived.The objective and method of the compatibility analysis are determined.With the thermal analysis software,the temperature fields are calculated for different lengths of the main baffle,different radii of apertures,different lengths of the outer baffle with a 3’ tilt angle and 16’ tilt angle,and different tilt angles of the outer baffle with a 200 mm length.A series of configurations and sizes of the baffles are studied with the goals of both thermal control and elimination of stray light.The design of the baffle structure of SST is achieved:the main baffle of length 4100 mm,the internal shield of radius 494 mm,the outer baffle of length 200 mm,and the outer baffle of tilt angle 3’ are successfully designed.This paper presents the relationship between the thermal control design and stray light elimination plan in the SST.The aims of the optimal design of the baffle structure of SST are reached.The thoughts and methods of the optimal analysis are also useful for similar optical telescopes designed for solar observation.

  14. Modeling of Alcator C-Mod Divertor Baffling Experiments

    Energy Technology Data Exchange (ETDEWEB)

    D. P. Stotler; C. S. Pitcher; C. J. Boswell; T. K. Chung; B. LaBombard; B. Lipschultz; J. L. Terry; R. J. Kanzleiter

    2000-11-29

    A specific Alcator C-Mod discharge from the series of divertor baffling experiments is simulated with the DEGAS 2 Monte Carlo neutral transport code. A simple two-point plasma model is used to describe the plasma variation between Langmuir probe locations. A range of conductances for the bypass between the divertor plenum and the main chamber are considered. The experimentally observed insensitivity of the neutral current flowing through the bypass and of the D alpha emissions to the magnitude of the conductance is reproduced. The current of atoms in this regime is being limited by atomic physics processes and not the bypass conductance. The simulated trends in the divertor pressure, bypass current, and D alpha emission agree only qualitatively with the experimental measurements, however. Possible explanations for the quantitative differences are discussed.

  15. Rapid production of biodiesel in mesoscale oscillatory baffled reactors

    Energy Technology Data Exchange (ETDEWEB)

    Phan, A.N.; Harvey, A.P.; Eze, V. [School of Chemical Engineering and Advanced Materials, Newcastle Upon Tyne (United Kingdom)

    2012-07-15

    Continuous alkali-catalyzed transesterification of rapeseed oil with methanol was carried out in three mesoreactor designs. The induction time decreased with oscillatory Reynolds number for all three reactors. Stable steady states were achieved within induction times of 1.5, 2.5, and 4.0 residence times for the integral, wire wool, and helical baffle designs, respectively. Both experimental and simulated results indicated that under the given conditions there is an optimal residence time for homogeneous transesterification. Higher residence times resulted in reduced fatty acid methyl ester content due to the saponification side reaction. The results demonstrate that biodiesel can be produced at an industrially acceptable level of conversion (> 95 %) in < 5 min residence time. This requires a combination of high catalyst concentration and good mixing. (Copyright copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  16. Wastewater treatment in a hybrid activated sludge baffled reactor

    International Nuclear Information System (INIS)

    A novel hybrid activated sludge baffled reactor (HASBR), which contained both suspended and attached-growth biomass perfect mixing cells in series, was developed by installing standing and hanging baffles and introducing plastic brushes into a conventional activated sludge (CAS) reactor. It was used for the treatment of domestic wastewater. The effects on the operational performance of developing the suspended and attached-growth biomass and reactor configuration were investigated. The change of the flow regime from complete-mix to plug-flow, and the addition of plastic brushes as a support for biofilm, resulted in considerable improvements in the COD, nitrogen removal efficiency of domestic wastewater and sludge settling properties. In steady state, approximately 98 ± 2% of the total COD and 98 ± 2% of the ammonia of the influent were removed in the HASBR, when the influent wastewater concentration was 593 ± 11 mg COD/L and 43 ± 5 mg N/L, respectively, at a HRT of 10 h. These results were 93 ± 3 and 6 ± 3% for the CAS reactor, respectively. Approximately 90 ± 7% of the total COD was removed in the HASBR, when the influent wastewater concentration was 654 ± 16 mg COD/L at a 3 h HRT, and in the organic loading rate (OLR) of 5.36 kg COD m-3 day-1. The result for the CAS reactor was 60 ± 3%. Existing CAS plants can be upgraded by changing the reactor configuration and introducing biofilm support media into the aeration tank

  17. Industrially Experimental Investigations and Development of the Curve-ROD Baffle Heat Exchanger

    Institute of Scientific and Technical Information of China (English)

    严良文; 吴金星; 王志文

    2004-01-01

    The conventional heat exchanger with segmental baffles is prone to bring forth fluid-induced vibration of heat transfer tubes and increase the pressure drop of shell-side greatly at higher fluid flow velocity. In order to avoid the above defects, the ROD-baffle heat exchanger has been developed. However, its collocation of heat transfer tubes is conventionally in square, which leads to fewer heat transfer area per unit volume. Based on the ROD-baffle heat exchanger, a new type curve-ROD baffle has been developed, and an industrial investigation of the curve-ROD baffle heat exchanger with normal triangular collocation has been carried into execution. In this paper, two equations using the Reynolds number were acquired to predict the heat transfer coefficients of the shell-side and tubeside. The experimental results show that the shell-side heat transfer and pressure drop characteristics of the curve-ROD baffle heat exchanger are superior to those of the segmental baffle one.

  18. Dynamic Stress Affecting the Radial Baffle on an Industrial Mixing Unit with a Pitched Blade Impeller

    Directory of Open Access Journals (Sweden)

    J. Kratěna

    2000-01-01

    Full Text Available This paper presents a study of dimensioning under fatigue stress of a standard radial baffle in an industrial mixing unit (T = 5 m with a pitched blade impeller under a turbulent regime of flow of an agitated liquid. The fatigue stress of the radial baffle is calculated from the known experimentally determined distribution of the dynamic pressure affecting the standard radial baffle in a pilot plant agitated system. Asymmetrical distribution of the dynamic pressure along the height of the baffle significantly affects the thickness of the baffle as well as the dimensions of the doublefillet weld fixing the baffle to the vessel wall. Our results are valid for standard pitched blade impellers with four or six inclined blades (D/T = 1/3, a = 45° and off-bottom clearances h/T = 0.2, 0.35 and 0.5 pumping liquid downwards in a cylindrical mixing vessel with a flat bottom and four baffles (b/T = 0.1 when the Reynolds number exceeds ten thousand.

  19. Dynamic Stress Affecting the Radial Baffle on an Industrial Mixing Unit with a Pitched Blade Impeller

    OpenAIRE

    J. Kratěna; I. Fořt; O. Brůha; Růžička, M. (Marek)

    2000-01-01

    This paper presents a study of dimensioning under fatigue stress of a standard radial baffle in an industrial mixing unit (T = 5 m) with a pitched blade impeller under a turbulent regime of flow of an agitated liquid. The fatigue stress of the radial baffle is calculated from the known experimentally determined distribution of the dynamic pressure affecting the standard radial baffle in a pilot plant agitated system. Asymmetrical distribution of the dynamic pressure along the height of the ba...

  20. Optimum design of the carbon fiber thin-walled baffle for the space-based camera

    Science.gov (United States)

    Yan, Yong; Song, Gu; Yuan, An; Jin, Guang

    2011-08-01

    The thin-walled baffle design of the space-based camera is an important job in the lightweight space camera research task for its stringent quality requirement and harsh mechanical environment especially for the thin-walled baffle of the carbon fiber design. In the paper, an especially thin-walled baffle of the carbon fiber design process was described and it is sound significant during the other thin-walled baffle design of the space camera. The designer obtained the design margin of the thin-walled baffle that structural stiffness and strength can tolerated belong to its development requirements through the appropriate use of the finite element analysis of the walled parameters influence sensitivity to its structural stiffness and strength. And the designer can determine the better optimization criterion of thin-walled baffle during the geometric parameter optimization process in such guiding principle. It sounds significant during the optimum design of the thin-walled baffle of the space camera. For structural stiffness and strength of the carbon fibers structure which can been designed, the effect of the optimization will be more remarkable though the optional design of the parameters chose. Combination of manufacture process and design requirements the paper completed the thin-walled baffle structure scheme selection and optimized the specific carbon fiber fabrication technology though the FEM optimization, and the processing cost and process cycle are retrenchment/saved effectively in the method. Meanwhile, the weight of the thin-walled baffle reduced significantly in meet the design requirements under the premise of the structure. The engineering prediction had been adopted, and the related result shows that the thin-walled baffle satisfied the space-based camera engineering practical needs very well, its quality reduced about 20%, the final assessment index of the thin-walled baffle were superior to the overall design requirements significantly. The design

  1. Effect of Baffles on the Sloshing in Road Tankers Carrying LPG: A Comparative Numerical Study

    Directory of Open Access Journals (Sweden)

    J. L. Bautista-Jacobo

    2015-01-01

    Full Text Available This work presents a comparative numerical study of the effect of using baffles, and its design, on the behavior of sloshing in a partially filled road tanker carrying LPG. Navier-Stokes equations and standard k-ε turbulence model are used to simulate fluid movement; the Volume of Fluid (VOF method is used to track the liquid-gas interface. Velocity distributions, sloshing stabilization times, and contours of turbulent kinetic energy, which are of high importance in choosing the best design of baffles, are shown. The results show sloshing stabilization times of 22 and 21 s for road tankers with cross-shaped (Type I and X-shaped (Type II baffles, respectively, finding lower values of turbulent kinetic energy for Type II design, being, therefore, the best design of baffles for damping of sloshing and vehicle control among studied ones.

  2. Thermal Test Verification of Emission Control through Directional Baffles for the James Webb Space Telescope

    Science.gov (United States)

    Garrison, Matthew; Rashford, Robert; Switzer, Timothy; Shaw, David; White, Bryant; Lynch, Michael; Huber, Frank; Bachtell, Neal

    2009-01-01

    The thermal performance of NASA s planned James Webb Space Telescope is highly reliant on a collection of directional baffles that are part of the Integrated Science Instrument Module Electronics Compartment. In order to verify the performance of the baffle concept, two test assemblies were recently fabricated and tested at the Goddard Space Flight Center. The centerpiece of the testing was a fixture that used bolometers to measure the emission field through the baffles while the radiator panels and baffles ran a flight-like temperature. Although not all test goals were able to be met due to facility malfunctions, the test was able to prove the design viability enough to gain approval to begin manufacturing the flight article.

  3. Liquid sloshing in partly-filled laterally-excited circular tanks equipped with baffles

    Science.gov (United States)

    Hasheminejad, Seyyed M.; Mohammadi, M. M.; Jarrahi, Miad

    2014-01-01

    Linear potential theory in conjunction with the conformal mapping technique are employed to develop rigorous mathematical models for two-dimensional transient sloshing in non-deformable baffled horizontal circular cylindrical vessels, filled with inviscid incompressible fluids to arbitrary depths, and subjected to arbitrary time-dependent lateral accelerations. Three common baffle configurations are considered, namely, a pair of free surface-touching horizontal side baffles, and a central surface-piercing or bottom-mounted vertical baffle of arbitrary extension. The first few normalized antisymmetric/symmetric sloshing frequencies of the partially-filled tanks are tabulated for selected baffle extension and fill depth ratios. Also, the effects of liquid fill depth or baffle length parameter on the impulsive, total and modal convective mass ratios are examined. A ramp-step function is used to replicate the lateral acceleration excitation encountered in an idealized turning maneuver. Durbin's numerical Laplace transform inversion scheme was applied to solve the resulting truncated linear sets of ordinary differential equations in the time-domain. The effects of excitation input time, fill level, and baffle configuration/extension on the force and moment amplification factors are illustrated through appropriate design charts. Furthermore, the transient hydrodynamic responses to a real seismic event are calculated and the effectiveness of baffle configuration/length on suppression of the induced destabilizing lateral forces are examined. Limiting cases are considered and rigorous verifications are made by comparison with the available data as well as with the numerical simulations performed by using a commercial CFD software package.

  4. 3D NUMERICAL STUDY ON LAMINAR FORCED CONVECTION IN V-BAFFLED SQUARE CHANNEL

    Directory of Open Access Journals (Sweden)

    Amnart Boonloi

    2013-01-01

    Full Text Available The article presents a mathematical study of fully developed periodic laminar flow visualization and heat transfer characteristics in an isothermal wall square-channel fitted with V-shaped baffles on one wall. The computations based on the finite volume method together with the SIMPLE algorithm have been performed. The investigation covers a range of Re based on the hydraulic diameter of the channel, Re = 100-1200. To create a pair of main streamwise vortex flows through the tested section, the V-baffles with the attack angle of 30° with the main flow direction are mounted in tandem and pointing downstream on the lower channel wall only. Effects of different baffle heights and pitches on heat transfer and pressure drop in the channel are examined and the results obtained are compared with smooth channel with no baffle. The numerical result shows that the presence of the V-baffle yields a significant heat transfer enhancement compared with the smooth channel. It is visible that the main vortex flows, a pair of streamwise twisted vortex (P-vortex can induce impingement flows on the walls leading to a drastic increase in heat transfer rate over the channel. In addition, the increase in the baffle height leads to the rise in the heat transfer and pressure loss while that in the baffle pitch provides the opposite trend. The predicted results expose that the maximum thermal enhancement factors for the V-baffles with BR = 0.3, 0.3 and 0.4; and PR = 1, 1.5 and 2 are, respectively, about 2.44, 2.29 and 2.37 at higher Re.

  5. Experimental investigation of heat transfer and flow over baffles of different heights

    Science.gov (United States)

    Habib, M. A.; Mobarak, A. M.; Sallak, M. A.; Hadi, E. A. A.; Affify, R. I.

    1994-05-01

    The phenomenon of flow separation in ducts with segmented baffles has many engineering applications, for example, shell-and-tube heat exchangers with segmented baffles, labyrinth shaft seals, laser curtain seals, air-cooled solar collectors, and internally cooled turbine blades. In the present work, an experimental investigation has been done to study the characteristics of the turbulent flow and heat transfer inside the periodic cell formed between segmented baffles staggered in a rectangular duct. In particular, flow field, pressure loss, and local and average heat transfer coefficients were obtained. The experimental runs were carried out for different values of Reynolds numbers and baffle heights (window cuts) at uniform wall heat flux condition along the top and bottom walls. The results indicate that the pressure loss increases as the baffle height does, for a given flow rate. Also, the local and average heat transfer parameters increase with increasing Reynolds number and baffle height. However, the associated increase in the pressure loss was found to be much higher than the increase in the heat transfer coefficient.

  6. Buoyancy convection in a square cavity with mutually orthogonal heat generating baffles

    Energy Technology Data Exchange (ETDEWEB)

    Hakeem, A.K. Abdul [UGC-DRS Center for Fluid Dynamics, Department of Mathematics, Bharathiar University, Coimbatore 641 046 (India)], E-mail: abdulhakeem6@yahoo.co.in; Saravanan, S. [UGC-DRS Center for Fluid Dynamics, Department of Mathematics, Bharathiar University, Coimbatore 641 046 (India)], E-mail: sshravan@lycos.com; Kandaswamy, P. [UGC-DRS Center for Fluid Dynamics, Department of Mathematics, Bharathiar University, Coimbatore 641 046 (India)], E-mail: pgkswamy@yahoo.co.in

    2008-08-15

    A two-dimensional numerical solution for buoyancy induced convection in a square cavity with discretely heat generating baffles is presented in the context of cooling of electronic equipments. The walls of the cavity are subjected to either isothermal temperature or outward isoflux. The Grashof number and Prandtl number are fixed at 10{sup 6} and 0.71, respectively. The effects of different locations of the baffles are reported in terms of streamlines and temperature contours. The results obtained clearly show that the fluid flow and temperature fields strongly depend on location of the baffles. The movement of either the horizontal or vertical plate produces no significant changes in the overall heat transfer rate except when one of them is wall mounted in the presence of isothermal cavity walls. In the case of isoflux cavity walls the overall heat transfer rate gets suppressed for the upward movement of the horizontal baffle and enhanced for the horizontal movement of the vertical baffle in the core region of the cavity. When one of the baffles moves closer to a cavity wall thermal boundary layer is formed and hence conduction becomes dominant in between them in the case of isothermal cavity walls. But in general the presence of isoflux cavity walls arrests crowding of isotherms.

  7. Biological processing in oscillatory baffled reactors: operation, advantages and potential.

    Science.gov (United States)

    Abbott, M S R; Harvey, A P; Perez, G Valente; Theodorou, M K

    2013-02-01

    The development of efficient and commercially viable bioprocesses is essential for reducing the need for fossil-derived products. Increasingly, pharmaceuticals, fuel, health products and precursor compounds for plastics are being synthesized using bioprocessing routes as opposed to more traditional chemical technologies. Production vessels or reactors are required for synthesis of crude product before downstream processing for extraction and purification. Reactors are operated either in discrete batches or, preferably, continuously in order to reduce waste, cost and energy. This review describes the oscillatory baffled reactor (OBR), which, generally, has a niche application in performing 'long' processes in plug flow conditions, and so should be suitable for various bioprocesses. We report findings to suggest that OBRs could increase reaction rates for specific bioprocesses owing to low shear, good global mixing and enhanced mass transfer compared with conventional reactors. By maintaining geometrical and dynamic conditions, the technology has been proved to be easily scaled up and operated continuously, allowing laboratory-scale results to be easily transferred to industrial-sized processes. This is the first comprehensive review of bioprocessing using OBRs. The barriers facing industrial adoption of the technology are discussed alongside some suggested strategies to overcome these barriers. OBR technology could prove to be a major aid in the development of commercially viable and sustainable bioprocesses, essential for moving towards a greener future. PMID:24427509

  8. CFD Analysis of Shell and Tube Heat Exchanger to Study the Effect of Baffle Cut on the Pressure Drop

    OpenAIRE

    Avinash D Jadhav; Tushar A Koli

    2014-01-01

    The shell side design of a shell and tube heat exchanger; in particular the baffle spacing, baffle cut and shell diameter dependencies of the heat transfer coefficient and the pressure drop are investigated by numerically modelling a small heat exchanger. The flow and temperature fields inside the shell are resolved using a commercial CFD package. A set of CFD simulations is performed for a single shell and single tube pass heat exchanger with a variable number of baffles and turb...

  9. Transcatheter occlusion of baffle leaks following atrial switch procedures for transposition of the great vessels (d-TGV).

    Science.gov (United States)

    Balzer, David T; Johnson, Mark; Sharkey, Angela M; Kort, Henry

    2004-02-01

    Baffle-related complications following atrial switch procedures for transposition are relatively common. Transcatheter treatment of baffle stenosis has an established role as a therapeutic modality. However, transcatheter device closure of atrial baffles leaks has rarely been reported. We report four patients who underwent device closure of baffle leaks using the Amplatzer septal occluder following atrial switch procedures in order to demonstrate the safety and utility of this method of treatment and to establish its role as a suitable alternative to surgical closure. PMID:14755824

  10. The baffle-barrel-bolting analysis program: evolution and technical accomplishments

    Energy Technology Data Exchange (ETDEWEB)

    Schwirian, R.E.; Forsyth, D.R.; Snyder, M.D.; Bhandari, D.R.; Barsic, J.A.; Rabenstein, W.D. [Westinghouse Electric Company, Pittsburgh, Pennsylvania (United States)

    2001-07-01

    In Westinghouse pressurized water reactors (PWR) the reactor core is surrounded by baffle plates, which provide lateral restraint for the fuel assemblies at the core boundary. Baffle plates are attached to horizontal supports called former plates by baffle-former bolts. The formers are attached to the core barrel which also provides vertical support for the core. The B3 analysis program addresses the possibility of reduced baffle-former bolting in Westinghouse U.S. domestic plant designs with respect to the relevant design criteria. Since safety is the overriding motivation for the program, faulted events have received the most in-depth attention. This focus has been reinforced by the fact that the loads produced by the loss-of-coolant-accident (LOCA) have usually been the most limiting of all those considered. Consequently, much of the presentation below deals with the development of analysis techniques and acceptance criteria to demonstrate that LOCA-induced loads on the bolts and the fuel assemblies will be acceptable with significantly reduced baffle-former bolting. A discussion of the other faulted, normal, and upset analyses performed as part of the program will also be presented. (author)

  11. Dynamic characteristics and design criteria of fuel rod assemblies in a baffle jet flow

    International Nuclear Information System (INIS)

    During recent refuelling operations of a PWR type nuclear power plant it was found that several fuel assemblies located at baffle joint were damaged. It was assumed that the damage had been caused by severe vibration of fuel rods induced by coolant leakage through baffle joint. Model testing was con-ducted to identify the vibration mechanism and to obtain the safety criteria for fuel assemblies in a baffle jet flow. Fuel rods are long beams supported along their length by seven grid assemblies. Those prototype rods were simulated as single span simply supported beams. Model assemblies are 4 x 4 and 5 x 4 bundles of simply supported beams with a pitch ratio of 1.33. Flow tests were carried out in a water loop of 40 GPM. It was found that rod assemblies in a jet flow experience large amplitude vibration caused by jet induced instability. The stability boundary of rod assemblies is determined to be Vc/fD=2.3 √(D/h)(msub(o) deltasub(o))/(rho D2). Based on the stability boundary provided, safety limit of baffle gap is calculated as to be 1.6 x 10-3 in. The effect of the position of fuel rod assemblies relative to the baffle joint was investigated. And it was found that the susceptibility of rod assemblities to vibration increases as the stand off distance shortens. (Author)

  12. Microfluidic characteristics of a multi-holed baffle plate micro-reactor

    International Nuclear Information System (INIS)

    As part of a larger project aiming at development of a miniaturized hydrogen generator for small mobile/onboard fuel cell applications, a series of experiments was conducted on a novel micro-reactor to examine the effectiveness of its design in promoting the mixing of reactant agents. The reactor is essentially a tubular vessel fitted with a multi-holed baffle plate mounted on a central tube. The mixing phenomenon within the micro-reactor was studied using the micro-PIV (micro-particle image velocimetry) flow visualization technique. Experiments were conducted on a 1:1 scale replica of the reactor. Results indicate that the application of the multi-holed baffle plate considerably improves the mixing performance of the reactor when compared with a simpler co-axial jet tubular reactor. However, the geometrical characteristics of the baffle plate and central tube are found to have dramatic impacts upon the flow structure and mixing patterns within the reactor. Hence, the optimization of the reactor geometry is required to achieve the desirable mixing performance. For the range of Reynolds numbers studied here, the optimum reactor geometry is achieved when the central tube and baffle holes are of similar diameters and baffle holes are located half way between the stream-wise axis and the reactor wall

  13. NUMERICAL SIMULATION OF FLUID FLOW BEHAVIOUR ON SCALE UP OF OSCILLATORY BAFFLED COLUMN

    Directory of Open Access Journals (Sweden)

    WAH KENG SERN

    2012-02-01

    Full Text Available The fluid dynamics of oscillatory flow in a baffled column of 145 mm diameter was investigated numerically in this work. This numerical simulation was carried out by a 2D laminar unsteady solver using CFD package Fluent® 6.3. From the simulation, data on surface velocity were collected and velocity ratio was calculated to determine the intensity of mixing which were the main operating parameters in oscillatory flow in a baffled column. The suitable operating parameters of oscillatory baffled column of 145 mm diameter were also determined in this work. It was found that the oscillation amplitude was more dominant for obtaining desirable mixing results compare to oscillation frequency.

  14. Analytical and Experimental Study of Recycling Baffled Double-Pass Solar Air Heaters with Attached Fins

    Directory of Open Access Journals (Sweden)

    Chun Sheng Lin

    2013-03-01

    Full Text Available The study of the heat transfer of solar air heaters with a new design using an absorbing plate with fins and baffles, which facilitate the recycling of flowing air, is reported. The mathematical formulation and analytical analysis for such a recyclic baffled double-pass solar air heater were developed theoretically. The performance of the device was studied experimentally as well. The theoretical predicted and experimental results were compared with another design, i.e., a downward-type single-pass solar air heater without recycle and double-pass operations reported in our previous work. Significant improvement in heat-transfer efficiency is achieved with the baffle and fin design due to the recycling heating and the extended heat transfer area. The effects of mass flow rate and recycle ratio on the heat-transfer efficiency enhancement as well as on the power consumption increment are also discussed.

  15. Validation of High-Resolution CFD Method for Slosh Damping Extraction of Baffled Tanks

    Science.gov (United States)

    Yang, H. Q.; West, Jeff

    2016-01-01

    Determination of slosh damping is a very challenging task as there is no analytical solution. The damping physics involve the vorticity dissipation which requires the full solution of the nonlinear Navier-Stokes equations. As a result, previous investigations and knowledge were mainly carried out by extensive experimental studies. A Volume-Of-Fluid (VOF) based CFD program developed at NASA MSFC was applied to extract slosh damping in a baffled tank from the first principle. First, experimental data using water with subscale smooth wall tank were used as the baseline validation. CFD simulation was demonstrated to be capable of accurately predicting natural frequency and very low damping value from the smooth wall tank at different fill levels. The damping due to a ring baffle at different liquid fill levels from barrel section and into the upper dome was then investigated to understand the slosh damping physics due to the presence of a ring baffle. Based on this study, the Root-Mean-Square error of our CFD simulation in estimating slosh damping was less than 4.8%, and the maximum error was less than 8.5%. Scalability of subscale baffled tank test using water was investigated using the validated CFD tool, and it was found that unlike the smooth wall case, slosh damping with baffle is almost independent of the working fluid and it is reasonable to apply water test data to the full scale LOX tank when the damping from baffle is dominant. On the other hand, for the smooth wall, the damping value must be scaled according to the Reynolds number. Comparison of experimental data, CFD, with the classical and modified Miles equations for upper dome was made, and the limitations of these semi-empirical equations were identified.

  16. On the dynamic spatial response of a heat exchanger tube with intermittent baffle contacts

    International Nuclear Information System (INIS)

    Flow-induced vibration in heat exchanger tubes can result in fretting wear at the baffle supports and subsequent tube failure. As one step in correlating the random flow excitation to the rate of fretting wear, this paper presents a dynamic finite element technique for predicting the motions and baffle contact forces of a single heat exchanger tube. Using a modal superposition approach, the modal equations of motion are generated and numerically integrated. The predicted results are compared with experimental data for both planar and spatial vibration of harmonically excited cantilevered beams with a clearance support at the free end. (Auth.)

  17. REVIEW OF HEAT TRANSFER ENHANCEMENT IN DIFFERENT TYPES OF BAFFLES AND THEIR ORIENTATIONS.

    Directory of Open Access Journals (Sweden)

    S.P.WALDE

    2012-04-01

    Full Text Available The use of baffles in channel is commonly used for passive heat transfer enhancement strategy in single phase internal flow. Considering the rapid increase in energy demand, effective heat transfer enhancement techniques have become important task worldwide. Some of the applications of passive heat transfer enhancement strategies are in process industries, thermal regenerator, Shell and tube type heat exchanger, Internal cooling system of gas turbine blades, radiators for space vehicles and automobiles, etc. Thepresent paper is a review of different types of baffles and its arrangement. According to recent studies these are known to be economic heat transfer augmentation tools.

  18. Numerical investigation on a novel shell-and-tube heat exchanger with plate baffles and experimental validation

    International Nuclear Information System (INIS)

    Highlights: • A novel shell-and-tube heat exchanger with plate baffles is proposed. • Heat transfer and pressure drop of computational calculations are studied. • Experimental method is carried out to verify the modeling approach. • Path lines, temperature field and pressure field are analyzed. - Abstract: A novel shell-and-tube heat exchanger with new plate baffles is proposed. It is numerically investigated in comparison with a shell-and-tube heat exchanger with rod baffles. Commercial softwares FLUENT 6.3 and GAMBIT 2.3 are adopted for modeling and computational calculations. The modeling approach is verified with experimental approach. The shell-side results of heat transfer, flow performance, and comprehensive performance are analyzed. The Nusselt number for the plate baffles heat exchanger is around 128–139% of that for the rod baffles heat exchanger. The pressure drop for the novel one is about 139–147% of that for the rod baffles heat exchanger. Overall, the novel plate baffles heat exchanger illustrates evidently higher comprehensive performance (115–122%) than the rod baffles one. The temperature field, pressure field, and path lines are analyzed to demonstrate the advantage of the novel shell-and-tube heat exchanger

  19. Shell side numerical analysis of a shell and tube heat exchanger considering the effects of baffle inclination angle on fluid flow using CFD

    OpenAIRE

    Raj Karuppa Thundil R.; Ganne Srikanth

    2012-01-01

    In this present study, attempts were made to investigate the impacts of various baffle inclination angles on fluid flow and the heat transfer characteristics of a shell-and-tube heat exchanger for three different baffle inclination angles namely 0°,10° and 20°. The simulation results for various shell and tube heat exchangers, one with segmental baffles perpendicular to fluid flow and two with segmental baffles inclined to the direction of fluid flow are compared for their performance. ...

  20. Irradiation-Induced Degradation Effects on Baffle-Former-Barrel Assembly of Reactor Vessel Internal

    International Nuclear Information System (INIS)

    Components of RVI are consisted of austenitic stainless steel materials which are known to have good strength, ductility, toughness and corrosion resistance. However, when placed in a PWR environment, these properties undergo changes due to long-term exposure to neutron irradiation, high temperature, reactor water, and loading. Especially irradiation aging in the reactor vessel internal components is characterized by a decrease in ductility and fracture toughness, increase in yield and ultimate tensile strength, and potential volume changes due to void formation. It is very important to determine when and where irradiation susceptibility may occur for the continued operation. This paper introduces the aging management strategy for the pressurized water reactor internal and investigates the effects of the irradiation-induced degradation of the baffle-former-barrel (BFB) assembly of the pressurized water reactor operating in Korea. This paper provides the methodologies and results for the functionality analysis on the baffle-former-barrel assembly. The highest temperatures are yielded from EOC of high leakage loading. The most highly irradiated areas are also closed to the core such as internal corners of the baffle plates. Coincidentally, the largest distortion occurs between these baffle plates. The distortion is carried by the bolts holding these plates. Characteristic to void swelling is the exponential growth with time. Void swelling predictions are therefore highly sensitive to the assumed fuel cycle management

  1. 49 CFR 178.337-5 - Bulkheads, baffles and ring stiffeners.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 2 2010-10-01 2010-10-01 false Bulkheads, baffles and ring stiffeners. 178.337-5 Section 178.337-5 Transportation Other Regulations Relating to Transportation PIPELINE AND HAZARDOUS MATERIALS SAFETY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION HAZARDOUS MATERIALS REGULATIONS SPECIFICATIONS FOR PACKAGINGS Specifications...

  2. Investigation of Nitrogen Removal Efficiency from Wastewater using Modified Anaerobic Baffled Reactor (MABR

    Directory of Open Access Journals (Sweden)

    H Ganjidoust

    2010-02-01

    Full Text Available "n "nBackgrounds and Objectives : Nitrogen compounds in wastewater are mainly in four types of organic, am- monia, nitrite and nitrate. Total nitrogen concentration in municipal wastewater is usually within 25 to 45 mg/L as nitrogen. The most important problem with nitrogen is its oxygen demand and human health effect."nMaterials and Methods: Anaerobic Baffled Reactor (ABR is a system in which baffles are used to direct  wastewater flow. During 9 months study, a 15 liter modified ABR (104*30*15 cm with eight baffled com- partments was used for nitrification-denitrification processes. In the seventh compartment, the wastewater was aerated to oxidize ammonia to nitrite and nitrate."nResults : Denitrification was done in the first four compartments with removal efficiency from 60 to 84 per- cent for nitrite and nitrate, respectively. During the shock loading study (4 times of the last influent, a sharp decrease in nitrogen removal rate was observed which was then returned to the previous efficiency after 11 days. Artificial neural network was used to evaluate and process the data in which the observed error in 10 patterns was less than 15 percent."nConclusion : Anaerobic baffled reactor with an influent of up to 200 mg/L has capability to remove total  nitrogen concentration to less than the standard level of Iranian Department of Environment of 50 mg/L as nitrate and 10 mg/L as nitrogen.

  3. Thermal transient analysis in a nozzle with an inner thermal baffle

    International Nuclear Information System (INIS)

    The study presents the analysis of the temperature history of a nozzle provided by an inner thermal baffle subjected to cold thermal shocks from the initial temperature (approx.= 5400C) with an about 150C/sec thermal gradient. The used instrumentation includes thermocouples to measure the temperature versus time at various points along the axial length of the nozzle. All instrumentation was put on the outside surface of the stucture. To uniform the temperature at the initial action point of the thermal baffle a little flow of sodium passes in the anular interspace between the nozzle and the thermal baffle. The by-pass sodium flow is not constant and also the inlet Na temperature is variable in time. The calculation of the sodium flow rate between the nozzle and the thermal baffle is made by an ad-hoc finite differences code. The calculation of the fluid temperature is made in transitory regime appreciating the cooling temperature rate of Na in contact with the structural components that it skins and its calorific capacity. The theoretical-experimental comparison of the trend of temperature in time at different heights shows that there is a very good identity for the different points of the structure. (orig./GL)

  4. A Computational Fluid Dynamics Study of Swirling Flow Reduction by using Anti-vortex Baffle

    Science.gov (United States)

    Yang, H. Q.; Peugeot, John W.; West, Jeff S..

    2013-01-01

    An anti-vortex baffle is a liquid propellant management device placed adjacent to an outlet of the propellant tank. Its purpose is to substantially reduce or eliminate the formation of free surface dip and vortex, as well as prevent vapor ingestion into the outlet, as the liquid drains out through the flight. To design an effective anti-vortex baffle, Computational Fluid Dynamic (CFD) simulations were undertaken for the NASA Ares I vehicle LOX tank subjected to the simulated flight loads with and without the anti-vortex baffle. The Six Degree-Of-Freedom (6- DOF) dynamics experienced by the Crew Launch Vehicle (CLV) during ascent were modeled by modifying the momentum equations in a CFD code to accommodate the extra body forces from the maneuvering in a non-inertial frame. The present analysis found that due to large moments, the CLV maneuvering has significant impact on the vortical flow generation inside the tank. Roll maneuvering and side loading due to pitch and yaw are shown to induce swirling flow. The vortical flow due to roll is symmetrical with respect to the tank centerline, while those induced by pitch and yaw maneuverings showed two vortices side by side. The study found that without the anti-vortex baffle, the swirling flow caused surface dip during the late stage of drainage and hence early vapor ingestion. The flow can also be non-uniform in the drainage pipe as the secondary swirling flow velocity component can be as high as 10% of the draining velocity. An analysis of the vortex dynamics shows that the swirling flow in the drainage pipe during the Upper Stage burn is mainly the result of residual vortices inside the tank due to conservation of angular momentum. The study demonstrated that the swirling flow in the drainage pipe can be effectively suppressed by employing the anti-vortex baffle.

  5. Studi Numerik Pengaruh Baffle Inclination Pada Alat Penukar Kalor Tipe Shell And Tube Terhadap Aliran Fluida Dan Perpindahan Panas

    Directory of Open Access Journals (Sweden)

    Rezky Fadil Arnaw

    2014-09-01

    Full Text Available Heat exchanger atau alat penukar kalor merupakan suatu peralatan yang digunakan untuk memindahkan sejumlah energi dalam bentuk panas dari satu fluida ke fluida yang lain. Perpindahan panas tersebut terjadi dari suatu fluida yang suhunya lebih tinggi ke fluida lain yang suhunya lebih rendah. Pada tugas akhir ini akan dilakukan penelitian tentang pengaruh baffle inclination terhadap aliran fluida dan perpindahan panas pada alat penukar kalor tipe shell and tube. Dalam penelitian ini akan dilakukan tiga variasi sudut baffle inclination yaitu 0º, 10° dan 20° dengan besar laju aliran massa yang divariasikan yaitu sebesar 0.5 kg/s, 1 kg/s dan 2 kg/s. Tipe baffle yang digunakan adalah single segmental baffle dengan baffle cut sebesar 36% dan menggunakan arah aliran jenis parallel. Hasil analisa simulasi menunjukkan bahwa laju aliran massa yang meningkat akan menyebabkan kenaikan pressure drop yang cukup drastis dan penurunan temperatur outlet. Alat penukar kalor dengan baffle inclination 0° memiliki nilai perpindahan panas terbaik jika dibandingkan dengan baffle inclination 10° dan 20°.

  6. Studi Numerik Pengaruh Baffle Inclination Pada Alat Penukar Kalor Tipe U – Tube Terhadap Aliran Fluida Dan Perpindahan Panas

    Directory of Open Access Journals (Sweden)

    Reza Hidayatullah

    2014-09-01

    Full Text Available Alat penukar kalor sangat berpengaruh dalam industri terhadap keberhasilan keseluruhan rangkaian proses, karena kegagalan operasi alat ini baik akibat kegagalan mekanikal maupun opersional dapat menyebabkan berhentinya operasi unit. Penelitian terhadap desain heat exchanger masih terus dilakukan untuk mencari kinerja dari heat exchanger yang paling optimal, baik pada bagian baffle cut dan baffles inclination maupun susunan dari tube dengan menggunakan heat exchanger ukuran kecil sebagai model. Berdasarkan pada permasalahan di atas, maka dilakukan penelitian terhadap kinerja heat exchanger tipe U-tube dengan memvariasikan baffle inclination. Penelitian ini dilakukan secara numerik dengan variasi baffle inclination sebesar 0o, 10o, 20o dan variasi laju aliran massa sebesar 0,5 kg/s, 1kg/s, dan 2 kg/s. Tube yang digunakan adalah tipe U-tube yang disusun secara persegi. Model viskous yang digunakan adalah turbulensi model yaitu k-ε standar, dimana fluida yang digunakan adalah air pada boundary condition. Hasil analisa numerik menunjukkan adanya pengaruh baffle inclination pada alat penukar kalor tipe U – tube terhadap aliran fluida dan perpindahan panas. Peningkatan laju aliran massa dapat meningkatkan pressure drop secara cepat, alat penukar kalor shell and tube tipe U – tube dengan baffle inclination 20o memiliki unjuk kerja yang terbaik dibandingkan dengan baffle inclination 0o dan 10o.

  7. Power correlation for pitched blade paddle impeller in agitated vessels with and without baffles; Keisha padoruyoku no kakuhan shoyo doryoku no sokan

    Energy Technology Data Exchange (ETDEWEB)

    Hiraoka, S.; Kamei, N.; Kato, Y.; Tada, Y.; Hyeong, G.; Yamaguchi, T. [Nagoya Inst. of Tech. (Japan)

    1997-11-01

    The power consumption for a pitched blade paddle impeller in both baffled and non-baffled agitated vessels was measured over a wide range of Reynolds numbers from laminar to turbulent flow regimes. Power consumption for a non-baffled vessel was well correlated with the same correlation as that for a paddle impeller by modifying the coefficients in the correlation with blade angle. Power consumption in a baffled vessel was also well correlated with a correlation method similar to Kamei`s one for a paddle impeller. The fully-baffled condition and the corresponding power number were presented by the following equations. 10 refs., 7 figs.

  8. Buckling behaviour of PFBR main vessel and its thermal baffles under seismic loadings

    International Nuclear Information System (INIS)

    The special feature of pool type fast breeder reactor is the usage of very large sized thin shell structures for its reactor vessels. Due to the large diameter to thickness ratio (around 700 to 900), design of these vessels poses challenging structural mechanics problems particularly under seismic loading. An important threat to structural integrity of reactor vessels is the buckling risk during seismic events. The buckling design involves determination of critical buckling load and comparing it with operating load, to ensure that enough safety factors recommended by RCC-MR are available at all loading levels (RCC-MR 1985). The determination of critical buckling load particularly under seismic loading is a complicated task due to dynamic effects, non-axisymmetric nature of loading, material and geometrical nonlinearities, effect of geometric imperfections and boundary conditions and the interaction of different modes of buckling. Based on literature survey and extensive benchmark studies, the above complexities involved in the buckling analysis have been resolved and subsequent analysis is done for the main vessel and its thermal baffle of Prototype Fast Breeder Reactor (PFBR). The integrity of main vessel is very important since it forms an important part of primary containment and also carries around 1250 t of radioactive sodium. The integrity of thermal baffles is not very important during Safe Shutdown Earthquake (SSE) (level D) loading. However, for the operational basis earthquake (OBE) (Level-B loading), thermal baffles should be designed for meeting buckling criteria since either the loss of their integrity or large displacements may affect the cooling passage for the cold sodium flow and in turn, the temperature of main vessel may rise above the creep temperature. While the straight portion of main vessel is subjected to shear and bending mode of buckling, its dished end is subjected to shell mode buckling during seismic events. The dynamic pressure

  9. Analytical approach to transforming filter design for sound field recording and reproduction using circular arrays with a spherical baffle.

    Science.gov (United States)

    Koyama, Shoichi; Furuya, Ken'ichi; Wakayama, Keigo; Shimauchi, Suehiro; Saruwatari, Hiroshi

    2016-03-01

    A sound field recording and reproduction method using circular arrays of microphones and loudspeakers with a spherical baffle is proposed. The spherical baffle is an acoustically rigid object on which the microphone array is mounted. The driving signals of the loudspeakers must be obtained from the signals received by the microphones. A transform filter for this signal conversion is analytically derived, which is referred to as the wave field reconstruction filter. The proposed method using a spherical baffle is compared with methods using an array of directional microphones and a microphone array mounted on a cylindrical baffle. Numerical simulations indicated that the proposed method is advantageous for sound field recording and reproduction compared with the other two methods. The results of measurement experiments in a real environment are also demonstrated. PMID:27036240

  10. Experimental Investigation on Heat Transfer and Frictional Characteristics of Shell-and-tube Heat exchangers with Different Baffles and Tubes

    Science.gov (United States)

    Wang, C.; Zhu, J. G.; Sang, Z. F.

    2010-03-01

    In this study, the heat transfer and tube frictional characteristics of the helixchangers (shell-and-tube heat exchanger with helical baffles) with spirally corrugated and smooth tubes and the conventional shell-and-tube heat exchanger with smooth tubes were experimentally obtained. The results show that the helixchangers with the spirally corrugated tube and the smooth tubes enhance the total heat transfer coefficient about 26% and 7% on the average than the segmental baffled heat exchanger. In the tube side, the spirally corrugated tube leads to about 28% average increase on convective heat transfer performance and about 24% average increase on pressure drop than the smooth tube, but its conversion efficiency is still higher. The helical baffle could enhance the shell-side condensation coefficient by 13%, and the spirally corrugated tube could help the helixchanger with it enhance remarkably the condensation performance by 53% than the segmental baffled heat exchanger.

  11. Experimental investigation on performances of trisection helical baffled heat exchangers for oil/water–water heat transfer

    International Nuclear Information System (INIS)

    Highlights: • Oil/water–water heat transfer performance tests of different schemes were conducted. • 12–28° incline angled helical baffle heat exchangers and segment one were studied. • Smaller incline angle is, higher are the shell side ho, Δpo and comprehensive index. • Both ho and ho/Δpo of 12° helical scheme are 50% higher than those of segment one. • Correlations formulae of shell side Nuo and Euzo for cothSTHXs are presented. - Abstract: The trisection helical baffled shell-and-tube heat exchangers have structural features of more suitable to the equilateral triangular tube layouts and less baffle parts. In particular the circumferential overlap trisection helical baffled shell-and-tube heat exchangers are of anti-shortcut structure that accommodates one row tubes in each circumferential overlapped zone between adjacent baffles for dampening shortcut leakage. The performance tests were conducted on both oil–water and water–water heat transfer in heat exchangers with equilateral triangle tube layout of 16 tubes including five helical baffle schemes with incline angles of 12°, 16°, 20°, 24°, 28° and a segmental baffled one for comparison. The test results show that both the shell side heat transfer coefficient ho and pressure drop Δpo increase but the comprehensive index ho/Δpo decreases with the increase of the mass flow rate of all schemes; and that the shell side heat transfer coefficient, pressure drop and the comprehensive index ho/Δpo decrease with the increase of the baffle incline angle at certain mass flow rate, except that the curves of comprehensive index ho/Δpo of 12° and 16° helical baffle schemes are almost coincide. The average values of shell side heat transfer coefficient, the comprehensive index ho/Δpo of the 12° helical baffled scheme are about 50% higher than those of the segmental one with almost same pressure drop. The correlation equations for shell side Nusselt number and axial Euler number are

  12. Simulation of the influence of the baffle on flowing field in the anode baking ring furnace

    Institute of Scientific and Technical Information of China (English)

    周萍; 梅炽; 周孑民; 周乃君; 徐琼辉

    2002-01-01

    In an anode baking horizontal flue ring furnace, the temperature distribution is one of the key factors influencing the quality of baked anode and is closely correlated with the gas flow. To understand the gas flow distribution in the flue, Navier-Stokes equation with "k-ε" two-equation turbulence model was adopted and the simulation on the gas flow was performed. The numerical simulation results showed that the even direction of gas flow should be considered in the design of flue baffles and the gas flow distribution was really uneven in the flue in practical use. By adjusting the number and location of flue baffles rationally, the even distribution of gas flow can be improved obviously.

  13. Space- and Ground-Based Crystal Growth Using a Baffle (CGB)

    Science.gov (United States)

    Ostrogorsky, A. G.; Marin, C.; Peignier, T.; Duffar, T.; Volz, M.; Jeter, L.; Luz, P.

    2001-01-01

    The composition of semiconductor crystals produced in space by conventional melt-growth processes (directional solidification and zone melting) is affected by minute levels of residual micro-acceleration, which causes natural convection. The residual acceleration has random magnitude, direction and frequency. Therefore, the velocity field in the melt is apriori unpredictable. As a result, the composition of the crystals grown in space can not be predicted and reproduced. The method for directional solidification with a submerged heater or a baffle was developed under NASA sponsorship. The disk-shaped baffle acts as a partition, creating a small melt zone at the solid-liquid interface. As a result, in ground based experiment the level of buoyancy-driven convection at the interface is significantly reduced. In several experiments with Te-doped GaSb, nearly diffusion controlled segregation was achieved.

  14. Validation of High-Resolution CFD Method for Slosh Damping Extraction of Baffled Cryogenic Propellant Tanks

    Science.gov (United States)

    Yang, H. Q.; West, Jeff

    2016-01-01

    Propellant slosh is a potential source of disturbance critical to the stability of space vehicles. The slosh dynamics are typically represented by a mechanical model of a spring-mass-damper. This mechanical model is then included in the equation of motion of the entire vehicle for Guidance, Navigation and Control analysis. A Volume-Of-Fluid (VOF) based Computational Fluid Dynamics (CFD) program developed at MSFC was applied to extract slosh damping in the baffled tank from the first principle. First the experimental data using water with sub-scale smooth wall tank were used as the baseline validation. It is demonstrated that CFD can indeed accurately predict low damping values from the smooth wall at different fill levels. The damping due to a ring baffles at different depths from the free surface was then simulated, and fairly good agreement with experimental measurement was observed. Comparison with an empirical correlation of Miles equation is also made.

  15. Effects of Perforated Baffle on Reducing Sloshing in Rectangular Tank:Experimental and Numerical Study

    Institute of Scientific and Technical Information of China (English)

    薛米安; 林鹏智; 郑金海; 马玉祥; 苑晓丽; Viet-Thanh NGUYEN

    2013-01-01

    A liquid sloshing experimental rig driven by a wave-maker is designed and built to study liquid sloshing problems in a rectangular liquid tank with perforated baffle. A series of experiments are conducted in this experimental rig to estimate the free surface fluctuation and pressure distribution by changing external excitation frequency of the shaking table. An in-house CFD code is also used in this study to simulate the liquid sloshing in three-dimensional (3D) rectangular tank with perforated baffle. Good agreements of free surface elevation and pressure between the numerical results and the experimental data are obtained and presented. Spectral analysis of the time history of free surface elevation is conducted by using the fast Fourier transformation.

  16. Internal heat transfer and pressure drop measurements in a variously baffled shell and tube heat exchanger

    Science.gov (United States)

    Galindo, P.

    1984-06-01

    Heat transfer coefficients, pressure distributions, and fluid flow patterns on the shell side of shell and tube heat exchangers are discussed. The main focus was to quantify the effect of the size of the baffle window on the heat transfer coefficient, which was measured at each tube in the bundle and at three Reynolds numbers. Pressure drops were obtained by measuring detailed pressure distributions within the exchangers. The flow visualizations provided fluid flow patterns adjacent to the shell wall, to the baffle plates, and at each tube of the array. Performance comparisons among the exchangers were carried out holding the heat transfer surface area fixed together with either the pumping power, the mass flow rate, or the pressure drop. Numerical evaluations of commonly employed design procedures are presented using the present data as a means for rank ordering their validity. Tinker's design method provided the best predictions of the present heat transfer and pressure drop results, which are unaffected by leakage and bypass.

  17. Performance of a shell-and-tube heat exchanger with spiral baffle plates

    International Nuclear Information System (INIS)

    In a conventional shell-and-tube heat exchanger, fluid contacts with tubes flowing up and down in a shell, therefore there is a defect in the heat transfer with tubes due to the stagnation portions. Fins are attached to the tubes in order to increase heat transfer efficiency, but there exists a limit. Therefore, it is necessary to improve heat exchanger performance by changing the fluid flow in the shell. In this study, a highly efficient shell-and-tube heat exchanger with spiral baffle plates is simulated three-dimensionally using a commercial thermal-fluid analysis code, CFX4.2. In this type of heat exchanger, fluid contacts with tubes flowing rotationally in the shell. It could improve heat exchanger performance considerably because stagnation portions in the shell could be removed. It is proved that the shell-and-tube heat exchanger with spiral baffle plates is superior to the conventional heat exchanger in terms of heat transfer

  18. Influences of prolate spheroidal baffle of sound diffraction on spatial directivity of acoustic vector sensor

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    The directivity of acoustic vector sensor (AVS) will be distorted by the sound diffraction of the AVS carrier. In this paper,the scattering of a plane acoustic wave from a prolate spheroid baffle is considered. At first,the sound diffraction of prolate spheroidal baffle is established,then the mathematical expressions of sound pressure field and particle vibration velocity field of sound diffraction are derived and the characteristic of the directivity of pressure and velocity of sound diffraction field at different frequencies and distances is analyzed. The directivity of AVS is determined by the amplitude and phase difference of diffraction wave and incident wave,which possesses a close relationship with frequency and incident angle. Finally,the calculated results are compared with the experimental results.

  19. Studi Numerik Pengaruh Baffle Inclination Pada Alat Penukar Kalor Tipe U – Tube Terhadap Aliran Fluida Dan Perpindahan Panas

    OpenAIRE

    Reza Hidayatullah; Bambang Arip Dwiyantoro

    2014-01-01

    Alat penukar kalor sangat berpengaruh dalam industri terhadap keberhasilan keseluruhan rangkaian proses, karena kegagalan operasi alat ini baik akibat kegagalan mekanikal maupun opersional dapat menyebabkan berhentinya operasi unit. Penelitian terhadap desain heat exchanger masih terus dilakukan untuk mencari kinerja dari heat exchanger yang paling optimal, baik pada bagian baffle cut dan baffles inclination maupun susunan dari tube dengan menggunakan heat exchanger ukuran kecil sebagai model...

  20. Thermal transient analysis in a nozzle with an inner thermal baffle

    International Nuclear Information System (INIS)

    The paper presents an example of application of the Delfine code in a non linear thermal transient study. The code is part of finite elements CASTEM System developed in CEA Saclay. The study refers about the analysis of the thermal history of a structure that is subjected to thermal exchange with a fluid flowing in forced convection in open loop. In the first part it's given the approach used in the computer program to solve the problem and then the experimental theoretical study of a plant component. The study presents the analysis of the temperature history of a nozzle provided by an inner thermal baffle subjected to cold thermal shocks from the initial temperature (approximately 5400C) with an about 150C/sec thermal gradient. The used instrumentation includes thermocouples to measure the temperature versus time at various points along the axial length of the nozzle. All instrumentation was put on the outside surface of the structure. To uniform the temperature at the initial action point of the thermal baffle a little flow of sodium passes in the angular interspace between the nozzle and the thermal baffle. The by-pass sodium flow is not costant and also the inlet Na temperature is variable in time. The calculation of the sodium flow rate between the nozzle and the thermal baffle is made by an ad-hoc finite differences code. The calculation of the fluid temperature is made in transitory regime appreciating the cooling temperature rate of Na in contact with the structural components that it skins and its calorific capacity. The theoretical-experimental comparison of the trend of temperature in time at different heights shows that there is a very good identity for the different points of the structure

  1. Power consumption in agitated vessels with dual pitched blade turbines: baffle length and impeller spacing effects

    Energy Technology Data Exchange (ETDEWEB)

    Markopoulos, J.; Babalona, E.; Tsiliopoulou, E.; Tasopoulou, K. [Department of Chemical Engineering, Aristotle University of Thessaloniki, Univ. Box. 453, GR-54124 Thessaloniki (Greece)

    2005-09-01

    The power consumed in mechanically agitated vessels is an important parameter, especially for the energy requirements and the heat and mass transfer efficiencies of these systems. Power consumption does not only depend on the impeller type, the fluid properties and the stirring speed, but also on the geometry of the agitated system, including the impeller spacing and the length of the baffles in the mixing vessel. (Abstract Copyright [2005], Wiley Periodicals, Inc.)

  2. Combustor having mixing tube bundle with baffle arrangement for directing fuel

    Energy Technology Data Exchange (ETDEWEB)

    Hughes, Michael John; McConnaughhay, Johnie Franklin

    2016-08-23

    A combustor includes a tube bundle that extends radially across at least a portion of the combustor. The tube bundle includes an upstream surface axially separated from a downstream surface, and a plurality of tubes extend from the upstream surface through the downstream surface to provide fluid communication through the tube bundle. A barrier extends radially inside the tube bundle between the upstream and downstream surfaces, and a baffle extends axially inside the tube bundle between the upstream surface and the barrier.

  3. Langmuir probes design for the actively cooled divertor baffle in WEST

    Energy Technology Data Exchange (ETDEWEB)

    Cacace, Maurizio, E-mail: maurizio.cacace@hotmail.it [CREATE, Universitàdi Napoli Federico II, Dipartimento di Ingegneria Industriale, P.le Tecchio 80, 80125 Napoli (Italy); Batal, Tristan; Corre, Yann [CEA, IRFM, F-13108 Saint-Paul-Lez-Durance (France); Di Gironimo, Giuseppe, E-mail: giuseppe.digironimo@unina.it [CREATE, Universitàdi Napoli Federico II, Dipartimento di Ingegneria Industriale, P.le Tecchio 80, 80125 Napoli (Italy); Gunn, Jamie P.; Pascal, Jean-Yves; Salasca, Sophie [CEA, IRFM, F-13108 Saint-Paul-Lez-Durance (France)

    2015-04-15

    Highlights: • Design of probes has followed an iterative approach. • CAD activity and FE thermo-mechanical analyses were performed in order to optimize the design. • The present design of Langmuir probes guarantees thermal contact efficiency and geometric simplicity. - Abstract: The WEST project (W-Environment in Steady-State Tokamak) aims to transform the Tore Supra limiter configuration to an x-point divertor, providing a test bed for ITER-like plasma-facing components (actively cooled W monoblocs) under high heat flux, steady-state plasma irradiation. The lower divertor includes an actively cooled, W-coated CuCrZr baffle to provide neutral compression and improve particle exhaust. As part of the new diagnostic equipment of Tore Supra within WEST project, a set of Langmuir probes will find place on the baffle in order to provide plasma flux and electron temperature measurements for physics studies and real-time machine protection functions during steady-state discharges. On the baffle top surface, irradiation coming from the plasma, energetic ripple-ions losses, photons and energetic neutrals from charge exchange reactions produce power fluxes up to 3 MW/m{sup 2}, representing a challenge for the Langmuir probes operating conditions. In this paper Copper–Chrome–Zirconium (CuCrZr) cylindrical probe concept design is proposed. Finite element thermo-mechanical analysis (FEA) confirmed the consistency of this solution under the steady-state plasma condition in the worst case (highest thermal load)

  4. Heat transfer in tube bundles of heat exchangers with flow baffles induced forced mixing

    International Nuclear Information System (INIS)

    Thermal analysis of shell-and-tube heat exchangers is being investigated through geometric modeling of the unit configuration in addition to considering the heat transfer processes taking place within the tube bundle. The governing equations that characterize the heat transfer from the shell side fluid to the tube side fluid across the heat transfer tubewalls are indicated. The equations account for the heat transfer due to molecular conduction, turbulent thermal diffusion, and forced fluid mixing among various shell side fluid channels. The analysis, though general in principle, is being applied to the Clinch River Breeder Reactor Plant-Intermediate Heat Exchanger, which utilizes flow baffles appropriately designed for induced forced fluid mixing in the tube bundle. The results of the analysis are presented in terms of the fluid and tube wall temperature distributions of a non-baffled and baffled tube bundle geometry. The former case yields axial flow in the main bundle region while the latter is associated with axial/cross flow in the bundle. The radial components of the axial/cross flow yield the necessary fluid mixing that results in reducing the thermal unbalance among the heat transfer to the allowable limits. The effect of flow maldistribution, present on the tube or shell sides of the heat exchangers, in altering the temperature field of tube bundles is also noted

  5. Langmuir probes design for the actively cooled divertor baffle in WEST

    International Nuclear Information System (INIS)

    Highlights: • Design of probes has followed an iterative approach. • CAD activity and FE thermo-mechanical analyses were performed in order to optimize the design. • The present design of Langmuir probes guarantees thermal contact efficiency and geometric simplicity. - Abstract: The WEST project (W-Environment in Steady-State Tokamak) aims to transform the Tore Supra limiter configuration to an x-point divertor, providing a test bed for ITER-like plasma-facing components (actively cooled W monoblocs) under high heat flux, steady-state plasma irradiation. The lower divertor includes an actively cooled, W-coated CuCrZr baffle to provide neutral compression and improve particle exhaust. As part of the new diagnostic equipment of Tore Supra within WEST project, a set of Langmuir probes will find place on the baffle in order to provide plasma flux and electron temperature measurements for physics studies and real-time machine protection functions during steady-state discharges. On the baffle top surface, irradiation coming from the plasma, energetic ripple-ions losses, photons and energetic neutrals from charge exchange reactions produce power fluxes up to 3 MW/m2, representing a challenge for the Langmuir probes operating conditions. In this paper Copper–Chrome–Zirconium (CuCrZr) cylindrical probe concept design is proposed. Finite element thermo-mechanical analysis (FEA) confirmed the consistency of this solution under the steady-state plasma condition in the worst case (highest thermal load)

  6. Computational Investigation on Fully Developed Periodic Laminar Flow Structure in Baffled Circular Tube with Various BR

    Directory of Open Access Journals (Sweden)

    Withada Jedsadaratanachai

    2014-01-01

    Full Text Available This paper presents a 3D numerical analysis of fully developed periodic laminar flow in a circular tube fitted with 45° inclined baffles with inline arrangement. The computations are based on a finite volume method, and the SIMPLE algorithm has been implemented. The characteristics of fluid flow are presented for Reynolds number, Re = 100–1000, based on the hydraulic diameter (D of the tube. The angled baffles were repeatedly inserted at the middle of the test tube with inline arrangement to generate vortex flows over the tested tube. Effects of different Reynolds numbers and blockage ratios (b/D, BR with a single pitch ratio of 1 on flow structure in the tested tube were emphasized. The flows in baffled tube show periodic flow at x/D ≈ 2-3, and become a fully developed periodic flow profiles at x/D ≈ 6-7, depending on Re, BR and transverse plane positions. The computational results reveal that the higher of BR and closer position of turbulators, the faster of fully developed periodic flow profiles.

  7. A three-dimensional numerical investigation of trapezoid baffles effect on non-isothermal reactant transport and cell net power in a PEMFC

    International Nuclear Information System (INIS)

    Highlights: • We study how angle and height of trapezoid baffle affect PEMFC net power. • The jet-type, trapping, and blockage effects augment non-isothermal transport in flow channel. • Greater angles and heights of trapezoid baffles provide more reactant to the catalyst layer. • Baffles of 1.5 mm and 90° fully block flow channel to show bad heat transfer and large pressure drop. • Maximum enhancement of cell net power is 90% with baffles of 60° angle and 1.125 mm height. - Abstract: The present study performed a three-dimensional numerical simulation to observe how trapezoid baffles affect non-isothermal reactant transports and cell net power in the proton exchange membrane fuel cell (PEMFC) by the SIMPLE-C method. The geometric parameters of trapezoid baffles installed in the gas channel employed in this study include the angle and height with the same gas diffusion and catalyst layers to realize the cell net power considering the effect of liquid water formation on the fluid flow field. The cell net power is adopted to evaluate the real enhancement of cell performance due to the additional pumping power induced by the pressure loss through the PEMFC. The results illustrated that compared with traditional gas channel without baffles, the novel gas channel with trapezoid baffles, whose angle is 60° and height is 1.125 mm, enhances the cell net power best by approximately 90% among all trapezoid baffle designs

  8. Kinetic study of treatment of wastewater contains food preservative agent by anaerobic baffled reactor : An overview

    International Nuclear Information System (INIS)

    The characteristic of wastewater of food industries with preservative substances is high content of organic substances, degradable and high total suspended solid. High organic content in this waste forced the treatment is biologically and pointed out to anaerobic treatment. Anaerobic showed the better performance of degradation than aerobic for high content organic and also for toxic materials. During that day the treatment of food wastewater is aerobically which is high consume of energy required and high volume of sludge produced. The advantage of anaerobic is save high energy, less product of sludge, less requirement of nutrients of microorganism and high efficiency reduction of organic load. The high efficiency of reduction will reduce the load of further treatment, so that, the threshold limit based on the regulation would be easy to achieve. Research of treatment of wastewater of food industries would be utilized by both big scale industries and small industries using addition of preservative substances. The type reactor of anaerobic process is anaerobic baffled reactor that will give better contact between wastewater and microorganism in the sludge. The variables conducted in this research are the baffled configuration, sludge height, preservative agent contents, hydralic retention time and influence of micro nutrients. The respons of this research are the COD effluent, remaining preservative agent, pH, formation of volatile fatty acid and total suspended solid. The result of this research is kinetic model of the anaerobic baffled reactor, reaction kinetic of preservative agent degradation and technology of treatment wastewater contains preservative agent. The benefit of this research is to solve the treatment of wastewater of food industries with preservative substance in order to achieve wastewater limit regulation and also to prevent the environmental deterioration

  9. Kinetic study of treatment of wastewater contains food preservative agent by anaerobic baffled reactor : An overview

    Energy Technology Data Exchange (ETDEWEB)

    Sumantri, Indro; Purwanto,; Budiyono [Chemical Engineering Department, Faculty of Engineering, Diponegoro University Jl. Prof. H. Soedarto, SH, Kampus Baru Tembalang, Semarang (Indonesia)

    2015-12-29

    The characteristic of wastewater of food industries with preservative substances is high content of organic substances, degradable and high total suspended solid. High organic content in this waste forced the treatment is biologically and pointed out to anaerobic treatment. Anaerobic showed the better performance of degradation than aerobic for high content organic and also for toxic materials. During that day the treatment of food wastewater is aerobically which is high consume of energy required and high volume of sludge produced. The advantage of anaerobic is save high energy, less product of sludge, less requirement of nutrients of microorganism and high efficiency reduction of organic load. The high efficiency of reduction will reduce the load of further treatment, so that, the threshold limit based on the regulation would be easy to achieve. Research of treatment of wastewater of food industries would be utilized by both big scale industries and small industries using addition of preservative substances. The type reactor of anaerobic process is anaerobic baffled reactor that will give better contact between wastewater and microorganism in the sludge. The variables conducted in this research are the baffled configuration, sludge height, preservative agent contents, hydralic retention time and influence of micro nutrients. The respons of this research are the COD effluent, remaining preservative agent, pH, formation of volatile fatty acid and total suspended solid. The result of this research is kinetic model of the anaerobic baffled reactor, reaction kinetic of preservative agent degradation and technology of treatment wastewater contains preservative agent. The benefit of this research is to solve the treatment of wastewater of food industries with preservative substance in order to achieve wastewater limit regulation and also to prevent the environmental deterioration.

  10. Kinetic study of treatment of wastewater contains food preservative agent by anaerobic baffled reactor : An overview

    Science.gov (United States)

    Sumantri, Indro; Purwanto, Budiyono

    2015-12-01

    The characteristic of wastewater of food industries with preservative substances is high content of organic substances, degradable and high total suspended solid. High organic content in this waste forced the treatment is biologically and pointed out to anaerobic treatment. Anaerobic showed the better performance of degradation than aerobic for high content organic and also for toxic materials. During that day the treatment of food wastewater is aerobically which is high consume of energy required and high volume of sludge produced. The advantage of anaerobic is save high energy, less product of sludge, less requirement of nutrients of microorganism and high efficiency reduction of organic load. The high efficiency of reduction will reduce the load of further treatment, so that, the threshold limit based on the regulation would be easy to achieve. Research of treatment of wastewater of food industries would be utilized by both big scale industries and small industries using addition of preservative substances. The type reactor of anaerobic process is anaerobic baffled reactor that will give better contact between wastewater and microorganism in the sludge. The variables conducted in this research are the baffled configuration, sludge height, preservative agent contents, hydralic retention time and influence of micro nutrients. The respons of this research are the COD effluent, remaining preservative agent, pH, formation of volatile fatty acid and total suspended solid. The result of this research is kinetic model of the anaerobic baffled reactor, reaction kinetic of preservative agent degradation and technology of treatment wastewater contains preservative agent. The benefit of this research is to solve the treatment of wastewater of food industries with preservative substance in order to achieve wastewater limit regulation and also to prevent the environmental deterioration.

  11. The baffled microtiter plate: increased oxygen transfer and improved online monitoring in small scale fermentations.

    Science.gov (United States)

    Funke, Matthias; Diederichs, Sylvia; Kensy, Frank; Müller, Carsten; Büchs, Jochen

    2009-08-15

    Most experiments in screening and process development are performed in shaken bioreactors. Today, microtiter plates are the preferred vessels for small-scale microbial cultivations in high throughput, even though they have never been optimized for this purpose. To interpret the experimental results correctly and to obtain a base for a meaningful scale-up, sufficient oxygen supply to the culture liquid is crucial. For shaken bioreactors this problem can generally be addressed by the introduction of baffles. Therefore, the focus of this study is to investigate how baffling and the well geometry affect the maximum oxygen transfer capacity (OTR(max)) in microtiter plates. On a 48-well plate scale, 30 different cross-section geometries of a well were studied. It could be shown that the introduction of baffles into the common circular cylinder of a microtiter plate well doubles the maximum oxygen transfer capacity, resulting in values above 100 mmol/L/h (k(L)a > 600 1/h). To also guarantee a high volume for microbial cultivation, it is important to maximize the filling volume, applicable during orbital shaking. Additionally, the liquid height at the well bottom was examined, which is a decisive parameter for online-monitoring systems such as the BioLector. This technology performs fiber-optical measurements through the well bottom, therefore requires a constant liquid height at all shaking frequencies. Ultimately, a six-petal flower-shaped well geometry was shown to be the optimal solution taking into account all aforementioned criteria. With its favorable culture conditions and the possibility for unrestricted online monitoring, this novel microtiter plate is an efficient tool to gain meaningful results for interpreting and scaling-up experiments in clone screening and bioprocess development. PMID:19449392

  12. Post-Service Examination of PWR Baffle Bolts, Part I. Examination and Test Plan

    Energy Technology Data Exchange (ETDEWEB)

    Leonard, Keith J. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Sokolov, Mikhail A. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Gussev, Maxim N. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

    2015-04-30

    In support of extended service and current operations of the US nuclear reactor plants, the Oak Ridge National Laboratory (ORNL), through the Department of Energy (DOE), Light Water Reactor Sustainability (LWRS) Program, is coordinating with Ginna Nuclear Power Plant, The Westinghouse Electric Company, LLC, and ATI Consulting, the selective procurement of baffle bolts that were withdrawn from service in 2011 and currently stored on site at Ginna. The goal of this program is to perform detailed microstructural and mechanical property characterization of baffle former bolts following in-service exposures. This report outlines the selection criteria of the bolts and the techniques to be used in this study. The bolts available are the original alloy 347 steel fasteners used in holding the baffle plates to the baffle former structures within the lower portion of the pressurized water reactor vessel. Of the eleven possible bolts made available for this work, none were identified to have specific damage. The bolts, however, did show varying levels of breakaway torque required in their removal. The bolts available for this study varied in peak fluence (highest dose within the head of the bolt) between 9.9 and 27.8x1021 n/cm2 (E>1MeV). As no evidence for crack initiation was determined for the available bolts from preliminary visual examination, two bolts with the higher fluence values were selected for further post-irradiation examination. The two bolts showed different breakaway torque levels necessary in their removal. The information from these bolts will be integral to the LWRS program initiatives in evaluating end of life microstructure and properties. Furthermore, valuable data will be obtained that can be incorporated into model predictions of long-term irradiation behavior and compared to results obtained in high flux experimental reactor conditions. The two bolts selected for the ORNL study will be shipped to Westinghouse with bolts of

  13. Active control of radiated sound power from a baffled, rectangular panel

    DEFF Research Database (Denmark)

    Mørkholt, Jakob

    Active control of radiated sound power from a rectangular baffled panel by minimisation of an accurate power estimate, using piezoceramic actuators, has been investigated. Computer simulations have shown that minimising a power estimate obtained by discretised integration of the far field intensity...... with an array of eleven microphones in front of the panel, is very close to minimising the actual radiated sound power. Practical experiments where such an array estimate has been minimised using the filtered X LMS algorithm have shown that substantial reductions of radiated sound power can be obtained...

  14. Active control of radiated sound power from a baffled, rectangular panel

    DEFF Research Database (Denmark)

    Mørkholt, Jakob

    1996-01-01

    Active control of radiated sound power from a rectangular baffled panel by minimisation of an accurate power estimate, using piezoceramic actuators, has been investigated. Computer simulations have shown that minimising a power estimate obtained by discretised integration of the far field intensity...... with an array of eleven microphones in front of the panel, is very close to minimising the actual radiated sound power. Practical experiments where such an array estimate has been minimised using the filtered X LMS algorithm have shown that substantial reductions of radiated sound power can be obtained over...

  15. Investigation of the effects of baffle orientation, baffle cut and fluid viscosity on shell side pressure drop and heat transfer coefficient in an e-type shell and tube heat exchanger

    OpenAIRE

    Mohammadi, Koorosh

    2011-01-01

    The commercial CFD code FLUENT is used to determine the effect of baffle orientation and baffle cut as well as viscosity of the working fluid on the shell-side heat transfer and pressure drop of a shell and tube heat exchanger. The shell and tube heat exchangers considered follow the TEMA standards. The investigation has been completed in three stages: 1. The shell and tube heat exchanger consists of 660 plain tubes with fixed outside diameter which are arranged in a triangular layout. Hor...

  16. Influence of scattered light on accurate CCD flat fielding --- necessity of modifying baffles of some existent reflectors

    Science.gov (United States)

    Yao, B. A.; Zhang, C. S.; Sheng, C. J.; Peng, Y. L.

    2005-07-01

    This paper is the continuation of paper [1]. In this paper we further show that the difference between twilight flat field and night sky exposure is mainly due to the existence of scattered light. Like Grundahl and Sorensen, we also made the pinhole images of the 1.56m at the Shanghai Observatory and the 63cm of the Nanjing University to show the existence of scattered light intuitively. Both the 1.56m and the 63cm reflectors have normal designed baffles. Therefore it is the common weakness of all standard designed reflectors having only two baffles mounted in front of the primary and secondary mirrors which are not enough to protect the CCD cameras from scattered light in getting accurate flat fields. It is of great importance to modify the primary mirror baffle of all similar reflectors in order to get more accurate flat fielding.

  17. Effect of Baffle on Gravity-Gradient-Excited Slosh Waves and Spacecraft Moment and Angular-Momentum Fluctuations in Microgravity

    Science.gov (United States)

    Hung, R. J.; Lee, C. C.

    1995-01-01

    The dynamical behavior of fluids affected by the asymmetric gravity gradient acceleration has been investigated. In particular, the effects of surface tension on partially filled rotating fluids applicable to a full-scale Gravity Probe-B Spacecraft dewar tank with and without baffles are studied. Results of slosh wave excitation along the liquid-vapor interface induced by gravity gradient acceleration indicate that the gravity gradient acceleration is equivalent to the combined effect of a twisting force and a torsional moment acting on the spacecraft. The results are clearly seen from one-up one-down and one-down one-up oscillations in the cross-section profiles of two bubbles in the vertical (r, z)-plane of the rotating dewar, and from the eccentric contour of the bubble rotating around the axis of the dewar in a horizontal (r, theta)-plane. As the viscous force, between liquid and solid interface, greatly contributes to the damping of slosh wave excitation, a rotating dewar with baffles provides more areas of liquid-solid interface than that of a rotating dewar without baffles. Results show that the damping effect provided by the baffles reduces the amplitude of slosh wave excitation and lowers the degree of asymmetry in liquid-vapor distribution. Fluctuations of angular momentum and fluid moment caused by the slosh wave excited by gravity gradient acceleration with and without baffle boards are also investigated. It is also shown that the damping effect provided by the baffles greatly reduces the amplitudes of angular momentum and fluid moment fluctuations.

  18. Inspection and replacement of baffle assembly screws inside American reactor vessels

    International Nuclear Information System (INIS)

    The baffle assembly inside the vessel of a 900 MWe reactor designed by Framatome, is made up of 44 plates fixed on 8 horizontal supports by a system of about 1000 screws. These plates undergo high neutron flux and the problem of screw cracking appeared at the end of the eighties in the first-generation reactors. The first operation on a large scale concerning the screws of a Westinghouse type reactor, was performed on the Tihange-1 power plant where Framatome controlled 960 screws and replaced 91. In 1997 as a consequence of the Belgian and French feedback experience, American plant operators launched a vast program of preventive actions: material analysis, inspection of baffle plate screws and replacement of defective screws. This program was held in cooperation with EPRI (electric power research institute) and under the control of NRC (nuclear regulatory commission). Framatome Technologies Inc (FTI) was in charge of the in-situ inspection and replacement of the screws. FTI designed special tools and equipment adapted to the 2-loop American reactors but the basis ideas were those applied on the Tihange reactor. The successful experience of FTI has allowed the firm to be commissioned for 6 2-loops American reactors. (A.C.)

  19. Pilot scale application of anaerobic baffled reactor for biologically enhanced primary treatment of raw municipal wastewater.

    Science.gov (United States)

    Hahn, Martha J; Figueroa, Linda A

    2015-12-15

    A four-cell anaerobic baffled reactor (ABR) was operated for two years treating raw municipal wastewater at ambient water and air temperatures of 12-23 °C and -10 to 35 °C, respectively. The 1000-L pilot reactor operated at a 12-h hydraulic residence time and was located in the Headworks building of the Plum Creek Water Reclamation Authority. The average influent was TSS = 510 ± 400 mg/L, BOD5 = 320 ± 80 mg/L and the average removal of TSS and BOD5 was 83 ± 10% and 47 ± 15%, respectively. The TSS and BOD removal exceeded that of conventional primary clarification, with no wasting of the settled solids over the two-years and stoichiometric production of methane. The estimated energy content of the biogas produced per unit volume of wastewater treated averaged 0.45 kWh/m(3). The TSS and total COD removal in the first cell averaged 75 ± 15% and 43 ± 14%, respectively, but methane production was only 20% of the total observed for the full ABR. The performance of the ABR relative to the extent of solids hydrolysis and methane production can be varied by the number of cells and hydraulic residence time. The anaerobic baffled reactor is an energy-positive technology that can be used for biologically enhanced primary treatment of raw municipal wastewater in cold climates. PMID:26414605

  20. Hydrodynamic characteristics of a four-compartment periodic anaerobic baffled reactor

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Periodic anaerobic baffled reactor (PABR) is a novel reactor based on the design concept of anaerobic baffled reactor (ABR).Residence time distribution (RTD) studies on both clean and working reactors at the same hydraulic residence time (HRT) of 2 d were carried out to investigate the dead spaces and mixing patterns in PABRs at different organic loading rates (OLRs) in various switching manners and frequencies. The results showed that the fraction of dead space in PABR was similar to that in ABR, which was low in comparison with other reactor designs. Dead space may be divided into two categories, hydraulic and biological. In RTD studies without biomass, the hydraulic dead space in the PABR run in an "every second" switching manner with T = 2 d was the lowest whereas that in the PABR run in a T = ∞ (ABR) switching manner was the highest. The same trend was obtained with the total dead space in RTD studies with biomass no matter what the OLR was. Biological dead space was the major contributor to dead space but affected decreasingly at higher OLR whichever switching manner the PABR run in. The flow patterns within the PABRs were intermediate between plug-flow and perfectly mixed under all the conditions tested.

  1. Valuation and modelling of helminth eggs removal in baffled and unbaffled ponds treating anaerobic effluent.

    Science.gov (United States)

    von Sperling, M; Chernicharo, C A L; Soares, A M E; Zerbini, A M

    2003-01-01

    The paper evaluates and models helminth eggs removal in a combined UASB (Upflow Anaerobic Sludge Blanket) reactor-maturation pond system (one baffled and one unbaffled pond in parallel). The system is comprised of demonstration-scale units, treating actual domestic sewage from Itabira city, Brazil. The paper addresses the following points: (i) removal of helminth eggs from the wastewater in the system; (ii) comparison of the observed removal efficiency with the predictions using the Ayres et al. model; (iii) accumulation of helminth eggs in the sludge; (iv) viability of eggs in the sludge; (v) distribution of helminth species in the sludge. The removal efficiency of helminth eggs from the wastewater in both ponds was 100% for most of the time (0 counts in the final effluent). The predictions of helminth eggs removal according to the Ayres et al. model can be considered reasonable. After one year of operation, 88% of the eggs in the sludge remained viable. Helminth eggs counts in the sludge tended to decrease along the baffled pond length (from first to last compartment). The prevailing helminth species found in the sludge from both ponds was Ascaris lumbricoides. PMID:14510201

  2. 3D numerical simulation and structural optimization of the rod baffle heat exchanger

    Institute of Scientific and Technical Information of China (English)

    YAN Liang-wen; PAN Lei; KAN Shu-lin

    2009-01-01

    Because of the complexities of fluid dynamics equations and the structure of heat exchangers, few theoretical solutions have been acquired to specify the shell side characteristics of the rod baffle heat exchanger (RBHE). Based on the platform of PHEONICS version 3.5.1, a three-dimensionai numerical method for predicting the turbulent fluid flow behavior in the shell side of the rod baffle heat exchangers is developed in this paper. With this method, modeling of the tube bundle is carried out based on the porous media concept using volumetric porosities and applicable flow resistance correlations. Turbulence effects are modeled using a standard κ-ε model. It is shown that the simulation results and experimental results are in good agreement in the shell side. The maximum absolute deviation value of pressure drops is less than 5%, and that of the heat transfer coefficients is less than 8%. Furthermore, the numerical model is used to optimize the structure of the RBHE and improves its performance.

  3. Assessment of Interaction between Baffles and Impeller Blades in Stirred Tanks

    Directory of Open Access Journals (Sweden)

    Gradov Dmitry

    2016-01-01

    Full Text Available In this work, the sensitivity of hydrodynamics on stirrer position is considered when the Multiple Reference Frame technique is applied to simulate mixing tanks of single and multiphase systems. A typical stirred reactor equipped with four baffles and a six blade Rushton turbine was chosen for the studies. Operational conditions of constant speed (5 rps and 2.653·10−4 m/s gas superficial velocity with single bubble size (1 mm were set. The reactor was simulated in Fluent 15 with four different impeller blade positions. The results were averaged and validated against experimental data produced by Particle Image Velocimetry. The comparison was made using profiles of velocity components along the sampled lines representing various zones of the vessel. The impeller angle of rotation with respect to baffle position was found to contribute to the overall reactor hydrodynamics especially for multiphase systems. Averaging of the simulation results was found to improve the accuracy of the simulated mixing hydrodynamics.

  4. Effect of Segmental Baffles at Different Orientation on the Performances of Single Pass Shell and Tube Heat Exchanger

    OpenAIRE

    Neeraj kumar; Dr. Pradeep kumar Jhinge

    2014-01-01

    In present work, experimentation of single pass, counter flow shell and tube heat exchanger containing segmental baffles at different orientations has been conducted to calculate some parameters (heat transfer rate and pressure drop) at different Reynolds number in laminar flow. In the present work, an attempt has been made to study the effect of increase in Reynolds number at different angular orientation “θ” of the baffles. The range of “θ” vary from 0° to 45° (i.e 0°, 15°, 30° and 45°) and...

  5. Shell side numerical analysis of a shell and tube heat exchanger considering the effects of baffle inclination angle on fluid flow using CFD

    Directory of Open Access Journals (Sweden)

    Raj Karuppa Thundil R.

    2012-01-01

    Full Text Available In this present study, attempts were made to investigate the impacts of various baffle inclination angles on fluid flow and the heat transfer characteristics of a shell-and-tube heat exchanger for three different baffle inclination angles namely 0°,10° and 20°. The simulation results for various shell and tube heat exchangers, one with segmental baffles perpendicular to fluid flow and two with segmental baffles inclined to the direction of fluid flow are compared for their performance. The shell side design has been investigated numerically by modeling a small shell-and-tube heat exchanger. The study is concerned with a single shell and single side pass parallel flow heat exchanger. The flow and temperature fields inside the shell are studied using non-commercial CFD software tool ANSYS CFX 12.1. For a given baffle cut of 36 %, the heat exchanger performance is investigated by varying mass flow rate and baffle inclination angle. From the CFD simulation results, the shell side outlet temperature, pressure drop, recirculation near the baffles, optimal mass flow rate and the optimum baffle inclination angle for the given heat exchanger geometry are determined.

  6. Metallurgical examinations update of baffle bolts removed from operating French PWR. Microstructural investigations of a baffle to former bolt located on a high level of the internal structures

    International Nuclear Information System (INIS)

    This paper presents the microstructural investigations conducted on a cracked baffle to former bolt extracted from an upper former level of the internal structures of a French Pressurized Water Reactor (PWR). Extensive microstructural investigations using Light Microscopy, Scanning Electron Microscopy and Transmission Electron Microscopy (TEM) have been conducted to understand the degradation mechanisms of this bolt. TEM investigations have revealed neutron irradiation damage in the microstructure of the bolt such as Frank loops and cavities and/or bubbles. The number of features per unit volume as a function of diameter was determined in the head and in the shank of the bolt. The obtained results are relatively similar to those obtained for other damaged bolts extracted from PWR-type reactors and irradiated in similar conditions (dose and temperature). The irradiation damage has induced an evolution of the mechanical properties (hardening of the material), as revealed by the hardness measurements along the bolt, with a higher average value in the head (400 HV), compared to the shank (15 mm under the head), about 340 HV. The metallurgical investigations have confirmed that this bolt was damaged by Irradiation Assisted Stress Corrosion Cracking (IASCC)

  7. On the capacity of continuous powder classification in a gas-fluidized bed with horizontal sieve-like baffles

    NARCIS (Netherlands)

    Bosma, JC; Hoffmann, AC

    2003-01-01

    Using horizontal sieve-like baffles in fluidized beds increases the tendency of particle mixtures to segregate. This may be utilized to devise a new process for dry classification of particles according to size or density. To predict the capacity of a continuous classification process based on this

  8. An ALE finite element method for baffled fuel container in yawing motion

    International Nuclear Information System (INIS)

    A computational analysis of engineering problems with moving domain or/and boundary according to either Lagrangian or Eulerian approach may encounter inherent numerical difficulties, the extreme mesh distortion in the former and the material boundary indistinctness in the latter. In order to overcome such defects in classical numerical approaches, the ALE (Arbitrary Lagrangian Eulerian) method is widely being adopted in which the finite element mesh moves with arbitrary velocity. This paper is concerned with the ALE finite element formulation, aiming at the dynamic response analysis of baffled fuel-storage container in yawing motion, for which the coupled time integration scheme, the remeshing and smoothing algorithm and the mesh velocity determination are addressed. Numerical simulation illustrating theoretical works is also presented

  9. Modeling the performance of an anaerobic baffled reactor with the variation of hydraulic retention time.

    Science.gov (United States)

    Li, Jianzheng; Shi, En; Antwi, Philip; Leu, Shao-Yuan

    2016-08-01

    Anaerobic baffled reactors (ABRs) have been widely used in engineering but very few models have been developed to simulate its performance. Based on the integration of biomass retention and liquid-gas mass transfer of biogas into the biochemical process derived in the International Water Association (IWA) Anaerobic Digestion Model No.1 (ADM1), a mathematical model was developed to predict volatile fatty acids (VFAs), chemical oxygen demand (CODCr) and biogas in a 4-compartment ABR operated with variable hydraulic retention time (HRT). The model was calibrated and validated with the experimental data obtained from the reactor when the HRT decreased from 2.0 to 1.0d by stages. It was found that the predicted VFAs, CODCr and biogas agreed well with the experimental data. Consequently, the developed model was a reliable tool to enhance the understanding among the mechanisms of the anaerobic digestion in ABRs, as well as to reactor's designing and operation. PMID:27174615

  10. Acoustic centering of a baffled piston in the circular harmonics domain.

    Science.gov (United States)

    Shabtai, Noam R; Vorländer, Michael

    2016-03-01

    The acoustic center of radiating sources is relevant to the modeling of radiation patterns and to their effective implementation in acoustical applications and computer models. However, the acoustic center of the sources may not be unique and therefore should be defined. Previously studied source centering algorithms used analytic methods for specific acoustic models, or applied post processing methods on a recorded sound from an acoustic source that was surrounded by a spherical microphone array. This work performs an acoustic centering of a radiating circular baffled piston that is formed by an open termination of a circular pipe. A signal processing based acoustic centering algorithm is redefined for this case and is shown to be correlated with the effective length of the pipe. PMID:27036274

  11. Design of an Electrical Impedance Tomography Sensor for Flow Measurement in an Oscillatory Baffled Reactor

    Science.gov (United States)

    Vilar, G.; Williams, R. A.; Wang, M.

    2007-06-01

    In this paper, a new application of electrical impedance tomography (EIT) for an advanced on-line measurement is presented. This application involves the design, manufacture and adaptation of an EIT sensor for the measurement in an oscillatory baffled reactor (OBR). The main goal is to develop of a novel measurement and modeling method for control of the OBR. The reactor itself enables the production of water-in-oil/oil-in water emulsions along with the use of chemical reagents for a variety of manufacturing processes. Use of electrical tomography facilitates detailed measurement of the concentration and flow of components in the reactor. The paper reports on design philosophy of the EIT for this application that has not, to our knowledge, been reported previously.

  12. Swirl and buoyancy effects on mixing performance of baffle-plate-type miniature confined multijet

    Energy Technology Data Exchange (ETDEWEB)

    Tatsumi, Kazuya, E-mail: tatsumi@mbox.kudpc.kyoto-u.ac.j [Department of Mechanical Engineering and Science, Kyoto University, Kyoto 606-8501 (Japan); Tanaka, Miyako [Department of Mechanical Engineering, Osaka Prefecture University, Osaka 599-8531 (Japan); Woodfield, Peter L. [Research Center for Hydrogen Industrial Use and Storage, National Institute of Advanced Industrial Science and Technology, Fukuoka 819-0395 (Japan); Nakabe, Kazuyoshi [Department of Mechanical Engineering and Science, Kyoto University, Kyoto 606-8501 (Japan)

    2010-02-15

    A three-dimensional numerical simulation was carried out to examine the effects of swirl and buoyancy-driven flows on the mixing performance of a baffle-plate-type miniature confined multijet. Swirl flow was produced by inclining the jet nozzles surrounding the central jet in the circumferential direction. The results obtained were compared with those of the non-swirl case. The swirl flow interrupted the radial secondary flow generated in the region adjacent to the baffle plate. This interruption decreased the size of the reverse flow region, resulting in a deterioration of the mixing performance. This behavior was more noticeable in the case of a large swirl number. During the study of the buoyancy effect, the operating direction of the gravitational force was changed with respect to the central axis of the mixing chamber, i.e. the attack angles were 0 deg., 90 deg. and 180 deg. The buoyancy effect was negligible when the operating direction was parallel to the chamber axis. However, when the attack angle was 90 deg., asymmetric distributions of mixture fraction and flow velocity were obtained, and the mixing performance was found to be poor. In the swirl-accompanied cases, the effect of buoyancy force was apparent even when the operating direction was parallel to the central axis. The swirl flow, which reduced the secondary flow effects of the reverse and radial flows, tended to increase the effect of the buoyancy force on the multijet flow. On the other hand, the swirl flow prevented the mixture fraction distribution to be asymmetric in the case of buoyancy with 90 deg. attack angle. These tendencies became more conspicuous for flows with stronger swirl.

  13. Radiative divertor and SOL experiments in open and baffled divertors on DIII-D

    International Nuclear Information System (INIS)

    We present recent progress towards an understanding of the physical processes in the divertor and scrape-off-layer (SOL) plasmas in DIII-D. This has been made possible by a combination of new diagnostics, improved computational models, and changes in divertor geometry. We have focused primarily on ELMing H-mode discharges. The physics of Partially Detached Divertor (PDD) plasmas, with divertor heat flux reduction by divertor radiation enhancement using D2 puffing, has been studied in 2-D, and a model of the heat and particle transport has been developed that includes conduction, convection, ionization, recombination, and flows. Plasma and impurity particle flows have been measured with Mach probes and spectroscopy and these flows have been compared with the UEDGE model. The model now includes self-consistent calculations of carbon impurities. Impurity radiation has been increased in the divertor and SOL with 'puff and pump' techniques using SOL D2 puffing, divertor cryopumping, and argon puffing. The important physical processes in plasma-wall interactions have been examined with a DiMES probe, plasma characterization near the divertor plate, and the REDEP code. Experiments comparing single-null (SN) plasma operation in baffled and open divertors have demonstrated a change in the edge plasma profiles. These results are consistent with a reduction in the core ionization source calculated with UEDGE. Divertor particle control in ELMing H-mode with pumping and baffling has resulted in reduction in H-mode core densities to ne/ngw=0.25. Divertor particle exhaust and heat flux has been studied as the plasma shape was varied from a lower SN, to a balanced double null (DN), and finally to an upper SN. (author)

  14. Experimental study on the disinfection efficiencies of a continuous-flow ultrasound/ultraviolet baffled reactor.

    Science.gov (United States)

    Zhou, Xiaoqin; Guo, Hao; Li, Zifu; Zhao, Junyuan; Yun, Yupan

    2015-11-01

    A self-designed continuous-flow ultrasound/ultraviolet (US/UV) baffled reactor was tested in this work, and the disinfection efficiency of secondary effluent from a wastewater treatment plant (WWTP) was investigated in terms of the different locations of ultrasonic transducers inside the reactor under similar input power densities and specific energy consumptions. Results demonstrated that the two-stage simultaneous US/UV irradiation in both chambers 2 and 3 at a flow rate of 1200 L/h performed excellent disinfection efficiency. It achieved an average feacal coliforms concentration of 201±78 colony forming unit (CFU)/L in the effluent and an average of (4.24±0.26) log10 reduction. Thereafter, 8 days of continuous operation was performed under such a condition. A total of 31 samples were taken, and all the samples were analyzed in triplicate for feacal coliforms analysis. Experimental results showed that feacal coliforms concentrations remained at about 347±174 CFU/L under the selected optimum disinfection condition, even if the influent concentrations fluctuated from 3.97×10(5) to 3.57×10(6) CFU/L. This finding implied that all effluents of continuous-flow-baffled-reactor with simultaneous US/UV disinfection could meet the requirements of the discharge standard of pollutants for municipal WWTP (GB 18918-2002) Class 1-A (1000 CFU/L) with a specific energy consumption of 0.219 kWh/m(3). Therefore, the US/UV disinfection process has great potential for practical applications. PMID:26186823

  15. FLOW AND HEAT TRANSFER CHARACTERISTICS IN SHELL SIDE OF SHELL-AND-TUBE HEAT EXCHANGERS WITH SEPARATED BAFFLES PARALLEL TO SEGMENTAL BAFFLES%平行流分隔板管壳式换热器壳侧流场与传热性能

    Institute of Scientific and Technical Information of China (English)

    王杨君; 邓先和; 陈颖; 李志武

    2004-01-01

    A shell-and-tube heat exchanger with separated baffles parallel to segmental baffles was proposed, and an investigation on velocity distribution, heat transfer and flow resistance characteristics in the shell side of the proposed heat exchanger and traditional single segmental baffled shell-and-tube heat exchanger was reported. After the experiment, the empirical relations of heat transfer and flow resistance were obtained. The heat transfer enhancement comprehensive evaluation factor η was in the range from 1.15 to 1.20 for Reynolds number (1.25×104-3.35×104). The resuhs indicated that flow field uniformization was enhanced in the shell side of shell-and-tube heat exchangers by two separated baffles parallel to segmental baffles and the performance of heat transfer was improved by controlling the dimension of vortices. The results could be used as reference in further research.

  16. Validation of Slosh Model Parameters and Anti-Slosh Baffle Designs of Propellant Tanks by Using Lateral Slosh Testing

    Science.gov (United States)

    Perez, Jose G.; Parks, Russel A.; Lazor, Daniel R.

    2012-01-01

    The slosh dynamics of propellant tanks can be represented by an equivalent pendulum-mass mechanical model. The parameters of this equivalent model, identified as slosh model parameters, are slosh mass, slosh mass center of gravity, slosh frequency, and smooth-wall damping. They can be obtained by both analysis and testing for discrete fill heights. Anti-slosh baffles are usually needed in propellant tanks to control the movement of the fluid inside the tank. Lateral slosh testing, involving both random testing and free-decay testing, are performed to validate the slosh model parameters and the damping added to the fluid by the anti-slosh baffles. Traditional modal analysis procedures are used to extract the parameters from the experimental data. Test setup of sub-scale test articles of cylindrical and spherical shapes will be described. A comparison between experimental results and analysis will be presented.

  17. Light/dark cycle of microalgae cells in raceway ponds: Effects of paddlewheel rotational speeds and baffles installation.

    Science.gov (United States)

    Chen, Zhijie; Zhang, Xinru; Jiang, Zeyi; Chen, Xuehui; He, Hongzhou; Zhang, Xinxin

    2016-11-01

    The aim of this work was to study the light/dark (L/D) cycle in raceway ponds (RWPs) by the computational fluid dynamics (CFD) method via determining the hydrodynamics of culture media and cell trajectories. The effects of paddlewheel rotational speed and flow-deflector baffles installation on the L/D cycle were analyzed. The results indicated that, the L/D cycles of microalgae cells decreased with the increase of the paddlewheel rotational speeds, when the paddlewheel rotational speeds ranged from 5 to 12rpm. In addition, the installation of the flow-deflector baffles in RWPs can greatly increase the light time and the ratio of light time to L/D cycle for microalgae cells. The study provided an effective method to characterize the L/D cycles in RWPs, and may have important implications for designing the effective large-scale microalgae culture system. PMID:27504995

  18. Optimizing gas transfer to improve growth rate of Haematococcus pluvialis in a raceway pond with chute and oscillating baffles.

    Science.gov (United States)

    Yang, Zongbo; Cheng, Jun; Li, Ke; Zhou, Junhu; Cen, Kefa

    2016-08-01

    Up-down chute and oscillating (UCO) baffles were used to generate vortex and oscillating flow field to improve growth rate of Haematococcus pluvialis in a raceway pond. Effects of gas flow rate, solution velocity, and solution depth on solution mass transfer coefficient and mixing time were evaluated using online pH and dissolved oxygen probes. Mass transfer coefficient increased by 1.3 times and mixing time decreased by 33% when UCO baffles were used in the H. pluvialis solution, resulting in an 18% increase in biomass yield with 2% CO2. The H. pluvialis biomass yield further increased to 1.5g/L, and astaxanthin composition accumulated to 29.7mg/L under relatively higher light intensity and salinity. PMID:27140817

  19. Coliform and helminth eggs removal in a combined UASB reactor-baffled pond system in Brazil: performance evaluation and mathematical modelling.

    Science.gov (United States)

    von Sperling, M; Chernicharo, C A L; Soares, A M E; Zerbini, A M

    2002-01-01

    The paper presents the monitoring results of a pilot UASB reactor followed by a baffled polishing pond treating domestic sewage in Brazil. Longitudinal profiles of E coli and helminth eggs along the baffled pond have been undertaken. The experimental results have been compared with von Sperling's model for coliform removal and Ayres' model for helminth eggs removal, and the fitting was considered satisfactory in both cases. The distribution of the helminth species along the system is also presented. PMID:12188551

  20. Experimental and Computational Investigations of Baffle Location Effect on the Performance of Oil and Water Separator Tanks

    OpenAIRE

    Abdullah Rozi; Hussein Haitham A.; Md Said Md Azlin

    2016-01-01

    Gravity separator tanks are used to separate oil from water in treatment units. Achieving the best flow uniformity in a separator tank will improve the maximum removal efficiency of oil globules from water. In this study, the effect on hydraulic performance of different baffle structure positions inside a tank was investigated. Experimental data and 2D computation fluid dynamics were used for analysis. In the numerical model, two-phase flow (drift flux model) was used to validate one-phase fl...

  1. LIQUID FLOW IN IMPELLER SWEPT REGIONS OF BAFFLED AND UNBAFFLED VESSELS WITH A TURBINE-TYPE AGITATOR

    OpenAIRE

    Yoshida, M; H. Ebina,; H. Shirosaki; Ishioka, K.; K. Oiso

    2015-01-01

    Abstract Liquid flow in the impeller swept region of vessels with a turbine-type agitator was examined for the flow path between the neighboring blades of the rotating impeller. Visualization of the flow and its measurement were done using particle tracking velocimetry with a camera rotating along with the impeller. Internal liquid flow of the impeller differed when the velocity magnitudes were compared in conditions with and without baffles. Larger circumferential and radial velocities were ...

  2. Studi Numerik Pengaruh Baffle Inclination Pada Alat Penukar Kalor Tipe Shell And Tube Terhadap Aliran Fluida Dan Perpindahan Panas

    OpenAIRE

    Rezky Fadil Arnaw; Bambang Arip Dwiyantoro

    2014-01-01

    Heat exchanger atau alat penukar kalor merupakan suatu peralatan yang digunakan untuk memindahkan sejumlah energi dalam bentuk panas dari satu fluida ke fluida yang lain. Perpindahan panas tersebut terjadi dari suatu fluida yang suhunya lebih tinggi ke fluida lain yang suhunya lebih rendah. Pada tugas akhir ini akan dilakukan penelitian tentang pengaruh baffle inclination terhadap aliran fluida dan perpindahan panas pada alat penukar kalor tipe shell and tube. Dalam penelitian ini akan dilaku...

  3. DESIGN OF HELICAL BAFFLE IN SHELL AND TUBE HEAT EXCHANGER WITH USING COPPER OXIDE(II) NANO PARTICLE

    OpenAIRE

    R.N.S.V.Ramakanth

    2015-01-01

    Heat exchangers being one of the most important heat & mass transfer apparatus in industries like oil refining, chemical engineering, electric power generation etc. are designed with preciseness for optimum performance and lo ng service life. This paper experimental inve stgation of helical baffle heat exchanger using the Kern method with varied shell side flow rates. This is a proven method used in counter flow design of Hea...

  4. Experimental investigation on a semi-circular trough-absorber solar still with baffles for fresh water production

    International Nuclear Information System (INIS)

    Highlights: • Experiments are carried out to analyze the performance. • Baffles are placed in the absorber to increase the residence time of water with solar intensity. • Yield of fresh water from present solar still is 16.66% more than a conventional solar still. • Payback period of the present model is quicker. - Abstract: The main objective of this research is to increase the contact time of water in the basin to enhance yield of fresh water by using a semicircular absorber solar still with baffles. An experimental as well as theoretical investigation is carried out. The productivity and efficiency of present still are analyzed with the influence of the number baffles and the water flow rate. A good agreement between the experimental and theoretical results is observed. The results indicate that, the daily yield of present solar still is higher than that for conventional still approximately by 16.66%. The outlet water temperature present solar still is high subsequently, it can be coupled with multi-state of solar stills to increase productivity. Therefore, the present solar still can be sufficiently extended for other continuous solar desalination systems. Economic analysis concluded that, the payback period of the present model solar still is quicker while comparing it with other solar still

  5. Prediction of void swelling in the baffle ring of WWER-1000 reactors for service life of 30-60 years

    Science.gov (United States)

    Kalchenko, A. S.; Bryk, V. V.; Lazarev, N. P.; Voyevodin, V. N.; Garner, F. A.

    2013-06-01

    Major internal components of WWER-type nuclear reactors are made from annealed 18Cr10NiTi steel, a close analog to AISI 321. Void swelling of the baffle ring in particular could be a major factor limiting operation of the reactor beyond the current 30 years license. A predictive swelling equation is needed to forecast the spatial variation of swelling so as to identify those areas requiring additional attention. Available data on the swelling of this steel arising from irradiation in the BOR-60 fast reactor was combined with data from a heavy ion accelerator at higher displacement rates to formulate a predictive equation of swelling for the WWER-relevant range of temperature, irradiation dose and dose rates. This equation was used to estimate the swelling distribution over a cross-section of the baffle ring of a WWER reactor during a service life up to 60 years, reaching a local maximum of ˜30% swelling. It was shown that void swelling extends over a larger portion of the baffle ring than previously expected and exhibits a very complex and irregular distribution in response to complex distributions of temperature and dpa rate. Most importantly, as operation is extended beyond 30 years several areas of the ring may experience swelling in excess of 10% where void-induced embrittlement begins and one area may exceed 20% after 45 years, a swelling level where a complete loss of ductility is known to occur.

  6. Enhancement of Performance of Shell and Tube Heat Exchanger Using Pertinent Leakage Flow Between Baffle and Tube Bundles

    Energy Technology Data Exchange (ETDEWEB)

    Hap, Nguyen Van; Lee, Geun Sik [Ulsan University, Ulsan (Korea, Republic of)

    2015-03-15

    In this study, the effects of the leakage flow between the baffle and tube bundles on the performance of a shell and tube heat exchanger (STHE) were examined using the commercial software ANSYS FLUENT v.14. A computational fluid dynamics model was developed for a small STHE with five different cases for the ratio of the leakage cross-sectional area to the baffle cross-sectional area, ranging from 0 to 40%, in order to determine the optimum leakage flow corresponding to the maximum outlet temperature. Using fixed tube wall and inlet temperatures for the shell side of the STHE, the flow and temperature fields were calculated by increasing the Reynolds number from 4952 to 14858. The present results showed that the outlet temperature, pressure drop, and heat transfer coefficient were strongly affected by the leakage flow, as well as the Reynolds number. In contrast with a previous researchers finding that the leakage flow led to simultaneous decreases in the pressure drop and heat transfer rate, the present study found that the pertinent leakage flow provided momentum in the recirculation zone near the baffle plate and thus led to the maximum outlet temperature, a small pressure drop, and the highest heat transfer rate. The optimum leakage flow was shown in the case with a ratio of 20% among the five different cases.

  7. CFD analysis of heat transfer and friction factor charaterstics in a circular tube fitted with horizontal baffles twisted tape inserts

    Science.gov (United States)

    Salman, Sami D.; Kadhum, Abdul Amir H.; Takriff, Mohd S.; Bakar Mohamad, Abu

    2013-12-01

    Swirl/vortex flow generator is an important form of passive augmentation techniques. Twisted-tape is one of the most important members of this form which is used extensively in different type heat exchangers. This paper reports the effect of twisted tape inserts on heat transfer and friction factor characteristics in circular tube under constant heat flux and laminar flow conditions using CFD simulation. Plain twisted tape inserts with twist ratios (y = 2.93, 3.91) and baffled twisted tape inserts with twist ratio (y = 2.93) have been used for the simulation using Fluent version 6.3.26. The results obtained by simulation matched with the literature correlations for plain tube with the discrepancy of less than ± 8% for Nusselt number and ± 6.25% for friction factor. The results have also revealed that the heat transfer in term of the Nusselt number enhanced with increases of Reynolds number, decreases of twist ratio and baffle insert. Among the various twist ratios, the twisted tape with twist ratio of y=2.93 and baffle is offered a maximum heat transfer enhancement.

  8. Analysis of the Effect of Variation of Baffle Height on the Liquid Sloshing In the Tank with CFD Approach

    Directory of Open Access Journals (Sweden)

    Suresh Patil. G. L,

    2015-12-01

    Full Text Available Sloshing is a common physical phenomenon which occurs in moving tanks with contained liquid masses, such as liquid cargo carriers, rockets, aircrafts, and the seismically excited storage tanks, dams, reactors, and nuclear vessels. The sloshing frequencies of contained liquid are essential in the analysis and design of the liquid tanks and the associated structures. In this paper an attempt made with the VOF model and considered with immiscible fluids by solving a single set of momentum equations and tracking the volume fraction of each of the fluids throughout the domain. Further investigated the effect of the vertical baffle heights on the liquid sloshing in a three-dimensional (3D rectangular tank. studied dynamic analysis of sloshing in rectangular tanks with multiple vertical baffles. ANSYS-CFX software was used to study this dynamic analysis subjected to random excitations including earthquake induced motions. analytically estimated hydrodynamic damping ratio for liquid sloshing phenomenon in a partially filled rectangular tank for baffles. They used the velocity potential formulation and linear wave theory for analytic calculations.

  9. Enhancement of Performance of Shell and Tube Heat Exchanger Using Pertinent Leakage Flow Between Baffle and Tube Bundles

    International Nuclear Information System (INIS)

    In this study, the effects of the leakage flow between the baffle and tube bundles on the performance of a shell and tube heat exchanger (STHE) were examined using the commercial software ANSYS FLUENT v.14. A computational fluid dynamics model was developed for a small STHE with five different cases for the ratio of the leakage cross-sectional area to the baffle cross-sectional area, ranging from 0 to 40%, in order to determine the optimum leakage flow corresponding to the maximum outlet temperature. Using fixed tube wall and inlet temperatures for the shell side of the STHE, the flow and temperature fields were calculated by increasing the Reynolds number from 4952 to 14858. The present results showed that the outlet temperature, pressure drop, and heat transfer coefficient were strongly affected by the leakage flow, as well as the Reynolds number. In contrast with a previous researchers finding that the leakage flow led to simultaneous decreases in the pressure drop and heat transfer rate, the present study found that the pertinent leakage flow provided momentum in the recirculation zone near the baffle plate and thus led to the maximum outlet temperature, a small pressure drop, and the highest heat transfer rate. The optimum leakage flow was shown in the case with a ratio of 20% among the five different cases.

  10. CFD analysis of heat transfer and friction factor charaterstics in a circular tube fitted with horizontal baffles twisted tape inserts

    International Nuclear Information System (INIS)

    Swirl/vortex flow generator is an important form of passive augmentation techniques. Twisted-tape is one of the most important members of this form which is used extensively in different type heat exchangers. This paper reports the effect of twisted tape inserts on heat transfer and friction factor characteristics in circular tube under constant heat flux and laminar flow conditions using CFD simulation. Plain twisted tape inserts with twist ratios (y = 2.93, 3.91) and baffled twisted tape inserts with twist ratio (y = 2.93) have been used for the simulation using Fluent version 6.3.26. The results obtained by simulation matched with the literature correlations for plain tube with the discrepancy of less than ± 8% for Nusselt number and ± 6.25% for friction factor. The results have also revealed that the heat transfer in term of the Nusselt number enhanced with increases of Reynolds number, decreases of twist ratio and baffle insert. Among the various twist ratios, the twisted tape with twist ratio of y=2.93 and baffle is offered a maximum heat transfer enhancement

  11. Experimental study of hydrodynamic and operation start of a baffled anaerobic reactor treating sewage

    Directory of Open Access Journals (Sweden)

    Ana Carolina Silveira Perico

    2009-12-01

    Full Text Available It is important to provide individual sanitation systems for sewage peri-urban communities or rural areas to minimize impacts on the environment and human health caused by sewage discharge in natura into water resources. In this context, the anaerobic digestion of effluent has been one of the main considered technologies due to easy implementation, material minimization and reduction in waste production. The objective of this work was to study a Baffled Anaerobic Reactor (BAR including its hydrodynamic characteristics, percentile of inoculum to be applied and reactor operation start. It was concluded that the flow is dispersed with 3.84% of dead spaces and that 20% of the cow manure provided best results; however, due to the high fiber content of the manure, its use is not recommended as inoculum. The BAR system, composed of four chambers, presented good performance for sewage treatment of a rural community in terms of organic substance removal (COD, turbidity and solids meeting effluent disposal standards of these parameters considering the Federal and Minas Gerais State legislation, in Brazil, even in a transient phase of operation, at temperatures below 20°C. However, the effluents from the BAR can’t be released into water bodies without other parameters such as nitrogen, phosphorus, fecal coliforms, and others are investigated to be conforming to those standards.

  12. Effect of ramp length and slope on the efficacy of a baffled fish pass.

    Science.gov (United States)

    Baker, C F

    2014-02-01

    This study evaluated the effect of ramp length and slope on fish passage over baffled ramps with 15° and 30° gradients. Three fish species indigenous to New Zealand were tested: the redfin bully Gobiomorphus huttoni, the common bully Gobiomorphus cotidianus and the inanga Galaxias maculatus with ramp lengths of 3, 4·5 and 6 m. As slope and ramp length increased, passage success rate decreased for G. maculatus and G. cotidianus. At a slope of 15°, both G. maculatus and G. cotidianus could pass all ramp lengths tested with the highest success rate on the 3 m ramp. As the gradient increased to 30°, G. maculatus could only pass the 3 m ramp, and G. cotidianus were incapable of passing any ramp. Gobiomorphus huttoni were the only test species capable of climbing the wetted margin of the ramps. Increasing ramp slope significantly reduced passage success for G. huttoni, but ramp length, up to the maximum used in this study, had no significant influence on successful passage. PMID:24417428

  13. Removal of Organic Load in Communal Wastewater by using the Six Stage Anaerobic Baffle Reactor (ABR

    Directory of Open Access Journals (Sweden)

    Trilita Minarni Nur

    2016-01-01

    Full Text Available The reduction of water quality in the urban drainage is a crucial problem to overcome because it can affect the health of community. This fact encouraged the researcher to conduct the research in efforts to increase the water quality in the drainage. One of the solutions to increase the water quality in the drainage is that the domestic wastewater must be treated at first before it is flown through the drainage. Furthermore, the wastewater treatment was conducted by employing the communal wastewater processor. The research was aimed at knowing the capability of Anaerobic Baffle Reactor with the six-stage design in communal wastewater processor in efforts to decrease the organic load. This research was conducted in a laboratory scale. Meanwhile, the sort of waste used was taken from the domestic wastewater of settlement by varying its discharge and waste concentration flowing into the waste processor. Finally, the research result showed that the reduction of organic load of COD was reaching up to 92%, N was 85% and Phosphate was 50%.

  14. Numerical simulations of dynamic coupling between shallow-water sloshing and horizontal vessel motion with baffles

    Science.gov (United States)

    Alemi Ardakani, H.; Turner, M. R.

    2016-06-01

    The coupled motion between shallow water sloshing in a moving vessel with baffles and the vessel dynamics is considered. Here the vessel dynamics is restricted to horizontal motion such as in tuned liquid dampers. It was shown by (Turner et al 2013 Phys. Fluids 25 112102) that partitioning a moving vessel into n separate compartments leads to an interesting dynamical behaviour of the system. Also, under particular input parameter values an internal (n+1)-fold 1:\\cdots :1 resonance can be generated, where the frequency of the sloshing fluid in each compartment is equal, and equal to the frequency of the vessel itself. Here the form of the sloshing eigenmodes at this resonance are derived in the shallow-water limit. Using the Lagrangian formulation of the problem, an efficient numerical algorithm is implemented to solve the fully nonlinear system of equations based on the implicit midpoint rule. This algorithm is simple, fast and maintains the energy partition between the vessel and the fluid over long times. In this work numerical results are presented for dynamical vessel/sloshing motion attached to a nonlinear spring.

  15. Biologic treatment of wastewater from cassava flour production using vertical anaerobic baffled reactor (VABR

    Directory of Open Access Journals (Sweden)

    Gleyce T Correia

    2008-08-01

    Full Text Available The estimate cassava production in Brazil in 2007 was of 25 million tons (= 15% of the world production and most of it is used in the production of flour. During its processing, waste that can cause environmental inequality is generated, if discharged inappropriately. One of the liquid waste generated, manipueira, is characterized by its high level of organic matter. The anaerobic treatment that uses a vertical anaerobic baffled reactor (VABR inoculated with granulated sludge, is one of the ways of treating this effluent. The anaerobic biodigestion phases are separated in this kind of reactor, allowing greater stability and resistance to load shocks. The VABR was built with a width/height rate of 1:2. The pH, acidity, alkalinity, turbidity and COD removal were analyzed in 6 different regions of the reactor, which was operated with an increasing feeding from ? 2000 to ? 10000 mg COD L?¹ and HRT between 6.0 and 2.5 days. The VABR showed decreasing acidity and turbidity, an increase in alkalinity and pH, and 96% efficiency in COD removal with 3-day HRT and feeding of 3800 mg COD L?¹.

  16. Velocity profiles in a baffled vessel with single or double pitched-blade turbines

    Energy Technology Data Exchange (ETDEWEB)

    Armenante, P.M.; Chou, C.C. [New Jersey Inst. of Tech., Newark, NJ (United States). Dept. of Chemical Engineering, Chemistry, and Environmental Science

    1996-01-01

    A laser-Doppler velocimetry (LDV) apparatus and a computational fluid dynamic (CFD) software package (FLUENT) were used to experimentally determine and numerically predict the velocities in a baffled vessel agitated by one or two 45{degree} pitched-blade turbines. The flow characteristics in the impeller regions were measured by LDV and used as boundary conditions in the numerical computations. Turbulence effects were simulated using either the {kappa}-{epsilon} model or algebraic stress model (ASM). The CFD predictions were compared to the LDV measurements in terms of average velocities in all three directions as well as turbulent kinetic energies. Predictions based on ASM were typically in closer agreement with the experimental data than those based on the {kappa}-{epsilon} model. Flow patterns in both configurations were dominated by the axial and tangential components. The presence of the upper impeller altered the flow considerably, producing a strong vertical recirculation pattern between the impellers and significantly reducing the circulation flow below the lower impeller.

  17. Membrane fouling behavior in anaerobic baffled membrane bioreactor under static operating condition.

    Science.gov (United States)

    Liu, Jiadong; Jia, Xiaolan; Gao, Bo; Bo, Longli; Wang, Lei

    2016-08-01

    A novel AnMBR combined with ABR as the anaerobic baffled membrane bioreactor (ABMBR) was developed for membrane fouling mitigation without any turbulence intensifying strategy to reduce the energy consumption further. The filtration time of this system lasted 14-25days under stable condition only with back-flushing every 48h. The polysaccharide accounted for 6.85±3.1% amount of total filter cake and the protein accounted for 4.12±2.1%, which took 79.12% and 11.12% of total area in laser scanning confocal microscope (CLSM) image. After filtration, 83.72±10.97% of turbidity, 59.28±16.46% of polysaccharide, 16.51% of tryptophan and 37.61% of humic-like substrates were rejected, respectively. The total membrane resistance at the end of each cycle was (4.47±0.99)×10(13)m(-1). And the resistance from filter cake was (4.15±1.00)×10(13)m(-1), which accounted for of 92.6±3.4% of total membrane resistance. PMID:27179954

  18. The anaerobic baffled reactor (ABR) treating communal wastewater under mesophilic conditions: a review.

    Science.gov (United States)

    Reynaud, N; Buckley, C A

    2016-01-01

    A review concerning the anaerobic baffled reactor (ABR) treating communal wastewater under mesophilic conditions is presented. Existing studies indicate strong resilience of the reactor towards loading variations and shock-loads. The compartmentalisation of the ABR is a strongly stabilising factor with feed fluctuations being evened out across reactor chambers. Significant chemical oxygen demand (COD) reduction occurs almost exclusively in the first three chambers. The hydraulic rather than the organic loading rate is treatment limiting. Laboratory-scale studies show high treatment efficiencies of above 80% COD removal. It was found that most laboratory-scale studies do not factor in important aspects of field operation, such as diurnal fluctuations of feed characteristics, adequate start-up periods and periods of constant loading and optimised chamber outlet design, and never studied the effect of loading on sludge digestion. Performance data on full-scale ABR implementations, however, are extremely scarce, and existing studies are without exception affected by site-specific treatment-limiting factors hindering the extrapolation of generally valid conclusions. In view of a large-scale roll-out, communal ABRs are not sufficiently understood. Current challenges concerning the optimisation of reactor design require numerous well-monitored long-term full-scale reactor investigations. Existing ABR investigations yield encouraging results, supporting that the ABR may be one of the solutions answering the global call for low-maintenance, robust treatment systems. PMID:26877027

  19. Dynamics of the Flow Pattern in a Baffled Mixing Vessel with an Axial Impeller

    Directory of Open Access Journals (Sweden)

    O. Brůha

    2007-01-01

    Full Text Available This paper deals with the primary circulation of an agitated liquid in a flat-bottomed cylindrical stirred tank. The study is based on experiments, and the results of the experiments are followed by a theoretical evaluation. The vessel was equipped with four radial baffles and was stirred with a six pitched blade impeller pumping downwards. The experiments were concentrated on the lower part of the vessel, where the space pulsations of the primary loop, originated due to the pumping action of the impeller. This area is considered to be the birthplace of the flow macroinstabilities in the system – a phenomenon which has been studied and described by several authors. The flow was observed in a vertical plane passing through the axis of the vessel. The flow patterns of the agitated liquid were visualized by means of Al micro particles illuminated by a vertical light knife and scanned by a digital camera. The experimental conditions corresponded to the turbulent regime of agitated liquid flow.It was found that the primary circulation loop is elliptical in shape. The main diameter of the primary loop is not constant. It increases in time and after reaching a certain value the loop disintegrates and collapses. This process is characterized by a certain periodicity and its period proved to be correlated to the occurrence of flow macroinstability. The instability of the loop can be explained by a dissipated energy balance.  When the primary loop reaches the level of disintegration, the whole impeller power output is dissipated and under this condition any flow alteration requiring additional energy, even a very small vortex separation, causes the loop to collapse. 

  20. Simultaneous denitrification and anaerobic digestion in GRAnular Bed Baffled Reactor (GRABBR)

    International Nuclear Information System (INIS)

    This study elucidates the characteristics of compartmentalised anaerobic system seeded with UASB granules, called GRAanular Bed Baffled Reactor (GRABBR), for combined denitrification and anaerobic digestion processes. The reactor was used for the treatment of glucose enriched synthetic wastewater with various nitrate concentrations. The study was carried out with a 10 litre working volume GRABBR divided into 5 equal compartments operating at organic loading rate (OLR) of 20 kg COD/m3.d with a hydraulic retention time (HRT) of 6 hours. At these conditions, phase separation (between acidogenesis and methanogenesis) was created in the system and then the effect of varying nitrate concentrations (50-200 mg/l NO3-N) in the acidogenic zone (i.e. first compartment) was studied. Due to its unique compartmentalised design, denitrification was the major pathway for nitrate reduction with no noticeable dissimilatory nitrate reduction to ammonia (DNRA). More than 84% of all added nitrates were removed in the acidogenic zone, showing that acidogens possess high denitrifying capabilities. The denitrification rate increased with increase in nitrate concentration, with maximum value estimated as 175 mg NO3-N/l.h at influent nitrate concentration of 200 mg/l NO3-N in the acidogenic zone. Although nitrate addition resulted in lower methane production, COD removal efficiencies improved by up to 8% when compared with the reactor performance before nitrate addition. Furthermore, the alkalinity produced during denitrification improved the stability of the system by controlling the decrease in pH resulting from acidogenesis. The system encouraged simultaneous denitrification and anaerobic digestion in a single unit by accommodating denitrifiers in the early compartments and allowing methanogenesis to flourish in the downstream compartments of the system, thus minimising inhibition to methane producing bacteria by nitrates. (author)

  1. Inactivation of Escherichia coli in a baffled pond with attached growth: treating anaerobic effluent under the Sahelian climate.

    Science.gov (United States)

    Moumouni, D A; Andrianisa, H A; Konaté, Y; Ndiaye, A; Maïga, A H

    2016-01-01

    This study aimed to investigate and understand the zero-level detection of Escherichia coli (E. coli) at the outlet of an improved waste stabilization pond. Wastewaters were collected from the International Institute for Water and Environmental Engineering (2iE) campus and were subjected to biological treatment. The system included two-stage Anaerobic Reactors followed by a Baffled Pond (AR-BP) with recycled plastic media as a medium for attached growth and a control pond (CP). Three vertical baffles were installed, giving four compartments in the baffled pond (BP). The research was conducted on the pilot scale from March to July 2014, by monitoring E. coli, pH, temperature, dissolved oxygen (DO) and chlorophyll-a in each compartment and at different depths. The results show that E. coli concentrations were lower in top layers of all compartments with an undetectable level in the last compartment up to 0.60 m deep. E. coli mean removal efficiencies and decay rates were achieved by significant difference in BP (4.5 log-units, 9.1 day(-1)) and CP (1.1 log-units, 1.1 day(-1)). Higher values of pH (≥9), temperature (≥32°C), DO (≥ 8 mg/L) and chlorophyll-a (≥ 1000 µg/L) were observed at the surface of BP, whereas lower values were shown at the bottom. Sedimentation combined with the synergetic effects of the physicochemical parameters and environmental factors would be responsible for the inactivation of E. coli in BP. It was concluded that the AR-BP could be applied as an alternative low-cost wastewater treatment technology for developing countries and recommended for reuse of their effluent for restricted peri-urban irrigation. PMID:26496019

  2. Numerical model for the thermal-hydraulic solution of shell-and-U-tubes heat exchanger with segmental baffles

    International Nuclear Information System (INIS)

    A numerical model has been developed to calculate the flow, pressure and temperature distribution of steady-state |for the tube and shell-side fluids in a shell-and-U-tubes heat exchanger with segmental baffles. It was based on the Subchannel Analysis Method- The model, checked with experimental results from one heat exchanger, predicted with good accuracy outlet temperatures for both fluids. The method, implemented ' in a computer program of low cost and easy application, can be used in the design and performance evaluation of commercial units.(author)

  3. Enhanced solution velocity between dark and light areas with horizontal tubes and triangular prism baffles to improve microalgal growth in a flat-panel photo-bioreactor.

    Science.gov (United States)

    Yang, Zongbo; Cheng, Jun; Xu, Xiaodan; Zhou, Junhu; Cen, Kefa

    2016-07-01

    Novel horizontal tubes and triangular prism (HTTP) baffles that generate flow vortices were developed to increase solution velocity between dark and light areas and thus improve microalgal growth in a flat-panel photo-bioreactor. Solution velocity, mass-transfer coefficient, and mixing time were measured with a particle-imaging velocimeter, dissolved oxygen probes, and pH probes. The solution mass-transfer coefficient increased by 30% and mixing time decreased by 21% when the HTTP baffles were used. The solution velocity between dark and light areas increased from ∼0.9cm/s to ∼3.5cm/s, resulting in a decreased dark-light cycle period to one-fourth. This enhanced flashing light effect with the HTTP baffles dramatically increased microalgae biomass yield by 70% in the flat-panel photo-bioreactor. PMID:27038260

  4. Cultivation of Chlorella vulgaris in a pilot-scale sequential-baffled column photobioreactor for biomass and biodiesel production

    International Nuclear Information System (INIS)

    Highlights: • A new sequential baffled photobioreactor was developed to cultivate microalgae. • Organic fertilizer was used as the main nutrients source. • Negative energy balance was observed in producing microalgae biodiesel. - Abstract: Pilot-scale cultivation of Chlorella vulgaris in a 100 L sequential baffled photobioreactor was carried out in the present study. The highest biomass yield attained under indoor and outdoor environment was 0.52 g/L and 0.28 g/L, respectively. Although low microalgae biomass yield was attained under outdoor cultivation, however, the overall life cycle energy efficiency ratio was 3.3 times higher than the indoor cultivation. In addition, negative energy balance was observed in producing microalgae biodiesel under both indoor and outdoor cultivation. The minimum production cost of microalgae biodiesel was about RM 237/L (or USD 73.5/L), which was exceptionally high compared to the current petrol diesel price in Malaysia (RM 3.6/L or USD 1.1/L). On the other hand, the estimated production cost of dried microalgae biomass cultivated under outdoor environment was RM 46/kg (or USD 14.3/kg), which was lower than cultivation using chemical fertilizer (RM 111/kg or USD 34.4/kg) and current market price of Chlorella biomass (RM 145/kg or USD 45/kg)

  5. Pollutant removal from municipal wastewater employing baffled subsurface flow and integrated surface flow-floating treatment wetlands.

    Science.gov (United States)

    Saeed, Tanveer; Al-Muyeed, Abdullah; Afrin, Rumana; Rahman, Habibur; Sun, Guangzhi

    2014-04-01

    This article reports pollutant removal performances of baffled subsurface flow, and integrated surface flow-floating treatment wetland units, when arranged in series for the treatment of municipal wastewater in Bangladesh. The wetland units (of the hybrid system) included organic, inorganic media, and were planted with nineteen types of macrophytes. The wetland train was operated under hydraulic loading fluctuation and seasonal variation. The performance analyses (across the wetland units) illustrated simultaneous denitrification and organics removal rates in the first stage vertical flow wetland, due to organic carbon leaching from the employed organic media. Higher mean organics removal rates (656.0 g COD/(m(2)·day)) did not completely inhibit nitrification in the first stage vertical flow system; such pattern could be linked to effective utilization of the trapped oxygen, as the flow was directed throughout the media by the baffle walls. Second stage horizontal flow wetland showed enhanced biodegradable organics removal, which depleted organic carbon availability for denitrification. The final stage integrated wetland system allowed further nitrogen removal from wastewater, via nutrient uptake by plant roots (along with nitrification), and generation of organic carbon (by the dead macrophytes) to support denitrification. The system achieved higher E. coli mortality through protozoa predation, E. coli oxidation, and destruction by UV radiation. In general, enhanced pollutant removal efficiencies as demonstrated by the structurally modified hybrid wetland system signify the necessity of such modification, when operated under adverse conditions such as: substantial input organics loading, hydraulic loading fluctuation, and seasonal variation. PMID:25079402

  6. ENERGY PERFORMANCE IMPROVEMENT, FLOW BEHAVIOR AND HEAT TRANSFER INVESTIGATION IN A CIRCULAR TUBE WITH V-DOWNSTREAM DISCRETE BAFFLES

    Directory of Open Access Journals (Sweden)

    Withada Jedsadaratanachai

    2013-01-01

    Full Text Available A mathematical study has been carried out to examine periodic laminar flow and heat transfer characteristics in a three-dimensional isothermal wall circular tube with 45° in-line V-discrete baffles. The computations are based on the Finite Volume Method (FVM and the SIMPLE algorithm has been implemented. The fluid flow and heat transfer characteristics are presented for Reynolds numbers based on the diameter of the circular tube ranging from 100 to 1200. To generate main streamwise vortex flows through the tested section, V-discrete baffles with an attack angle of 45° are mounted in tandem with in-line arrangement and pointing downstream (V-Downstream inserted in the middle of the tested tube. Effects of different Blockage Ratio (b/D, BR and Pitch Ratio (P/D, PR on heat transfer and pressure drop in the tube are studied. It is apparent that the main vortex flows can induce impinging flows on a wall of the interbaffle cavity leading to extreme increases in heat transfer rate over the circular tube. In addition, the rise in the BR and reduce of PR results in the increase in the Nusselt number and friction factor values. The computational results show that the optimum thermal enhancement factor is around 2.5 at BR = 0.15, PR = 1 and Re = 1200.

  7. Studies of high-{delta} (baffled) and low-{delta} (open) pumped divertor operation on DIII-D

    Energy Technology Data Exchange (ETDEWEB)

    Allen, S.L.; Fenstermacher, M.E. [Lawrence Livermore National Lab., CA (United States); Greenfield, C.M. [General Atomics, San Diego, CA (United States)] [and others

    1998-08-01

    The authors report new experimental results with the RDP-OB (Radiative Divertor Project-outer baffle) and cryopump in both upper single-null (USN) and double-null (DN) ELMing H-mode discharges. The baffled divertor reduced the core ionization ({approximately}2--2.5{times}), in reasonable agreement with predictions from UEDGE/DEGAS modeling ({approximately}3.75{times}). The upper cryopump achieved density control of n{sub e}/n{sub gw} {approximately} 0.22 (line density/Greenwald density) with Z{sub eff} {approximately} 2 in high-{delta} plasmas. The measured exhaust is comparable to the lower pump, except at lower core electron densities (n{sub e} < 5 {times} 10{sup 19} m{sup {minus}3}). Efficient impurity exhaust was obtained with deuterium SOL flow. Preliminary experiments with DN operation has shown that the particle exhaust to the upper pump depends on the up/down magnetic balance. Preliminary experiments indicate that the DN exhaust is roughly 40--50% of the USN exhaust at n{sub e} {approximately} 4 {times} 10{sup 19} m{sup {minus}3}.

  8. Two-phase flow on the shell-side of a segmentally baffled shell-and-tube heat exchanger

    International Nuclear Information System (INIS)

    This paper reviews work carried out at the National Engineering Laboratory, UK., related to pressure drop flow patterns and phase distribution on the shell-side of segmentally baffled shell-and-tube heat exchangers. The experimental work reported was carried out using air/water mixtures in model exchangers of rectangular cross section with tube nests containing approximately 40 tubes. Data were obtained on crossflow pressure drop and on the pressure drop attributable to the windows. In certain configurations the void fraction and flow pattern maps were obtained. The geometric conditions examined related to configurations appropriate to operation as condensers and boilers. Correlations for pressure drop and void fraction were developed and flow pattern maps obtained

  9. Seismic design optimization of IHP cooling baffle in nuclear power plant%核电厂IHP通风围板的抗震设计优化

    Institute of Scientific and Technical Information of China (English)

    徐峰

    2012-01-01

    核电厂一体化堆顶组件(IHP)通风围板为驱动机构磁轭线圈的冷却提供了间隙均匀的通道.为了优化IHP通风围板的设计,根据ANSI/AISC N690分析了当前设计的通风围板的关键结构件在D级使用限制下的应力和变形并对关键结构件进行了初步设计优化,然后对IHP通风围板进行了有限元分析并对通风围板进行了最终设计改进.经过抗震设计优化通风围板的最大应力值分布趋于均匀.本文对抗震类设备的设计优化具有一定的参考价值.%Integrated head package (IHP) cooling baffle supplies uniform gap cooling channel for control rod drive mechanism coil stack. For optimizing design of IHP cooling baffle, stress and deformation of cooling baffle key parts were analyzed at Level D service limit according to ANSI/AISC 690, and primary optimization of key parts was processed. Then the cooling baffle was analyzed using finite element method, and final design improvement of baffle was made. The result shows better maximum stress distribution is obtained after optimization. This paper could be referenced for design optimization of seismic components.

  10. Influence of presence of inclined centered baffle and corrugation frequency on natural convection heat transfer flow of air inside a square enclosure with corrugated side walls

    Energy Technology Data Exchange (ETDEWEB)

    Hussain, Salam Hadi; Jabbar, Mohammed Yousif; Mohamad, Ahmad Saddy [Mechanical Engineering Department, College of Engineering, Babylon University, Babylon Province (Iraq)

    2011-09-15

    The main objective of this study is to investigate the effect of presence of insulated inclined centered baffle and corrugation frequency on the steady natural convection in a sinusoidal corrugated enclosure. The present study is based on such a configuration where the two vertical sinusoidal walls are maintained at constant low temperature whereas a constant heat flux source whose length is 80% of the width of the enclosure is discretely embedded in the bottom wall. The remaining parts of the bottom wall and the top wall are adiabatic. The finite volume method has been used to solve the governing Navier-Stokes and the energy conservation equations of the fluid medium in the enclosure in order to investigate the effects of baffle inclination angles, corrugation frequencies and Grashof numbers on the fluid flow and heat transfer in the enclosure. The values of the governing parameters are the Grashof number Gr (10{sup 3}-10{sup 6}), the corrugation frequencies CF (1, 2 and 3), baffle inclination angles (0 deg. {<=} {phi} {<=} 150 deg.) and Prandtl number Pr (0.71). Results are presented in the form of streamline and isotherm plots. The results of this investigation are illustrated that the average Nusselt number increases with increase in both the Grashof number and corrugation frequency for different baffle inclination angles and the presence of inclined baffle and increasing the corrugation frequency have significant effects on the average Nusselt numbers, streamlines and isotherms inside the enclosure. The obtained numerical results have been compared with literature ones, and it gives a reliable agreement. (authors)

  11. 波形折流杆换热器的开发和工业化实验研究%Industrially Experimental Investigations and Development of the Curve-ROD Baffle Heat Exchanger

    Institute of Scientific and Technical Information of China (English)

    严良文; 吴金星; 王志文

    2004-01-01

    The conventional heat exchanger with segmental baffles is prone to bring forth fluid-induced vibration of heat transfer tubes and increase the pressure drop of shell-side greatly at higher fluid flow velocity. In order to avoid the above defects, the ROD-baffle heat exchanger has been developed. However, its collocation of heat transfer tubes is conventionally in square, which leads to fewer heat transfer area per unit volume. Based on the ROD-baffle heat exchanger, a new type curve-ROD baffle has been developed, and an industrial investigation of the curve-ROD baffle heat exchanger with normal triangular collocation has been carried into execution. In this paper, two equations using the Reynolds number were acquired to predict the heat transfer coefficients of the shell-side and tubeside. The experimental results show that the shell-side heat transfer and pressure drop characteristics of the curve-ROD baffle heat exchanger are superior to those of the segmental baffle one.

  12. Magnetically insulated baffled probe for real-time monitoring of equilibrium and fluctuating values of space potentials, electron and ion temperatures, and densities

    International Nuclear Information System (INIS)

    By restricting the electron-collection area of a cold Langmuir probe compared to the ion-collection area, the probe floating potential can become equal to the space potential, and thus conveniently monitored, rather than to a value shifted from the space potential by an electron-temperature-dependent offset, i.e., the case with an equal-collection-area probe. This design goal is achieved by combining an ambient magnetic field in the plasma with baffles, or shields, on the probe, resulting in species-selective magnetic insulation of the probe collection area. This permits the elimination of electron current to the probe by further adjustment of magnetic insulation which results in an ion-temperature-dependent offset when the probe is electrically floating. Subtracting the floating potential of two magnetically insulated baffled probes, each with a different degree of magnetic insulation, enables the electron or ion temperature to be measured in real time.

  13. Numerical time-dependent 3D simulation of flow pattern and heat distribution in an ammonothermal system with various baffle shapes

    Science.gov (United States)

    Erlekampf, J.; Seebeck, J.; Savva, P.; Meissner, E.; Friedrich, J.; Alt, N. S. A.; Schlücker, E.; Frey, L.

    2014-10-01

    A numerical analysis of an ammonothermal synthesis process for the bulk growth of nitride crystals was performed. The analysis includes the development of a thermal model for a lab-scale ammonothermal autoclave, which was validated by in situ temperature measurements and applied to tailor the temperature field inside the autoclave. Based on the results of the global thermal 2D simulations, a local 3D model was used to include convective phenomena in the analysis. Moreover, the influence of the baffle and different baffle shapes on the flow velocity was investigated. Fluctuations of the temperature as well as the flow velocities occur, indicating that 3D considerations are essential to accurately investigate the heat and mass transport in ammonothermal systems.

  14. Evaluation of Baffle Fixes Film up Flow Sludge Blanket Filtration (BFUSBF) System in Treatment of Wastewaters from Phenol and 2,4-Dinitrophenol Using Daphnia Magna Bioassay

    OpenAIRE

    Mohammad Javad Ghannadzadeh; Ahmad Jonidi Jafari; Abbas Rezaee; Fatemeh Eftekharian; Ali Koolivand

    2016-01-01

    Background: Phenol and nitrophenol are common compounds found in different types of industrial wastewater known as serious threats to human health and natural environment. In this study, Daphnia magna was used to evaluate the effectiveness of "baffle fixes film up flow sludge blanket filtration" (BFUSBF) system in elimination of phenolic compounds from water. Methods: D. magna cultures were used as toxicity index of phenol and 2,4-DNP mixtures after treatment by a pilot BFUSBF system which...

  15. RESEARCH ADVANCES IN ANAEROBIC BAFFLED REACTOR (ABR)%折流式厌氧反应器(ABR)的研究进展

    Institute of Scientific and Technical Information of China (English)

    王建龙; 韩英健; 钱易

    2000-01-01

    Anaerobic baffled reactor (ABR) is a new high efficient anaerobic treatmen t system. ABR has some advantages over other anaerobic reactors, such as sim ple design,inexpensive to construct,stable to hydraulic and organic shock load ings, and high treatment efficiency. Different types of ABR are described, the study progress and application situation are summarized, and the future development is prospected in this paper. Fig 2, Tab 2, Ref 45

  16. Frequency and Magnitude Analysis of the Macro-instability Related Component of the Tangential Force Affecting Radial Baffles in a Stirred Vessel

    OpenAIRE

    P. Hasal; J. Kratěna; I. Fořt

    2002-01-01

    Experimental data obtained by measuring the tangential component of force affecting radial baffles in a flat-bottomed cylindrical mixing vessel stirred with pitched blade impellers is analysed. The maximum mean tangential force is detected at the vessel bottom. The mean force value increases somewhat with decreasing impeller off-bottom clearance and is noticeably affected by the number of impeller blades. Spectral analysis of the experimental data clearly demonstrated the presence of its macr...

  17. 3D simulation on the unit duct in the shell side of the ROD baffle heat exchanger%杆支撑换热器壳侧单元流道的三维模拟

    Institute of Scientific and Technical Information of China (English)

    吴金星; 董其伍; 刘敏珊; 魏新利

    2006-01-01

    The ROD baffle heat exchanger can slightly enhance the shell side heat transfer coefficient with the significant reduction of pressure loss due to the shell side fluid flowing longitudinally through tube bundle, which leads to the reduction of the manufacture and running cost and in some cases to the dimensions reduction of the heat exchangers. Because of the complexities of fluid dynamics equations and the structure of heat exchangers, few theoretical researches have been accomplished to specify the shell side characteristics of the ROD baffle heat exchanger. A unit duct model in the shell side of the longitudinal flow type heat exchanger has been developed based on suitable simplification. A numerical analysis on shell side of the ROD baffle heat exchanger has been carried out at constant wall temperature to obtain the characteristics of heat transfer and pressure drop. The numerical results show that the ROD baffles placed vertically and horizontally in the unit duct continue to shear and comminute the streamline flow when the fluid crosses over the ROD-baffles, and change the fluid flow directions, and then the continuity and stability of the fluid are destroyed. The effect of disturbing flow can promote fluid turbulent intensity and effectively enhance heat transfer. The numerical analyses can provide the theoretical bases for optimizing the structure of ROD baffle heat exchanger and improving its performance.

  18. The energy-saving anaerobic baffled reactor membrane bioreactor (EABR-MBR) system for recycling wastewater from a high-rise building.

    Science.gov (United States)

    Ratanatamskul, Chavalit; Charoenphol, Chakraphan

    2015-01-01

    A novel energy-saving anaerobic baffled reactor-membrane bioreactor (EABR-MBR) system has been developed as a compact biological treatment system for reuse of water from a high-rise building. The anaerobic baffled reactor (ABR) compartment had five baffles and served as the anaerobic degradation zone, followed by the aerobic MBR compartment. The total operating hydraulic retention time (HRT) of the EABR-MBR system was 3 hours (2 hours for ABR compartment and very short HRT of 1 hour for aerobic MBR compartment). The wastewater came from the Charoen Wisawakam building. The results showed that treated effluent quality was quite good and highly promising for water reuse purposes. The average flux of the membrane was kept at 30 l/(m2h). The EABR-MBR system could remove chemical oxygen demand, total nitrogen and total phosphorus from building wastewater by more than 90%. Moreover, it was found that phosphorus concentration was rising in the ABR compartment due to the phosphorus release phenomenon, and then the concentration decreased rapidly in the aerobic MBR compartment due to the phosphorus uptake phenomenon. This implies that phosphorus-accumulating organisms inside the EABR-MBR system are responsible for biological phosphorus removal. The research suggests that the EABR-MBR system can be a promising system for water reuse and reclamation for high-rise building application in the near future. PMID:26067504

  19. Evaluation of neutron fluence in nuclear reactor internal structures due to IASCC (Focused on the baffle structure for Kori Unit 2 reactor)

    International Nuclear Information System (INIS)

    Neutron fluence evaluation has been currently performed on the reactor vessel itself in an operating nuclear power plant in order to evaluate the radiation embrittlement which is directly related to plant safety as well as plant operating licence and has never been done on reactor internal structures such as baffle former bolt based on the operating history, However, as the operating year increases, damages may occur in the internal structures and resulting in the shutdown of the plant and the replacement of the structure causing economic disadvantage as well as severe effect in the integrity of the plant. Neutron flux and fluences on the baffle area for thr Kori unit 2 has been performed from the start of the reactor until 21st fuel cycle using real plant operating conditions such as operating temperature, pressure and fuel loading pattern and the maximum fluence in the baffle area was evaluated as about 4.3 x 1022 [n/cm2] at the 21st cycle and about 6.8 x 1022 [n/cm2] at the end of life (32EFPY) when assuming the average plant performance to be 80%

  20. Perbandingan Desain IPAL Proses Atached Growth Anaerobic Filter dengan Suspended Grwoth Anaerobic Baffled Reactor untuk Pusat Pertokoan di Kota Surabaya

    Directory of Open Access Journals (Sweden)

    Abdul Hamid

    2014-09-01

    Full Text Available Perencanaan IPAL dilakukan dengan mengidentifikasi karakteristik dan kuantitas limbah dari pusat pertokoan X di Surabaya. Selanjutnya ditetapkan baku mutu dan kriteria desain. Perhitungan desain meliputi dimensi dan rencana anggaran biaya. Dari hasil perhitungan desain didapatkan desain rinci IPAL unit Anaerobic Filter meliputi dimensi bak ekualisasi (2,2 m x 1,1 m x 1,3 m, Bak Pengendap kompartemen I (7 m x 2,5 m x 1,25 kompartemen II (3,5 m x 2,5 m x 1,25 m, AF tiap kompartemen (1,25 m x 0,56 m x 1,25 m sebanyak 6 buah. Desain rinci Unit IPAL Anaerobic Baffled Reactor meliputi dimensi bak ekualisasi (2,2 m x 1,1 m x 1,3 m, Bak Pengendap (8 m x 2 m x 1,5 m, ABR tiap kompartemen (0,75 m x 4 m x 1,5m sebanyak 7 buah. Biaya konstruksi unit AF sebesar Rp 178.383.868,- dan Rp 4.688.912,-/ bulan untuk OM. Sedangkan biaya konstruksi unit ABR Rp 239.247.347,- serta Rp 4.677.801,-/bulan untuk OM.

  1. Effects of Temperature and Hydraulic Residence Time (HRT) on Treatment of Dilute Wastewater in a Carrier Anaerobic Baffled Reactor

    Institute of Scientific and Technical Information of China (English)

    HUA-JUN FENG; LI-FANG HU; DAN SHAN; CHENG-RAN FANG; DONG-SHENG SHEN

    2008-01-01

    To examine the effect of hydraulic residence time (HRT) on the performance and stability,to treat dilute wastewater at different operational temperatures in a carrier anaerobic baffled reactor (CABR),and hence to gain a deeper insight into microbial responses to hydraulic shocks on the base of the relationships among macroscopic performance,catabolic intermediate,and microcosmic alternation.Methods COD,VFAs,and microbial activity were detected with constant feed strength (300 mg/L) at different HRTs (9-18 h) and temperatures (10℃-28℃) in a CABR.Results The removal efficiencies declined with the decreases of HRTs and temperatures.However,the COD removal load was still higher at short HRT than at long HRT.Devastating reactor performance happened at temperature of 10℃ and at HRT of 9 h.HRTs had effect on the VFAs in the reactor slightly both at high and low temperatures,but the reasons differed from each other.Microbial activity was sensitive to indicate changes of environmental and operational parameters in the reactor.Conclusion The CABR offers to certain extent an application to treat dilute wastewater under a hydraulic-shock at temperatures from 10℃ to 28℃.

  2. EFFECT OF SULFATE LOADING RATE AND ORGANIC LOADING RATE ON ANAEROBIC BAFFLED REACTORS USED FOR TREATMENT OF SANITARY LANDFILL LEACHATES

    Directory of Open Access Journals (Sweden)

    O. Burbano-Figueroa

    2015-06-01

    Full Text Available AbstractThis study investigated the effect of organic loading rate (OLR and sulfate loading rate (SLR on landfill leachate treatment by a lab-scale anaerobic baffled reactor (ABR. Landfill leachate contained a concentration of organic matter between 3966 and 5090 mg COD.L-1 and no detectable amounts of sulfate. Reactors were started-up by feeding them with iron-sulfate at a SLR of 0.05 g SO42-.L-1.day-1 (4 weeks. Factorial design and response surface techniques were used to evaluate and optimize the effects of these operating variables on COD removal. ABRs were operated at OLRs ranging from 0.30 up to 6.84 g COD.L-1.day-1 by changes in influent volumetric flow. SO42- was added to the influent at a SRL from 0.06 to 0.13 g SO42-.L-1.day-1. The highest value of COD removal (66% was reached at an OLR of 3.58 g COD.L-1.day-1 and SLR of 0.09 g SO4-2.L-1.day-1 with a COD/SO4-2 ratio of 40. Under these conditions sulfate is mainly used for molecular hydrogen consumption while organic matter is preferentially degraded via methanogesis.

  3. HEAT TRANSFER COEFFICIENT AND FRICTION FACTOR CHARACTERISTICS OF A GRAVITY ASSISTED BAFFLED SHELL AND HEAT-PIPE HEAT EXCHANGER

    Directory of Open Access Journals (Sweden)

    P. Raveendiran

    2015-06-01

    Full Text Available The heat transfer coefficients and friction factors of a baffled shell and heat pipe heat exchanger with various inclination angles were determined experimentally; using methanol as working fluid and water as heat transport fluid were reported. Heat pipe heat exchanger reported in this investigation have inclination angles varied between 15o and 60o for different mass flow rates and temperature at the shell side of the heat exchanger. All the required parameters like outlet temperature of both hot and cold side of heat exchanger and mass flow rate of fluids were measured using an appropriate instrument. Different tests were performed from which condenser side heat transfer coefficient and friction factor were calculated. In all operating conditions it has been found that the heat transfer coefficient increases by increasing the mass flow rate and angle of inclination. The reduction in friction factor occurs when the Reynolds number is increased. The overall optimum experimental effectiveness of GABSHPHE has found to be 42% in all operating conditioning at ψ = 45o.

  4. Stormwater Field Evaluation and Its Challenges of a Sediment Basin with Skimmer and Baffles at a Highway Construction Site

    Directory of Open Access Journals (Sweden)

    Xing Fang

    2015-06-01

    Full Text Available A field-scale data collection plan to monitor and evaluate the performance of a sediment basin design was developed and implemented using portable automatic stormwater samplers, flow modules, a rain gauge, and inflow weirs. The design configuration consisted of a skimmer as the primary dewatering device, three coir baffles installed inside the basin, polyacrylamide flocculant blocks and ditch checks in the inflow channel. A sediment basin built on a highway construction site in Franklin County, Alabama, U.S. using the aforementioned design configuration was monitored over 16 rainfall events from 15 November 2011 to 6 February 2012. The basin effectively removed sediments during the early stages of construction when the correct type of polyacrylamide flocculant blocks was used, e.g., 97.9% of sediment removal after a rainfall event on 16 November 2011. It is difficult and challenging to dose sediment-laden stormwater inflow with an exact amount of flocculating agent across all runoff producing events since rainfall is a stochastic variable. Based upon results from this study, it is recommended that a minimum volume of 251.9 m3/ha of contributing drainage area be used to sufficiently size a basin, which is still significantly under-designed for a 2-year, 24-h storm event in the southeast. This paper presents challenges and lessons learned regarding sediment basin design, monitoring, and performance that are beneficial to future studies.

  5. Microbiological studies of an anaerobic baffled reactor: microbial community characterisation and deactivation of health-related indicator bacteria.

    Science.gov (United States)

    Lalbahadur, T; Pillay, S; Rodda, N; Smith, M; Buckley, C; Holder, F; Bux, F; Foxon, K

    2005-01-01

    This WRC funded project has studied the appropriateness of the ABR (anaerobic baffled reactor) for on-site primary sanitation in low-income communities. A 3,000 L pilot reactor was located at the Kingsburgh wastewater treatment plant south of Durban, South Africa. Feed to the reactor was raw domestic wastewater containing a significant proportion of particulate organic matter. The compartments of the ABR were routinely monitored for pH, COD, and gas production, among other physical-chemical determinants. The microbial population in each compartment was analysed by fluorescent in situ hybridisation, using general oligonucleotide probes for eubacteria and archeae and a suite of 10 genera or family specific probes. Scanning electron microscopy was conducted on the sludge fraction of each compartment. Mixed fractions from each compartment were also analysed for health-related indicator bacteria (total coliforms and E. coli). Results indicated that methanogenesis was not occurring to the expected extent in the latter compartments, and that this was probably due to a hydraulic load limitation. This contrasted with earlier studies on industrial effluent, for which the organic load was exclusively in soluble form. Inactivation of health-related indicator bacteria was less than 1 log, indicating the need for an additional post-treatment of the effluent to protect community health. PMID:16104417

  6. Biomethanation of vegetable market waste in an anaerobic baffled reactor: Effect of effluent recirculation and carbon mass balance analysis.

    Science.gov (United States)

    Gulhane, Madhuri; Khardenavis, Anshuman A; Karia, Sneha; Pandit, Prabhakar; Kanade, Gajanan S; Lokhande, Satish; Vaidya, Atul N; Purohit, Hemant J

    2016-09-01

    In the present study, feasibility of biomethanation of vegetable market waste in a 4-chambered anaerobic baffled reactor (ABR) was investigated at 30d hydraulic retention time and organic loading rate of 0.5gVS/L/d for one year. Indicators of process stability viz., butyrate/acetate and propionate/acetate ratios were consistent with phase separation in the different chambers, which remained unaltered even during recirculation of effluent. Chemical oxygen demand (COD) and volatile solids (VS) removal efficiencies were observed to be consistently high (above 90%). Corresponding biogas and methane yields of 0.7-0.8L/g VS added/d and 0.42-52L/g VS added/d respectively were among the highest reported in case of AD of vegetable waste in an ABR. Process efficiency of the ABR for vegetable waste methanation, which is indicated by carbon recovery factor showed that, nearly 96.7% of the input carbon considered for mass balance was accounted for in the product. PMID:27133362

  7. Device to measure underwater the hardness of a vertical wall of the core baffle assembly of a pressurized water nuclear reactor

    International Nuclear Information System (INIS)

    The device comprises a hollow vertical rod handled from the edge of the pool. A body integral with the rod at its lower end, has a mobile piston, housed in a first chamber, provided with bearing means to fit against two perpendicular walls; a second piston housed in the second chamber carries a hardness measuring head to make a mark on the wall opposite to one of the two perpendicular walls. A source of hydraulic fluid communicates with the chambers through the rod. The invention applies, more particularly, to the determination of influence of irradiation on the walls of the core baffle assembly of a nuclear reactor, after a certain operating period

  8. Effective Increase of Crystal Area during Sublimation Growth of 6H-SiC by Using the Cone-shaped Baffle

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    A novel design of crucible is proposed in this paper for the growth of SiC crystals. The relation between grown crystal shape and temperature distribution in a growth chamber was discussed. It is pointed out that the crystal shape had a close relationship with temperature distribution. The calculations suggested that the radial temperature field of the growing crystal became homogenous by setting up the cone-shaped baffle in the growth chamber. By modifying the crucible design and temperature distribution in the growth chamber, it is possible to enhance the enlargement of crystal, and also possible to keep grown surface flat.

  9. Harvey Cushing and pituitary Case Number 3 (Mary D.): the origin of this most baffling problem in neurosurgery.

    Science.gov (United States)

    Pascual, José María; Prieto, Ruth

    2016-07-01

    From the very beginning of his career, Harvey Williams Cushing (1869-1939) harbored a deep interest in a complex group of neoplasms that usually developed at the infundibulum. These were initially known as "interpeduncular" or "suprasellar" cysts. Cushing introduced the term "craniopharyngioma" for these lesions, which he believed represented one of the most baffling problems faced by neurosurgeons. The patient who most influenced Cushing's thinking was a 16-year-old seamstress named "Mary D.," whom he attended in December 1901, exactly the same month that Alfred Fröhlich published his seminal article describing an adiposogenital syndrome in a young boy with a pituitary cyst. Both Cushing's and Fröhlich's patients showed similar symptoms caused by the same type of tumor. Notably, Cushing and Fröhlich had met one another and became good friends in Liverpool the summer before these events took place. Their fortunate relationship led Cushing to realize that Fröhlich's syndrome represented a state of hypopituitarism and provided a useful method of diagnosing interpeduncular cysts. It is noteworthy that Cushing's very first neurosurgical procedure on a pituitary tumor was performed in the case of Mary D.'s "interpeduncular cyst," on February 21, 1902. Cushing failed to remove this lesion, which was later found during the patient's autopsy. This case was documented as Pituitary Case Number 3 in Cushing's masterpiece, The Pituitary Body and Its Disorders, published in 1912. This tumor was considered "a teratoma"; however, multiple sources of evidence suggest that this lesion actually corresponded to an adamantinomatous craniopharyngioma. Unfortunately, the pathological specimens of this lesion were misplaced, and this prompted Cushing's decision to retain all specimens and documents of the cases he would operate on throughout his career. Accordingly, Mary D.'s case crystallized the genesis of the Cushing Brain Tumor Registry, one of Cushing's major legacies to

  10. Evaluation of Baffle Fixes Film up Flow Sludge Blanket Filtration (BFUSBF System in Treatment of Wastewaters from Phenol and 2,4-Dinitrophenol Using Daphnia Magna Bioassay

    Directory of Open Access Journals (Sweden)

    Mohammad Javad Ghannadzadeh

    2016-02-01

    Full Text Available Background: Phenol and nitrophenol are common compounds found in different types of industrial wastewater known as serious threats to human health and natural environment. In this study, Daphnia magna was used to evaluate the effectiveness of "baffle fixes film up flow sludge blanket filtration" (BFUSBF system in elimination of phenolic compounds from water. Methods: D. magna cultures were used as toxicity index of phenol and 2,4-DNP mixtures after treatment by a pilot BFUSBF system which consisted of baffle in anoxic section and biofilm in aerobic sections. Initial concentrations were 312 mg/L phenol and 288 mg/L 2,4-dinitrophenol (2,4-DNP. Results: Bioassay tests showed that D. magna was influenced by the toxicity of phenol and 2,4 DNP mixtures. The comparison between the toxicity of initial phenol and 2,4-DNP mixtures and the output toxic unit (TU derived from BFUSBF treatment system showed that the TU of the effluent from BFUSBF reactor was much lower than that of the solution that entered the reactor. Conclusion: Based on the acute toxicity test, BFUSBF process could reduce phenol and 2,4-DNP in aqueous solutions. Therefore, it is possible to use BFUSBF process as an appropriate treatment option for wastewaters containing phenolic compounds.

  11. Investigation on the hydrodynamic behaviors of the clarifier with an interior baffle in WWTP by using of radiotracer 99mTc

    International Nuclear Information System (INIS)

    The hydrodynamic behaviors of the clarifier with an interior baffle in a wastewater treatment plant was investigated by using a radiotracer 99mTc(30 40 mCi) to verify the results of CFD(Computational Fluid Dynamics) modelling in the previous study. The clarifier model was manufactured with consideration to the hydraulic similarity(1/21) of a plant(L x W x H : 2.6 x 0.4 x 0.2 m). By installation of an interior baffle to the clarifier, the strong density current at the bottom of the clarifier decreased substantially and increased the area of sludge settling zone, which were visualized successfully from the radiotracer experiment. Also the portion of short circuit stream changed from 48% to 32% and the mean residence time of sludge decreased from 940 sec to 810 sec, which corresponds to the results of CFD modelling. As a result, it is anticipated that radiotracer technology can be used as important tool for designing new wastewater treatment plants and verifying their performances after structural modifications

  12. 基于ReWorks操作系统的自动检票机研究%STUDY ON REWORKS OPERATING SYSTEM-BASED BAFFLE GATE

    Institute of Scientific and Technical Information of China (English)

    周向争

    2013-01-01

    以基于Reworks操作系统的自动检票机实例为背景,研究如何应用Reworks操作系统的特点,实现基于ReWorks操作系统的检票机硬件和软件设计;介绍编译环境和进行调试的一些方法.为自动售检票系统(AFC)终端设备的研发提供经验.%Taking the examples of ReWorks operating system-based baffle gate as the background,we study how to apply the characteristics of ReWorks operating system,and realise the hardware and software design for ReWorks operating system-based baffle gate; In the paper we introduce the compiling environment and some methods of debugging,these provide the experiences for the research and development of automatic fare collection system (AFC) terminal equipments.

  13. Calculation of baffle effect and mutual interaction between elements for an underwater acoustic conformal array with application to the optimization of projecting beampattern

    Institute of Scientific and Technical Information of China (English)

    HE ZhengYao; MA YuanLiang

    2007-01-01

    The boundary element theory together with the optimization method is used to calculate the driving voltage weighting vector of a conformal array of underwater acoustic projecting transducers to obtain a low-sidelobe beampattern. At first, the relationship between the acoustic radiated field and the vibration velocity of the array is formulated from the boundary element equation when the boundary impedance of the array baffle is specified. Then, the mutual impedance matrix of the array is calculated, and the relationship between the driving voltage and the vibration velocity of the transducers is presented based on the equivalent circuit principle. At last, the driving voltage weighting vector of the array is calculated through an optimization method to obtain a low-sidelobe projecting beampattern. Computer simulation is conducted for a 14-element conformal array. An experiment has been carried out to measure the radiation directivity of the array in an anechoic water tank. The calculated and the experimental results show that the proposed method accounts for the acoustic effect of the baffle and the mutual interactions among transducers successfully and obtain a low-sidelobe projecting beampattern, and at the same time provide the largest amplitude of pressure in the axial direction when the maximum amplitude of the driving voltage weighting vectors keeps unchanged.

  14. Numerical simulation of heat transfer enhancement in shell side of shell-and-tube heat exchanger with leading type shutter baffles

    International Nuclear Information System (INIS)

    For overcoming the contradiction between the performance improvement and fluid flow resistance increase in shell-and-tube heat exchanger, a new concept of 'Sideling Flow' in shell side is presented, and a type of new high efficiency energy saving shell-and-tube heat exchanger with leading type shutter baffles in shell side, sideling flow heat exchanger is invented. Besides, the 'Field Synergy Principle' is adopted to analyze its heat transfer enhancement mechanism, and it is indicated that there is the perfect synergy between the velocity field and temperature grads field in shell side of this type of new heat exchanger. Effects of the structure parameters on the fluid flow and heat transfer are investigated through numerical simulation, and the numerical results are in good agreement with the experimental data. (authors)

  15. Vibration Analysis and Influence of Tubular Heat Exchangers Affected by Baffle Structure Size%折流板结构尺寸对热交换器振动的影响分析

    Institute of Scientific and Technical Information of China (English)

    郭涛; 赵崇卫; 马虹

    2015-01-01

    为了评估折流板结构尺寸对热交换器振动的影响,在分析各种振动机理的基础上,以海洋石油平台代表性热交换器实例为研究对象,利用 FORTRAN 语言编制计算程序,对不同折流板结构尺寸对热交换器振动的影响进行理论研究。研究结果表明,减小折流板间距对防止流体弹性不稳定振动、湍流抖振、漩涡脱落和声振均非常有效;减小折流板切割率对流体弹性不稳定振动影响不大,但对防止湍流抖振、漩涡脱落和声振较为有效。针对不同振动问题,调整折流板间距或切割率非常有效。%In order to evaluate heat exchanger vibration impact affected by baffle structure,u-sing a typical example of heat exchanger as research object,by FORTRAN program language,to analyze all kinds of vibration mechanism of different baffle structure size.Research results show that,reducing baffle spacing is very effective to prevent fluid elastic instability,turbulence buffe-ting vibration,vortex shedding and resonance vibration.Changing baffle cutting rate have little effect of fluid elastic instability vibration,but very effective to prevent turbulence buffeting,vor-tex shedding and resonance vibration.Therefore,according to the different vibration problems, adjust the baffle spacing or cutting rate is very effective.

  16. Frequency and Magnitude Analysis of the Macro-instability Related Component of the Tangential Force Affecting Radial Baffles in a Stirred Vessel

    Directory of Open Access Journals (Sweden)

    P. Hasal

    2002-01-01

    Full Text Available Experimental data obtained by measuring the tangential component of force affecting radial baffles in a flat-bottomed cylindrical mixing vessel stirred with pitched blade impellers is analysed. The maximum mean tangential force is detected at the vessel bottom. The mean force value increases somewhat with decreasing impeller off-bottom clearance and is noticeably affected by the number of impeller blades. Spectral analysis of the experimental data clearly demonstrated the presence of its macro-instability (MI related low-frequency component embedded in the total force at all values of impeller Reynolds number. The dimensionless frequency of the occurrence of the MI force component is independent of stirring speed, position along the baffle, number of impeller blades and liquid viscosity. Its mean value is about 0.074. The relative magnitude (QMI of the MI-related component of the total force is evaluated by a combination of proper orthogonal decomposition (POD and spectral analysis. Relative magnitude QMI was analysed in dependence on the frequency of the impeller revolution, the axial position of the measuring point in the vessel, the number of impeller blades, the impeller off-bottom clearance, and liquid viscosity. Higher values of QMI are observed at higher impeller off-bottom clearance height and (generally QMI decreases slightly with increasing impeller speed. The QMI value decreases in the direction from vessel bottom to liquid level. No evident difference was observed between 4 blade and 6 blade impellers. Liquid viscosity has only a marginal impact on the QMI value.

  17. Study of vibration analysis method for fluid-structure interaction of a top-entry loop type FBR; experiment and analysis of the thermal baffle in the reactor vessel

    International Nuclear Information System (INIS)

    This paper presents the results of vibration experiments and analyses using a finite element method (FEM) performed on a thermal baffle of the reactor vessel wall in a top-entry loop type fast breeder reactor (FBR). Two types of tests and analyses were carried out. The first 'Multiple Cylinder Test' was to understand the fluid-structure interacting vibration of thin multiple cylinders (flexible thermal baffle), using a 1/5-scale model of the reactor vessel and the thermal baffle of the top-entry loop type FBR reactor structure. The second 'Non-linear Effect Test' was to understand the basic phenomena of fluid-structure interacting vibration under non-linear fluid pressure conditions, using a rigid double cylindrical basic model. The results of the multiple cylinder test showed that in the beam vibration including oval mode, the natural frequency can be well estimated by FEM analysis code FINAS. The results of the non-linear effect tests showed that virtual mass is constant even under non- linear pressure conditions, and virtual mass can be well estimated by a formulation based on potential flow theory. (author)

  18. Effect of Six Missile-Bay Baffle Configurations and a Rocket End Plate on Ejection Releases of an MB-1 Rocket from a 0.05 Scale Model of the Convair F-106A Airplane

    Science.gov (United States)

    Hinson, William F.; Lee, John B.

    1959-01-01

    As a continuation of an investigation of the release characteristics of an MB-1 rocket carried internally by the Convair F-106A airplane, six missile-bay baffle configurations and a rocket end plate have been investigated in the 27- by 27-inch preflight jet of the NASA Wallops Station. The MB-1 rocket used had retractable fins and was ejected from a missile bay modified by the addition of six different baffle configurations. For some tests a rocket end plate was added to the model. Dynamically scaled models (0.04956 scale) were tested at a simulated altitude of 22,450 feet and Mach numbers of 0.86, 1.59, and 1.98, and at a simulated altitude of 29,450 feet and a Mach number of 1.98. The results of this investigation indicate that the missile-bay baffle configurations and the rocket end plate may be used to reduce the positive pitch amplitude of the MB-1 rocket after release. The initial negative pitching velocity applied to the MB-1 rocket might then be reduced in order to maintain a near-level-flight attitude after release. As the fuselage angle of attack is increased, the negative pitch amplitude of the rocket is decreased.

  19. On the effect of added impurity on crystal purity of urea in an oscillatory baffled crystallizer and a stirred tank crystallizer

    Science.gov (United States)

    McLachlan, Hannah; Ni, Xiong-Wei

    2016-05-01

    Previous work has indicated that crystals produced in oscillatory baffled crystallisers (OBC) from a relatively 'pure' starting environment gave statistically higher purities than that in stirred tank crystallisers (STC) under comparable conditions. In this work, a known amount of biuret (the impurity) was added to the 'pure' urea system and the results show that the OBC still produced higher purity crystals than the STC, although these purity values were statistically lower than from the 'pure' environment in both vessels. By evaluating crystallisation rates of both urea and biuret, we noticed that these rates are higher in the STC than in the OBC, which would have led to small crystals in the former vessel. The CSD data however gave the opposite result where the CSD is wider with more, large crystals in the STC than in the OBC, in particular in the presence of added impurity. These larger crystals are likely formed due to agglomeration coupled with incorporation of impurity, which leads to a lower purity.

  20. The invention of the roll crusher with the baffle plate%一种带挡料板的对辊破碎机的研发

    Institute of Scientific and Technical Information of China (English)

    杨东彪; 王晓娟; 余春晖

    2015-01-01

    This paper developed a roll crusher which including the roller bracket, driving roller and the driven roller. The roll crusher is mainly used for ore crushing. It’s feature is the baffle plate which set up between the first bearing seat of the driving shaft and the second bearing seat of the driven shaft. Its advantage is to prevent the material into the guide plane and make the face of the guide plane easily be clean .It can prolong the service life of crusher and greatly improve the working efficiency.%文章研发了一种对辊破碎机,主要用于矿石破碎,包括辊筒支架、主动辊筒和从动辊筒,其特点在于主动轴的第一轴承座与从动轴第二轴承座之间设置有挡料板,其优点在于该对辊破碎机可防止物料在工作时进入到导轨平面,使得导轨平面易于清理,这样不仅可以延长破碎机的使用寿命而且大大提高了工作效率。

  1. Development and application of a two-dimensional computer code for the investigation of the transient behaviour of a steam reformer with segmental baffles

    International Nuclear Information System (INIS)

    This study deals with the theoretical description of heat transport and flow distribution in a helium-heated steam reformer with segmental baffles. For this purpose a two-dimensional, transient computer code is developed, which is described in detail. A first application of this code is demonstrated by designing an 8.25 MW steam reformer for the planned AVR-process heat plant. In a parameter study the sensitivity of such a heat exchanger to the variation of some constructional features is demonstrated and the above mentioned 8.25 MW steam reformer is optimized by the aid of the so gained knowledge. Finally the transient behaviour of the hot gas duct and the steam reformer of the AVR-process heat plant during start up is investigated. It is shown, that, from the technical point of view, it will be possible to start operating the process heat loop with a helium temperature above 600degC while keeping within safety requirements. (orig.)

  2. Reduction of COD and Turbidity of Effluent in the Swine Productions Unit Employing Anaerobic Baffled Reactor (ABR Followed by Biological Filters and Sand Filter

    Directory of Open Access Journals (Sweden)

    Euzebio Beli

    2010-04-01

    Full Text Available The growing swine production is constantly in conflict with the environment due to the lack of environmental management directed to the cycle of animal production and the industrial sector, mainly due to the mishandling of slurry produced. In association with large concentrations of confined animals appear huge dumps of organic matter, inorganic nutrients and gaseous emissions, which require special care for its disposal to the environment. The aim of this study was to evaluate the use of an anaerobic baffled reactor (ABR in series with two downflow biological filters, followed by a sand filter as a polishing treatment. It were analyzed the reduction of COD and turbidity, and the behavior of pH in all phases of treatment. The removal of COD in the conjugated system, which occurred during treatment ranged from 74.55% to 94.41% with an average removal of 84.24%. In turn, the removal of turbidity from the period ranged from 53.07% to 96.11% with an average removal of 85.49%. In the studied period the pH changed from 5,6 to 8,4. This system was efficient in the removal of COD and turbidity of swine wastewater.

  3. Physical-chemical and operational performance of an anaerobic baffled reactor (ABR treating swine wastewater - 10.4025/actascitechnol.v32i4.7203

    Directory of Open Access Journals (Sweden)

    Erlon Lopes Pereira

    2010-12-01

    Full Text Available Since hog raising concentrates a huge amount of swine manure in small areas, it is considered by the environmental government organizations to be one of the most potentially pollutant activities. Therefore the main objective of this research was to evaluate by operational criteria and removal efficiency, the performance of a Anaerobic Baffled Reactor (ABR, working as a biological pre-treatment of swine culture effluents. The physical-chemical analyses carried out were: total COD, BOD5, total solids (TS, fix (TFS and volatiles (TVS, temperature, pH, total Kjeldahl nitrogen, phosphorus, total acidity and alkalinity. The ABR unit worked with an average efficiency of 65.2 and 76.2%, respectively, concerning total COD and BOD5, with a hydraulic retention time (HRT about 15 hours. The results for volumetric organic loading rate (VOLR, organic loading rate (OLR and hydraulic loading rate (HLR were: 4.46 kg BOD m-3 day-1; 1.81 kg BOD5 kg TVS-1 day-1 and 1.57 m3 m-3 day-1, respectively. The average efficiency of the whole treatment system for total COD and BOD5 removal were 66.5 and 77.8%, showing an adequate performance in removing the organic matter from swine wastewater.

  4. Relationships between chemical oxygen demand (COD) components and toxicity in a sequential anaerobic baffled reactor/aerobic completely stirred reactor system treating Kemicetine

    International Nuclear Information System (INIS)

    In this study the interactions between toxicity removals and Kemicetine, COD removals, intermediate products of Kemicetine and COD components (CODs originating from slowly degradable organics, readily degradable organics, inert microbial products and from the inert compounds) were investigated in a sequential anaerobic baffled reactor (ABR)/aerobic completely stirred tank reactor (CSTR) system with a real pharmaceutical wastewater. The total COD and Kemicetine removal efficiencies were 98% and 100%, respectively, in the sequential ABR/CSTR systems. 2-Amino-1 (p-nitrophenil)-1,3 propanediol, l-p-amino phenyl, p-amino phenol and phenol were detected in the ABR as the main readily degradable inter-metabolites. In the anaerobic ABR reactor, the Kemicetin was converted to corresponding inter-metabolites and a substantial part of the COD was removed. In the aerobic CSTR reactor the inter-metabolites produced in the anaerobic reactor were completely removed and the COD remaining from the anerobic reactor was biodegraded. It was found that the COD originating from the readily degradable organics did not limit the anaerobic degradation process, while the CODs originating from the slowly degradable organics and from the inert microbial products significantly decreased the anaerobic ABR reactor performance. The acute toxicity test results indicated that the toxicity decreased from the influent to the effluent of the aerobic CSTR reactor. The ANOVA test statistics showed that there was a strong linear correlation between acute toxicity, CODs originating from the slowly degradable organics and inert microbial products. A weak correlation between acute toxicity and CODs originating from the inert compounds was detected.

  5. 隧道内缓冲结构对高速列车微压波的影响%The Influence of Baffle Structure on Micro-pressure Wave Generated by High-speed Train Entering a Tunnel

    Institute of Scientific and Technical Information of China (English)

    臧俊; 薛雷平

    2013-01-01

    采用数值方法模拟列车通过隧道的过程,并使用前人的实验数据对计算模型进行了验证.研究了隧道内挡板缓冲结构对微压波强度的影响,揭示挡板装置产生微压波的双峰特征,得到挡板大小和挡板安装位置对微压波强度的影响规律.结果表明,在隧道内合理地安装挡板能有效地削减隧道内压缩波强度,从而削减隧道出口处徼压波强度.%A compressive wave will be generated when a high-speed train enters a tunnel. Then the com-pressive wave will travel with the velocity of sound to the outlet of the tunnel and radiate a micro-pressure wave into the field outside of the tunnel. A numerical method was used to simulate the process that the high-speed train enters a tunnel. Also the experimental data was used to verify the computational model. On this base, the influence of the baffle structure on the micro-pressure wave was studied. The result shows that two micro-pressure waves will be generated with the baffle assembled in the tunnel. Also we the influence of the position and size of the baffle on the micro-pressure wave was got.

  6. Hybrid FAHP (fuzzy analytical hierarchy process)-FTOPSIS (fuzzy technique for order preference by similarity of an ideal solution) approach for performance evaluation of the V down perforated baffle roughened rectangular channel

    International Nuclear Information System (INIS)

    In the present study a methodology has been proposed to evaluate the performance of the V down perforated baffle roughened rectangular channel using hybrid FAHP-FOPSIS approach. The hybrid FAHP (fuzzy analytical hierarchy process) and FTOPSIS (fuzzy technique for order preference by similarity of an ideal solution) approach, taking into account PDAs (performance defining attributes), such as Nusselt number ratio, friction factor ratio, thermohydraulic performance parameter and effective efficiency, was used for the performance prediction of the V down perforated baffle roughened rectangular channel. The weight of different PDAs was evaluated by FAHP; Nurat (0.060, 0.093, 0.138), frat (0.045, 0.066, 0.105), ε (0.170, 0.244, 0.352) and ηeff (0.431, 0.597, 0.821), respectively. FTOPSIS was employed to determine the optimum ranking of the V down perforated baffle roughened rectangular channel and the values obtained as; C6 > C5 > C8 > C7 > C9 > C10 > C2>C11 > C12 > C1 > C3 > C13 > C14 > C4 >  C15 > C16. The test plate (alternative) with an open area ratio (β) of 24%, relative roughness pitch (P/e) of 2 and relative roughness height (e/H) of 0.4, exhibits the optimal formulation. - Highlights: • Combined FAHP and FTOPSIS MCDM approach applied for performance prediction. • The weight of performance defining attribute is calculated using FAHP. • Ranking of alternatives is carried out using FTOPSIS. • The optimum test plate configuration is β: 24%, P/e: 2 and e/H: 0.4

  7. The Kingman Report: Baffling Directions.

    Science.gov (United States)

    Preen, David; Saunders, Mick

    1989-01-01

    Examines the Kingman Report (Report of the Committee of Inquiry into the Teaching of English Language, HMSO, 1988). Finds that an analysis of the report shows it to abound in confusions and omissions. (MM)

  8. Reator compartimentado anaeróbio/aeróbio: sistema de baixo custo para tratamento de esgotos de pequenas comunidades Anaerobic/aerobic baffled reactor: low cost system for sewage treatment in small communities

    Directory of Open Access Journals (Sweden)

    Gustavo H. R. da Silva

    2005-06-01

    Full Text Available No Brasil são conhecidas e usadas várias técnicas de tratamento de esgoto, desde os mais sofisticados sistemas de tratamento aos mais simples processos. Uma alternativa economicamente viável aos sistemas de tratamento de esgotos sanitários é o processo anaeróbio, o qual tem recebido especial atenção nas pesquisas desenvolvidas no País, notadamente os reatores anaeróbios de alta taxa, unidades compactas e com boa eficiência de tratamento. Dentre as alternativas tecnológicas capazes de proporcionar as referidas variações das condições ambientais necessárias à ocorrência dos processos, está o uso de reatores compartimentados anaeróbio/aeróbio. Este trabalho apresenta, como alternativa, um reator compartimentado anaeróbio/aeróbio, tratando esgoto sanitário, como possibilidade de ser utilizado em pequenas comunidades urbanas e rurais. O desempenho do sistema foi avaliado em diversos tempos de detenção hidráulica (TDH, nos quais os melhores valores de Demanda Química de Oxigênio Total (DQOtotal - 73,7% e Sólidos em Suspensão Totais (SST - 78,8%, foram obtidos com TDHtotal de 8 horas (4 horas para a fase anaeróbia e 4 horas para a fase aeróbia. O reator compartimentado apresentou a característica de estabilidade operacional necessária aos sistemas de baixo custo.Several techniques of sewage treatment, from the most sophisticated to the simplest processes, are known in Brazil. An economically viable alternative for the systems of treatment of sanitary sewage is the anaerobic process, which has been given special attention in Brazilian research programs, mainly in the field of high rate anaerobic reactors as they are compact units and have high efficiency. The use of baffled anaerobic/aerobic reactors is one technological solution to provide the necessary variations in environmental conditions to foster the processes mentioned. In this paper an alternative is presented in the form of a baffled anaerobic

  9. Farklı Hidrolik Bekletme Sürelerinin Anaerobik Perdeli Reaktörde Sülfat İndirgenmesi Üzerine Etkisi / Effect of Different Hydraulic Retention Time (HRT on Sulfate Reduction in Anaerobic Baffled Reactor

    Directory of Open Access Journals (Sweden)

    Şebnem ÖZDEMİR

    2012-12-01

    üresinin 2 gün olduğu çalışma koşullarında çıkış suyundaki KOİ ve SO4-2 verimleri %84 ile %88 olarak gözlemlenirken bekleme süresinin 0,5 gün olduğu çalışma koşullarında ise bu değer %80 ve %75 olarak gözlemlenmiştir. Ayrıca bekleme süresinin 2 gün olduğu çalışma koşullarında son bölmedeki sülfür oluşum verimi % 75 iken, bekleme süresi 0,5 güne indirildiğinde aynı bölmedeki sülfür oluşum veriminin %96’a çıktığı gözlemlenmiştir. Çıkarımlar ve Özgün Değer: Yapılan bu çalışma ile yüksek sülfat konsantrasyona sahip atıksuların arıtımında anaerobik perdeli reaktörün iyi bir alternatif olabileceği kanıtlanmıştır. Ayrıca çıkış sülfat ve sülfür konsantrasyonlarının değişen HBS’den etkilenmediği gözlenmiştir. Effect of Different Hydraulic Retention Time (HRT on Sulfate Reduction in Anaerobic Baffled Reactor Design and Method: The anaerobic baffled reactor (ABR is a modification of up-flow anaerobic sludge blanket (UASB reactor. A laboratory scale ABR was inoculated with an effluent of a full scale anaerobic digester located in Kayseri Wastewater Treatment Plant, Turkey. Before inoculation, the sludge was sieved to remove coarse materials. The ABR was 20 cm wide, 80 cm long, 20 cm deep and constructed from glass, with a working volume of 19 L. Reactor was divided into four equal 4.75 L compartments by vertical baffles, each compartment having down-comer and riser regions created by further vertical baffle. The lower parts of down-comer baffles were angled at 450 in order to direct the flow evenly through the riser. Ethanol and sulfate are consumed as electron donor and electron acceptor, respectively. Sulfate, dissolved sulfide, pH, alkalinity and chemical oxygen demand (COD have measured three times a week. Aim: There are varying structures and concentrations of sulfate compounds in natural waters. In addition, the amount of sulfate is higher in some industrial wastewaters In addition, some

  10. Microfluidic bioprocess control in baffled microtiter plates

    OpenAIRE

    Funke, Matthias

    2011-01-01

    The efficiency of biotechnological production processes depends on selecting the best performing biocatalyst and the optimal operation conditions. Thus, during the screening and process development phases, many experiments have to be conducted, which conflicts with the demand to speed up drug development processes. This conflict is addressed, for example, by the fiber-optic online-monitoring system BioLector which utilizes the wells of shaken microtiter plates (MTPs) as small-scale fermenters...

  11. Treatment of Molasses Alcohol Wastewater by Anaerobic Baffled Reactor%厌氧折流板反应器处理糖蜜酒精废水的研究

    Institute of Scientific and Technical Information of China (English)

    赵宸艺; 陈源龙; 蒋永荣; 韦添尹

    2012-01-01

    Removal efficiency of anaerobic baffled reactor (ABR) treating molasses alcohol industrial wastewater was investigated, which had succeeded in treating simulated molasses alcohol wastewater. During the experiments of 30 days, chemical oxygen demand (COD) and sulfate (SO4 2-) removal efficiency, volatile fatty acid (VFA).pH and sulfide(S2-) distribution in each compartment were studied. Experimental results showed that under the conditions of the load of COD and SO4 2- as 4.8 kg/(m3·d) and 0.32 kg/(m3·d),the removal efficiency of COD and SO4 2- were 83% and 98% respectively. The change of VFA concentration and pH in each compartment were basically identical. S2- concentration in each compartment was low, and S2- concentrations in Compartment 4 and 5 were less than 40 mg/L. Multi-phase separation characteristics (acidogenic phase and methanogenic phase, sulfate-reducing phase and sulfur-producing phase) that had formed during simulated molasses alcohol wastewater treatment were remained, which would ensure the removal efficiency of ABR treating molasses alcohol industrial wastewater.%为探究厌氧折流板反应器(ABR)对糖蜜酒精实际废水的处理效果,该实验采用已成功处理人工模拟糖蜜酒精废水的ABR,研究了该反应器处理糖蜜酒精工业废水过程中COD和SO42-的去除效果,以及各隔室VFA、pH和S2-的分布规律.实验结果表明,反应器处理糖蜜酒精工业废水,在30d内达到稳定,COD和SO42-负荷分别为4.8 kg/(m3·d)和0.32 kg/(m3 ·d),COD和SO42-的去除率分别为83%和98%.反应器内各隔室挥发性脂肪酸(VFA)浓度变化规律与pH值变化规律一致,各隔室硫化物(S2-)浓度较低,其中第4、5隔室的S2-浓度低于40 mg/L.反应器内微生物菌群仍能保持处理模拟废水时形成的多相(产酸硫酸盐还原相和生成硫单质产甲烷相)分离特征,保证了ABR对实际工业废水的处理效率.

  12. Uso de leitos cultivados de fluxo vertical por batelada no pós-tratamento de efluente de reator anaeróbio compartimentado Post-treatment of effluent of anaerobic baffled reactor using batchwise vertical flow constructed wetland beds

    Directory of Open Access Journals (Sweden)

    Marcelo Mazzola

    2005-06-01

    Full Text Available Neste trabalho avaliou-se o desempenho de um Reator Anaeróbio Compartimentado (RAC de duas câmaras em série, seguido de três leitos cultivados (constructed wetlands de fluxo vertical por batelada. A unidade experimental, em escala piloto, foi instalada na Faculdade de Engenharia Agrícola - UNICAMP, Campinas, SP, Brasil. O volume total do reator era de 2,3 m³ (TDH de 12 h. O efluente do RAC foi tratado em três leitos, dois cultivados com macrófitas (gêneros Typha sp. e Eleocharis sp. e um utilizado como controle (não cultivado. Os leitos, com 2,0 m³ cada um e brita #2 (24 - 35 mm como meio suporte, operaram com fluxo vertical por batelada (com tempos de reação de 24, 48, 72 e 96 h. Na avaliação do RAC, observou-se tendência de estabilização dos parâmetros pH, alcalinidade, ácidos voláteis, sólidos sedimentáveis e suspensos totais, porém a remoção de DQO revelou-se limitada (50%. Nos leitos cultivados o aumento do tempo de reação (até 72 h foi acompanhado pelo aumento de remoção de turbidez, DQO, fósforo e nitrato. O melhor desempenho de remoção de fósforo total foi obtido no leito vegetado com Typha sp para os tempos de 72 e 96 h, respectivamente, de 30 e 25%.This study evaluated the performance of vertical constructed wetlands treating effluent of anaerobic baffled reactor. The anaerobic reactor volume was 2.3 m³; it was operated with daily flow of 4.6 m³ (12 hours Hydraulic Retention Time. The reactor effluent was split into three wetlands beds, two of them cultivated with macrophytes (Typha sp. and Eleocharis sp., and one control. The wetlands were operated as a batch reactor. The medium utilized was gravel, the size ranging from 7 to 12 mm. The reaction time for each cycle (filling - reaction - drainage was 24, 48, 72, and 96 h. The anaerobic reactor achieved the following removal rates: settable solids, 93%; suspended solids, 80%; and COD 39%. The increase in reaction time (up to 72 h for the constructed

  13. Japanese Invasion Baffled Radically the Modernization of China's Judicial System

    OpenAIRE

    Chunlan Qiu; Keke Liu

    2009-01-01

    It is the critical time for China to generate and develop the modern judicial system when Japan invaded. Japanese aggression interrupted China’s recovering its legal right and the process to promote the modern judicial system. The invasion brought a great loss to the judicial resources. The relatively stable colonial rule, as well as the war itself, was harmful. Both stood on the way of China's judicial modernization.

  14. Physical-chemical and operational performance of an anaerobic baffled reactor (ABR treating swine wastewater = Desempenho físico-químico e operacional de um reator anaeróbio compartimentado (RAC como tratamento biológico preliminar de efluentes de suinocultura

    Directory of Open Access Journals (Sweden)

    Erlon Lopes Pereira

    2010-10-01

    Full Text Available Since hog raising concentrates a huge amount of swine manure in smallareas, it is considered by the environmental government organizations to be one of the most potentially pollutant activities. Therefore the main objective of this research was to evaluate by operational criteria and removal efficiency, the performance of a Anaerobic Baffled Reactor (ABR, working as a biological pre-treatment of swine culture effluents. The physical-chemical analyses carried out were: total COD, BOD5, total solids (TS, fix (TFS and volatiles (TVS, temperature, pH, total Kjeldahl nitrogen, phosphorus, total acidity and alkalinity. The ABR unit worked with an average efficiency of 65.2 and 76.2%, respectively, concerning total COD and BOD5, with a hydraulic retention time (HRT about 15 hours. The results for volumetric organic loading rate (VOLR, organic loading rate (OLR andhydraulic loading rate (HLR were: 4.46 kg BOD m-3 day-1; 1.81 kg BOD5 kg TVS-1 day-1 and 1.57 m3 m-3 day-1, respectively. The average efficiency of the whole treatment system for total COD and BOD5 removal were 66.5 and 77.8%, showing an adequate performancein removing the organic matter from swine wastewater.A suinocultura por ser uma atividade pecuária concentradora de dejetos em pequenas áreas é considerada, pelos órgãos de gerência ambiental, como uma das atividades mais degradadoras do meio ambiente. Nesta pesquisa objetivou-se, por conseguinte, avaliar a utilização de um reator anaeróbio compartimentado (RAC, como unidade de prétratamento de um reator tipo UASB, em escala piloto, na adequação ambiental dos efluentes de suinocultura, avaliando critérios operacionais e a eficiência. As análises físico-químicasrealizadas foram: DQOtotal, DBO5, sólidos totais (ST, fixos (SF e voláteis (SV, temperatura, pH, nitrogênio total Kjeldahl, fósforo, acidez total e alcalinidade. A unidade RAC trabalhou com eficiência de 65,2 e 76,2% para a remoção de DQOtotal e DBO5

  15. Desempenho de processo anaeróbio em dois estágios (reator compartimentado seguido de reator UASB para tratamento de águas residuárias de suinocultura Performance of two-stage anaerobic process (baffled reactor (ABR followed by an upflow sludge blanket reactor (UASB treating swine wastewater

    Directory of Open Access Journals (Sweden)

    Gracie F. R. Fernandes

    2006-04-01

    Full Text Available Avaliou-se o efeito das águas residuárias de suinocultura com concentrações de sólidos suspensos totais em torno de 6.000 mg L-1 (DQOtotal variando de 7.557 a 11.640 mg L-1 no desempenho de processo anaeróbio em dois estágios compostos por reator compartimentado (ABR e reator de fluxo ascendente com manta de lodo (UASB, instalados em série, em escala-piloto (volumes de 530 e 120 L, respectivamente, submetidos a tempos de detenção hidráulica (TDH de 56 a 18 h no primeiro reator e de 13 a 4 h no segundo reator. As eficiências médias de remoção de DQOtotal variaram de 71,1 a 87,5% no reator ABR e de 41,5 a 50,1% no reator UASB, resultando em valores médios de 86,8 a 94,9% para o sistema de tratamento anaeróbio em dois estágios com carga orgânica volumétrica (COV, na faixa de 5,05 a 10,12 kg DQOtotal (m³ d-1, no reator ABR, e de 2,83 a 9,63 kg DQOtotal (m³ d-1, no reator UASB. As eficiências de remoção de SST e SSV foram da ordem de 95,6%. O teor de metano no biogás manteve-se acima de 70% para os dois reatores. A produção volumétrica de metano máxima de 0,755 m³ CH4 (m³ d-1 ocorreu no reator 1, com COV de 10,12 kg DQOtotal (m³ d-1 e TDH de 18 h. Os valores médios de pH variaram na faixa de 7,2 a 8,0 para os efluentes dos reatores 1 e 2. Os ácidos voláteis totais mantiveram-se estáveis com concentrações abaixo de 200 mg L-1. Com variações abruptas e acentuadas de concentrações de SST e DQOtotal do afluente, os reatores mantiveram as eficiências de remoção de DQO e sólidos suspensos, em torno de 70%, e a qualidade do biogás, com 80% de CH4.In this work it was evaluated the effect of swine wastewater with total suspended solid (TSS concentration around 6000 mg L-1 (CODtotal from 7557 to 11640 mg L-1 on the performance of two stage anaerobic process constituted of anaerobic baffled reactors (ABR and an upflow sludge blanket reactor (UASB installed in series, in pilot scale testing (volumes of 530 L and

  16. Remoção de matéria orgânica, de nutrientes e de coliformes no processo anaeróbio em dois estágios (reator compartimentado seguido de reator UASB para o tratamento de águas residuárias de suinocultura Organic matter, nutrients and coliforms removal in two-stage anaerobic process (anaerobic baffled reactor followed by UASB reactor for swine wastewater treatment

    Directory of Open Access Journals (Sweden)

    Mário S. de Abreu Neto

    2009-03-01

    Full Text Available Neste trabalho, avaliou-se o efeito das águas residuárias de suinocultura, com concentrações médias de sólidos suspensos totais variando de 4.591 a 13.001 mg L-1, no desempenho de processo anaeróbio, em dois estágios, compostos por reator compartimentado (ABR e reator de fluxo ascendente com manta de lodo (UASB, instalados em série, em escala- -piloto (volumes de 530 e 120 L, respectivamente, submetidos a tempos de detenção hidráulica (TDH de 60; 36 e 24 h no primeiro reator, e de 13,6; 8,2 e 5,4 h no segundo reator. As eficiências médias de remoção de DQOtotal variaram de 69 a 84% no reator ABR e de 39 a 58% no reator UASB, resultando em valores médios de 87 a 94% para o sistema de tratamento anaeróbio em dois estágios, com carga orgânica volumétrica (COV na faixa de 11,5 a 18,0 g DQOtotal (L d-1 no reator ABR, e de 4,2 a 13,4 g DQOtotal (L d-1 no reator UASB. A produção volumétrica máxima de metano de 0,227 m³ CH4 (m³ reator d-1 ocorreu no reator UASB, com COV de 10,6 g DQOtotal (L d-1 e TDH de 5,4 h. As maiores eficiências de remoção de coliformes totais e termotolerantes (99,7%, DQOdiss (94%, SST (96%, NTK (71%, P-total (61% e outros nutrientes, no sistema de tratamento anaeróbio em dois estágios, foram obtidas com o TDH de 73,6 h e temperatura climatológica média de 24,6 °C, aplicando-se a menor COV (de 11,5 g DQOtotal (L d-1 no reator ABR, e de 4,2 g DQOtotal (L d-1 no reator UASB com a maior concentração de SST do afluente (13.001 mg L-1.In this work it was evaluated the effect of swine wastewater with mean total suspended solid (TSS concentration ranging from 4.591 to 13.001 mg L-1 on the performance of the anaerobic process in two stages composed of anaerobic baffled reactors (ABR and an upflow sludge blanket reactor (UASB, installed in series, in pilot scale testing (volumes of 530 and 120 L, respectively and with hydraulic detention times (HDT of 60; 36 and 24 h in the ABR reactor and 13.6; 8.2 and

  17. Evaluation Of Communal Wastewater Treatment Plant Operating Anaerobic Baffled Reactor And Biofilter

    Directory of Open Access Journals (Sweden)

    Evy Hendriarianti

    2016-02-01

    Full Text Available Construction of communal Waste Water Treatment Plant, WWTP in city of Malang since 1998 but until recently had never done an evaluation the performance. Communal WWTP performance evaluation is needed to see how far the efficiency of processing result. Until now, Environmental Agency Malang City only measure effluent from WWTP Communal  to know the suitability  with domestic wastewater quality standards. Effluent quality data in 2014 showed value above the quality standard of domestic wastewater from East Java Governor Regulation No. 72 in 2013 for parameters BOD and COD. WWTP Communal USRI research objects are on a six (6 locations by involving the user community during the planning, construction, operation and maintenance. Technology choice of ABR followed by a biofilter reactor with the stone media proved capable of processing organic matter of BOD and COD with the removal levels respectively by 78% -99% and 71% -99%. As for the parameters of TSS, NO3 and PO4 have the ranges of removal respectively by 56% -100%, (43% - 72%, (2% - 13%. Ratio BOD and COD in influent are low and ranged from 0.22 to 0.41. From the evaluation shows that high organic matter concentrations in influent along with the HRT and operation time high will result in a higher removal level

  18. Evaluation Of Communal Wastewater Treatment Plant Operating Anaerobic Baffled Reactor And Biofilter

    OpenAIRE

    Evy Hendriarianti; Nieke Karnaningroem

    2016-01-01

    Construction of communal Waste Water Treatment Plant, WWTP in city of Malang since 1998 but until recently had never done an evaluation the performance. Communal WWTP performance evaluation is needed to see how far the efficiency of processing result. Until now, Environmental Agency Malang City only measure effluent from WWTP Communal  to know the suitability  with domestic wastewater quality standards. Effluent quality data in 2014 showed value above the quality standard of domestic wastewat...

  19. Flow rate measurements in a draft tube baffle crystallizer using a radioactive flow follower technique

    International Nuclear Information System (INIS)

    Flow rates produced by two different propellers (designated PR-L and PR-R), designed and manufactured by two different companies and used in a draft tube crystallizer, have been measured by means of a neutrally buoyant radioactive flow follower technique. Comparison of the results indicates that the flow rates produced by the propeller PR-L were higher than the propeller PR-R. From the measured flow rates, the characteristic flow numbers of the propellers were calculated and used to predict the behaviour of the propeller for varying operating conditions. The flow numbers ranged from 0.3 to 0.5 and 0.4 to 1.3 for PR-R and PR-L respectively

  20. Removal of Organic Load in Communal Wastewater by using the Six Stage Anaerobic Baffle Reactor (ABR)

    OpenAIRE

    Trilita Minarni Nur; Hendrasarie Novirina; Wahjudijanto Iwan

    2016-01-01

    The reduction of water quality in the urban drainage is a crucial problem to overcome because it can affect the health of community. This fact encouraged the researcher to conduct the research in efforts to increase the water quality in the drainage. One of the solutions to increase the water quality in the drainage is that the domestic wastewater must be treated at first before it is flown through the drainage. Furthermore, the wastewater treatment was conducted by employing the communal was...

  1. Heat Transfer and Hydrodynamic Investigations of a Baffled Slurry Bubble Comumn

    Institute of Scientific and Technical Information of China (English)

    S.C.Saxena; Z.D.Chen

    1992-01-01

    Heat transfer and hydrodynamic investigations have been conducted in a 0.108 m internal diameter bubble column at ambient conditions,The colum is equipped with seven 19mm diameter tubes arranged in an equilateral triangular pitch of 36.5mm.A monsanto synthetic heat transfer fluid,Therminol-66 having a viscosity of 39.8 cP at 303 K,is used as a liquid medium,Magnetite powders.average diameters 27.7 and 36.6um,in five concentrations up to 50 weitht percent in the slurry,are used,As a ges phase,industrial grade nitrogen of purity 99.6 percent is employed.Gas holdup in different operating modes and regimes have been measured for the two-and three-phase systems over a superficial gas velocity range up to 0.20 m/s in the semi-batch moed.Heat transfer coefficients are measured at different tube locations in the bundle at different radial and vertical locations over a range of operating conditions,all these data are compared with the existing literature correlations and models.New correlations are proposed.

  2. Thermal model and analysis of the BELA transmitter Stavroudis baffle in Mercury orbit

    OpenAIRE

    Del Togno, Simone

    2009-01-01

    In the frame of the ESA BepiColombo mission to the planet Mercury the German Aerospace Center (DLR), in cooperation with the University of Bern, is designing the first European laser altimeter for planetary exploration (BELA). While orbiting Mercury the solar flux reaches 14 kW and strikes on the instrument at angles of > 38 deg from the instrument line of sight. The planet surface reaches 700 K while the view factor with the instrument aperture is high due to the low orbit altitude. Un...

  3. The Design, Construction and Test of stray light suppression baffles for the CHAMP satellite

    DEFF Research Database (Denmark)

    Jørgensen, John Leif

    1997-01-01

    The Advanced Stellar Compass, to be delivered from IAU to the CHAMP project, requires some kind of stray-light suppressing shade to be mounted in front of the lens, in order to minimize the thermal impact and to maximize the performance envelope when subjected to non-stellar external light sources...

  4. Study of fluid flow in baffled vessels stirred by a Rushton standard impeller

    Czech Academy of Sciences Publication Activity Database

    Chára, Zdeněk; Kysela, Bohuš; Konfršt, Jiří; Fořt, I.

    2016-01-01

    Roč. 272, č. 3 (2016), s. 614-628. ISSN 0096-3003 R&D Projects: GA ČR GAP101/12/2274 Institutional support: RVO:67985874 Keywords : trailing vortices * rushton impeller * PIV measurements * DES * numerical simulation Subject RIV: BK - Fluid Dynamics Impact factor: 1.551, year: 2014

  5. Effect of the LHC Beam Screen Baffle on the Electron Cloud Buildup

    CERN Document Server

    Romano, Annalisa; Li, Kevin; Rumolo, Giovanni

    2016-01-01

    Electron Cloud (EC) has been identified as one of the major intensity-limiting factors in the CERN Large Hadron Collider (LHC). Due to the EC, an additional heat load is deposited on the perforated LHC beam screen, for which only a small cooling capacity is available. In order to preserve the superconducting state of the magnets, pumping slots shields were added on the outer side of the beam screens. In the framework of the design of the beam screens of the new HL-LHC triplets, the impact of these shields on the multipacting process was studied with macroparticle simulations. For this purpose multiple new features had to be introduced in the PyECLOUD code. This contribution will describe the implemented simulation model and summarize the outcome of this study.

  6. Perbandingan Desain IPAL Proses Atached Growth Anaerobic Filter dengan Suspended Grwoth Anaerobic Baffled Reactor untuk Pusat Pertokoan di Kota Surabaya

    OpenAIRE

    Abdul Hamid; Mohammad Razif

    2014-01-01

    Perencanaan IPAL dilakukan dengan mengidentifikasi karakteristik dan kuantitas limbah dari pusat pertokoan X di Surabaya. Selanjutnya ditetapkan baku mutu dan kriteria desain. Perhitungan desain meliputi dimensi dan rencana anggaran biaya. Dari hasil perhitungan desain didapatkan desain rinci IPAL unit Anaerobic Filter meliputi dimensi bak ekualisasi (2,2 m x 1,1 m x 1,3 m), Bak Pengendap kompartemen I (7 m x 2,5 m x 1,25) kompartemen II (3,5 m x 2,5 m x 1,25 m), AF tiap kompartemen (1,25 ...

  7. Analysis of Rupture Occurred in Baffle in Draft Tube%导流筒挡板断裂分析

    Institute of Scientific and Technical Information of China (English)

    王轶; 陈念椿; 韩伟

    2011-01-01

    对旋桨式搅拌器导流筒挡板断裂实例进行了分析,结果表明导流筒挡板的断裂系由流体的周向运动而产生的静压作用在挡板上,使挡板弯曲疲劳所致,增加挡板的抗弯截面模量及增加导流筒的旋转刚度都可以对导流筒挡板起到加强作用,并且在导流筒设计时应对挡板进行疲劳分析.

  8. 折流生物膜反应器的研制及优化%Design and optimization of baffled biofilm reactor

    Institute of Scientific and Technical Information of China (English)

    江帆; 陈维平; 王春; 王一军

    2009-01-01

    根据河流污水处理的特点,在较短的反应流程中,增加污水和生物载体的接触时间,设计了折流生物膜反应器,进行污水处理实验,并采用多相流和多孔介质模型耦合进行反应器的结构优化计算分析,计算结果表明.折流板生物载体折叠角度以140°为佳.反应器器壁为外加的直壁型.

  9. Nadine Dorries’ proposals for abstinence education are baffling, off-point and inimical to young women’s, as well as men’s, sexual health

    OpenAIRE

    Drouet, Sophie

    2011-01-01

    Sophie Drouet argues that compulsory abstinence education would endanger young women’s capacities to make informed decisions about their sex lives, burden them with the exclusive responsibility of not getting pregnant, shame them for having sex, and prescribe a dangerously retrograde attitude towards female sexuality.

  10. Comparison of a networks-of-zones fluid mixing model for a baffled stirred vessel with three-dimensional electrical resistance tomography

    International Nuclear Information System (INIS)

    Reliable models for the simulation of mixing vessels are important for the understanding of real-life mixing problems. To achieve these models, information about the mixing in the system must be measured to compare with the predicted values. Electrical resistance tomography has the capability to measure spatial and temporal changes within a vessel in three dimensions even in optically inaccessible environments. This paper discusses the creation of a network-of-zones model for the prediction of mixing within a vessel with a Cowles disc-type agitator. Solving of the network-of-zones simplified transport equations for the vessel predicts the concentration distribution of an inert tracer added to the vessel. The change in this distribution with time is calculated and compared with visual inspection of the vessel. The concentration distribution inside the vessel is also measured using electrical resistance tomography and shows good agreement with the predicted values

  11. Production of bioenergy in anaerobic baffled reactor (ABR) and sludge blanket (UASB) in the treatment os swine waste water; Producao de bioenergia em reatores anaerobios compartimentado (RAC) e de manta de lodo (UASB) no tratamento de efluentes de suinocultura

    Energy Technology Data Exchange (ETDEWEB)

    Moterani, Fabricio; Pereira, Erlon Lopes; Campos, Claudio M.M. [Universidade Federal de Lavras (DEG/UFLA), MG (Brazil). Dept. de Engenharia], email: fabricio_moterani@yahoo.com.br

    2011-07-01

    The biogas is obtained in the processes of degradation of organic matter by the action of bacterial consortium in the environment. The aim of this study was to evaluate the biogas production in anaerobic UASB and ABR in swine wastewater treatment. For this we used the theoretical estimated and actual production of biogas measured by anaerobic gasometers installed in the units. Methane was determined by gas chromatography (GC) and its theoretical output was 66 LCH4 kgSVT d{sup -1} and 11.9 LCH4 kgSVT d{sup -1} and 24.7 m{sup 3} d{sup -1} and 5.4 m{sup 3} d{sup -1} to ABR and UASB, respectively. Regarding the actual production of biogas in the reactor provided by the gas tank, found the values of 1,166.4 m{sup 3}; 0.1 m{sup 3}; 27.4 m{sup 3} and 12,598.5 m{sup 3} of biogas for compartments 1, 2 and 3 and ABR for the UASB reactor, respectively, totaling, production of 13,792.4 m{sup 3} in the units together, with an average of 113 m{sup 3} of biogas per day. But, it concludes with this research that the use of effluent from produce energy through biogas in swine farming is effective, which can be used in rural productive system itself. (author)

  12. 我国社会资本现状及其对公民政策参与的阻滞%The Current Situation of Social Capital in China and Its Baffle to Citizen Policy Participation

    Institute of Scientific and Technical Information of China (English)

    蔡新燕

    2012-01-01

    With the new progress of China's democratic and political construction, the importance of citizen policy participation has increasingly been the focus. The effective policy participate is relied on the good trust and cooperative relations between government and citizens, and the establishment of such relation is based on the full development of social capital as a precondition. Now social capital in our country has many defects, such as lack of social credit system, the non-perfect of rules and system, the weakness of organizational foundation of citizen policy participation, and the path dependence on traditional policy process, which restricts our citizen policy participation.%随着中国民主政治建设的新进展,公民政策参与的重要性日益为人们所重视。有效的政策参与依赖于政府与公民之间的良好信任与合作关系,而信任与合作关系的建立以社会资本的充分发展为前提。目前我国的社会资本存在诸多缺陷,如社会诚信体系的缺失、各种规则和制度的不健全、公民政策参与组织基础的薄弱以及传统政策过程的路径依赖等,制约着我国公民政策参与。

  13. Staged electrostatic precipitator

    Energy Technology Data Exchange (ETDEWEB)

    Miller, Stanley J.; Almlie, Jay C.; Zhuang, Ye

    2016-03-01

    A device includes a chamber having an air inlet and an air outlet. The device includes a plurality of stages including at least a first stage adjacent a second stage. The plurality of stages are disposed in the chamber and each stage has a plurality of discharge electrodes disposed in an interior region and is bounded by an upstream baffle on an end proximate the air inlet and bounded by a downstream baffle on an end proximate the air outlet. Each stage has at least one sidewall between the upstream baffle and the downstream baffle. The sidewall is configured as a collection electrode and has a plurality of apertures disposed along a length between the upstream baffle and the downstream baffle. The upstream baffle of the first stage is positioned in staggered alignment relative to the upstream baffle of the second stage and the downstream baffle of the first stage are positioned in staggered alignment relative to the downstream baffle of the second stage.

  14. Relay telescope for high power laser alignment system

    Science.gov (United States)

    Dane, C. Brent; Hackel, Lloyd; Harris, Fritz B.

    2006-09-19

    A laser system includes an optical path having an intracavity relay telescope with a telescope focal point for imaging an output of the gain medium between an image location at or near the gain medium and an image location at or near an output coupler for the laser system. A kinematic mount is provided within a vacuum chamber, and adapted to secure beam baffles near the telescope focal point. An access port on the vacuum chamber is adapted for allowing insertion and removal of the beam baffles. A first baffle formed using an alignment pinhole aperture is used during alignment of the laser system. A second tapered baffle replaces the alignment aperture during operation and acts as a far-field baffle in which off angle beams strike the baffle a grazing angle of incidence, reducing fluence levels at the impact areas.

  15. Numerical Study of Liquid Sloshing on Anti-sloshing Device Using Open Cell Metal Foams in Oil Tank

    Science.gov (United States)

    Zhang, Y.; Qu, Z. G.; Tao, W. Q.; Lu, T. J.

    2010-03-01

    A new baffle structure design named open-cell metal foams baffle for anti-sloshing device in oil tank is presented in this study. Numerical simulation study on the liquid sloshing with various baffles is carried out using FLUENT with the volume-of-fluid (VOF) model. Four types of baffles were studied, namely non-baffle (type A), conventional parallel-baffle (type B), cross-baffle (type C) and open- cell metal foams baffles (type D). The oil velocity distribution, centroid and oil occupancy in the sloshing process is revealed in the case of vehicle speeding up and turning respectively. It is found that type D reduce velocity of oil, increase the value of oil occupancy in the suction pipe entrance of the oil tank and lower the centroid of oil obviously comparing with the other types. As for the same open-cell metal foam pore density, lower open-cell metal foam porosity has much better effect of inhibition of liquid sloshing, but there is little deviation among different porosity for the absolute value. Moreover, according to the same porosity, the oil centroid can be lowered obviously with the increase of pore density. The results of type D show practical significance and referable guideline for baffles design to improve the safety and stability of vehicle.

  16. Desempenho de processo anaeróbio em dois estágios (reator compartimentado seguido de reator UASB) para tratamento de águas residuárias de suinocultura Performance of two-stage anaerobic process (baffled reactor (ABR) followed by an upflow sludge blanket reactor (UASB)) treating swine wastewater

    OpenAIRE

    Gracie F. R. Fernandes; Roberto A. de Oliveira

    2006-01-01

    Avaliou-se o efeito das águas residuárias de suinocultura com concentrações de sólidos suspensos totais em torno de 6.000 mg L-1 (DQOtotal variando de 7.557 a 11.640 mg L-1) no desempenho de processo anaeróbio em dois estágios compostos por reator compartimentado (ABR) e reator de fluxo ascendente com manta de lodo (UASB), instalados em série, em escala-piloto (volumes de 530 e 120 L, respectivamente), submetidos a tempos de detenção hidráulica (TDH) de 56 a 18 h no primeiro reator e de 13 a ...

  17. Analysis of particle transport in a gas target divertor

    Energy Technology Data Exchange (ETDEWEB)

    Ohtsu, Shigeki; Tanaka, Satoru [Tokyo Univ. (Japan). Faculty of Engineering

    1996-10-01

    2-dimensional modelling of divertor plasma was performed with three types of the divertor geometry configuration. Pumping is effective to reduce neutral recycling to core region in the configuration without baffle. In baffle configuration, a good shielding of neutrals in the divertor region can be achieved. The dome configuration reduces plasma density near the null region and flow shear near the separatrix. (author)

  18. Experimental Study of Inlet/Outlet Flow Characteristics in Tube-side of Shell and Tube Heat Exchanger

    International Nuclear Information System (INIS)

    The inlet/outlet flow in the tube-side of the shell and tube heat exchanger was experimentally measured to investigate the effect of the porous baffle on uniform flow distribution. A 1/3rd scale-downed model of a heat exchanger was used and particle image velocimetry was applied for measuring the instantaneous velocity vector fields. The absolute errors in the flow rate were calculated and compared for the tube-side with and without the porous baffle, by varying the flow rate from 60 to 90 LPM. The results revealed that the porous baffle can improve flow uniformity and reduce the absolute error in the flow rate of the model with the baffle by about 74%, compared to that without the baffle. This result can be used for improving the performance and design of the shell and tube heat exchanger

  19. Shell side CFD analysis of a small shell-and-tube heat exchanger

    Energy Technology Data Exchange (ETDEWEB)

    Ozden, Ender [Department of Mechanical Engineering, Middle East Technical University, 06531 Ankara (Turkey); Tari, Ilker, E-mail: itari@metu.edu.t [Department of Mechanical Engineering, Middle East Technical University, 06531 Ankara (Turkey)

    2010-05-15

    The shell side design of a shell-and-tube heat exchanger; in particular the baffle spacing, baffle cut and shell diameter dependencies of the heat transfer coefficient and the pressure drop are investigated by numerically modeling a small heat exchanger. The flow and temperature fields inside the shell are resolved using a commercial CFD package. A set of CFD simulations is performed for a single shell and single tube pass heat exchanger with a variable number of baffles and turbulent flow. The results are observed to be sensitive to the turbulence model selection. The best turbulence model among the ones considered is determined by comparing the CFD results of heat transfer coefficient, outlet temperature and pressure drop with the Bell-Delaware method results. For two baffle cut values, the effect of the baffle spacing to shell diameter ratio on the heat exchanger performance is investigated by varying flow rate.

  20. Shell side CFD analysis of a small shell-and-tube heat exchanger

    International Nuclear Information System (INIS)

    The shell side design of a shell-and-tube heat exchanger; in particular the baffle spacing, baffle cut and shell diameter dependencies of the heat transfer coefficient and the pressure drop are investigated by numerically modeling a small heat exchanger. The flow and temperature fields inside the shell are resolved using a commercial CFD package. A set of CFD simulations is performed for a single shell and single tube pass heat exchanger with a variable number of baffles and turbulent flow. The results are observed to be sensitive to the turbulence model selection. The best turbulence model among the ones considered is determined by comparing the CFD results of heat transfer coefficient, outlet temperature and pressure drop with the Bell-Delaware method results. For two baffle cut values, the effect of the baffle spacing to shell diameter ratio on the heat exchanger performance is investigated by varying flow rate.

  1. Sızma Testleri İçin Bir Model Ağ Üzerinde Siber Saldırı Senaryolarının Değerlendirilmesi

    Directory of Open Access Journals (Sweden)

    Tuncay YİĞİT

    2014-06-01

    Full Text Available The scope of this work is to investigate the effects of baffle cut and baffle spacing on the heat transfer coefficient and pressure drop in a shell and tube heat exchanger. For this aim, analyses are made for a standard dimensioned heat exchanger with variable baffle cut and spacing. It is observed that both heat transfer coefficient and pressure drops values decrease with the increase of baffle cut and baffle spacing. This paper demonstrates successful application of Genetic Algorithm for the optimal design of shell-and-tube heat exchangers. Approximate design methods for shell-and-tube have been investigated and a generalized procedure has been developed to run the GA algorithm and to find the global minimum heat exchanger area

  2. Üniversite Sanayi İşbirliği ve Fen Bilimleri Enstitüleri

    Directory of Open Access Journals (Sweden)

    Mehmet Cengiz KAYACAN

    2014-07-01

    Full Text Available The scope of this work is to investigate the effects of baffle cut and baffle spacing on the heat transfer coefficient and pressure drop in a shell and tube heat exchanger. For this aim, analyses are made for a standard dimensioned heat exchanger with variable baffle cut and spacing. It is observed that both heat transfer coefficient and pressure drops values decrease with the increase of baffle cut and baffle spacing. This paper demonstrates successful application of Genetic Algorithm for the optimal design of shell-and-tube heat exchangers. Approximate design methods for shell-and-tube have been investigated and a generalized procedure has been developed to run the GA algorithm and to find the global minimum heat exchanger area

  3. Experimental Study of Inlet/Outlet Flow Characteristics in Tube-side of Shell and Tube Heat Exchanger

    Energy Technology Data Exchange (ETDEWEB)

    Tu, Xin Cheng; Wang, Kai; Kim, Hyoung-Bum [Gyeongsang National University, Jinju (Korea, Republic of); Park, Seung-Ha [Donghwa Entec Co. Ltd., Busan (Korea, Republic of)

    2014-07-15

    The inlet/outlet flow in the tube-side of the shell and tube heat exchanger was experimentally measured to investigate the effect of the porous baffle on uniform flow distribution. A 1/3rd scale-downed model of a heat exchanger was used and particle image velocimetry was applied for measuring the instantaneous velocity vector fields. The absolute errors in the flow rate were calculated and compared for the tube-side with and without the porous baffle, by varying the flow rate from 60 to 90 LPM. The results revealed that the porous baffle can improve flow uniformity and reduce the absolute error in the flow rate of the model with the baffle by about 74%, compared to that without the baffle. This result can be used for improving the performance and design of the shell and tube heat exchanger.

  4. Comparison of transient and stationary neutral pressure response in the DIII-D advanced divertor

    International Nuclear Information System (INIS)

    The DIII-D divertor baffle system was designed to facilitate density control in long pulse H-mode discharges by removing a particle flux equal to the neutral beam fueling rate (∼20 Torr-1/s) with a ∼1mTorr neutral pressure under the baffle (p0). Initial measurements of the baffle pressure indicated that p0∼ 10 mTorr (without pumping or biasing), a value much in excess of that required for long pulse density control. Radial sweeps of the X-point position have been employed to determine the maximum p0, as well as to establish the dependence of this pressure on geometry. An estimate of the particle equilibration time for the baffle system has been made by studying the baffle pressure response to ''giant'' ELM effects. ''Steady state'' experiments in which the X-point position was fixed for ∼2.5s have also been carried out and steady baffle pressures were observed. The scaling of baffle pressure with plasma parameters has been found to be similar under transient and ''steady state'' conditions. Detailed modeling of these experiments with the B2, DEGAS, and WDIFFUSE (wall model) codes has been made

  5. Divertor bypass in the Alcator C-Mod tokamak

    Science.gov (United States)

    Pitcher, C. S.; LaBombard, B.; Danforth, R.; Pina, W.; Silveira, M.; Parkin, B.

    2001-01-01

    The Alcator C-Mod divertor bypass has for the first time allowed in situ variations to the mechanical baffle design in a tokamak. The design utilizes small coils which interact with the ambient magnetic field inside the vessel to provide the torque required to control small flaps of a Venetian blind geometry. Plasma physics experiments with the bypass have revealed the importance of the divertor baffling to maintain high divertor gas pressures. These experiments have also indicated that the divertor baffling has only a limited effect on the main chamber pressure in C-Mod.

  6. Ventilation and exhaust ducts for dry storage facilities with self-heating radioactive materials

    International Nuclear Information System (INIS)

    The storage facilities are cooled by natural convection. In order to achieve this, the air inlet and outlet openings or ducts for the PWR and BWR fuel store are arranged at the level of the roof structure. There are two types of air inlet openings arranged on top and on the sides respectively but having got common inlet ducts. Air supply is improved by means of baffle noses, baffle edges, and baffle plates. The exhaust air ducts terminate near the roof structure, the openings having got dropping edges, protective sills and separating plates. (orig./PW)

  7. Shell-side distribution and the influence of inlet conditions in a model of a disc-and-doughnut heat exchanger

    Science.gov (United States)

    Founti, M. A.; Vardis, C.; Whitelaw, J. H.

    1985-09-01

    Measurements of wall pressure and of three orthogonal velocity components with their corresponding fluctuations are reported for two systems of alternating and equi-spaced doughnut and disc baffles axisymmetrically located in a water turbulent pipe flow, simulating the isothermal shell-side flow in shell and tube heat exchangers. The influence of inlet Reynolds number and of asymmetric inlet flow conditions was studied for two geometries. The velocity field was dominated by the pressure gradient and the flow around each individual baffle was influenced by the relative position of its neighbouring baffles.

  8. Numerical Model Analysis of Fluid-Elastic Instability of Thin Rectangular Plate Due to Overflow

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    A circular thermal baffle weir is located close to the main vessel of liquid sodium cooled pool type fast breeder reactors (fast reactor for short thereafter). During operation of the fast reactor, a little part of liquid sodium flows from

  9. 78 FR 27951 - Foreign-Trade Zone (FTZ) 75-Phoenix, Arizona; Notification of Proposed Production Activity...

    Science.gov (United States)

    2013-05-13

    ... blocks; protective shipping devices; high voltage covers; gear plates; plates; XFR tubes; tubes; flow... nut fixtures; clamp and baffle flappers; riveting anvils; alignment kits; crimp fixtures; assembly... assemblies; switches; light-board switches; electrical- connector receptacles; housings; control...

  10. Stray radiation V; Proceedings of the Meeting, San Diego, CA, Aug. 18-20, 1986

    Science.gov (United States)

    Breault, Robert P.

    Various papers on stray radiation are presented. The topics considered include: improved facility for BRDF/BTDF optical scatter measurements; comparison of two BRDF measuring systems; in-vacuum BR/TDF measurement apparatus; ultraviolet and visible BRDF data on spacecraft thermal control and optical baffle materials; interactive, graphical, CAD integrated tool for stray radiation analysis; OARDAS - a new ray-based stray radiation analysis program; stray light analysis with APART/PADE, version 8.7; and use of specular black coatings in well-baffled optical systems. Also addressed are: Hipparcos telescope stray light protection; stray light from diffraction gratings; stray light analysis of the Cryogenic Limb Array Etalon Spectrometer; scatterometer for DIRBE; stray light analysis and suppression in small angle BRDF/BTDF measurement; reflective baffle system with multiple bounces; analysis of the all-specular Linlor baffle design; and elimination of spurious response in a scanning optical system.

  11. Damages of lower internals in high neutron fluence: materials assessment contributions

    International Nuclear Information System (INIS)

    Baffle jetting observed during the eighties has revealed baffle/former bolts cracking. If baffle jetting can be solved by UP FLOW conversion, bolts cracking is a problem for baffle plates behaviour. To understand the cracking mechanism, EDF approach consisted to determine the service conditions and the material properties after in service failure. A cartography of fluence, temperature and mechanical stresses was calculated for all the bolts. Destructive examinations included fractography, hardness and tensile tests, low strain rate stress corrosion tests, microstructural (TEM) and chemical analysis; these tests were performed on bolts extracted from Nuclear Units. On the basis of published data, all these results lead us to propose damaged mechanisms. (authors). 4 figs., 9 tabs., 11 refs

  12. Mathematical Modelling Of Cyanide Inhibition on Cassava Wastewater Treatment

    OpenAIRE

    E. Onukwugha

    2013-01-01

    Anaerobic Baffled Reactors (ABR) is used to evaluate the extent of cyanide inhibition of cassava wastewater treatment. The reactor has aspect ratio of 4:1:1. Kinetic analyses of specific growth rate μmax and half saturation constant

  13. A pool type liquid helium cryopump

    International Nuclear Information System (INIS)

    Design and fabrication details of a pool type Liquid Helium Cryopump are described. It has got a liquid helium capacity of 5 litres and a/ pumping surface area of about 450 sq. cms. Three types of baffles having different geometries are used for radiation shield. Effect on pumping speed for argon, carbon dioxide and nitrogen gas using the baffles is determined at various pressures. The circular array baffle geometry provides the maximum pumping speed. Using circular array type baffle the maximum pumping speed for nitrogen, argon and carbon dioxide are 2700 1/s, 3600 1/s, 2550 1/s respectively at a pressure of 6.0 x 10-4 torr. The ultimate pressure obtained is 3.0 x 10-8 torr. (author)

  14. The Big Idea

    CERN Multimedia

    Matthews, Robert

    2005-01-01

    Symmetry has shaped our Universe, and has inspired some of the world's greatest scientists to unlock the secrets of the Universe, but also baffled many more along the way. Symmetry is not as simple as it may at first appear...

  15. Flow mechanism and heat transfer enhancement in longitudinal-flow tube bundle of shell-and-tube heat exchanger

    Institute of Scientific and Technical Information of China (English)

    LIU Wei; LIU ZhiChun; WANG YingShuang; HUANG SuYi

    2009-01-01

    ormer is superior to that of the latter.Compared with rod baffle heat exchanger,heat transfer coefficient of the heat exchanger under investigation is higher under same pressure drop,especially under the high Reynolds numbers.

  16. Remoção de matéria orgânica, de nutrientes e de coliformes no processo anaeróbio em dois estágios (reator compartimentado seguido de reator UASB) para o tratamento de águas residuárias de suinocultura Organic matter, nutrients and coliforms removal in two-stage anaerobic process (anaerobic baffled reactor followed by UASB reactor) for swine wastewater treatment

    OpenAIRE

    Mário S. de Abreu Neto; Roberto A. de Oliveira

    2009-01-01

    Neste trabalho, avaliou-se o efeito das águas residuárias de suinocultura, com concentrações médias de sólidos suspensos totais variando de 4.591 a 13.001 mg L-1, no desempenho de processo anaeróbio, em dois estágios, compostos por reator compartimentado (ABR) e reator de fluxo ascendente com manta de lodo (UASB), instalados em série, em escala- -piloto (volumes de 530 e 120 L, respectivamente), submetidos a tempos de detenção hidráulica (TDH) de 60; 36 e 24 h no primeiro reator, e de 13,6; 8...

  17. Reducing Scattered Light in CCD Images at the CTIO 0.9m Telescope

    Science.gov (United States)

    Barnaby, D.; Rauscher, B. J.

    1998-12-01

    We have been studying luminous halos around spiral galaxies in very deep near-infrared K-band images (limiting surface brightness =24 mag arcsec(-2) ; lambda_ {c} = 2.35 mu m). Following our successful detection of a halo around the southern spiral galaxy ESO 240-G11 (Rauscher et al. 1998), we collected optical CCD images of candidate galaxies at the Cerro Tololo Interamerican Observatory (CTIO) 0.9 m telescope from 17-21 Sept 1998. Because light scattered by the telescope can mask or mimic faint, extended emission, we took precautions to minimize stray and scattered light. To assess the amount of scattered light, we collected images of the telescope pupil using a pinhole camera, which we constructed by laying a sheet of aluminum foil, perforated with a submillimeter hole, 19 mm in front of the CCD. These images showed that the telescope did scatter light on the order of a few percent over a radius of about 2 arcminutes. Supressing this extraneous light was highly desirable, since halo surface brightness can be baffles. One baffle consisted of a 0.95 m diameter tube added as an extension to the telescope, which has a closed-tube design. The other 2 baffles were diaphragms mounted between the primary baffle (the ``chimney'') and the shutter. These baffles effectively eliminated the largest sources of scattered light, which appear to be the edge of the secondary baffle and the inner surface of the chimney (Figure 1, http:// astro.uchicago.edu/home/web/barnaby/sctrdlite98.html). In this paper, we quantify the reduction in scattered light and examine the most useful location to add baffles to this telescope. Acknowledgements. We thank the CTIO Telescope Operations staff for their help in constructing and installing the baffles. We also thank support astronomer Nick Suntzeff for suggesting the pinhole tests. Rauscher, B. J. et al. 1998, ApJ, 506, 116

  18. Low NO sub x regenerative burner

    Energy Technology Data Exchange (ETDEWEB)

    Hovis, J.E.; Finke, H.P.

    1991-01-08

    This patent describes improvements in a regenerative burner having a regenerative bed, a burner port and a fuel nozzle. The improvement comprises: a burner baffle having apertures therein for selectively directing combustion air and inducing combustion gas recirculation into a primary combustion zone for suppressing NO{sub x} emissions, the baffle and the fuel nozzle being positioned substantially adjacent the burner port and being substantially coplanar in a plane perpendicular to a burner axis.

  19. Hystérésis et réduction de sons auto-entretenus commandées par effet Coanda

    Science.gov (United States)

    Guérin, Sébastien; Allery, Cyrille; Sakout, Anas

    An air flow crossing two baffles in tandem inside a duct, generates strong self-sustained tones. Four radial slots created on the upstream baffle, leads to a large hysteresis loop of the sound pressure level when velocity varies, the second branch of which corresponds with a reduction of the self-sustained tones. Measurements of velocity show that a Coanda effect happens on the jets issued from the slots, which induces this flow behaviour.

  20. COMPARATIVE THERMAL ANALYSIS OF HELIXCHANGER WITH SEGMENTAL HEAT EXCHANGER USING BELL-DELAWARE METHOD

    OpenAIRE

    S. Pavithran; P. V. Hadgekar; Shinde, S. S.

    2012-01-01

    Heat exchangers are important heat transfer apparatus in oil refining, chemical engineering, environmental protection, electric power generation etc. The present work modifies the existing Bell-Delaware method used for conventional heat exchanger, taking into consideration the helical geometry of Helixchanger. Thermal analysis was carried out to study the impacts of various baffle inclination angles on fluid flow and heat transfer of heat exchangers with helical baffles. The analysis was con...

  1. DECOLORIZATION AND BIOLOGICAL DEGRADATION OF AZO DYE REACTIVE RED2 BY ANAEROBIC/AEROBIC SEQUENTIAL PROCESS

    OpenAIRE

    A. Naimabadi ، H. Movahedian Attar ، A. Shahsavani

    2009-01-01

    This study investigates the anaerobic treatability of reactive Red2 in an anaerobic/aerobic sequential process. Laboratory scale anaerobic baffled reactor and fixed activated sludge reactor were operated at different organic loadings and hydraulic retention times. The effects of shock dye concentration on the chemical oxygen demand and color removal efficiencies were investigated in the anaerobic baffled reactor. The effect of hydraulic retention time on the color and chemical oxygen demand r...

  2. Research on liquid sloshing performance in vane type tank under microgravity

    Science.gov (United States)

    Hu, Q.; Li, Y.; Liu, J. T.; Liang, J. Q.

    2016-05-01

    Propellant management device (PMD) in vane type tank mainly comprises of vane type structure parts, whose performance of restraining liquid sloshing should satisfy spacecraft requirements of high stabilization and fast orbital maneuver. Aiming at liquid sloshing performance in vane type tank under microgravity environment, gas-liquid flow model based on the volume of fluid (VOF) method was put forward, and via numerical simulation liquid sloshing performances of vane type PMD with anti-sloshing baffles and without anti-sloshing baffles in microgravity were analyzed and compared. Simulation results reveal that liquid sloshing performance of vane type PMD with anti-sloshing baffles is markedly superior vane type PMD without anti-sloshing baffles and the baffles make liquid surface become stable fast. Then by comparing between results of microgravity experiments and results of numerical simulations, they are very similar. According to present research, vane type PMD with antisloshing baffles has better effects on restraining liquid sloshing and is able to restrain observably propellant sloshing in tanks in order to satisfy spacecraft requirements of high stabilization and fast orbital maneuver.

  3. Microgravity Science Glovebox Investigations SUBSA

    Science.gov (United States)

    Ostrogorsky, A.; Marin, C.; Vogel, M.; Volz, M. P.; Luz, P.; Jeter, L.; Spivey, Reggie; Duffar, Thierry; Geveden, Rex D. (Technical Monitor)

    2001-01-01

    Solidification Using a Baffle in Sealed Ampoules (SUBSA) is a Microgravity Science Glovebox Investigation manifested for the UF2 flight, on the U.S. Orbiter 111, to the International Space Station (ISS). SUBSA complements the "parent" flight investigation CG13 (Space-and Groundbased Crystal Growth Using a Baffle). During directional solidification, the disk-shaped baffle acts as a partition, creating a small melt zone at the solid-liquid interface. As a result, the level of buoyancy-driven convection at the interface is significantly reduced. In space, the baffle will reduce convection driven by residual micro acceleration. The baffle reduces the Rayleigh number (Ra) of the melt by a factor of 103. The combined effect of the baffle and microgravity will yield a reduction in Ra by a factor of 107 to 109 approaching effectively the acceleration conditions in "nanogravity". The results of ground based tests and numerical modeling will be presented. The furnace for directional solidification (flight hardware and the ground unit) was developed by Tec-Masters Inc. The flight ampoules were produced jointly at Rensselaer, Tec-Masters Inc. and Crystallod Inc.

  4. Maintenance method for irradiation assisted stress corrosion cracking of PWR core internals

    International Nuclear Information System (INIS)

    Irradiation-assisted stress corrosion cracking of IASCC is a well-known result of age-related degradation of baffle former bolts which are an integral component of PWR core internals. However, methods for analyzing the causes and assessing IASCC have yet to be established and are being studied. The baffle former bolts are components of the baffle structure and in order to maintain the integrity of the baffle structure, an effective approach for maintaining the bolts must be provided. This paper proposes an effective method of maintaining the functions of the baffle structure by improving the configuration and/or material of baffle former bolts. A relaxed configuration of the bolt neck reduces the stress and can approximately halve the damage caused by IASCC. An improvement in the threshold value of materials vulnerability to IASCC would not only extend the service life of all bolts but could also substantially retard IASCC of the bolts installed at upper and lower ends where flux is low. If the threshold fluence to IASCC could be made higher than approximately 5x1025 n/m2 (E>0.1 MeV, 340degC), the bolts installed at lower and upper ends, which are conventionally replaced 30 years after plant start-up, would remain intact for 60 years after start-up. Hence, this approach is a very effective maintenance measure. (author)

  5. Combustion device for hydrogen contained in atmosphere of reactor container

    International Nuclear Information System (INIS)

    A helical-shaped heater of a combustion device is protruded horizontally from a terminal member secured to a structural member such as a building wall inside the reactor container. A plurality of bent rectangular outer cover members, namely, C-shape cross sectioned baffles are disposed in an annular shape each at an interval in the circumferential direction. The baffle having a C-shaped cross section is concave radially inwardly and turn-back portions are formed on both sides. The turn-back portion acts as a gutter for flowing dropped spray water of emergency cooling water. Bent rectangular inner cover members, namely, C-shape cross sectioned baffles are formed being opposed to each gap between adjacent outer C-shape cross sectioned baffles. The inner C-shape cross sectioned baffles are concave radially outwardly in the cross section being reversed to the outer C-shape cross sectioned baffles, and turned back portions are formed on both sides. (I.N.)

  6. A New Method Solving Contact/Detach Problem in Fluid and Structure Interaction Simulation with Application in Modeling of a Safety Valve

    Directory of Open Access Journals (Sweden)

    Zheng Guo

    2010-01-01

    Full Text Available A new virtual baffle methodology is implemented to solve contact/detach problem which is often encountered in fluid and structure interaction simulations while using dynamic grids technique. The algorithm is based on tetrahedral unstructured grid, and a zero thickness baffle face is generated between actually contacted two objects. In computation process, this baffle face is divided into two parts representing convective and blocked area, respectively; the area of each part is calculated according to the actual displacement between the two objects. Convective part in a baffle face is treated as inner interface between cells, and on blocked part wall boundary condition is applied; so convective and blocking effect can be achieved on a single baffle face. This methodology can simulate real detaching process starting from contact, that is, zero displacement, while it has no restriction to minimum grid cell size. The methodology is then applied in modeling of a complicated safety valve opening process, involving multidisciplinary fluid and structure interaction and dynamic grids. The results agree well with experimental data, which proves that the virtual baffle method is successful.

  7. Second-Law based thermodynamic analysis of a novel heat exchanger

    Energy Technology Data Exchange (ETDEWEB)

    He, Y.L.; Lei, Y.G.; Tao, W.Q.; Zhang, J.F.; Chu, P.; Li, R. [State Key Laboratory of Multiphase Flow in Power Engineering, Xi' an Jiaotong University (China)

    2009-01-15

    In the present investigation, second-law based thermodynamics analysis was applied to a new heat exchanger with helical baffles. The helical baffles are designed as quadrant ellipses and each baffle occupies one quadrant of the cross-section of the shell side. Experimental tests were carried out with cold water in the tube side with a constant flow rate, and hot oil on the shell side with flow rate range from 4-24 m{sup 3}/h. The temperatures and pressures for the inlet and outlet of both sides were measured. The heat transfer, pressure drop, entropy generation, and exergy loss of the new heat exchanger were investigated and compared with the results for a conventional shell-and-tube heat exchanger with segmental baffles. The computed results indicated that both the entropy generation number and exergy losses of the new heat exchanger design are lower than those of the heat exchanger with segmental baffles, which means that the novel heat exchanger has a higher efficiency than the heat exchanger with segmental baffles, from the second-law based thermodynamics viewpoint. (Abstract Copyright [2009], Wiley Periodicals, Inc.)

  8. Flow distribution analysis in nuclear heat exchangers with application to CRBRP-IHX

    International Nuclear Information System (INIS)

    The shell side flow distribution of a shell-and-tube heat exchanger, in which the shell side fluid moves downwards in an axial/cross flow combination dictated by the design of the flow baffles, is examined. Depending on the degree of overlapping and perforation of the baffles, the magnitude of the cross flow component can be controlled in a manner compatible with the unit design. Axial/cross flow field would yield a relatively small pressure drop on the shell side, and in the meantime it creates sufficient fluid mixing to minimize any thermal unbalance among the heat transfer tubes. Such requirements are essential in the design of nuclear heat exchangers similar to the CRBRP-IHX. The present flow distribution analysis utilizes two models: The lumped model and the detailed model. The lumped model employs an overall flow distribution and pressure drop approach to determine the magnitudes of the axial and cross flow components as a function of the baffle overlapping and baffle perforation. The detailed model utilizes more of a fundamental approach in solving the governing equations for the conservation of mass and momentum of a turbulent flowing fluid in a nodal mesh. The mesh incorporates distributed resistances resulting from the presence of the heat transfer tubes and the flow baffles in the tube bundle. The model employs a modified version of the computer code VARR II tailored specifically to the analysis of the shell side flow of heat exchangers. The results of both models are indicated and compared with emphasis on demonstrating the influence of the baffle overlapping and baffle perforation on the flow field and the pressure distribution

  9. Influence of Wind Buffeting on the 3.6 m Telescope

    Science.gov (United States)

    Griffin, S.; Haar, S.; Walker, E.; Whiting, A.; Williams, S.

    2013-09-01

    Unsteady wind loading is the largest dynamic loading on most large ground telescopes. The maximum operational windspeed not only sets requirements on the wind load rejection performance of the mount control system but also is a significant driver for tracker error rejection. In addition, turbulence due to the wind contributes to wavefront distortion. With the recent interest in daylight imaging, introduction of a baffle that reduces background light during the day may further accentuate wind loading on the 3.6 m telescope. The initial daylight configuration of the telescope has been to operate without a baffle and to use operational constraints to avoid angles close to the sun. This configuration offers reasonable daylight performance but is susceptible to stray light that limits achievable signal-to-noise ratio. Also under test is a unique baffled configuration where the telescope is shrouded to increase target signal-to-noise ratio. Traditional baffles increase jitter and wind loading due to increased exposed area to the wind and increase wavefront distortion due to thermal gradients introduced by the baffle. The 3.6 m telescope baffle has been designed out of an opaque fabric to limit the negative impacts on jitter and wavefront distortion while increasing signal-to-noise ratio for daylight imaging. The intent of the design is to limit high frequency transmission of wind loading by the relatively compliant fabric and to allow some circulation using the fabric's porosity to limit thermal gradients. The fabric design also facilitates the extension to a deployable design, since it is relatively easy to deploy and stow compared to a traditional approach. This paper will present analytical results predicting jitter and mount control performance with and without the baffle as well as signal-to-noise ratio predictions with and without the baffle. The jitter results will use measured wind loading in conjunction with a system line-of-sight model for performance

  10. Seasonal variations of microbial community in a full scale oil field produced water treatment plant

    Directory of Open Access Journals (Sweden)

    Q. Xie

    2016-01-01

    Full Text Available This study investigated the microbial community in a full scale anaerobic baffled reactor and sequencing batch reactor system for oil-produced water treatment in summer and winter. The community structures of fungi and bacteria were analyzed through polymerase chain reaction–denaturing gradient gel electrophoresis and Illumina high-throughput sequencing, respectively. Chemical oxygen demand effluent concentration achieved lower than 50 mg/L level after the system in both summer and winter, however, chemical oxygen demand removal rates after anaerobic baffled reactor treatment system were significant higher in summer than that in winter, which conformed to the microbial community diversity. Saccharomycotina, Fusarium, and Aspergillus were detected in both anaerobic baffled reactor and sequencing batch reactor during summer and winter. The fungal communities in anaerobic baffled reactor and sequencing batch reactor were shaped by seasons and treatment units, while there was no correlation between abundance of fungi and chemical oxygen demand removal rates. Compared to summer, the total amount of the dominant hydrocarbon degrading bacteria decreased by 10.2% in anaerobic baffled reactor, resulting in only around 23% of chemical oxygen demand was removed in winter. Although microbial community significantly varied in the three parallel sulfide reducing bacteria, the performance of these bioreactors had no significant difference between summer and winter.

  11. A dynamic ultrasonic emitter inspired by horseshoe bat noseleaves.

    Science.gov (United States)

    Fu, Yanqing; Caspers, Philip; Müller, Rolf

    2016-01-01

    The emission of biosonar pulses in horseshoe bats (family Rhinolophidae) differs from technical sonar in that it has dynamic features at the interface to the free field. When the horseshoe bats emit their biosonar pulses through the nostrils, the walls of a horn-shaped baffle (anterior leaf) are in motion while diffracting the outgoing ultrasonic wave packets. Here, biomimetic reproductions of the dynamic emission shapes of horseshoe bats have been studied for their ability to impose time-variant signatures onto the outgoing pulses. It was found that an elliptical sound outlet with rotating baffles that were attached along the direction of the major axis can be well suited for this purpose. Most importantly, concave baffle shapes were found to produce strongly time-dependent devices characteristics that could reach a root-mean-square-difference between beampatterns of almost 6 dB within a rotation angle of 10°. In contrast to this, a straight baffle shape needs to be rotated over 60° for a similar result. When continuously rotated in synchrony with the emitted pulses, the concave biomimetic baffles produced time-variant device characteristics that depended jointly on direction, frequency, and time. Since such device properties are so easily produced, it appears well worthwhile to explore their use in engineering. PMID:27127194

  12. An approximate method to acoustic radiation problems: element radiation superposition method

    Institute of Scientific and Technical Information of China (English)

    wANG Bin; TANG weilin; FAN Jun

    2008-01-01

    An approximate method is brought forward to predict the acoustic pressure based on the surface velocity.It is named Element Radiation Superposition Method(ERSM).The study finds that each element in Acoustic Transfer Vector(ATV)equals the acoustic pressure radiated by the corresponding surface element vibrating in unit velocity and other surface elements keep still.that is the acoustic pressure radiated by the corresponding baffled pistonvibrating in unit velocity.So,it utilizes the acoustic pressure radiated by a baffled piston to establish the transfer relationship between the surfaEe velocity and the acoustic pressure.The total acoustic pressure is obtained through summing up the products of the surface velocity and the transfer quantity.It adopts the regular baffle to fit the actual baffle in order to calculate the acoustic pressure radiated by the baffled piston.This approximate method has larger advantage in calculating speed and memory space than Boundary Element Method.Numerical simulations show that this approximate method is reasonable and feasible.

  13. Minimizing shell-and-tube heat exchanger cost with genetic algorithms and considering maintenance

    Energy Technology Data Exchange (ETDEWEB)

    Wildi-Tremblay, P.; Gosselin, L. [Universite Laval, Quebec (Canada). Dept. de genie mecanique

    2007-07-15

    This paper presents a procedure for minimizing the cost of a shell-and-tube heat exchanger based on genetic algorithms (GA). The global cost includes the operating cost (pumping power) and the initial cost expressed in terms of annuities. Eleven design variables associated with shell-and-tube heat exchanger geometries are considered: tube pitch, tube layout patterns, number of tube passes, baffle spacing at the centre, baffle spacing at the inlet and outlet, baffle cut, tube-to-baffle diametrical clearance, shell-to-baffle diametrical clearance, tube bundle outer diameter, shell diameter, and tube outer diameter. Evaluations of the heat exchangers performances are based on an adapted version of the Bell-Delaware method. Pressure drops constraints are included in the procedure. Reliability and maintenance due to fouling are taken into account by restraining the coefficient of increase of surface into a given interval. Two case studies are presented. Results show that the procedure can properly and rapidly identify the optimal design for a specified heat transfer process. (author)

  14. Development of response models for the Earth Radiation Budget Experiment (ERBE) sensors. Part 3: ERBE scanner measurement accuracy analysis due to reduced housekeeping data

    Science.gov (United States)

    Choi, Sang H.; Chrisman, Dan A., Jr.; Halyo, Nesim

    1987-01-01

    The accuracy of scanner measurements was evaluated when the sampling frequency of sensor housekeeping (HK) data was reduced from once every scan to once every eight scans. The resulting increase in uncertainty was greatest for sources with rapid or extreme temperature changes. This analysis focused on the mirror attenuator mosaic (MAM) baffle and plate and scanner radiometer baffle due to their relatively high temperature changes during solar calibrations. Since only solar simulator data were available, the solar temperatures were approximated on these components and the radiative and thermal gradients in the MAM baffle due to reflected sunlight. Of the two cases considered for the MAM plate and baffle temperatures, one uses temperatures obtained from the ground calibration. The other attempt uses temperatures computed from the MAM baffle model. This analysis shows that the heat input variations due largely to the solar radiance and irradiance during a scan cycle are small. It also demonstrates that reasonable intervals longer than the current HK data acquisition interval should not significantly affect the estimation of a radiation field in the sensor field-of-view.

  15. DECOLORIZATION AND BIOLOGICAL DEGRADATION OF AZO DYE REACTIVE RED2 BY ANAEROBIC/AEROBIC SEQUENTIAL PROCESS

    Directory of Open Access Journals (Sweden)

    A. Naimabadi ، H. Movahedian Attar ، A. Shahsavani

    2009-04-01

    Full Text Available This study investigates the anaerobic treatability of reactive Red2 in an anaerobic/aerobic sequential process. Laboratory scale anaerobic baffled reactor and fixed activated sludge reactor were operated at different organic loadings and hydraulic retention times. The effects of shock dye concentration on the chemical oxygen demand and color removal efficiencies were investigated in the anaerobic baffled reactor. The effect of hydraulic retention time on the color and chemical oxygen demand removal efficiencies were also investigated in the aerobic reactor. The studies were carried out in continuous mode and the effluent of the anaerobic baffled reactor was used as feed for the fixed activated sludge reactor. Chemical oxygen demand removal efficiency of 54.5% was obtained at HRT =1 day in the anaerobic reactor. The average color removal was 89.5%. Chemical oxygen demand removal efficiency of 69% was obtained at HRT =7 h in the aerobic fixed activated sludge reactor. A slight decrease of the color was also observed in the aerobic reactor. This investigation has shown that successful treatment of a highly colored wastewater is possible in the anaerobic baffled reactor. Also the results showed that, anaerobic biological system has higher efficiency in dye removal than fixed activated sludge system, while aerobic system has higher efficiency in chemical oxygen demand removal comparing with the anaerobic baffled reactor.

  16. Radioactive waste solidification device

    International Nuclear Information System (INIS)

    A stirrer is disposed in a kneading vessel to which a solidifying material and water are supplied as starting materials for a paste. A baffle plate is situated vertically to a side wall in the kneading vessel, and formed at one place in circumferential direction of the kneading vessel. The baffle plate is situated above stirring blades so as not to abut against the rotating stirring blades. A discharge pipe for supplying the paste formed in the kneading vessel to a solidifying vessel is connected to the bottom of the kneading vessel. A washing water supply pipe having a pump and a valve is connected between the washing water tank and the kneading vessel. Since the baffle plate is disposed in the kneading vessel, washing performance for the rotating shaft of the stirrer can be improved by a simple constitution. (I.S.)

  17. Monolithic fuel injector and related manufacturing method

    Science.gov (United States)

    Ziminsky, Willy Steve; Johnson, Thomas Edward; Lacy, Benjamin; York, William David; Stevenson, Christian Xavier

    2012-05-22

    A monolithic fuel injection head for a fuel nozzle includes a substantially hollow vesicle body formed with an upstream end face, a downstream end face and a peripheral wall extending therebetween, an internal baffle plate extending radially outwardly from a downstream end of the bore, terminating short of the peripheral wall, thereby defining upstream and downstream fuel plenums in the vesicle body, in fluid communication by way of a radial gap between the baffle plate and the peripheral wall. A plurality of integral pre-mix tubes extend axially through the upstream and downstream fuel plenums in the vesicle body and through the baffle plate, with at least one fuel injection hole extending between each of the pre-mix tubes and the upstream fuel plenum, thereby enabling fuel in the upstream plenum to be injected into the plurality of pre-mix tubes. The fuel injection head is formed by direct metal laser sintering.

  18. Calculation and measurement of neutron flux in internal parts of the VVER-1000 mock-up

    International Nuclear Information System (INIS)

    Highlights: • Measurement of reaction rates in reactor baffle simulator. • Comparison of calculated and measured reaction rates in reactor baffle. • Measurement of fast neutron spectra in reactor baffle cooling channel. • Determination of 3He attenuation in lateral reflector model. - Abstract: The radiation situation in the reactor’s internal stainless steel parts is an important parameter during reactor operation. They are the most radiation-stressed structures because they are very close to the fuel. Knowledge of neutron flux distribution is important both for estimation of radiation-induced swelling of internal parts, radiation heating, and internal part activation. This paper aims to compare the experimental and calculation reaction rate distribution in a VVER-1000 mock-up placed in reactor LR-0

  19. Flow mechanism and heat transfer enhancement in longitudinal-flow tube bundle of shell-and-tube heat exchanger

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    The flow disturbance and heat transfer mechanism in the tube bundle of rod baffle shell-and-tube heat exchanger were analyzed, on the basis of which and combined with the concept of heat transfer enhancement in the core flow, a new type of shell-and-tube heat exchanger with combination of rod and van type spoiler was designed. Corresponding mathematical and physical models on the shell side about the new type heat exchanger were established, and fluid flow and heat transfer characteristics were numerically analyzed. The simulation results showed that heat transfer coefficient of the new type of heat exchanger approximated to that of rod baffle heat exchanger, but flow pressure drop was much less than the latter, indicating that comprehensive performance of the former is superior to that of the latter. Compared with rod baffle heat exchanger, heat transfer coefficient of the heat exchanger under investigation is higher under same pressure drop, especially under the high Reynolds numbers.

  20. Method to design shell-side pressure drop constrained tubular heat exchangers

    International Nuclear Information System (INIS)

    In shell and tube heat exchangers, the triple segmental baffle arrangement has been infrequently used, even though the potential of this baffle system for high thermal effectiveness with low pressure drop is generally known. This neglect seems to stem from the lack of published design guidelines on the subject. Lately, however, with the rapid growth in the size of nuclear heat exchangers, the need to develop unconventional baffling pattern has become increasingly important. A method to utilize effectively the triple segmental concept to develop economical designs is presented herein. The solution technique given in this paper is based on a flow model named ''Piecewise Continuous Cosine Model.'' The solution procedure easily lends itself to detailed analysis to determine safety against flow-induced vibrations. 20 refs

  1. Numerical Modeling of the Fluid Flow in Continuous Casting Tundish with Different Control Devices

    Directory of Open Access Journals (Sweden)

    Zhu He

    2013-01-01

    Full Text Available Numerical simulations were conducted to study the melt flow under the influence of control devices in a T-type two-strand bloom caster tundish via the open source Computational Fluid Dynamics software OpenFOAM. Three different cases were studied: a bare tundish, a tundish with two pairs of baffles, and a tundish equipped with a turbulence inhibitor and a pair of baffles. Turbulence inhibitor and baffles arrangement showed an improvement of the fluid flow characteristics, yielding lower values of dead volume and higher values of plug flow. With a turbulence inhibitor, the velocity of metal which flows directly toward the tundish floor is smaller and the turbulence kinetic energy of the melt top surface is lower than the other two arrangements.

  2. Fluid-dynamic characterization of real-scale raceway reactors for microalgae production

    International Nuclear Information System (INIS)

    The fluid dynamic characterization of a 100 m length × 1 m wide channel raceway photobioreactor was carried out. The effects of water depth, liquid velocity and the presence, or absence, of sump baffles to improve the CO2 supply transfer were considered in relation to on the power consumption, residence time and mixing in the reactor was studied. When operated at a depth of 20 cm, the power consumption was between 1.5 and 8.4 W m−3 depending on the forward velocity, with higher values occurring when the baffle was in place. Residence times and the degree of mixing at each section of the raceway (paddlewheel, bends, channels and sump) were measured experimentally. Mixing occurred mainly in the sump, paddlewheel and bends, with a maximum dispersion coefficient of 0.07 m2 s−1. These sections, however, only contributed a small fraction to the total volume of the raceway. Bodenstein numbers from 200 to 540 for the channel sections indicated plug-flow characteristics. Mixing times ranged from 1.4 to 6 h, with the presence of the baffle greatly increasing these times despite higher specific power consumption. A total of 15–20 circuits of the raceway were needed to achieve complete mixing without the baffle, compared to 30–40 cycles with the baffle. Vertical mixing was very poor whereas axial mixing was similar to that achieved in closed photobioreactors. The methodologies applied were shown to be useful in determining the fluid dynamics of a raceway photobioreactor. Equations useful in simulating the power consumption as a function of the design and operation parameters have been validated. -- Highlights: •Power consumption due to accessories can limit the use of raceway reactors for energy purposes. •Use of baffle to enhance mass transfer dramatically increases the power consumption in this type of photobioreactors. •High mixing time, in the order of hours, in raceway reactors limits the operation mode of these systems

  3. Tritium distribution on plasma facing graphite tiles of JT-60U

    International Nuclear Information System (INIS)

    Tritium distributions on the graphite divertor tiles, the dome units and the baffle plates of JT-60U were successfully measured. Poloidally, the highest tritium level was found at the dome top tiles and the outer baffle plates, where the plasma did not hit directly. On the other hand, although the toroidal tritium profiles on each tiles appeared uniform, detailed profiles in full toroidal direction clearly showed a periodic variation corresponding to the position of the magnetic field coils, indicating the ripple loss of high energy tritons as suggested by the OFMC code. Finally, the temperature increase owing to the plasma heat load was found to release the once retained tritium. (author)

  4. Space-dependent core/reflector boundary conditions generated by the boundary element method for pressurized water reactors

    Energy Technology Data Exchange (ETDEWEB)

    Itagaki, M. (Japan Atomic Energy Research Inst., Dept. of Nuclear Ship Engineering, Aza-Kitasekine, Oaza-Sekine, Mutsu, Aomori 035 (JP)); Brebbia, C.A. (Computational Mechanics Inst., Ashurst Lodge, Ashurst, Southampton SO4 2AA (GB))

    1991-03-01

    This paper reports on the boundary element method used to generate energy-dependent matrix-type boundary conditions along core/reflector interfaces and along baffle-plate surfaces of pressurized water reactors. This method enables one to deal with all types of boundary geometries including convex and concave corners. The method is applicable to neutron diffusion problems with more than two energy groups and also can be used to model a reflector with or without a baffle plate. Excellent eigenvalue and flux shape results can be obtained when the boundary conditions generated by this technique are coupled with core-only finite difference calculations.

  5. OARDAS - A New Ray-Based Stray Radiation Analysis Program

    Science.gov (United States)

    Rock, David F.

    1987-06-01

    The new Off-Axis Rejection Design Analysis Software (OARDAS) aids in modeling complex baffle configurations for generally asymmetric and folded optical systems in order to estimate their background suppression performance. This interactive program uses real raytracing and a combination of Monte Carlo and deterministic methods to aid the user in finding stray radiation paths and calculating stray backgrounds. User friendliness and flexibility were two primary goals in the program design. With its extensive graphics capability, OARDAS is a powerful tool for diagnosing and understanding complex radiation paths. This paper first gives an overview of OARDAS philosophy and capabilities and then shows how OARDAS is used to analyze a complex baffle design.

  6. Optical design for amateur reflecting telescopes based on tilted axial-symmetrical planoidal mirror

    Science.gov (United States)

    Chuprakov, Sergey A.

    2012-09-01

    Two-mirrors aplanatic optical design for amateur telescopes up to 0.5m class is described. The optical system is low cost, easy for adjusting, fast and large field of view can be used for visual and astrophotography. The method for calculation of baffles for straight light protection is described. The optical performances and sample shots for the builted device are presented. Keywords: two-mirrors system, all-reflecting schmidt system, aplanatic system, protection from straight light, baffles, obscuration, wide-field, telescopes for amateurs.

  7. Use of a Three Dimensional Printed Cardiac Model to Assess Suitability for Biventricular Repair.

    Science.gov (United States)

    Farooqi, Kanwal M; Gonzalez-Lengua, Carlos; Shenoy, Rajesh; Sanz, Javier; Nguyen, Khanh

    2016-05-01

    Three dimensional (3D) printing is rapidly gaining interest in the medical field for use in presurgical planning. We present the case of a seven-year-old boy with double outlet right ventricle who underwent a bidirectional Glenn anastomosis. We used a 3D cardiac model to assess his suitability for a biventricular repair. He underwent a left ventricle-to-aorta baffle with a right ventricle-to-pulmonary artery conduit placement. He did well postoperatively and was discharged home with no evidence of baffle obstruction and good biventricular function. A 3D printed model can provide invaluable intracardiac spatial information in these complex patients. PMID:27009890

  8. A capillary-driven micromixer: idea and fabrication

    International Nuclear Information System (INIS)

    Microfluidic systems have been drawing attention upon the various branches of engineering science and the allied areas within biology and biomedicine. In this paper, a fabrication of a capillary-driven micromixer using photoresist JSR and glasses is proposed. We design three types of planar capillary-driven micormixers with different sizes of baffles in the channel. Flow tests have shown that the micromixer with a baffle gap of 100 μm and space of 100 μm reaches a best mixing performance of 93% in gray-level image analysis. (paper)

  9. A capillary-driven micromixer: idea and fabrication

    Science.gov (United States)

    Lee, Chun-Te; Lee, Chun-Che

    2012-10-01

    Microfluidic systems have been drawing attention upon the various branches of engineering science and the allied areas within biology and biomedicine. In this paper, a fabrication of a capillary-driven micromixer using photoresist JSR and glasses is proposed. We design three types of planar capillary-driven micormixers with different sizes of baffles in the channel. Flow tests have shown that the micromixer with a baffle gap of 100 μm and space of 100 μm reaches a best mixing performance of 93% in gray-level image analysis.

  10. Advanced manufacturing technologies for the BeCOAT telescope

    Science.gov (United States)

    Sweeney, Michael N.; Rajic, Slobodan; Seals, Roland D.

    1994-02-01

    The beryllium cryogenic off-axis telescope (BeCOAT) uses a two-mirror, non re-imaging, off- axis, Ritchey Chretian design with all-beryllium optics, structures and baffles. The purpose of this telescope is the system level demonstration of advanced manufacturing technologies for optics, optical benches, and baffle assemblies. The key issues that are addressed are single point diamond turning of beryllium optics, survivable fastening techniques, minimum beryllium utilization, and technologies leading to self-aligning, all-beryllium optical systems.

  11. Prediction of Heat Transfer Rates for Shell-and-Tube Heat Exchangers by Artificial Neural Networks Approach

    Institute of Scientific and Technical Information of China (English)

    Qiuwang WANG; Gongnan XIE; Ming ZENG; Laiqin LUO

    2006-01-01

    This work used artificial neural network (ANN) to predict the heat transfer rates of shell-and-tube heat exchangers with segmental baffles or continuous helical baffles, based on limited experimental data. The Back Propagation (BP) algorithm was used in training the networks. Different network configurations were also studied. The deviation between the predicted results and experimental data was less than 2%. Comparison with correlation for prediction shows ANN superiority. It is recommended that ANN can be easily used to predict the performances of thermal systems in engineering applications, especially to model heat exchangers for heat transfer analysis.

  12. A new method to calculate pressure drop and shell-side heat transfer coefficient in a shell-and-tube heat exchanger

    International Nuclear Information System (INIS)

    A new method to calculate pressure drop (Δp) and shell-side heat transfer coefficient (h sub(c)) in a shell-and-tube heat exchanger with segmental baffles is presented. The method is based on the solution of the equations of conservation of mass and momentum between two baffles. The calculated distributions of pressure and velocities given respectively, Δp and h sub(c). The values of Δp and h sub(c) are correlated for a given geometry whit the shell side fluid properties and flow rate. The calculated and experimental results agree very well for a U-Tube heat exchanger. (Author)

  13. Axial Force at the Vessel Bottom Induced by Axial Impellers

    OpenAIRE

    I. Fořt; P. Hasal; A. Paglianti; F. Magelli

    2008-01-01

    This paper deals with the axial force affecting the flat bottom of a cylindrical stirred vessel. The vessel is equipped with four radial baffles and is stirred with a four 45° pitched blade impeller pumping downwards. The set of pressure transducers is located along the whole radius of the flat bottom between two radial baffles. The radial distribution of the dynamic pressures indicated by the transducers is measured in dependence on the impeller off-bottom clearance and impeller speed.It fol...

  14. Uji Eksperimental Optimasi Perpindahan Kalor Dan Penurunan Tekanan Pengaruh Jarak Sekat Pada Alat Penukar Kalor Selongsong Dan Tabung Dengan Susunan Tabung Belah Ketupat

    OpenAIRE

    Bangun, Positron

    2011-01-01

    Baffle spacing influence the flow turbulence on the shell side. The Degree of turbulent flow can increase the convection heat transfer and pressure drop. In this study conducted to determine the effect of baffle spacing on pressure drop and convection heat transfer in shell and tube heat exchangers for staggered-square tube arrangement. This investigation is done by flowing water as the hot fluid through the tube and the air as the cold fluid through the shell. The temperature of the water a...

  15. Development of a CFD Model for Secondary Final Settling Tanks in Water Pollution Control Plants

    Science.gov (United States)

    Gong, Minwei; Xanthos, Savvas; Ramalingam, Krish; Fillos, John

    2007-11-01

    To assess performance and evaluate alternatives to improve efficiency of the New York City the Wards Island Water Pollution Control Plant (WPCP) FSTs at peak loads, a 3D CFD model has been developed. Fluent was utilized as the base platform, where sub-models of the Suspended Solids (SS), settling characteristics, density currents and SS flocculation were incorporated. This was supplemented by field and bench scale experiments to quantify the coefficients integral to the sub-models. Model calibration and validation have been carried out by using the extensive set of data collected. The model can be used to evaluate different modes of operation, alternate hydraulic and solids loading rates, as well as addition of auxiliary components such as baffles to improve process performance. The model is being used to compare potential benefits for different alternatives of design and operation of the existing FSTs. After comparing series of inlet baffles, a baffle with 4 horizontal and 7 vertical slots has been recommended for installation in the FSTs. Additional baffle type, configurations and locations within the tank are also being evaluated to improve the performance of the FSTs especially during periods of poor settling and peak flow conditions.

  16. A NOVEL PROCESS FOR BIOLOGICAL NITROGEN REMOVAL FROM DAIRY WASTEWATER IN CONSTRUCTED WETLANDS

    Science.gov (United States)

    SUNY-ESF has a multidisciplinary P3 Team, although it is mainly composed of undergraduate students in forest engineering and graduate students in environmental and resources engineering. The Team has successfully enriched anammox bacteria in two vertical flow baffled biofilter...

  17. Retention and distribution of Cu, Pb, Cr, and Zn in a full-scale hybrid constructed wetland receiving municipal sewage

    NARCIS (Netherlands)

    Xiao, H.W.; Zhang, S.L.; Zhai, J.; He, Q.; Mels, A.R.; Ning, K.J.; Liu, J.

    2013-01-01

    This study was conducted to investigate the retention and distribution of Cu, Pb, Cr, and Zn in a hybrid constructed wetland (CW) that consists of both vertical baffled flow wetlands (VBFWs) and horizontal subsurface flow wetlands (HSSFs) with unique flow regimes and oxygen distribution. The heavy m

  18. Surreptitious hyperkalaemia and its complications

    OpenAIRE

    Morgenstern, Tilo; Kurp, Gregor; Mahmud, Hasan; Föller, Michael; Lang, Florian; Luft, Friedrich C.

    2008-01-01

    Surreptitious hyperkalaemia is not a common problem, particularly in patients not yet dialysis dependent. We encountered a patient who baffled her physicians and their consultants, who nonetheless proposed life-saving treatments and novel explanations. However, according to the maxim that common things are common and rare things are rare, we solved the problem by focusing on the accompanying anion.

  19. Innovative Fabric Show Every Month in Shanghai

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    It normally costs a long term for fabric manufacturers to develop a new product. The delay of marketing the innovative fabric not only affect the benefit of the textile mills, but also baffle the development of the industry. Shanghai Fabric Hall responses to this with a regular exhibition of

  20. Noise prevention

    Science.gov (United States)

    Methods for noise abatement are discussed. Noise nuisance, types of noise (continuous, fluctuating, intermittent, pulsed), and types of noise abatement (absorption, vibration damping, isolation) are defined. Rockwool panels, industrial ceiling panels, baffles, acoustic foam panels, vibration dampers, acoustic mats, sandwich panels, isolating cabins and walls, ear protectors, and curtains are presented.

  1. LARGE EDDY SIMULATIONS OF THE TURBULENT FLOW IN A STIRRED TANK

    DEFF Research Database (Denmark)

    Fan, Jianhua; Wang, Yundong; Fei, Weiyang

    2005-01-01

    Computational fluid dynamics (CFD) simulations of the fluid flow in a baffled, stirred tank with a single Rushton turbine are performed. The simulations are carried out on the “Shengcao-21C” supercomputer via commercial CFD software CFX5, using k-ε and large eddy simulation (LES) turbulence model...

  2. Large eddy simulations of flow instabilities in a stirred tank generate by a Rushton turbine

    DEFF Research Database (Denmark)

    Fan, Jianhua; Wang, Yundong; Fei, Weiyang

    2007-01-01

    The aim of this paper is to investigate the flow instabilities in a baffled, stirred tank generated by a single Rushton turbine by means of large eddy simulation (LES) and simulation using the k-ε turbulent model. A sliding mesh method was used for the coupling between the rotating and the statio...

  3. LARGE EDDY SIMULATIONS OF THE TURBULENT FLOW IN A STIRRED TANK

    DEFF Research Database (Denmark)

    Fan, Jianhua; Wang, Yundong; Fei, Weiyang

    Computational fluid dynamics (CFD) simulations of the fluid flow in a baffled, stirred tank with a single Rushton turbine are performed. The simulations are carried out on the “Shengcao-21C” supercomputer via commercial CFD software CFX5, using k-ε and large eddy simulation (LES) turbulence model...

  4. Numerical and experimental analysis of transient wave propagation through perforated plates for application to the simulation of LOCA in PWR

    International Nuclear Information System (INIS)

    Highlights: ► LOCA simulation: analyze effects of perforated plates on rarefaction waves propagation at reactor level. ► Localized impedance relations to account for singular head loss and acoustic delays. ► Experimental campaign to produce a reference solution for wave propagation through a thickorifice plate. ► Qualification of a reference CFD code to produce reflection/transmission solutions for any geometry. ► Calibration procedure for impedance relations using CFD reference solutions. - Abstract: Loss of coolant accident is characterized by a transient rarefaction wave propagating inside the primary loop after pipe break, resulting in fluid loading on internal structures, especially on the baffle surrounding the reactor core. In that case, loading comes from differences in rarefaction wave travel times, whether it propagates through the reactor core or through the by-pass between baffle and core barrel, yielding delays and pressure differences on both sides of baffle plates. Propagation is strongly influenced by geometric obstacles such as holes in baffle reinforcement plates, which cannot be represented in a numerical model of the whole primary loop and has then to be replaced by suitable impedance relations. A methodology to validate and calibrate such impedance models, based on specific experimental results and high-order CFD simulations, is thus proposed. Models are tested and integrated into EUROPLEXUS fast-transient fluid–structure dynamics software.

  5. Numerical investigation of flow and heat transfer in a novel configuration multi-tubular fixed bed reactor for propylene to acrolein process

    Science.gov (United States)

    Jiang, Bin; Hao, Li; Zhang, Luhong; Sun, Yongli; Xiao, Xiaoming

    2015-01-01

    In the present contribution, a numerical study of fluid flow and heat transfer performance in a pilot-scale multi-tubular fixed bed reactor for propylene to acrolein oxidation reaction is presented using computational fluid dynamics (CFD) method. Firstly, a two-dimensional CFD model is developed to simulate flow behaviors, catalytic oxidation reaction, heat and mass transfer adopting porous medium model on tube side to achieve the temperature distribution and investigate the effect of operation parameters on hot spot temperature. Secondly, based on the conclusions of tube-side, a novel configuration multi-tubular fixed-bed reactor comprising 790 tubes design with disk-and-doughnut baffles is proposed by comparing with segmental baffles reactor and their performance of fluid flow and heat transfer is analyzed to ensure the uniformity condition using molten salt as heat carrier medium on shell-side by three-dimensional CFD method. The results reveal that comprehensive performance of the reactor with disk-and-doughnut baffles is better than that of with segmental baffles. Finally, the effects of operating conditions to control the hot spots are investigated. The results show that the flow velocity range about 0.65 m/s is applicable and the co-current cooling system flow direction is better than counter-current flow to control the hottest temperature.

  6. A simulated test of physical starting and reactor physics on zero power facility of PWR

    International Nuclear Information System (INIS)

    The core neutron economics has been verified through experiments conducted at a zero power reactor with baffles of various thickness. A simulated test of physical starting of Qinshan PWR has been introduced. The feasibility and safety of the programme are verified. The research provides a valuable foundation for developing physical starting programme

  7. Deep simplicity chaos, complexity and the emergence of life

    CERN Document Server

    Gribbin, John

    2005-01-01

    The world around us can be a complex, confusing place. Earthquakes happen without warning, stock markets fluctuate, weather forecasters seldom seem to get it right - even other people continue to baffle us. How do we make sense of it all? This title illuminates the harmony underlying our existence.

  8. 40 CFR 61.181 - Definitions.

    Science.gov (United States)

    2010-07-01

    ... section as follows: Arsenic kitchen means a baffled brick chamber where inorganic arsenic vapors are cooled, condensed, and removed in a solid form. Control device means the air pollution control equipment... failure of air pollution control equipment or process equipment or of a process to operate in a normal...

  9. Nitrate Salt Surrogate Blending Scoping Test Plan

    Energy Technology Data Exchange (ETDEWEB)

    Anast, Kurt Roy [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2015-11-13

    Test blending equipment identified in the “Engineering Options Assessment Report: Nitrate Salt Waste Stream Processing”. Determine if the equipment will provide adequate mixing of zeolite and surrogate salt/Swheat stream; optimize equipment type and operational sequencing; impact of baffles and inserts on mixing performance; and means of validating mixing performance

  10. Retrospective dosimetry (or self dosimetry): Application to French Nuclear Power Plants

    International Nuclear Information System (INIS)

    In this text we give the dosimetry principle on irradiated materials such baffle screw, pressure vessel and control element cans. This measure, made by gammametry, is based on the steel activation and comparison with calculated measures by Actige code. 4 figs., 6 refs

  11. Parental Responses to Their Children's Cult Membership.

    Science.gov (United States)

    Schwartz, Lita Linzer

    Most of the literature relevant to today's religious cults has paid scant attention to the parents of cult members. Two recent studies (1979 and 1982) of parents of ex-cult members revealed that initial parental responses to a child's cult involvement ranged from anxiety to terror. In general, the parents were baffled by their children's new…

  12. The influence of the wind on the flight of the uncontrollable aircrafts

    Directory of Open Access Journals (Sweden)

    Vasiliy Makeyev

    2015-01-01

    Full Text Available This article represents research of influence of wind on flight of uncontrollable flying devices. It is offered the method of taking into account influence of permanent wind as well as baffling wind on flight of uncontrollable aircrafts stabilized with rotation and empennage

  13. Flow-induced vibration study in the LOFT steam generator

    Energy Technology Data Exchange (ETDEWEB)

    Carmichael, C.F.

    1977-10-18

    The consequences of flow induced vibration in the LOFT steam generator were studied. Tube-baffle contact and fretting wear are expected to occur while tube-tube contact is not predicted. The LOFT steam generator is, in all probability adequate from a fluid induced viewpoint for the scheduled service of the LOFT facility at power. 37 refs., 5 figs., 3 tabs.

  14. Mathematical Modelling Of Cyanide Inhibition on Cassava Wastewater Treatment

    Directory of Open Access Journals (Sweden)

    E. Onukwugha

    2013-09-01

    Full Text Available Anaerobic Baffled Reactors (ABR is used to evaluate the extent of cyanide inhibition of cassava wastewater treatment. The reactor has aspect ratio of 4:1:1. Kinetic analyses of specific growth rate μmax and half saturation constant

  15. Mutual Radiation Impedance of Uncollapsed CMUT Cells with Different Radii

    CERN Document Server

    Ozgurluk, Alper; Atalar, Abdullah; Koymen, Hayrettin

    2015-01-01

    A polynomial approximation is proposed for the mutual acoustic impedance between uncollapsed capacitive micromachined ultrasonic transducer (CMUT) cells with different radii in an infinite rigid baffle. The resulting approximation is employed in simulating CMUTs with a circuit model. A very good agreement is obtained with the corresponding finite element simulation (FEM) result.

  16. Optimization of water treatment facility by using radioisotope tracer

    Energy Technology Data Exchange (ETDEWEB)

    Jin, J. H.; Lee, M. J.; Jung, S. H.

    1997-01-01

    In order to get the optimization of conventional water treatment facility, radioisotope tracer technique was applied. It is desirable to set the baffles inside of mixing basin for the enhancement of mixing effect. It was appeared that most of flocs were settled down within 60 - 70 % of total length of sedimentation basin even with high flow rate. (author). 2 tabs., 32 figs.

  17. Flow Dynamics In Eccentrically Rotating Flasks Used For Dispersant Effectiveness Testing

    Science.gov (United States)

    The evaluation of dispersant effectiveness used for oil spills is commonly done using tests conducted in laboratory flasks. We used a Hot Wire Anemometer (HWA) to characterize mixing dynamics in the Swirling Flask (SF) and the Baffled Flask (BF), the latter is being considered b...

  18. Dissolved oxygen levels affect dimorphic growth by the entomopathogenic fungus Isaria fumosorosea

    Science.gov (United States)

    The entomopathogenic fungus Isaria fumosorosea is capable of dimorphic growth (hyphal or yeast-like) in submerged culture. In shake flask studies, we evaluated the impact of aeration on the mode of growth of I. fumosorosea. Using 250 mL baffled Erlenmeyer flasks, culture volumes of 50, 100, 150, a...

  19. A Stylistic Study on the Linguistic Deviations in E. E. Cummings' Poetry

    Science.gov (United States)

    Li, Xin; Shi, Mengchen

    2015-01-01

    Regarded as the pioneer of experimental poetry, E. E. Cummings' unconventional treatment of poetic language has reached an unprecedented acme, which has intrigued and baffled numerous scholars, researchers and readers alike. Nevertheless, the very existence of poetry, like other types of literary texts, demonstrates the significance and value of…

  20. In-vessel debris beds. Simplified approaches for evaluation codes

    International Nuclear Information System (INIS)

    Simplified model approaches are proposed for the following items: Molten Pool propagation In-Core; coolable corium mass In-Core, Analysis of risk of FCI for In-Core Pool Reflooding, Reflooding of debris containing metallic material, Corium flow in baffles, Effect of crust on Fuel Coolant Interaction, Gap cooling. (author)

  1. Characterisation of blast loading in complex, confined geometries using quarter symmetry experimental methods

    Science.gov (United States)

    Anthistle, T.; Fletcher, D. I.; Tyas, A.

    2016-03-01

    Explosions in confined spaces lead to complicated patterns of shock wave reflection and interactions which are best investigated by use of experimental tests or numerical simulations. This paper describes the design and outcome of a series of experiments using a test cell to measure the pressures experienced when structures were placed inside to alter the propagation of shock waves, utilising quarter symmetry to reduce the size of the required test cell and charge. An 80 g charge of PE4 (a conventional RDX-based plastic explosive) was placed at half height in one corner of the test cell, which represents the centre of a rectangular enclosure when symmetry is taken into consideration. Steel cylinders and rectangular baffles were placed within the test cell at various locations. Good reproducibility was found between repeated tests in three different arrangements, in terms of both the recorded pressure data and the calculated cumulative impulse. The presence of baffles within the test cell made a small difference to the pressures and cumulative impulse experienced compared to tests with no baffles present; however, the number and spacing of baffles was seen to make minimal difference to the experienced pressures and no noticeable difference to the cumulative impulse history. The paper presents useful experimental data that may be used for three-dimensional code validation.

  2. Synergetic Effects of Runaway and Disruption Induced by VDE on the First Wall Damage in HL-2A

    International Nuclear Information System (INIS)

    The plasma facing component in HL-2A has been damaged seriously after disruption, and for this reason its operation is suspended for maintenance. The experimental phenomena and plasma configurations, calculated by the current filament code (CF-code) using the plasma parameters measured by diagnostics and the signals of the magnetic probes, confirm that the first wall is damaged by the synergetic effects of runaway electrons and disruption induced by a vertical displacement event (VDE). When the plasma column is displaced upward/downward, the strong runaway electrons normally hit the baffle plate of the MP3 or MP1 coil in the upper and lower divertor during the disruption, causing the baffle plates to be holed and wrinkled by the energetic runaway current, and water (for cooling or heating the baffle plates) to leak into the vacuum vessel. Another disastrous consequence is that bellows underlying the baffle plate and outside the coil of MP3 for connecting two segments of the jacket casing pipe are punctured by arcing. The arc may be part of the halo current that forms a complete circuit. The experimental phenomena are indirect but compelling evidence for the existence of a halo current during the disruption and VDE, though the halo current has not been measured by the diagnostics in the HL-2A tokamak.

  3. Solidification of highly active liquid waste

    International Nuclear Information System (INIS)

    This document contains the annual progress reports on the following subjects: Joule ceramic melter; microwave vitrification; glass technology; identification, evaluation and review of potential alternative solidification processes; rotary kiln calcination; alternative glass feedstocks; volatile ruthenium trapping by solid adsorbents; irrigated baffle column dust scrubber. (author)

  4. MICROBIAL COMETABOLISM OF RECALCITRANT CHEMICALS IN CONTAMINATED AIR STREAMS

    Science.gov (United States)

    Chlorinated Solvents: The treatment system consists of a laboratory-scale hollow fiber membrane (HFM) module containing a center baffle and a radial cross-flow pattern on the shell side of the fibers. The shell and lumen fluids are contacting in a counter-current f...

  5. Beryllium assessment and recommendation for application in ITER plasma facing components

    Energy Technology Data Exchange (ETDEWEB)

    Barabash, V.; Tanaka, S.; Matera, R. [ITER Joint Central Team, Muenchen (Germany)

    1998-01-01

    The design status of the ITER Plasma Facing Components (PFC) is presented. The operational conditions of the armour material for the different components are summarized. Beryllium is the reference armour material for the Primary Wall, Baffle and Limiter and the back-up material for the Divertor Dome. The activities on the selection of the Be grades and the joining technologies are reviewed. (author)

  6. Integrated boiler, superheater, and decomposer for sulfuric acid decomposition

    Science.gov (United States)

    Moore, Robert; Pickard, Paul S.; Parma, Jr., Edward J.; Vernon, Milton E.; Gelbard, Fred; Lenard, Roger X.

    2010-01-12

    A method and apparatus, constructed of ceramics and other corrosion resistant materials, for decomposing sulfuric acid into sulfur dioxide, oxygen and water using an integrated boiler, superheater, and decomposer unit comprising a bayonet-type, dual-tube, counter-flow heat exchanger with a catalytic insert and a central baffle to increase recuperation efficiency.

  7. Thermal analysis of shell-side flow of shell-and tube heat exchanger using experimental and theoretical methods

    International Nuclear Information System (INIS)

    In this paper the thermal behavior of the shell-side flow of a shell-and-tu fe heat exchanger has been studied using theoretical and experimental methods. The experimental method Provided the effect of the major parameters of the shell-side flow on thermal energy exchange. In the numerical method, besides the effect of the major parameters, the effect of different geometric parameters and Re on thermal energy exchange in shell-side flow has been considered. Numerical analysis for six baffle spacings namely 0.20, 0.25, 0.33, 0.50, 0.66, and 1.0 of inside diameter of the shell and five baffle cuts namely 16%, 20%, 25%, 34%, and 46% of baffle diameter, have been carried out. In earlier numerical analyses, the repetition of an identical geometrical module of exchanger as a calculation domain has been studied. While in this work, as a new approach in current numerical analysis, the entire geometry of shell-and-tube heat exchanger including entrance and exit regions as a calculation domain has been chosen. The results show that the flow and heat profiles vary alternatively between baffles. A shell-and-tube heat exchanger of gas-liquid chemical reactor system has been used in the experimental method. Comparison of the numerical results show good agreement with experimental results of this research and other published experimental results over a wide rang of Reynolds numbers (1,000-1,000,000)

  8. 49 CFR 178.347-2 - Material and thickness of material.

    Science.gov (United States)

    2010-10-01

    ... Baffles When Used as Tank Reinforcement) Using Mild Steel (MS), High Strength Low Alloy Steel (HSLA... 30 Over 30 Thickness (MS) 0.100 0.100 0.115 0.129 0.129 0.143 0.156 Thickness (HSLA) 0.100 0.100 0... (MS), High Strength Low Alloy Steel (HSLA), Austenitic Stainless Steel (SS), or Aluminum...

  9. Physics and Psychophysics of High-Fidelity Sound. Part III: The Components of a Sound-Reproducing System: Amplifiers and Loudspeakers.

    Science.gov (United States)

    Rossing, Thomas D.

    1980-01-01

    Described are the components for a high-fidelity sound-reproducing system which focuses on various program sources, the amplifier, and loudspeakers. Discussed in detail are amplifier power and distortion, air suspension, loudspeaker baffles and enclosures, bass-reflex enclosure, drone cones, rear horn and acoustic labyrinth enclosures, horn…

  10. Mapping the geothermal potential of fault zones in the Belgium-Netherlands border region

    NARCIS (Netherlands)

    Loveless, S.; Pluymaekers, M.P.D.; Lagrou, D.; Boever, E. de; Doornenbal, H.; Laenen, B.

    2014-01-01

    Faults can determine the success or failure of low enthalpy geothermal projects. This is due to their capacity to behave as pathways or baffles to geothermal water (or both simultaneously) and their prevalence throughout the subsurface. Here we present an initial assessment of the possibility for fa

  11. Bulimia: Issues a University Counseling Center Needs To Address.

    Science.gov (United States)

    Whitner, Phillip A.; Shetterly, Arminta

    The eating disorder known as bulimia is a relatively new and baffling phenomenon. This paper raises questions that college and university counseling center professionals need to address regarding this phenomenon. The first section focuses on defining the term "bulimia" and its evolution. The second section identifies numerous symptoms that need to…

  12. Uniform reflective films deposited on large surfaces

    Science.gov (United States)

    1966-01-01

    Specially designed baffle which intercepts varying amounts of the vapor stream from an evaporant source, vacuum deposits films of uniform thickness on large substrates, using a single small area evaporation source. A mirror coated by this method will have a reflectance as high as 82 percent at 1216 angstroms with a variation of only plus/minus 2 percent over the surface.

  13. Re-design High Pressure Heater (HPH 5 pada Perusahaan Pembangkit Tenaga Listrik

    Directory of Open Access Journals (Sweden)

    Devia Gahana Cindi Alfian

    2013-09-01

    Full Text Available Boiler merupakan komponen utama yang ada pada pembangkit. Jika terjadi penurunan efisiensi pada boiler, maka listrik yang dihasilkan juga menurun. Berbagai cara  dilakukan untuk meningkatkan efisiensi dari boiler, salah satunya adalah menggunakan High Pressure Heater (HPH. HPH merupakan alat pemanas feedwater sebelum masuk ke boiler sehingga mengurangi kerja dari boiler. Saat ini kondisi HPH 5 yang ada di salah satu perusahaan pembangkit listrik sudah lama digunakan sehingga perlu dilakukan analisa untuk mengatahui performa dari HPH ini. Jika terjadi kebocoran atau kerusakan hanya dilakukan re-tubing yang selalu menggunakan design Original Equipment Manufacturing (OEM yang memakan waktu cukup lama dan biaya yang mahal. Proses analisa yang dimaksudkan adalah re-design sehingga apabila terjadi kerusakan dapat diganti dengan buatan sendiri. Pada perancangannya digunakan analisa termodinamika dan perpindahan panas dengan metode LMTD untuk mendapatkan dimensi tiap zona. Perhitungan yang dilakukan meliputi menentukan panjang masing-masing tiap zona HPH, laju perpindahan panas, overall heat transfer coefficient (U, luas perpindahan panas (A, perhitungan pressure drop (∆p untuk masing-masing zona. Hasil yang didapatkan pada analisa ini adalah dimensi zona desuperheating didapatkan panjang maksimal 2,94 m, luasan perpindahan panas efektif 231,7 m2, Overall Heat Transfer Coefficient 520,43 Watt/m2K, baffle spacing 0,345 m, jumlah baffle 8 buah. Pada zona Condensing didapatkan panjang maksimal 9,39 m, luasan perpindahan panas efektif 739,5 m2, Overall Heat Transfer Coefficient 3738,3 Watt/m2K, baffle spacing 1,8 m, jumlah baffle 4 buah. Sedangkan pada zona Subcooling didapatkan panjang maksimal 1,66 m, luasan perpindahan panas efektif 131 m2, Overall Heat Transfer Coefficient 3659,84 Watt/m2K, baffle spacing 0,345 m, jumlah baffle 4 buah. Sehingga didapatkan panjang total tube 14 m, total luasan perpindahan panas efektif  1.102,34 m2, Total Overall

  14. Histochemical study of the oviducal gland and analysis of the sperm storage tubules of Mustelus schmitti Springer, 1939 (Chondrichthyes, Triakidae

    Directory of Open Access Journals (Sweden)

    Fernanda Gabriela Elías

    2015-08-01

    Full Text Available Abstract: The paired oviducal glands of immature and mature females of Mustelus schmitti were examined macro and microscopically. Findings indicate that these glands possessed the same zonation as in most chondrichthyans from anterior to posterior: club, papillary, baffle and terminal zones. The whole gland is composed by simple tubular glands that connect with transverse grooves all along the organ. The club zone presents a typical indian club shape with a simple columnar and ciliated epithelium including secretory cells PAS (+ and AB (+. The papillary zone is characterized by lamella forming small and long cones in numbers of three. The epithelium of this zone contains ciliated cells with apical nuclei and secretory cells with basal nuclei that stain AB (+The baffle zone consists of apically flattened lamellae alternating with spinnerets which are small projections disposed by both sides of the plateau. This whole structure is present in number of 8 or 9 units. A simple columnar ciliated epithelium covers the plateau and spinnerets and no AB or PAS staining is observed. The epithelium of the terminal zone is PAS (- and AB (+, and elongated tubules, that run adjacent to the baffle zone are the site where groups of spermatozoa are clearly observed in the lumen. The epithelium of the sperm storage tubules do not stain with any of the dyes tested. Sperm was also observed in the baffle zone, presumably in its way to the fecundation in the oviduct because it displays no aggregation pattern and was between the folds of the epithelium. By scanning electron microscopy sperm was observed in the club and baffle zones in a gland which belonged to a pregnant female.

  15. Design of a decay tank for a pool type research reactor with a CFD model

    International Nuclear Information System (INIS)

    A conceptual primary cooling system (PCS) was designed for adequate cooling of the core of a research reactor. The primary coolant after passing through the reactor core contains many kinds of radio-nuclides. A decay tank provides a delayed transit time to ensure that the N-16 activity decreases enough before the coolant leaves the decay tank's shielding room. The size of the decay tank should be enlarged to provide sufficient transit time. However, there was a limitation: to minimize the tank size, it should be designed with an internal baffle, which affects the pressure loss in the system and net positive suction head (NPSH) of the PCS pump. Therefore, the decay tank should be optimized for size and the internal baffle. A vertical type decay tank was chosen to optimize the geometrical arrangement of PCS and the vertical internal baffle was installed to minimize the number of internal structures. The preliminary geometry of the tank and the internal baffle were determined to satisfy the required delayed transit time by calculating the maximum velocity and the flow path length of the circular and the annular sections of the tank. The commercially available CFD model, FLUENT, which solves the Navier-Stokes and turbulent models, was used to specifically design the decay tank with the preliminarily calculated geometry and the related flow rate. Several turbulence models, standard k-ε model, renormalization group (RNG) model, and realizable k-ε model, were conducted to isolate the root cause of these differences. By comparing the results of the velocity profile and the characteristics of each model, a detailed design study was simulated using the realizable k-ε model. A user-defined scalar equation was solved to estimate the delayed transit time. The size and the internal baffle that satisfy the required transit time were determined based on the CFD results. (author)

  16. Tube-in-shell heat exchangers

    International Nuclear Information System (INIS)

    Tube-in-shell heat exchangers normally comprise a bundle of parallel tubes within a shell container, with a fluid arranged to flow through the tubes in heat exchange with a second fluid flowing through the shell. The tubes are usually end supported by the tube plates that separate the two fluids, and in use the tube attachments to the tube plates and the tube plates can be subject to severe stress by thermal shock and frequent inspection and servicing are required. Where the heat exchangers are immersed in a coolant such as liquid Na such inspection is difficult. In the arrangement described a longitudinally extending central tube is provided incorporating axially spaced cylindrical tube plates to which the opposite ends of the tubes are attached. Within this tube there is a tubular baffle that slidably seals against the wall of the tube between the cylindrical tube plates to define two co-axial flow ducts. These ducts are interconnected at the closed end of the tube by the heat exchange tubes and the baffle comprises inner and outer spaced walls with the interspace containing Ar. The baffle is easily removable and can be withdrawn to enable insertion of equipment for inspecting the wall of the tube and tube attachments and to facilitate plugging of defective tubes. Cylindrical tube plates are believed to be superior for carrying pressure loads and resisting the effects of thermal shock. Some protection against thermal shock can be effected by arranging that the secondary heat exchange fluid is on the tube side, and by providing a thermal baffle to prevent direct impingement of hot primary fluid on to the cylindrical tube plates. The inner wall of the tubular baffle may have flexible expansible region. Some nuclear reactor constructions incorporating such an arrangement are described, including liquid metal reactors. (U.K.)

  17. Baseline design and requirements for the LSST rotating enclosure (dome)

    Science.gov (United States)

    Neill, D. R.; DeVries, J.; Hileman, E.; Sebag, J.; Gressler, W.; Wiecha, O.; Andrew, J.; Schoening, W.

    2014-07-01

    The Large Synoptic Survey Telescope (LSST) is a large (8.4 meter) wide-field (3.5 degree) survey telescope, which will be located on the Cerro Pachón summit in Chile. As a result of the wide field of view, its optical system is unusually susceptible to stray light; consequently besides protecting the telescope from the environment the rotating enclosure (Dome) also provides indispensible light baffling. All dome vents are covered with light baffles which simultaneously provide both essential dome flushing and stray light attenuation. The wind screen also (and primarily) functions as a light screen providing only a minimum clear aperture. Since the dome must operate continuously, and the drives produce significant heat, they are located on the fixed lower enclosure to facilitate glycol water cooling. To accommodate day time thermal control, a duct system channels cooling air provided by the facility when the dome is in its parked position.

  18. Bulk growth of GaSb and Ga{sub 1{minus}x}In{sub x}Sb

    Energy Technology Data Exchange (ETDEWEB)

    Dutta, P.S.; Ostrogorsky, A.G.; Gutmann, R.J.

    1997-05-01

    GaSb and InGaSb have been demonstrated to be suitable choices for high efficiency thermophotovoltaic (TPV) cells. Synthesis and growth of bulk GaSb single crystals and GaInSb polycrystals have been carried out by the vertical Bridgman technique, with a baffle immersed in the melt and by complete encapsulation of the melt by low melting temperature alkali halides or oxides. The critical roles of the baffle and the encapsulation are discussed. Efforts in obtaining device grade GaSb with superior structural and electrical properties and compositionally homogeneous GaInSb are described, emphasizing the key steps in the growth cycle developed to obtain good crystalline quality.

  19. Calculation of the performance of the INS iron-free π√2 spectrometer as a spectrograph

    International Nuclear Information System (INIS)

    The performance of the INS iron-free π√2 beta-ray spectrometer of the current-loop type is calculated with a view of using it as a spectrograph, i.e., in a multichannel mode with a position-sensitive proportional counter. For the momentum resolution of R = 0.01 and 0.1 % the usable momentum range as a spectrograph (+epsilon+ 0) and the line shapes on the focal plane are calculated. The transmission of the baffle is 0.025 and 0.13 % of 4π and the expected gain of data-collection efficiency over the single-channel mode is 140 and 40 for R = 0.01 and 0.1%, respectively. An effective tilting of the focal plane due to the entrance baffle is discussed as well as the problems with arrangement and testing of the position detector. (author)

  20. DAMPING COMPUTATION OF LIQUID SLOSHING IN CONTAINERS ABOARD SPACECRAFT

    Institute of Scientific and Technical Information of China (English)

    宝音贺西; 李俊峰; 高云峰; 王照林

    2003-01-01

    Under the non-rotating assumption, a method for the calculation of damping of fuel sloshing with small amplitude in containers aboard spacecraft is proposed in the present paper. And we have presented an eigen-value equation for sloshing damping and frequency computation. This equation may be solved by Ritz or Galerkin methods for a container of simple geometry or by finite element method for a container of arbitrary geometric shape even with rigid baffles. The simulated results show that the equivalent damping coefficients is directly proportional to fuel's viscosity, whereas it almost exhibits no influence on sloshing frequencies. The drawback of the proposed method lies in expensive computation cost. Thus far, it hasn't yet be applied to a container with elastic baffles.

  1. Experimental, Numerical, and Analytical Slosh Dynamics of Water and Liquid Nitrogen in a Spherical Tank

    Science.gov (United States)

    Storey, Jedediah Morse

    2016-01-01

    Understanding, predicting, and controlling fluid slosh dynamics is critical to safety and improving performance of space missions when a significant percentage of the spacecraft's mass is a liquid. Computational fluid dynamics simulations can be used to predict the dynamics of slosh, but these programs require extensive validation. Many experimental and numerical studies of water slosh have been conducted. However, slosh data for cryogenic liquids is lacking. Water and cryogenic liquid nitrogen are used in various ground-based tests with a spherical tank to characterize damping, slosh mode frequencies, and slosh forces. A single ring baffle is installed in the tank for some of the tests. Analytical models for slosh modes, slosh forces, and baffle damping are constructed based on prior work. Select experiments are simulated using a commercial CFD software, and the numerical results are compared to the analytical and experimental results for the purposes of validation and methodology-improvement.

  2. Modeling of axial vibrational control technique for CdTe VGF crystal growth under controlled cadmium partial pressure

    Science.gov (United States)

    Avetissov, I.; Kostikov, V.; Meshkov, V.; Sukhanova, E.; Grishechkin, M.; Belov, S.; Sadovskiy, A.

    2014-01-01

    A VGF growth setup assisted by axial vibrations of baffle submerged into CdTe melt with controlled Cd partial pressure was designed. An influence of baffle shape on flow velocity map, temperature distribution in CdTe melt and interface shape of growing crystal was analyzed by numerical simulation and physical modeling. To produce the desirable shape of crystal melt interface we slant under different angles vertical generatrix in a cylindrical disk and made chasing on faceplates of a disk. It was ascertained that a disk with conical generatrix formed more intensive convective flows from a faceplate with larger diameter. It was shown that at CdTe VGF crystal growth rate about 10 mm/h application of AVC technique made it possible to produce convex interface for 2 in. crystal diameter.

  3. Improving microalgal growth with reduced diameters of aeration bubbles and enhanced mass transfer of solution in an oscillating flow field.

    Science.gov (United States)

    Yang, Zongbo; Cheng, Jun; Lin, Richen; Zhou, Junhu; Cen, Kefa

    2016-07-01

    A novel oscillating gas aerator combined with an oscillating baffle was proposed to generate smaller aeration bubbles and enhance solution mass transfer, which can improve microalgal growth in a raceway pond. A high-speed photography system (HSP) was used to measure bubble diameter and generation time, and online precise dissolved oxygen probes and pH probes were used to measure mass-transfer coefficient and mixing time. Bubble diameter and generation time decreased with decreased aeration gas rate, decreased orifice diameter, and increased water velocity in the oscillating gas aerator. The optimized oscillating gas aerator decreased bubble diameter and generation time by 25% and 58%, respectively, compared with a horizontal tubular gas aerator. Using an oscillating gas aerator and an oscillating baffle in a raceway pond increased the solution mass-transfer coefficient by 15% and decreased mixing time by 32%; consequently, microalgal biomass yield increased by 19%. PMID:27035474

  4. Sensitivity to plant modelling uncertainties in optimal feedback control of sound radiation from a panel

    DEFF Research Database (Denmark)

    Mørkholt, Jakob

    1997-01-01

    Optimal feedback control of broadband sound radiation from a rectangular baffled panel has been investigated through computer simulations. Special emphasis has been put on the sensitivity of the optimal feedback control to uncertainties in the modelling of the system under control.A model of a...... rectangular baffled panel radiating into free field has been constructed. Secondary actuators have been modelled as vibrational inputs acting directly on the panel. A cost function proportional to the averaged radiated sound power and based on knowledge of the modal amplitudes of the panel has been derived in...... terms of a set of radiation filters modelling the radiation dynamics.Linear quadratic feedback control applied to the panel in order to minimise the radiated sound power has then been simulated. The sensitivity of the model based controller to modelling uncertainties when using feedback from actual and...

  5. Status of the eROSITA Telescope testing and calibrating the x-ray mirror assemblies

    Science.gov (United States)

    Burwitz, Vadim; Predehl, Peter; Bräuninger, Heinrich; Burkert, Wolfgang; Dennerl, Konrad; Eder, Josef; Friedrich, Peter; Fürmetz, Maria; Grisoni, Gabriele; Hartner, Gisela; Marioni, Fabio; Menz, Benedikt; Pfeffermann, Elmar; Valsecchi, Giuseppe

    2013-09-01

    The eROSITA X-ray observatory that will be launched on board the Russian Spectrum-RG mission comprises seven X-ray telescopes, each with its own mirror assembly (mirror module + X-ray baffle), electron deflector, filter wheel, and CCD camera with its control electronics. The completed flight mirror modules are undergoing many thorough X-ray tests at the PANTHER X-ray test facility after delivery, after being mated with the X-ray baffle, and again after both the vibration and thermal-vacuum tests. A description of the work done with mirror modules/assemblies and the test results obtained will be reported here. We report also on the environmental tests that have been performed on the eROSITA telescope qualification model.

  6. Numerical optimization for separation power of gas centrifuge

    International Nuclear Information System (INIS)

    In order to obtain higher separation power of the gas centrifuge, the code was developed to solve the flow-field of the counter-current to acquire the separation power, which was integrated with the iSight software, so a numerical optimization model for separation power was presented, in which the driver conditions and the geometry parameters of the waste baffle were optimized to get the maximum separation power using the sequential quadratic programming arithmetic, and the 12% higher results was acquired, which shows the feasibility of this method. The results also note that the separation power of gas centrifuge is sensitive to the driver conditions and the structure parameters of the waste baffle, so it is necessary to perform the optimization calculation for the certain gas centrifuge model. (authors)

  7. The role of sealing strips in tubular heat exchangers

    International Nuclear Information System (INIS)

    Tubular-type heat exchangers contain both baffle plates and sealing strips. The baffles force the flow to pass normal to the axes of the tubes and they serve to support the tubes. In order to facilitate assembly of the heat exchanger, a space exists between the tube bundle and the retaining shell. This space offers a hydraulic short circuit to the fluid, thus reducing the effectiveness of the device to exchange heat. Sealing strips, which are metal strips mounted on the shell and running parallel to the tubes, are introduced to partially block this leakage flow, thereby increasing the effectiveness of the device. The objectives of the research reported here are to experimentally determine the effectiveness of sealing strips, and to investigate the effects of their shape and location. Such results not only supply design information, but they serve to establish the accuracy of computer codes which have been developed for such heat exchangers. (author)

  8. Fermentation and microencapsulation of the nematophagous fungus Hirsutella rhossiliensis in a novel type of hollow beads.

    Science.gov (United States)

    Patel, Anant V; Jakobs-Schönwandt, Desiree; Rose, Thomas; Vorlop, Klaus-Dieter

    2011-03-01

    In this work, fermentation and formulation aspects of the nematophagous fungus Hirsutella rhossiliensis BBA were investigated. When incubated in 2% (w/w) glucose and 0.5% (w/w) yeast extract medium in a 1-L Erlenmeyer flask without baffles, heavy pellet formation was observed. Only 40% of the mycelium had a size less than 500 μm. When a flask with three baffles was used, the portion of mycelium fermentation results were obtained at 0.4 vvm and 400 rpm stirrer speed with 90% mycelium gluten and 0.5% (w/w) yeast extract could be replaced with 3% (w/w) autoclaved baker's yeast which was never used as capsule additive before. Radial growth of mycelium out of dried hollow beads containing 1% (w/w) biomass and 3% (w/w) baker's yeast was faster than for alginate beads containing equivalent amounts of biomass and yeast indicating a higher bio-control potential. PMID:21181150

  9. An Investigation of Heat Transfer in a Mechanically Agitated Vessel

    Directory of Open Access Journals (Sweden)

    A. Debab

    2011-01-01

    Full Text Available The objective of this study is to optimize experimental conditions of agitating a non-Newtonian liquid using experimental design methodology. The measurements of the temperatures have been carried out in a jacketed vessel equipped with Turbine impellers. The rheological properties of aqueous solutions of carboxymethylcellulose sodium salt had been studied using shear stress/shear rate data. The results of the experimental studies, concerning the effect of the diameter of the impeller, the impeller speed and baffled or unbaffled vessel on the overall heat transfer coefficient have been approximated in the form of equations. Based on the optimization criterion, an agitated vessel equipped with Flat Blade Disc Turbine (FBDT of diameter ratio d/D = 0.6 and baffles is proposed as the most advantageous for heat transfer processes.

  10. Two-dimensional streaming flows induced by resonating, thin beams.

    Science.gov (United States)

    Açikalin, Tolga; Raman, Arvind; Garimella, Suresh V

    2003-10-01

    Miniaturized resonating slender beams are finding increased applications as fluidic actuators for portable electronics cooling. Piezoelectric and ultrasonic "fans" drive a flexural mode of the beam into resonance thus inducing a streaming flow, which can be used to cool microelectronic components. This paper presents analytical, computational, and experimental investigations of the incompressible two-dimensional streaming flows induced by resonating thin beams. Closed-form analytical streaming solutions are presented first for an infinite beam. These are used to motivate a computational scheme to predict the streaming flows from a baffled piezoelectric fan. Experiments are conducted to visualize the asymmetric streaming flows from a baffled piezoelectric fan and the experimental results are found to be in close agreement with the predicted results. The findings are expected to be of relevance in the optimal design and positioning of these solid-state devices in cooling applications. PMID:14587580

  11. Various methods to improve heat transfer in exchangers

    Science.gov (United States)

    Pavel, Zitek; Vaclav, Valenta

    2015-05-01

    The University of West Bohemia in Pilsen (Department of Power System Engineering) is working on the selection of effective heat exchangers. Conventional shell and tube heat exchangers use simple segmental baffles. It can be replaced by helical baffles, which increase the heat transfer efficiency and reduce pressure losses. Their usage is demonstrated in the primary circuit of IV. generation MSR (Molten Salt Reactors). For high-temperature reactors we consider the use of compact desk heat exchangers, which are small, which allows the integral configuration of reactor. We design them from graphite composites, which allow up to 1000°C and are usable as exchangers: salt-salt or salt-acid (e.g. for the hydrogen production). In the paper there are shown thermo-physical properties of salts, material properties and principles of calculations.

  12. Analysis of field coordination on heat exchanger shell side with different diameter tubes and holding structure

    International Nuclear Information System (INIS)

    In order to overcome the disadvantages of the rod-baffle heat exchanger, which achieves the high heat transfer efficiency only at high flow velocity, and which with non compact layout of tubes and is weak in the resistance of operation mode changes, this paper proposed two sizes of heat exchange tubes and holding and support structures to replace the traditional rod-baffle support unit, to increase the heat exchange coefficient on shell side and the heat exchange effectiveness. Three-dimensional numerical simulation was conducted on the shellside flow field and heat exchange field by the CFD software, and the calculation method was proposed for the included angle for the shellside velocity-temperature gradient fields of the vertical flow heat exchanger with complex structure. The quantitative relationship of the field coordination angle for the shellside velocity field and temperature gradient field was obtained and it is proved that the new structure is with better field coordination relation. (authors)

  13. Validation of the CAFCA code in a bidimensional single phase flow through VACARM tests

    International Nuclear Information System (INIS)

    A shell and tubes heat exchanger mock-up has been especially built to validate the numerical code CAFCA with one phase flow. The mock-up is strictly bidimensional and the baffles can be easily changed to test various configurations. The mock-up is connected to a test facility with a power of 1 MW on which flows, temperatures and pressures are measured with accuracy. Numerous probes are put all along the shell, and allow the measure of pressure and temperature fields of the secondary flow. About 200 tests were performed on the mock-up with different geometrical configurations and in a wide range of Reynolds numbers. The influence of leakage between tubes and shell or baffles was also investigated. The comparison of measurements and calculation is quite satisfactory. Without any leakage, the average deviation is about 3% as well for the overall pressure drop as for the overall exchanged power. With leakage, it grows up to about 5%

  14. Numerical simulation of flow field in shellside of heat exchanger in nuclear power plant

    International Nuclear Information System (INIS)

    Heat exchanger is the important equipment of nuclear power plant. Numerical simulation can give the detail information inside the heat exchange, and has been an effective research method. The geometric structure of shell-and-tube heat exchanger is very complex and it is difficult to simulate the whole flow field presently. According to the structure characteristics of the heat exchanger, a periodic whole-section calculation model was presented. The numerical simulation of flow field in shellside of heat exchange of a nuclear power plant was done by using this model. The results of simulation show that heat transfer in the periodic section of the heat exchange is uniform, the heat transfer is enhanced by using baffles in heat exchange, and frictional resistance is primary from the effect of segmental baffles. (authors)

  15. Analysis and improvement of sound radiation performance of spherical cap radiator

    International Nuclear Information System (INIS)

    A spherical cap radiator is one of the important parts of an underwater wide-beam imaging system. The back radiation of a traditional spherical cap radiator, which is composed of a vibrating cap and a rigid baffle, is strong and its far-field directivity function may fluctuate in big amplitude in the vicinity of the polar axis. These shortcomings complicate the processing of the reflective waves received for imaging the targets. In this study, the back radiation is weakened by adding an acoustic soft material belt between the vibrating cap and the rigid baffle. And the fluctuation mentioned above is lowered remarkably by dividing the spherical cap radiator into many annuluses and a relatively smaller spherical cap, and by controlling the phase retardations of all elements appropriately. Furthermore, the numerical experiments are carried out by the finite element method (FEM) to prove the validity of the above methods. (classical areas of phenomenology)

  16. Combustor and method for distributing fuel in the combustor

    Energy Technology Data Exchange (ETDEWEB)

    Uhm, Jong Ho; Ziminsky, Willy Steve; Johnson, Thomas Edward; York, William David

    2016-04-26

    A combustor includes a tube bundle that extends radially across at least a portion of the combustor. The tube bundle includes an upstream surface axially separated from a downstream surface. A plurality of tubes extends from the upstream surface through the downstream surface, and each tube provides fluid communication through the tube bundle. A baffle extends axially inside the tube bundle between adjacent tubes. A method for distributing fuel in a combustor includes flowing a fuel into a fuel plenum defined at least in part by an upstream surface, a downstream surface, a shroud, and a plurality of tubes that extend from the upstream surface to the downstream surface. The method further includes impinging the fuel against a baffle that extends axially inside the fuel plenum between adjacent tubes.

  17. Design of viewing dumps for JT-60 Thomson scattering system

    International Nuclear Information System (INIS)

    This report describes the design of a system of viewing dumps and baffles for the JT-60 Thomson Scattering System. The design objectives for the viewing dumps are defined. Critical dimensions of the dumps and baffles are determined from the geometry of the Thomson scattering system and the tokamak. Electromagnetic forces are analyzed, and a thermal analysis of the viewing dumps is presented. In addition, the design and arrangement of the individual blades that comprise a viewing dump is analyzed in detail. Equations that relate the attenuation of incident light to several parameters of the blades and their arrangement are developed and tabulated. This information is useful, in general, for the design of viewing dumps. (author)

  18. Carbon deposition and deuterium inventory in ASDEX Upgrade

    International Nuclear Information System (INIS)

    Carbon erosion and deposition in the ASDEX Upgrade divertor was investigated using a poloidal section of marked divertor tiles and silicon samples below the divertor structure. The whole inner divertor is a net carbon deposition area, while a large fraction of the outer divertor is erosion dominated and the roof baffle tiles show a complicated distribution of erosion and deposition areas. In total, 43.7 g B+C were redeposited, of which 88% were deposited on tiles and 9% in remote areas (below roof baffle, on vessel wall structures). Identified carbon sources in the main chamber are too low by a factor of ten to explain the observed carbon divertor deposition, but carbon erosion is observed at the outer divertor tiles. Deuterium is trapped mainly on the surfaces of the inner divertor tiles. The long term retention in codeposited hydrocarbon layers is about 3% of the total deuterium fuel input. (author)

  19. Prevalence and effect of myths in clinical orthopaedics in Western part of Uttar Pradesh

    OpenAIRE

    Arun Vashisht; Avinash Rastogi

    2016-01-01

    Background: Myths in the field of medicine regarding the treatment of health problems are frequently observed, which may not only retard the recovery but often be harmful for the patients. We were baffled to see lot of patients under the influence of certain myths about treatment of their orthopaedic ailments. The aim of this observational, prospective study was to dispel the misconceptions and to create awareness in the society about the bad effects of these myths. Methods: 1285 patients...

  20. Cognitive Dimensions of Predator Responses to Imperfect Mimicry

    OpenAIRE

    Lars Chittka; Daniel Osorio

    2007-01-01

    Many palatable animals, for example hoverflies, deter predators by mimicking well-defended insects such as wasps. However, for human observers, these flies often seem to be little better than caricatures of wasps—their visual appearance and behaviour are easily distinguishable from those which they are attempting to mimic. This imperfect mimicry baffles evolutionary biologists, because one might expect natural selection to do a more thorough job. Here we discuss two types of cognitive process...

  1. Diagnostics for the DIII-D radiative divertor

    Energy Technology Data Exchange (ETDEWEB)

    Nilson, D.G. [Lawrence Livermore National Lab., CA (United States); Brooks, N.H.; Smith, J.P.; Snider, R.T.

    1995-10-01

    This paper reviews the design of new diagnostics and the modifications to existing diagnostics needed to carry out radiative divertor experiments in DIII-D following installation in late 1996 of a set of baffle structures that will restrict the backflow to the core plasma of neutral deuterium atoms and impurity gases. The divertor slots formed by the new baffle structures will inhibit the easy view of the divertor legs and target plates that the open divertor geometry in DIII-D currently affords. We review a basic set of diagnostics that are needed to demonstrate the reduction of divertor heat loading and radiative dissipation of energy within the divertor. This will include IR cameras, bolometry, foil bolometers, and Langmuir probes. Within the limits of available funding, we will implement a supplemental set of instruments which provide a more detailed understanding of the underlying physical processes. Many existing diagnostics require only re-aiming to provide proper coverage of the initial 23 cm long divertor plasma configuration (X- point to floor distance). Other diagnostics need extensive reconfiguration using in-vessel fiber-optic bundles or high power laser mirrors. The new divertor baffle panels provide a protective shelf for diagnostic hardware mounted underneath them, but the water cooling channels in the panels limit the permissible size of through holes and, thereby, restrict the available views of under-the- baffle diagnostics. The successful resolution of the design and implementation of these diagnostic modifications is dependent on a strong coordination between GA and its many diagnostic collaborators.

  2. Histochemical study of the oviducal gland and analysis of the sperm storage tubules of Mustelus schmitti Springer, 1939 (Chondrichthyes, Triakidae)

    OpenAIRE

    Fernanda Gabriela Elías

    2015-01-01

    Abstract: The paired oviducal glands of immature and mature females of Mustelus schmitti were examined macro and microscopically. Findings indicate that these glands possessed the same zonation as in most chondrichthyans from anterior to posterior: club, papillary, baffle and terminal zones. The whole gland is composed by simple tubular glands that connect with transverse grooves all along the organ. The club zone presents a typical indian club shape with a simple columnar and ciliated epithe...

  3. Water separators - reheaters

    International Nuclear Information System (INIS)

    With the commencement of construction of light water reactors the need arose, because of the steam condition, for water separators and reheaters. In a brief chronological summary the various stages of development according to designs and specific performance data are compared and the advantages and disadvantages are contrasted. This paper describes cyclone separators and baffle plate separators and plain surface tube reheaters and finned tube elements in many different arrangements. (orig.)

  4. Remote systems requirements of the High Yield Lithium Injection Fusion Energy (HYLIFE) converter concept

    International Nuclear Information System (INIS)

    Remote systems will be required in the High Yield Lithium Injection Fusion Energy Converter power plant proposed by Lawrence Livermore Laboratory. During inspection operations, viewing of the chamber interior and certain pumps, valve fittings and welds must be done remotely. Ideas for remote maintenance of laser beam blast baffles, optics, and target material traps are described. Radioisotope sources and their distributions, and exposure rates at various points in the reactor vicinity are presented

  5. Study of limited angle swing laminography and its application in the inspection of flat components

    International Nuclear Information System (INIS)

    It is important to inspect the inner defects, density distribution of the multi-structure complex material. The conflict of resolution of reconstructed image and reconstruction efficiency baffled people long when applying radiation laminography to that kind of material. Limited angle swing laminography algorithm was put forward. A simulation of printed circuits board by MATLAB attested the rationality and high efficiency of this algorithm. Based upon the simulation, the principle of choosing optimal projection angle was discussed. Finally, an application example was given

  6. Study of limited angle swing laminography and its application in the inspection of flat components

    CERN Document Server

    Ming Ming; Wang Jing; Cheng Jian Ping; Wang Xue Wu; Kang Ke Jun

    2002-01-01

    It is important to inspect the inner defects, density distribution of the multi-structure complex material. The conflict of resolution of reconstructed image and reconstruction efficiency baffled people long when applying radiation laminography to that kind of material. Limited angle swing laminography algorithm was put forward. A simulation of printed circuits board by MATLAB attested the rationality and high efficiency of this algorithm. Based upon the simulation, the principle of choosing optimal projection angle was discussed. Finally, an application example was given

  7. A Computational Fluid Dynamics Modeling and Experimental Study of the Mixing Process for the Dispersion of the Synthetic Fibers in Wet-Lay Forming

    Directory of Open Access Journals (Sweden)

    Melur K. Ramasubramanian, Ph.D.

    2008-03-01

    Full Text Available In this paper, we present results from a computational fluid dynamics (CFD model for the mixing process used to disperse synthetic fibers in wet-lay process. We used CFD software, FLUENT, together with the MIXSIM user interface to accurately model the impeller geometry. A multiple reference frame (MRF model and standard k-e turbulence model were used to model the problem. After obtaining a converged solution for the mixing tank with water, a discrete phase model was constructed by injecting spherical particles into the flow. A mixing tank with baffles and a centrally located impeller was used in experiments. PET fibers (1.5 denier, 6.35, 12.7, and 38.7 mm at a concentration of 0.01% were mixed in water for the study. In regions behind the baffles, where the model predicted higher concentration of particles, experimental results showed a 34% higher concentration relative to the region in the high turbulence zone near the center. Instantaneous sheets were formed by rapidly dipping and removing a flat wire mesh strainer into the tank at two different locations to assess the state of dispersion in the tank. The sheets were transferred onto a blotting paper and examined under a microscope to count defects. Results show that the number of rope defects was 43% higher in sheets drawn from the region behind the baffles than in the sheets drawn from regions near the center of the tank. Changing baffles from a rectangular to a triangular cross section decreased the number of rope defects, but increased the number of log defects in the sample sheets at the same location. The CFD model can be used to optimize mixing tank design for wet lay fiber dispersion. The model provides further insight into the mixing process by predicting the effect of changes in design parameters on dispersion quality.

  8. Experimental characterisation and modelling of homogeneous solid suspension in an industrial stirred tank

    OpenAIRE

    Calvo, Sébastien; Delafosse, Angélique; Collignon, Marie-Laure; Crine, Michel; Toye, Dominique

    2013-01-01

    In this work, we study the conditions needed to reach homogeneous distribution of aluminium salts particles in water inside a torispherical bottom shaped stirred tank of 70 L equipped with a Pfaudler RCI type impeller and three equispaced vertical baffles. The aim of the present study is to develop a CFD model describing the quality of particle distribution in industrial scale tanks. This model, validated with experimental data, is used afterwards to develop scale-up and scale-down correl...

  9. Fast and frugal heuristics : tools of social rationality

    OpenAIRE

    Hertwig, R.; Herzog, S. M.

    2009-01-01

    Homo economicus cannot help but be puzzled by people's baffling array of social behaviors that conflict with economic theory. To accommodate these “deviant” behaviors within the standard view of rationality, defined in terms of probability theory, logic and rational choice theory, economists and psychologists tend to inject some psychology into the rational choice framework. In contrast, we propose to start afresh: We put forth the thesis that humans' social intelligence is not qualitatively ...

  10. Co-evolving Language and Social Structure Using a Genetic Algorithm

    OpenAIRE

    Lekvam, Torvald

    2014-01-01

    It is interesting how we can take a train of thought and transfer this into an other person's mind by pushing the air around us. Human language, this complex medium that distinctly separates humans from animals, has baffled scientists for centuries. But as it lacks of historical data, researchers wish to benefit from computer science and the field of artificial life to understand the origin of language. This thesis illuminates the potential for using agent-based models to in...

  11. Molten metal reactor and method of forming hydrogen, carbon monoxide and carbon dioxide using the molten alkaline metal reactor

    Science.gov (United States)

    Bingham, Dennis N.; Klingler, Kerry M.; Turner, Terry D.; Wilding, Bruce M.

    2012-11-13

    A molten metal reactor for converting a carbon material and steam into a gas comprising hydrogen, carbon monoxide, and carbon dioxide is disclosed. The reactor includes an interior crucible having a portion contained within an exterior crucible. The interior crucible includes an inlet and an outlet; the outlet leads to the exterior crucible and may comprise a diffuser. The exterior crucible may contain a molten alkaline metal compound. Contained between the exterior crucible and the interior crucible is at least one baffle.

  12. Perfection of NaNO3 single crystals grown by axial vibrational control technique in Czochralski configuration

    Science.gov (United States)

    Avetissov, I. Ch.; Sadovskiy, A. P.; Sukhanova, E. A.; Orlova, G. Yu.; Belogorokhov, I. A.; Zharikov, E. V.

    2012-12-01

    Perfection of NaNO3 single crystals grown by axial vibrational control technique in the Czochralski configuration (AVC-CZ) by submerging an oscillating baffle into the melt under the crystal was studied. The characteristics of AVC-CZ grown crystals were analyzed by micro-Raman technique, X-ray structural analysis and chemical dislocation etching. For the AVC-CZ grown NaNO3 single crystals the structure sensitive properties of high-quality were demonstrated.

  13. Active control of far-field sound radiated by a rectangular panel - a general analysis

    OpenAIRE

    Pan, Jie; Snyder, Scott D.; Hansen, Colin H.; Fuller, Chris R.

    1992-01-01

    In this paper a general analysis is presented for the active control of the far-field harmonic sound radiated by a rectangular panel that is built into an infinite baffle. In this analysis, the panel vibration may be generated by either airborne sound (incident sound field) or by structure borne vibrations. The far-field radiated sound is controlled either by acoustical sources or vibration sources. Minimization of both the local sound pressure and the total power output is considered. Analyt...

  14. Focusing on EFL reading theory and practice

    CERN Document Server

    Al-Mahrooqi, Rahma

    2014-01-01

    Reading, a complex and multi-faceted skill, is essential for life and academic success. While its mysteries still baffle first-language research, the nature of reading in a foreign language presents an even greater puzzle. However, given reading's importance for EFL students who study their specializations in English, and whose future employment may depend on their competence in it, researchers must continue to investigate foreign language reading and devise ways of improving students' capaci...

  15. Seasonal variations of microbial community in a full scale oil field produced water treatment plant

    OpenAIRE

    Xie, Q.; Bai, S; Y. Li; Liu, L; Wang, S.; Xi, J.

    2016-01-01

    This study investigated the microbial community in a full scale anaerobic baffled reactor and sequencing batch reactor system for oil-produced water treatment in summer and winter. The community structures of fungi and bacteria were analyzed through polymerase chain reaction–denaturing gradient gel electrophoresis and Illumina high-throughput sequencing, respectively. Chemical oxygen demand effluent concentration achieved lower than 50 mg/L level after the system in both summer and winter, ho...

  16. Improvement performance of Al-Wathba settling tank by a computational fluid dynamics model

    OpenAIRE

    Kriš, Jozef; Hadi, Ghawi A.

    2010-01-01

    An investigation has been carried out using the FLUENT Computational Fluid Dynamics (CFD) software, which uses the finite-volume method to determine whether it is feasible to improve the capacity and quality of the clarifier at the Al-Wathba Water Treatment Works (Iraq) by some relatively inexpensive means. Simulations were carried out with two dimensional, radially symmetric models, representing the existing configuration as well as a number of proposed modifications involving baffles and ad...

  17. Liquid Self-Balancing Device Effects on Flexible Rotor Stability

    OpenAIRE

    Leonardo Urbiola-Soto; Marcelo Lopez-Parra

    2013-01-01

    Nearly a century ago, the liquid self-balancing device was first introduced by M. LeBlanc for passive balancing of turbine rotors. Although of common use in many types or rotating machines nowadays, little information is available on the unbalance response and stability characteristics of this device. Experimental fluid flow visualization evidences that radial and traverse circulatory waves arise due to the interaction of the fluid backward rotation and the baffle boards within the self-balan...

  18. Effect of Algal Biofilm and Operational Conditions on Nitrogen Removal in Wastewater Stabilization Ponds

    OpenAIRE

    Babu, M.

    2011-01-01

    Discharge of nutrient rich wastewater causes eutrophication of surface water; therefore wastewater treatment before discharge is required. Wastewater stabilization ponds are low cost technology used by developing countries but not effective in nitrogen removal due to low nitrifier biomass in the water column. Introduction of surface area for attachment of nitrifiers has therefore been proposed. This thesis reports the performance of pilot scale wastewater stabilization ponds fitted with baffl...

  19. Contribution to the improvement of tubular-array heat exchangers; Contribution a l`amelioration des performances des echangeurs a faisceaux tubulaires

    Energy Technology Data Exchange (ETDEWEB)

    Zahzam, M. [Blida Univ., Blida (Algeria); Labraga, L. [Valenciennes Univ., Valenciennes (France); Lameche, A. [Institut algerien du Petrole, Boumerdes (Algeria); Labid, M. [Blida Univ., Blida (Algeria)

    1995-12-31

    Tubular-array heat exchangers are widely used in industrial processes. The effects of turbulence within the heat exchange tubes on the overall efficiency of the exchanger was experimentally measured. A simple but efficient model was developed to predict the effects of heat exchange at tube boundaries, residence times of the heat-carrying fluid and temperature profiles in the heat exchanger. Increasing turbulence within the tubes with baffles was also considered. 4 refs., 3 figs.

  20. Equivalent Vectors

    Science.gov (United States)

    Levine, Robert

    2004-01-01

    The cross-product is a mathematical operation that is performed between two 3-dimensional vectors. The result is a vector that is orthogonal or perpendicular to both of them. Learning about this for the first time while taking Calculus-III, the class was taught that if AxB = AxC, it does not necessarily follow that B = C. This seemed baffling. The…

  1. Con-Lib coalitions are now the norm in Europe

    OpenAIRE

    Hix, Simon

    2010-01-01

    The novelty of a peacetime coalition government in the UK has meant that most media commentators have been alternately baffled or sceptical about its prospects – on the grounds that novel things must fail. Yet Simon Hix’s survey of European governments shows that coalitions are very common indeed, and that the largest group of governments across the continent are centre-right coalitions.

  2. Depleted reservoir drilling : a study of the Ula field in the North Sea

    OpenAIRE

    Jokela, Tommy

    2010-01-01

    Ula is an oil field operated by BP in the southern part of the Norwegian North Sea. As the field matures depleted intervals are drilled to access remaining reserves. Drilling in highly mature fields is challenging, both with respect to loss of circulation and differential sticking. On the Ula field there is a pressure barrier/baffle isolating parts of the Ula reservoir units. This pressure barrier creates a pressure differential between the units. The units above the barrier (1...

  3. Oscillatory flow chemical reactors

    Directory of Open Access Journals (Sweden)

    Slavnić Danijela S.

    2014-01-01

    Full Text Available Global market competition, increase in energy and other production costs, demands for high quality products and reduction of waste are forcing pharmaceutical, fine chemicals and biochemical industries, to search for radical solutions. One of the most effective ways to improve the overall production (cost reduction and better control of reactions is a transition from batch to continuous processes. However, the reactions of interests for the mentioned industry sectors are often slow, thus continuous tubular reactors would be impractically long for flow regimes which provide sufficient heat and mass transfer and narrow residence time distribution. The oscillatory flow reactors (OFR are newer type of tube reactors which can offer solution by providing continuous operation with approximately plug flow pattern, low shear stress rates and enhanced mass and heat transfer. These benefits are the result of very good mixing in OFR achieved by vortex generation. OFR consists of cylindrical tube containing equally spaced orifice baffles. Fluid oscillations are superimposed on a net (laminar flow. Eddies are generated when oscillating fluid collides with baffles and passes through orifices. Generation and propagation of vortices create uniform mixing in each reactor cavity (between baffles, providing an overall flow pattern which is close to plug flow. Oscillations can be created by direct action of a piston or a diaphragm on fluid (or alternatively on baffles. This article provides an overview of oscillatory flow reactor technology, its operating principles and basic design and scale - up characteristics. Further, the article reviews the key research findings in heat and mass transfer, shear stress, residence time distribution in OFR, presenting their advantages over the conventional reactors. Finally, relevant process intensification examples from pharmaceutical, polymer and biofuels industries are presented.

  4. Detection of endotoxin on sterile catheters used for cardiac catheterization.

    OpenAIRE

    Kundsin, R B; Walter, C. W.

    1980-01-01

    Pyrogen reactions during cardiac catheterization are an alarming complication that frightens patients and baffles many physicans. This report describes a simple, reproducible, precise technique for the measurement of endotoxin-like activity on the inner and outer surfaces of catheters intended for intravascular insertion. This technique is useful in documenting the cause of patient reactions. Quality control procedures should be instituted following the manufacture of angiographic catheters s...

  5. The Implication of the Narrator's Puzzlement in Invisible Man

    Institute of Scientific and Technical Information of China (English)

    张吟松

    2008-01-01

    Ellison's Invisible Man tells the experiences of a young black in search of his cultural identity in American society in the first half of the 20th century. Because of the racial discrimination, tangible or intangible, his efforts were hindered every now and then and he was often baffled, not knowing "who he was". His confusion reflects the serious situation in which the American blacks were involved. His endeavors also suggest the American blacks' dream of establishing themselves in the society.

  6. Magic Words: How Language Augments Human Computation

    OpenAIRE

    Clark, Andy

    1998-01-01

    Of course, words aren’t magic. Neither are sextants, compasses, maps, slide rules and all the other paraphenelia which have accreted around the basic biological brains of homo sapiens. In the case of these other tools and props, however, it is transparently clear that they function so as to either carry out or to facilitate computational operations important to various human projects. The slide rule transforms complex mathematical problems (ones that would baffle or tax the unaided subject) i...

  7. Study of the Blending Efficiency of Pitched Blade Impellers

    OpenAIRE

    I. Fořt; T. Jirout; Rieger, F.; Allner, R.; R. Sperling

    2001-01-01

    This paper presents an analysis of the blending efficiency of pitched blade impellers under a turbulent regime of flow of an agitated low viscous liquid. The conductivity method is used to determine of the blending (homogenization) time of miscible liquids in pilot plant mixing equipment with standard radial baffles. For the given homogeneity degree (98 %) a three-blade pitched blade impeller is tested with various off-bottom clearances, vessel/ impeller diameter ratios and various impeller p...

  8. Power Input of High-Speed Rotary Impellers

    OpenAIRE

    K. R. Beshay; J. Kratěna; I. Fořt; O. Brůha

    2001-01-01

    This paper presents the results of an experimental investigation of the power input of pitched blade impellers and standard Rushton turbine impellers in a cylindrical vessel provided with four radial baffles at its wall under a turbulent regime of flow of an agitated liquid. The influence of the geometry of the pitched blade impellers (pitch angle, number of blades) and the off-bottom impeller clearance of both high-speed impellers tested on the impeller power input is determined in two sizes...

  9. Soft resonator of omnidirectional resonance for acoustic metamaterials with a negative bulk modulus

    OpenAIRE

    Xiaodong Jing; Yang Meng; Xiaofeng Sun

    2015-01-01

    Monopolar resonance is of fundamental importance in the acoustic field. Here, we present the realization of a monopolar resonance that goes beyond the concept of Helmholtz resonators. The balloon-like soft resonator (SR) oscillates omnidirectionally and radiates from all parts of its spherical surface, eliminating the need for a hard wall for the cavity and baffle effects. For airborne sound, such a low-modulus resonator can be made extremely lightweight. Deep subwavelength resonance is achie...

  10. Removal of Fecal Indicators, Pathogenic Bacteria, Adenovirus, Cryptosporidium and Giardia (oo)cysts in Waste Stabilization Ponds in Northern and Eastern Australia

    OpenAIRE

    Maxim Sheludchenko; Anna Padovan; Mohammad Katouli; Helen Stratton

    2016-01-01

    Maturation ponds are used in rural and regional areas in Australia to remove the microbial loads of sewage wastewater, however, they have not been studied intensively until present. Using a combination of culture-based methods and quantitative real-time PCR, we assessed microbial removal rates in maturation ponds at four waste stabilization ponds (WSP) with (n = 1) and without (n = 3) baffles in rural and remote communities in Australia. Concentrations of total coliforms, E. coli, enterococci...

  11. Literature survey for suppression of scattered light in large space telescopes

    Science.gov (United States)

    Tifft, W. G.; Fannin, B. B.

    1973-01-01

    A literature survey is presented of articles dealing with all aspects of predicting, measuring, and controlling unwanted scattered (stray) light. The survey is divided into four broad classifications: (1) existing baffle/telescope designs; (2) computer programs for the analysis/design of light suppression systems; (3) the mechanism, measurement, and control of light scattering; and (4) the advantages and problems introduced by the space environment for the operation of diffraction-limited optical systems.

  12. Optimization of a Finned Shell and Tube Heat Exchanger Using a Multi-Objective Optimization Genetic Algorithm

    OpenAIRE

    Heidar Sadeghzadeh; Mehdi Aliehyaei; Marc A. Rosen

    2015-01-01

    Heat transfer rate and cost significantly affect designs of shell and tube heat exchangers. From the viewpoint of engineering, an optimum design is obtained via maximum heat transfer rate and minimum cost. Here, an analysis of a radial, finned, shell and tube heat exchanger is carried out, considering nine design parameters: tube arrangement, tube diameter, tube pitch, tube length, number of tubes, fin height, fin thickness, baffle spacing ratio and number of fins per unit length of tube. The...

  13. On turbulence modelling of industrial heat exchanger flows

    International Nuclear Information System (INIS)

    The present research is focussed on the prediction of shell-side flow in shell-and-tube heat exchangers. In order to simplify the analysis, the flow field is divided into three regions: (a) the tube-free region, away from the shell, baffles and tubes, (b) the tube-filled region, and (c) the near-wall region. The flow within each region is modelled separately, but the solutions within consecutive regions must be matched near the corresponding boundaries. (author)

  14. Diagnostics for the DIII-D radiative divertor

    International Nuclear Information System (INIS)

    This paper reviews the design of new diagnostics and the modifications to existing diagnostics needed to carry out radiative divertor experiments in DIII-D following installation in late 1996 of a set of baffle structures that will restrict the backflow to the core plasma of neutral deuterium atoms and impurity gases. The divertor slots formed by the new baffle structures will inhibit the easy view of the divertor legs and target plates that the open divertor geometry in DIII-D currently affords. We review a basic set of diagnostics that are needed to demonstrate the reduction of divertor heat loading and radiative dissipation of energy within the divertor. This will include IR cameras, bolometry, foil bolometers, and Langmuir probes. Within the limits of available funding, we will implement a supplemental set of instruments which provide a more detailed understanding of the underlying physical processes. Many existing diagnostics require only re-aiming to provide proper coverage of the initial 23 cm long divertor plasma configuration (X- point to floor distance). Other diagnostics need extensive reconfiguration using in-vessel fiber-optic bundles or high power laser mirrors. The new divertor baffle panels provide a protective shelf for diagnostic hardware mounted underneath them, but the water cooling channels in the panels limit the permissible size of through holes and, thereby, restrict the available views of under-the- baffle diagnostics. The successful resolution of the design and implementation of these diagnostic modifications is dependent on a strong coordination between GA and its many diagnostic collaborators

  15. New approach for distinguishing the similarity of links

    Institute of Scientific and Technical Information of China (English)

    Jianyun XIANG; Maozhong GE; Zhiping WANG

    2008-01-01

    Based on the problem of distinguishing the similarity of links in the regenerative innovation design of a kinematic chain, a new approach using the standard power matrix of the adjacent matrix is presented in this paper. The implementation of the approach is illustrated with an example. This method solves the technically baffling problem in mechanism type synthesis and reduced redundant design scheme, and raises the reliability and the efficiency of the regenerative innova-tion design of the kinematic chain.

  16. Multi-Aperture Miniaturized Star Sensors, Modular Building Blocks for Small Satellite AOCS Systems

    OpenAIRE

    Rotteveel, Jeroen; Le Mair, Anita

    2009-01-01

    Accurate attitude determination is an important enabler for micro- and nanosatellite missions. For remote sensing applications and formation flying missions, the attitude of the spacecraft must be known and controlled with a high accuracy. ISIS introduces a modular and scalable attitude determination system based on a multi-aperture miniature star sensor. Based on a patented concept, the Multi-Aperture Baffled Starsensor, the attitude sensor integrates several apertures into a single star tra...

  17. DE-ENTRAINMENT COLUMN

    Science.gov (United States)

    Mooradian, A.J.

    1958-07-01

    A de-entrainnnent colunnn is described for removing substances from a stream of vapor coming from a distillation apparatus. The device comprises a hollow cylindrical body mounted with its axis vertical on a flange on the upper slde of a vaporizing vessel; two sintered metal circular discs through which all the vapor passes mounted in axially spaced relationship in the cylindrical body; and two semi-circular baffle plates mounted in spaced relationship between the discs.

  18. Development of gas entrainment mitigation devices for PFBR hot pool

    International Nuclear Information System (INIS)

    Highlights: ► Gas entrainment from sodium free surface creates various operational problems in SFR. ► The high free surface velocity causes vortex induced gas entrainment. ► Gas entrainment can be avoided by reducing free surface velocity magnitude. ► Ring type baffle plate has been developed for PFBR to mitigate gas entrainment. ► This paper reports the development of ring type baffle plate in detail. -- Abstract: The phenomenon of argon gas entrainment into primary sodium in the hot pool of a liquid Sodium cooled Fast Reactor (SFR) is investigated. A combined experimental and computational approach is proposed. Physical entrainment of argon into sodium is highly geometry dependent and the present study is focused on the Indian Prototype Fast Breeder Reactor (PFBR). The computational model which is used for parametric studies is validated against a 1/4 scale water model tests. Based on systematic experiments, the free surface velocity for onset of gas entrainment is determined to be 0.32 m/s, and the corresponding threshold value for the surface vorticity has been estimated as 8.3 s−1. A horizontal baffle plate attached to inner vessel is found to reduce the free surface velocity/vorticity effectively. The radial width of the baffle plate and its elevation has been optimized to be 0.125 m and 0.315 m from free surface by computational studies. The optimized device has been tested in the water model to confirm its satisfactory performance before its recommendation for PFBR

  19. Optical Coating Performance for Heat Reflectors of the JWST-ISIM Electronic Component

    Science.gov (United States)

    Rashford, Robert A.; Perrygo, Charles M.; Garrison, Matthew B.; White, Bryant K.; Threat, Felix T.; Quijada, Manuel A.; Jeans, James W.; Huber, Frank K.; Bousquet, Robert R.; Shaw, Dave

    2011-01-01

    A document discusses a thermal radiator design consisting of lightweight composite materials and low-emittance metal coatings for use on the James Webb Space Telescope (JWST) structure. The structure will have a Thermal Subsystem unit to provide passive cooling to the Integrated Science Instrument Module (ISIM) control electronics. The ISIM, in the JWST observatory, is the platform that provides the mounting surfaces for the instrument control electronics. Dissipating the control electronic generated-heat away from JWST is of paramount importance so that the spacecraft s own heat does not interfere with the infrared-light gathering of distant cosmic sources. The need to have lateral control in the emission direction of the IEC (ISIM Electronics Compartment) radiators led to the development of a directional baffle design that uses multiple curved mirrorlike surfaces. This concept started out from the so-called Winston non-imaging optical concentrators that use opposing parabolic reflector surfaces, where each parabola has its focus at the opposite edge of the exit aperture. For this reason they are often known as compound parabolic concentrators or CPCs. This radiator system with the circular section was chosen for the IEC reflectors because it offers two advantages over other designs. The first is that the area of the reflector strips for a given radiator area is less, which results in a lower mass baffle assembly. Secondly, the fraction of energy emitted by the radiator strips and subsequently reflected by the baffle is less. These fewer reflections reduced the amount of energy that is absorbed and eventually re-emitted, typically in a direction outside the design emission range angle. A baffle frame holds the mirrors in position above a radiator panel on the IEC. Together, these will direct the majority of the heat from the IEC above the sunshield away towards empty space.

  20. Plasma diagnostics for the DIII-D divertor upgrade

    International Nuclear Information System (INIS)

    The DIII-D tokamak is being upgraded to allow for divertor biasing, baffling, and pumping experiments. This paper gives an overview of the new diagnostics added to DIII-D as part of this Advanced Divertor Program. They include tile current monitors, fast reciprocating Langmuir probes, a fixed probe array in the divertor, fast neutral pressure gauges, and Hα measurements with TV cameras and fiber optics coupled to a high resolution spectrometer. 9 refs

  1. Liquid metal cooled nuclear reactor constructions

    International Nuclear Information System (INIS)

    A liquid metal cooled nuclear reactor construction is described comprising a reactor core submerged in a pool of liquid metal coolant contained in a vessel which is housed in a concrete containment vault, the roof structure of the vault having thermal insulation comprising a series of super-imposed spaced plates, with baffles disposed so as to restrict convectional flow of metal vapour through the interspaces of the plates and between the uppermost plate or plates and the vault roof structure. (author)

  2. Pressure thrust and pressure shock arrestor (mixer-diffusor device)

    International Nuclear Information System (INIS)

    A mixer-diffusor device for use in nuclear reactors to control the heat and pressure energy resulting from an accident is attached to the end of a hollow conduit from which a gaseous medium such as steam is to be expelled under pressure. The end of the hollow conduit is submerged under the surface of a body of liquid such as water. The mixer-diffusor comprises a conical baffle having an apex extending into the open end of the conduit. A skirt member is positioned around the end of the conduit so than an annular opening is formed between the wall of the conduit and one edge of the skirt member. The skirt member is tapered outwardly at essentially the same angle as the taper of the conical baffle. When the gaseous medium is expelled from the end of the conduit, the gaseous medium flows against and over the conical baffle thereby reducing the thrust forces of the conduit. As the gaseous medium passes the edge of the end of the conduit, the gaseous medium tends to suck the liquid through the annular opening. The liquid is then mixed with the gaseous medium causing the gaseous medium to form a plurality of small bubbles which are expelled from the opening between the skirt and the conical member. In this manner, the gaseous medium is substantially mixed and diffused with the liquid. (auth)

  3. Maintenance of the lower internal structures in EDF PWRs

    International Nuclear Information System (INIS)

    Lower PWR internals are subjected to two main ageing phenomena: fatigue in cylindrical thermal shield fasteners, and IASCC in baffle bolts. In France, the first one could concern only the 6 ''CPO series'' 900 MW reactors. Calculated usage factors show that fatigue is not a critical concern for these thermal shields during at least 40 years. Furthermore, in-service monitoring constitutes a suitable condition based maintenance. Up to now, it has not detected any anomaly, and neither did video inspections during the 1st ten year outages. Concerning baffle bolt cracking, the maintenance strategy fits into a plant operation at least 40 years too. It is based upon the following actions: ISI programme (26 inspections up to now), safety analysis (and determination of allowable degraded configurations on affected reactors), destructive examinations and, as an anticipation, a large R and D irradiation programme. The safety analysis and the prediction of behavior show no need of replacing bolts before the 2nd ten year outage or even later on the most affected reactors, i.e. the 6 CPO series ones. The 52 other EDF PWRs are more recent and, because of their improved design, less exposed to baffle bolt cracking. (author)

  4. Reactor vessel head permanent shield

    International Nuclear Information System (INIS)

    A nuclear reactor is described comprising: a nuclear reactor pressure vessel closure head; control rod drive mechanisms (CRDMs) disposed within the closure head so as to project vertically above the closure head; cooling air baffle means surrounding the control rod drive mechanisms for defining cooling air paths relative to the control rod drive mechanisms; means defined within the periphery of the closure head for accommodating fastening means for securing the closure head to its associated pressure vessel; lifting lugs fixedly secured to the closure head for facilitating lifting and lowering movements of the closure head relative to the pressure vessel; lift rods respectively operatively associated with the plurality of lifting lugs for transmitting load forces, developed during the lifting and lowering movements of the closure head, to the lifting lugs; upstanding radiation shield means interposed between the cooling air baffle means and the periphery of the enclosure head of shielding maintenance personnel operatively working upon the closure head fastening means from the effects of radiation which may emanate from the control rod drive mechanisms and the cooling air baffle means; and connecting systems respectively associated with each one of the lifting lugs and each one of the lifting rods for connecting each one of the lifting rods to a respective one of each one of the lifting lugs, and for simultaneously connecting a lower end portion of the upstanding radiation shield means to each one of the respective lifting lugs

  5. Indicators for technological, environmental and economic sustainability of ozone contactors.

    Science.gov (United States)

    Zhang, Jie; Tejada-Martinez, Andres E; Lei, Hongxia; Zhang, Qiong

    2016-09-15

    Various studies have attempted to improve disinfection efficiency as a way to improve the sustainability of ozone disinfection which is a critical unit process for water treatment. Baffling factor, CT10, and log-inactivation are commonly used indicators for quantifying disinfection credits. However the applicability of these indicators and the relationship between these indicators have not been investigated in depth. This study simulated flow, tracer transport, and chemical species transport in a full-scale ozone contactor operated by the City of Tampa Water Department and six other modified designs using computational fluid dynamics (CFD). Through analysis of the simulation results, we found that baffling factor and CT10 are not optimal indicators of disinfection performance. We also found that the relationship between effluent CT obtained from CT transport simulation and baffling factor depends on the location of ozone release. In addition, we analyzed the environmental and economic impacts of ozone contactor designs and upgrades and developed a composite indicator to quantify the sustainability in technological, environmental and economic dimensions. PMID:27322565

  6. Development of a compact W-shaped pumped divertor in JT-60U

    International Nuclear Information System (INIS)

    In JT-60U, the modification to a W-shaped pumped divertor will be completed in May 1997, aiming to realize sufficient reduction in heat flux to the targets and good H-mode confinement simultaneously. W-shaped geometry is optimized not only for forming radiative divertor plasmas and reducing the back flow of neutral particles but also for allowing various experimental configurations. Toroidally and poloidally segmented divertor plates, dome and baffles are arranged in a W-shaped poloidal configuration. The pumping speed can be changed during a shot by variable shutter valves in the three pumping ports under the outer baffle. The net throughput is enough for particle control in the steady radiative operations with high power NBI heating. Carbon fiber composite (CFC) tiles are used for the divertor targets and the divertor throat where large heat flux is expected. Gaps between two adjacent segments are carefully sealed to suppress the leak of neutral gas from the exhaust duct below the divertor and baffles. The strength of the whole structure is confirmed by an electromagnetic force analysis and structural analysis carried out for disruptions of 3 MA discharges with a halo current. (orig.)

  7. Example study for granular bioreactor stratification: Three-dimensional evaluation of a sulfate-reducing granular bioreactor

    Science.gov (United States)

    Hao, Tian-wei; Luo, Jing-hai; Su, Kui-zu; Wei, Li; Mackey, Hamish R.; Chi, Kun; Chen, Guang-Hao

    2016-01-01

    Recently, sulfate-reducing granular sludge has been developed for application in sulfate-laden water and wastewater treatment. However, little is known about biomass stratification and its effects on the bioprocesses inside the granular bioreactor. A comprehensive investigation followed by a verification trial was therefore conducted in the present work. The investigation focused on the performance of each sludge layer, the internal hydrodynamics and microbial community structures along the height of the reactor. The reactor substratum (the section below baffle 1) was identified as the main acidification zone based on microbial analysis and reactor performance. Two baffle installations increased mixing intensity but at the same time introduced dead zones. Computational fluid dynamics simulation was employed to visualize the internal hydrodynamics. The 16S rRNA gene of the organisms further revealed that more diverse communities of sulfate-reducing bacteria (SRB) and acidogens were detected in the reactor substratum than in the superstratum (the section above baffle 1). The findings of this study shed light on biomass stratification in an SRB granular bioreactor to aid in the design and optimization of such reactors. PMID:27539264

  8. The experimental of methane-air flame propagation in the tube with quadrate cross section

    Institute of Scientific and Technical Information of China (English)

    GUO Zi-ru; SHEN Zhao-wu; LU Shou-xiang; ZHOU Ning

    2005-01-01

    The flame propagation of methane-air mixture with various methane concentrations was experimentally investigated at venting flame acceleration tube with quadrate cross section under different obstacles presented. The flame shape and propagation speed was observed by high-speed color video camera. The explosion pressure was determined by piezoelectricity pressure transducers. The results are: The flame propagates in the shape of a hemisphere before the flame reaches the first baffle and flame propagation speed is not more than 15 m/s. When the flame propagates across the baffle, the flame begins to accelerate due to turbulence induced by obstacle.Blockage ratio has relatively greater effect on the flame propagation speed than repeated baffle number does. The flame propagation speed and the pressure at different location along the tube are maximum when methane-air mixture is near the chemical stoichoimetric ratio. The pressure increases with the distance from ignition end at first and the maximum pressure was obtained at the middle of tube, but the pressure decreases and again increases at venting end.

  9. CMOS self-powered monolithic light-direction sensor with digitalized output.

    Science.gov (United States)

    Wang, Hongyi; Luo, Tao; Lu, Zhijian; Song, Hongjiang; Christen, Jennifer Blain

    2014-05-01

    We present a novel self-powered chip to detect the direction of incident light. This chip directly provides digitized output without the need of any off-chip power supply or optical or mechanical components. The chip was implemented in a standard 0.5 μm CMOS process. A microscale metal baffle was created by stacking all metal layers, contacts, and vias available in the process to produce on-chip shadowing. N-well/p+ photodiode arrays are located on both sides of the baffle to sense light. The photocurrent generated by a photodiode depends on the size of the photodiode and the shadowing. The shadowed area depends on the incident angle of the light. A current mirror circuit is used to compare the currents generated by the photodiodes on the opposite sides of the baffle and, consequently, provide a digital signal to indicate the incident light angle. Compared with the ideal linear digital light-angle detector with the same resolution, the presented sensor achieved the maximum error of only 2 deg over 110 deg test range. PMID:24784060

  10. Removal of Fecal Indicators, Pathogenic Bacteria, Adenovirus, Cryptosporidium and Giardia (oocysts in Waste Stabilization Ponds in Northern and Eastern Australia

    Directory of Open Access Journals (Sweden)

    Maxim Sheludchenko

    2016-01-01

    Full Text Available Maturation ponds are used in rural and regional areas in Australia to remove the microbial loads of sewage wastewater, however, they have not been studied intensively until present. Using a combination of culture-based methods and quantitative real-time PCR, we assessed microbial removal rates in maturation ponds at four waste stabilization ponds (WSP with (n = 1 and without (n = 3 baffles in rural and remote communities in Australia. Concentrations of total coliforms, E. coli, enterococci, Campylobacter spp., Salmonella spp., F+ RNA coliphage, adenovirus, Cryptosporidium spp. and Giardia (oo cysts in maturation ponds were measured at the inlet and outlet. Only the baffled pond demonstrated a significant removal of most of the pathogens tested and therefore was subjected to further study by analyzing E. coli and enterococci concentrations at six points along the baffles over five sampling rounds. Using culture-based methods, we found a decrease in the number of E. coli and enterococci from the initial values of 100,000 CFU per 100 mL in the inlet samples to approximately 1000 CFU per 100 mL in the outlet samples for both bacterial groups. Giardia cysts removal was relatively higher than fecal indicators reduction possibly due to sedimentation.

  11. Flow model test development of CRBRP intermediate heat exchanger

    International Nuclear Information System (INIS)

    The details of these tests, flow data achieved, finalized design configurations of the flow distribution devices, and final interpretation of the results are given in this paper. The tests consist of the: Primary Inlet Plenum Flow Model Test which has the objective of finalizing the design of the primary flow inlet plenum configuration that results in a circumferentially uniform flow entering the tube bundle; Tube Bundle Flow Model Test which has the objective of achieving optimum design configurations for the flow baffles in the bundle, which is based on the baffles capability to create the necessary forced fluid mixing of the shell side flow within the pressure drop limitation imposed on the unit's design; and Intermediate Flow Model Test with its objective of confirming the design of the intermediate flow inlet plenum, which has a hemispherical shape with a ring baffle attached, in distributing the flow evenly among the tubes. The paper includes details of the flow fields within various test models in a wide range of operating flow rates. 2 refs

  12. Optimization of a Finned Shell and Tube Heat Exchanger Using a Multi-Objective Optimization Genetic Algorithm

    Directory of Open Access Journals (Sweden)

    Heidar Sadeghzadeh

    2015-08-01

    Full Text Available Heat transfer rate and cost significantly affect designs of shell and tube heat exchangers. From the viewpoint of engineering, an optimum design is obtained via maximum heat transfer rate and minimum cost. Here, an analysis of a radial, finned, shell and tube heat exchanger is carried out, considering nine design parameters: tube arrangement, tube diameter, tube pitch, tube length, number of tubes, fin height, fin thickness, baffle spacing ratio and number of fins per unit length of tube. The “Delaware modified” technique is used to determine heat transfer coefficients and the shell-side pressure drop. In this technique, the baffle cut is 20 percent and the baffle ratio limits range from 0.2 to 0.4. The optimization of the objective functions (maximum heat transfer rate and minimum total cost is performed using a non-dominated sorting genetic algorithm (NSGA-II, and compared against a one-objective algorithm, to find the best solutions. The results are depicted as a set of solutions on a Pareto front, and show that the heat transfer rate ranges from 3517 to 7075 kW. Also, the minimum and maximum objective functions are specified, allowing the designer to select the best points among these solutions based on requirements. Additionally, variations of shell-side pressure drop with total cost are depicted, and indicate that the pressure drop ranges from 3.8 to 46.7 kPa.

  13. Tube vibration in industrial size test heat exchanger

    International Nuclear Information System (INIS)

    Tube vibration data from tests of a specially built and instrumented, industrial-type, shell-and-tube heat exchanger are reported. The heat exchanger is nominally 0.6 m (2 ft) in dia and 3.7 m (12 ft) long. Both full tube and no-tubes-in-window bundles were tested for inlet/outlet nozzles of different sizes and with the tubes supported by seven, equally-spaced, single-segmental baffles. Prior to water flow testing, natural frequencies and damping of representative tubes were measured in air and water. Flow testing was accomplished by increasing the flow rates in stepwise fashion and also by sweeping through a selected range of flow rates. The primary variables measured and reported are tube accelerations and/or displacements and pressure drop through the bundle. Tests of the full tube bundle configuration revealed tube rattling to occur at intermediate flow rates, and fluidelastic instability, with resultant tube impacting, to occur when the flow rate exceeded a threshold level; principally, the four-span tubes were involved in the regions immediately adjacent to the baffle cut. For the range of flow rates tested, fluidelastic instability was not achieved in the no-tubes-in-window bundle; in this configuration the tubes are supported by all seven baffles and are, therefore, stiffer

  14. Strategies for Observing Self-excitation in the Madison Dynamo Experiment

    Science.gov (United States)

    Taylor, N. Z.; Kaplan, E. J.; Kendrick, R. D.; Nornberg, M. D.; Rahbarnia, K.; Rasmus, A. M.; Forest, C. B.; Spence, E. J.

    2010-11-01

    In the Madison Dynamo Experiment(MDE) two counter-rotating impellers drive a turbulent flow of liquid sodium in a one meter-diameter sphere. One of the goals of the experiment is to observe the spontaneous generation of magnetic field. Initial runs of the MDE saw intermittent bursts of a transverse dipole field similar to the induced field predicted by laminar kinematics, but no sustained self-excited field was observed. This poster will present recent results from the MDE after an equatorial baffle was installed to stabilize the position of the shear layer between the two counterrotating hemispheres and to help in the reduction of of large-scale turbulence and the motors were run up to maximum power. Required motor power indicates that the baffle has decreased the amount of turbulence in the flow. When run up to full power still no self-excited dynamo was observed, but there was significant amplification of the transverse dipole field with extended decay rates indicating we may be approaching the dynamo threshold. Future modifications to the experiment will also be presented exploring a subcritical dynamo transition by supplying a sufficiently strong magnetic field and the addition of poloidal baffles to optimize the helicity of the mean flow. This work is supported by the NSF/DOE partnership in plasma physics.

  15. Removal of Fecal Indicators, Pathogenic Bacteria, Adenovirus, Cryptosporidium and Giardia (oo)cysts in Waste Stabilization Ponds in Northern and Eastern Australia.

    Science.gov (United States)

    Sheludchenko, Maxim; Padovan, Anna; Katouli, Mohammad; Stratton, Helen

    2016-01-01

    Maturation ponds are used in rural and regional areas in Australia to remove the microbial loads of sewage wastewater, however, they have not been studied intensively until present. Using a combination of culture-based methods and quantitative real-time PCR, we assessed microbial removal rates in maturation ponds at four waste stabilization ponds (WSP) with (n = 1) and without (n = 3) baffles in rural and remote communities in Australia. Concentrations of total coliforms, E. coli, enterococci, Campylobacter spp., Salmonella spp., F+ RNA coliphage, adenovirus, Cryptosporidium spp. and Giardia (oo) cysts in maturation ponds were measured at the inlet and outlet. Only the baffled pond demonstrated a significant removal of most of the pathogens tested and therefore was subjected to further study by analyzing E. coli and enterococci concentrations at six points along the baffles over five sampling rounds. Using culture-based methods, we found a decrease in the number of E. coli and enterococci from the initial values of 100,000 CFU per 100 mL in the inlet samples to approximately 1000 CFU per 100 mL in the outlet samples for both bacterial groups. Giardia cysts removal was relatively higher than fecal indicators reduction possibly due to sedimentation. PMID:26729150

  16. Technology demonstration for reducing mercury emissions from small-scale gold refining facilities.

    Energy Technology Data Exchange (ETDEWEB)

    Habegger, L. J.; Fernandez, L. E.; Engle, M.; Bailey, J. L.; Peterson, D. P.; MacDonell, M. M.; U.S. Environmental Protection Agency

    2008-06-30

    Gold that is brought from artisanal and small-scale gold mining areas to gold shops for processing and sale typically contains 5-40% mercury. The uncontrolled removal of the residual mercury in gold shops by using high-temperature evaporation can be a significant source of mercury emissions in urban areas where the shops are located. Emissions from gold shop hoods during a burn can exceed 1,000 mg/m{sup 3}. Because the saturation concentration of mercury vapor at operating temperatures at the hood exhaust is less than 100 mg/m{sup 3}, the dominant component of the exhaust is in the form of aerosol or liquid particles. The U.S. Environmental Protection Agency (EPA), with technical support from Argonne National Laboratory (Argonne), has completed a project to design and test a technology to remove the dominant aerosol component in the emissions from gold shops. The objective was to demonstrate a technology that could be manufactured at low cost and by using locally available materials and manufacturing capabilities. Six prototypes designed by Argonne were locally manufactured, installed, and tested in gold shops in Itaituba and Creporizao, Brazil. The initial prototype design incorporated a pebble bed as the media for collecting the mercury aerosols, and a mercury collection efficiency of over 90% was demonstrated. Though achieving high efficiencies, the initial prototype was determined to have practical disadvantages such as excessive weight, a somewhat complex construction, and high costs (>US$1,000). To further simplify the construction, operation, and associated costs, a second prototype design was developed in which the pebble bed was replaced with slotted steel baffle plates. The system was designed to have flexibility for installation in various hood configurations. The second prototype with the baffle plate design was installed and tested in several different hood/exhaust systems to determine the optimal installation configuration. The significance of

  17. 推流器布置对氧化沟流场特性的影响%Effects of propeller layout position on flow characteristics in oxidation ditch

    Institute of Scientific and Technical Information of China (English)

    陈斌; 王炳祺; 张华; 王强; 王震

    2016-01-01

    To avoid sludge deposition in a running track type oxidation ditch,the layout position of four propellers was altered when the pool structure remained unchanged.The steady fluid flow field in the whole ditch is simulated by means of STARCCM + software plus the standard k -εturbulence model when these propellers were in operation.The velocity distribution in each section in the ditch and the velocity distribution in the whole flow field as well as the dead water zone were analysed to specify the optimal propeller layout position for the pool.The results show that the propellers′position has a great influence on velocity distribution,and a too large or too small distance between a propeller and the middle baffle wall can lead to an uneven velocity distribution and an enlarged dead water zone. Especially,when the distance is about 0.85 times the sum of the circular baffle wall radius and the distance of the circular baffle wall centre to the middle baffle wall,the average fluid velocity is as high as 0.35 m /s in the major sections observed with the smallest dead water zone.Flow separation zones are inevitable at the back of the circular baffle wall and the two ends of middle baffle wall,but they can be diminished by changing propellers′position.In addition,there is an obvious vortex phenome-non in the corners of the ditch by virtue of the interaction between the propellers and the pitch walls.%针对环形跑道式氧化沟污泥沉积现象,在池形结构不变的前提下,改变推流器的布置位置,以 STARCCM+软件为仿真平台,采用多面体网格划分方式,调用标准 k -ε湍流模型,对4台推流器同时开启状态下进行全流场模拟.分析流道各断面的速度分布、整体流场的流速分布以及流场死区率(速度低于某一值所占区域的比例),寻找适合于该池型结构的推流器最优布置方式.结果表明:推流器的安装位置对流速的分布至关重要,其与中间

  18. Effects of mixing energy and flow dynamics on chemical dispersion of crude oil. Volume 1

    International Nuclear Information System (INIS)

    Oil spills at sea can be treated with chemical dispersants to reduce the oil-water interfacial tension and facilitate entrainment of the oil into the water column as small droplets. Removing the floating oil protects surface-swelling organisms and sensitive shorelines. The environmental impacts can be further minimized if the dispersed oil droplets can be diluted into a sufficiently large volume of water by turbulent diffusion. Therefore, this study investigated the effects of mixing energy and mixing systems on dispersion effectiveness of Mars crude oil using 2 bench-scale experimental systems. Two dispersant HLB (hydrophile-lipofile balance) of 10 and 12 were tested for size distribution and dispersed oil droplets. Dispersion effectiveness was defined as the volume of mass fraction of floating oil that becomes entrained in the water column after mixing energy is introduced. The size distribution of the dispersed oil droplets provides another measure of dispersion effectiveness since smaller oil droplets have a stronger tendency to remain suspended in the water column. In this study, dispersion effectiveness was measured at 4 different energy dissipation rates in 2 different mixing systems, namely a baffled flask system and a paddle jar system. It was shown that even when the average energy dissipation rate was the same, the fluid flow dynamics were quite different in the two systems. The droplet-size distributions were multimodal, with 2 major modes occurring in dispersions produced in the baffled-flask system. The diameters of mean volume of the major modes were not found to be sensitive to changes in the energy dissipation rates. However, in the baffled-flask system, the distribution of oil among the modes was influenced by the energy dissipation rate. 25 refs., 5 figs

  19. Effects of mixing energy and flow dynamics on chemical dispersion of crude oil. Volume 1

    Energy Technology Data Exchange (ETDEWEB)

    Mukherjee, B.; Wrenn, B.A. [Washington Univ., St. Louis, MO (United States). Dept. of Energy, Environment and Chemical Engineering

    2007-07-01

    Oil spills at sea can be treated with chemical dispersants to reduce the oil-water interfacial tension and facilitate entrainment of the oil into the water column as small droplets. Removing the floating oil protects surface-swelling organisms and sensitive shorelines. The environmental impacts can be further minimized if the dispersed oil droplets can be diluted into a sufficiently large volume of water by turbulent diffusion. Therefore, this study investigated the effects of mixing energy and mixing systems on dispersion effectiveness of Mars crude oil using 2 bench-scale experimental systems. Two dispersant HLB (hydrophile-lipofile balance) of 10 and 12 were tested for size distribution and dispersed oil droplets. Dispersion effectiveness was defined as the volume of mass fraction of floating oil that becomes entrained in the water column after mixing energy is introduced. The size distribution of the dispersed oil droplets provides another measure of dispersion effectiveness since smaller oil droplets have a stronger tendency to remain suspended in the water column. In this study, dispersion effectiveness was measured at 4 different energy dissipation rates in 2 different mixing systems, namely a baffled flask system and a paddle jar system. It was shown that even when the average energy dissipation rate was the same, the fluid flow dynamics were quite different in the two systems. The droplet-size distributions were multimodal, with 2 major modes occurring in dispersions produced in the baffled-flask system. The diameters of mean volume of the major modes were not found to be sensitive to changes in the energy dissipation rates. However, in the baffled-flask system, the distribution of oil among the modes was influenced by the energy dissipation rate. 25 refs., 5 figs.

  20. Effects of mixing energy and flow dynamics on chemical dispersion of crude oil

    Energy Technology Data Exchange (ETDEWEB)

    Mukherjee, B.; Wrenn, B.A. [Washington Univ., St. Louis, MO (United States). Dept. of Energy, Environment and Chemical Engineering

    2007-07-01

    Oil spills at sea can be treated with chemical dispersants to reduce the oil-water interfacial tension and facilitate entrainment of the oil into the water column as small droplets. Removing the floating oil protects surface-swelling organisms and sensitive shorelines. The environmental impacts can be further minimized if the dispersed oil droplets can be diluted into a sufficiently large volume of water by turbulent diffusion. Therefore, this study investigated the effects of mixing energy and mixing systems on dispersion effectiveness of Mars crude oil using 2 bench-scale experimental systems. Two dispersant HLB (hydrophile-lipofile balance) of 10 and 12 were tested for size distribution and dispersed oil droplets. Dispersion effectiveness was defined as the volume of mass fraction of floating oil that becomes entrained in the water column after mixing energy is introduced. The size distribution of the dispersed oil droplets provides another measure of dispersion effectiveness since smaller oil droplets have a stronger tendency to remain suspended in the water column. In this study, dispersion effectiveness was measured at 4 different energy dissipation rates in 2 different mixing systems, namely a baffled flask system and a paddle jar system. It was shown that even when the average energy dissipation rate was the same, the fluid flow dynamics were quite different in the two systems. The droplet-size distributions were multimodal, with 2 major modes occurring in dispersions produced in the baffled-flask system. The diameters of mean volume of the major modes were not found to be sensitive to changes in the energy dissipation rates. However, in the baffled-flask system, the distribution of oil among the modes was influenced by the energy dissipation rate. 25 refs., 5 figs.

  1. Optimized chemical composition, working and heat treatment condition for resistance to irradiation assisted stress corrosion cracking of cold worked 316 and high-chromium austenitic stainless steel

    International Nuclear Information System (INIS)

    The authors have reported that the primary water stress corrosion cracking (PWSCC) in baffle former bolts made of austenitic stainless steels for PWR after long-term operation is caused by irradiation-induced grain boundary segregation. The resistance to PWSCC of simulated austenitic stainless steels whose chemical compositions are simulated to the grain boundary chemical composition of 316 stainless steel after irradiation increased with decrease of the silicon content, increases of the chromium content, and precipitation of M23C6 carbides at the grain boundaries. In order to develop resistance to irradiation assisted stress corrosion cracking in austenitic stainless steels, optimized chemical compositions and heat treatment conditions for 316CW and high-chromium austenitic stainless steels for PWR baffle former bolts were investigated. For 316CW stainless steel, ultra-low-impurities and high-chromium content are beneficial. About 20% cold working before aging and after solution treatment has also been recommended to recover sensitization and make M23C6 carbides coherent with the matrix at the grain boundaries. Heating at 700 to 725degC for 20 to 50 h was selected as a suitable aging procedure. Cold working of 5 to 10% after aging produced the required mechanical properties. The optimized composition of the high-chromium austenitic stainless steel contents 30% chromium, 30% nickel, and ultra-low impurity levels. This composition also reduces the difference between its thermal expansion coefficient and that of 304 stainless steel for baffle plates. Aging at 700 to 725degC for longer than 40 h and cold working of 10 to 15% after aging were selected to meet mechanical property specifications. (author)

  2. Preliminary results on the EUCLID NISP stray-light and ghost analysis

    Science.gov (United States)

    Geis, Norbert; Grupp, Frank; Prieto, Eric; Bender, Ralf

    2015-09-01

    The EUCLID mission within the European Space Agencies 2015 - 2025 Cosmic Vision framework addresses cosmological questions related to dark matter and dark energy. EUCLID is equipped with two instruments that are simultaneously observing patches of > 0:5 square degree on the sky. The VIS visual light high spacial resolution imager and the NISP near infrared spectrometer and photometer are separated by a di-chroic beam splitter. With its large FoV (larger than the full moon disk), together with high demands on the optical performance and strong requirements on in flight stability lead to very challenging demands on alignment and post launch { post cool-down optical element position. In addition the demanding requirements from spectroscopy and galaxy photometry lead to a highly demanding stray light and ghost control need. With this paper we present a preliminary - PDR level - analysis of ghosting and stray light levels in the EUCLID NISP near infrared spectrometer and photometer. The analysis presented focuses on the photometric channel, as this, together with the wide field of the instrument, shows most of the challenges and features of the instrument. As one requirement is to have a non vignetting design, extensive baffling is not possible, and only secondary and higher order light can be actively baffled. A comprehensive ZEMAX based analysis is being presented, showing in summary that baffles are only necessary due to the EUCLID fine guiding sensors auxiliary fields of view. The total level of contaminating light is thereafter dominated by stray light from dust on the lenses. Ghosts play a minor role.

  3. The Wide Angle Camera for the Rosetta Mission

    Science.gov (United States)

    Debei, S.; Angrilli, F.; Barbieri, C.; Bianchini, G.; da Deppo, V.; de Cecco, M.; Fornasier, S.; Guizzo, G.; Naletto, G.; Ragazzoni, R.; Saggin, B.; Tondello, G.; Zaccariotto, M.; Brunello, F.; Peron, F.

    1999-12-01

    The Wide Angle Camera (WAC) for the Rosetta mission had to fulfil many scientific requirements: Field of View of 12x12 sq deg and focal length of 140 mm, excellent optical throughput in the range 240 - 900 nm after 10 years in space, Encircled Energy of 80 ratio of 10E+4 in order to detect faint gaseous emission features around a bright nucleus, minimum exposure times of 10 msec with photometric accuracy better than 5x102, scattered light rejection for sources out of the FoV (e.g. Sun) and in the FoV (e.g. cometary nucleus), a cover to close off the cometary dust, an optical bench capable to maintain the optical alignment in a passive way and to support the shutter, the baffle, a double filter wheel and the Focal Plane Assembly. To these initial requirements several other constraints were added in the course of the design, in particular a very complex thermal profile, a massive shielding of the front FoV in order to protect the CCD from the cosmic radiation, and a very strict total mass envelope. These requirements called for an unconventional optical design, with 2 aspherical mirrors in an off-axis configuration (the primary mirror being convex), and a carefully studied 3-stage baffle. Both the shutter and the front cover provided extremely challenging technological goals, for the mechanical and for the electronics aspects of them. The paper describes all the main elements of the WAC. At present, the Structural Thermo Model has been delivered after successful completion of vibration and vacuum tests. The STM optical bench configuration has been slightly revised for the flight Model in order to provide more attenuation to the internal baffle.

  4. Influence of vibrations on heat-exchanger tubes. A literature survey

    International Nuclear Information System (INIS)

    During the last few years vibrations in heat-exchanger tubes have become a more and more serious problem due to increased demands for higher capacities of such components, which, for example, are included in nuclear power plants. These vibrations, which are most frequently induced by vortex shedding in the flow around the tubes, may sometimes cause impact fretting on the tubes and/or baffles where they are in contact with each other. Fretting may occur when two surfaces rub against each other under the influence of a vibrating movement, whereby the amplitudes are rather small (<0.25 mm). Some laboratory experiments have been reported with a combined impact and sliding movement, which is supposed to take place in heat exchangers. The influences of the clearance between the tube and baffle-hole surfaces, pressure normal to the contact surface, amplitude, frequency, time, atmosphere (also water) have been investigated for various material combinations. The finish of the tube and baffle-hole surfaces as well as the shape of the latter may also have an influence on the fretting phenomenon. However, any results from research on this matter have not been found in the literature so far. There are always difficulties in translating the above mentioned laboratory results into real operating conditions. In order to be able to judge whether a given heat exchanger might be subject to vibrational damages or not a few researchers have derived correlations between different flow-, design- and material parameters. That, on the basis of the design and actual operating conditions calculated value of such a correlation, will then indicate the risk of damages due to tube vibrations. (author)

  5. Investigation of free level fluctuations in a simulated model of a sodium cooled Fast Breeder Reactor using pulsating conductance monitoring device

    International Nuclear Information System (INIS)

    Highlights: ► An innovative approach for measurement of water level fluctuation is presented. ► Measurement was conducted with a PC based pulsating type level sensor. ► Deployed the technique in monitoring level fluctuation in PFBR simulated facility. ► The technique helped in validation of hot pool design of PFBR, India. - Abstract: A high resolution measurement technique for rapid and accurate monitoring of water level using an in-house built pulsating conductance monitoring device is presented. The technique has the capability of online monitoring of any sudden shift in water level in a reservoir which is subjected to rapid fluctuations due to any external factor. We have deployed this novel technique for real time monitoring of water level fluctuations in a specially designed ¼ scale model of the Prototype Fast Breeder Reactor (PFBR) at Kalpakkam, India. The water level measurements in various locations of the simulated test facility were carried out in different experimental campaigns with and without inclusion of thermal baffles to it in specific operating conditions as required by the reactor designers. The amplitudes and the frequencies of fluctuations with required statistical parameters in hot water pool of the simulated model were evaluated from the online time versus water level plot in more convenient way using system software package. From experimental results it is computed that the maximum free level fluctuation in the hot pool of PFBR with baffle plates provided on the inner vessel is 30 mm which is considerably less than the value (∼82 mm) obtained without having any baffle plates. The present work provided useful information for assessment of appropriate design which would be adopted in the PFBR for safe operation of the reactor.

  6. Oviducal gland microstructure of Raja miraletus and Dipturus oxyrinchus (Elasmobranchii, Rajidae).

    Science.gov (United States)

    Marongiu, Martina F; Porcu, Cristina; Bellodi, Andrea; Cuccu, Danila; Mulas, Antonello; Follesa, Maria C

    2015-11-01

    We studied the morphology and histology of the oviducal gland (OG) in the brown ray (Raja miraletus) and the long-nosed skate (Dipturus oxyrinchus) to understand its functional role in the reproductive strategy of these species. The external morphology of the gland was similar in both species, with lateral extensions like those found in other members of the Rajidae. Microscopic analysis showed a similar internal organization in both species. Immature and developing glands did not react to histochemical techniques. On reaching maturity, the OG had the largest width due to an increase in the production of secretory materials. In both species, the club zone of the gland showed a strong reaction to Periodic acid-Schiff (PAS) and alcian blue (AB) stains, indicating production of neutral and sulfated acid mucins. The secretory material produced by the papillary zone varied greatly between the two species. Both displayed tubular glands similar to those observed in the club zone, but in D. oxyrinchus the region near the lumen was intensely PAS+, whereas the last row of tubules of the brown ray stained intensely for a mixture of neutral and sulfated mucins. The baffle zone was the most conspicuous and extensive segment of all OGs, and it did not react to PAS/AB. The terminal zone, which is responsible for production of hair filaments, differed between the two species in terms of composition and organization of serous and mucous glands. This difference probably is related to the different substrates in which they release the egg capsules. Individual sperm detected in the brown ray baffle lamellae could be the result of a recent mating, whereas their presence in the deep recesses of the baffle and in the terminal zone of the long-nosed skate might indicate sperm storage. PMID:26474106

  7. 用升华法生长SiC晶体的一种新颖的坩埚设计%A Novel Design of Crucible for Sublimation Growth of SiC Single Crystals

    Institute of Scientific and Technical Information of China (English)

    张群社; 陈治明; 蒲红斌; 李留臣; 封先锋

    2006-01-01

    本文提出一个用PVT法生长SiC晶体的坩埚的新颖设计.分析了生长腔中有无锥形档板对腔内及籽晶温度场的影响;比较了档板取不同厚度时SiC粉源升华面和籽晶表面的温度分布.得出了在腔内增设档板后晶体生长面的温度更趋均匀的结论;获取了随着档板厚度的增加,腔内的轴向温度梯度随之增加,但同时晶体生长面的温度也会降低的设计原则.根据计算结果,选取档板厚度等于2mm为优化参数.%A novel design of crucible is firstly proposed in this paper. The effects of the cone-shaped bar in the growth chamber on the evolution of the temperature fields of the growth chamber and the seed are discussed, respectively. The influences of different thicknesses of the bar on the temperature distribution at SiC source powder and seed single crystal surfaces are also investigated systematically. The calculations suggest that the radial temperature field of the growing crystal became homogenous by setting up the coneshaped baffle in the growth cell. The axial temperature gradient is increased with the increase of the baffle thickness, but the growing temperature of SiC crystals falls down at the same time. By the simulation, we can conclude that the optimal baffle thickness is about 2mm, which is relatively favorable to improve the quality and to increase the yield of growing crystal.

  8. Design of the AP 600 passive containment cooling system structures

    International Nuclear Information System (INIS)

    The AP 600 is a greatly simplified 600 MWe Pressurized Water Reactor, for the 1990's and beyond. Among its major features, a passive containment cooling system (PCCS) is designed to remove the residual heat, directly from the containment steel vessel, and transmits it to the environment. The design and analysis of the PCCS structures is being performed jointly by ANSALDO and WESTINGHOUSE, as part of the AP 600 program under WESTINGHOUSE's overall leadership, and will be presented in this paper. The PCCS uses the steel containment wall as a heat transfer surface. The surrounding concrete shield building is used along with a baffle to direct air from the top located air inlets down to a lower elevation of the containment and back up along the containment vessel. In addition a water storage tank is housed in the shield building roof at an elevation sufficient to allow gravity drain of the water on top of the steel containment. The air and the evaporated water exhaust through a chimney in the roof of the shield building. For the roof, a reinforced concrete conical configuration, with a cylindrical stainless steel lined water tank, has been selected and a comprehensive feasibility study has been performed including seismic behaviour, constructability, prefabrication and modularization, adaptability to cope with the External Events strength requirements. For the PCCS air baffles general functional and structural design criteria have been established by including requirements for the air flow path configuration, leaded through the baffles, inspection and maintenance; a series of alternate designs have analyzed, leading to the selection of a reference configuration that will be briefly described. (author). 11 fig

  9. The nuclear heated steam reformer - design and semitechnical operating experiences

    International Nuclear Information System (INIS)

    Good operating experiences of the EVA I- and EVA II-plant have been described. Therein the comparison of the different catalyst concepts has been given. Further the behaviour of the bundle of EVA II plant by isolation of individual reformer tubes as well as the performance of the bundle under transient conditions have been explained. Different design concepts for a nuclear heated steam reformer based on the concentric tubes and baffles have been given. Main points of studies are constructional details, thermohydraulic of the bundle and stress analysis. It can be shown that the present standard of knowledge allows the application of the steam reformer for coal refinement with nuclear heat. (orig.)

  10. Low Melt Height Solidification of Superalloys

    Science.gov (United States)

    Montakhab, Mehdi; Bacak, Mert; Balikci, Ercan

    2016-06-01

    Effect of a reduced melt height in the directional solidification of a superalloy has been investigated by two methods: vertical Bridgman (VB) and vertical Bridgman with a submerged baffle (VBSB). The latter is a relatively new technique and provides a reduced melt height ahead of the solidifying interface. A low melt height leads to a larger primary dendrite arm spacing but a lower mushy length, melt-back transition length, and porosity. The VBSB technique yields up to 38 pct reduction in the porosity. This may improve a component's mechanical strength especially in a creep-fatigue type dynamic loading.

  11. A DESIGN RETROSPECTIVE OF THE DIII-D TOKAMAK

    International Nuclear Information System (INIS)

    OAK-B135 The DIII-D tokamak evolved from the earlier Doublet III device in 1986. Since then, the facility has undergone a number of changes including the installation of divertor baffles and pumping chambers in the vacuum vessel, the addition of a radiation shield, the development of extensive neutral beam and rf heating systems, and the addition of a comprehensive plasma control system. The facility has become the focus of a broad fusion plasma science research program. This paper gives an integrated picture of the facility and its capabilities

  12. DAWN OF A NEW COUNTRYSIDE The government is emphasizing modernization, innovation and mechanization to revitalize the farm sector in the current Five-Year Plan

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    The "farm question" has long baffled China's planners. Since 1979, when China began the reform and opening up process, the economy has developed rapidly, especially the secondary and tertiary sectors. By 2005, China's GDP was 18.2321 trillion yuan, nearly 30 times that in 1979. However, the primary sector has largely been left out of this growth with its proportion in GDP dropping from 25.6 percent in 1979 to 12.4 percent in 2005. Rural areas remain poor and living standards low. Past efforts to change t...

  13. Становление и развитие международной защиты прав женщин

    OpenAIRE

    Шакуро, Елена Александровна

    2000-01-01

    Раздел - "Международные отношения" The article considers the problem of achieving equality of men and women. A brief history of the issue demonstrates the complexity, which baffled various countries and societies in settling the problem of equal rights, beginning with eastern despotism, the democracies of Ancient Greece and Rome, the medieval times and ending with the 2000 special session of the UN General Assembly "Women in 2000: Equality of Men and Women, Peace and Development in the ...

  14. An imaginary tale the story of [the square root of] -1

    CERN Document Server

    Nahin, Paul J

    2006-01-01

    Today complex numbers have such widespread practical use--from electrical engineering to aeronautics--that few people would expect the story behind their derivation to be filled with adventure and enigma. In An Imaginary Tale, Paul Nahin tells the 2000-year-old history of one of mathematics' most elusive numbers, the square root of minus one, also known as i. He recreates the baffling mathematical problems that conjured it up, and the colorful characters who tried to solve them.In 1878, when two brothers stole a mathematical papyrus from the ancient Egyptian burial site in the Valley of Kings

  15. Vane structure design trade-off and performance analysis

    Science.gov (United States)

    Breault, Robert P.

    1989-04-01

    The APART/PADE and ASAP stray-light software packages (Breault, 1988) are applied to the design of vane structures to block direct propagation paths from the surfaces of optical baffles to other system components. Results for several typical systems are presented in extensive tables and graphs and analyzed. It is shown that vane angle and depth are significant parameters only for the first-order propagation path. Also evaluated are the amounts of particulate debris produced by degraded vane coatings and the effects of the resulting surface contamination on system performance.

  16. Space-based visible all-reflective stray light telescope

    Science.gov (United States)

    Wang, Dexter; Gardner, Leo R.; Wong, Wallace K.; Hadfield, Peter

    1991-08-01

    A 6-inch diameter aperture space-based visible telescope has been optimized to perform surveillance against the space background with earth albedo as a primary source of straylight. A three mirror off-axis anastigmat has been designed to cover a 1.4 degree(s) by 6.6 degree(s) field- of-view with 60 (mu) radian spatial resolution. The telescope body and optics are constructed of 6061-T6 aluminum to provide a thermally stable optical system. The optical elements are 'superfinished' to minimize scatter. Extensive baffles and stops are utilized to further reduce straylight. The telescope will be used on the Midcourse Space Experiment platform.

  17. A design retrospective of the DIII-D tokamak

    Science.gov (United States)

    Luxon, J. L.

    2002-05-01

    The DIII-D tokamak evolved from the earlier Doublet III device in 1986. Since then, the facility has undergone a number of changes including the installation of divertor baffles and pumping chambers in the vacuum vessel, the addition of a radiation shield, the development of extensive neutral beam and RF heating systems, and the addition of a comprehensive plasma control system. The facility has become the focus of a broad fusion plasma science research programme. An integrated picture of the facility and its capabilities is presented.

  18. Close-in nosecone configuration and blast damage in point backlight x-ray radiography

    Science.gov (United States)

    Fincke, J. R.; Workman, J. B.; Kryala, G. A.; Walsh, P. J.; Evans, S. C.; Tafoya, D.; Landers, D. J.

    2004-10-01

    Radiography of driven targets using point projection backlighting often requires extensive baffling to mitigate background x rays and physical damage due to target debris. One solution to this problem is a camera configuration that places the nosecone very close to the target such that extraneous light is excluded; however debris and blast damage becomes an issue. A successful close-in (design excludes stray light and survives the radiation flux and blast damage due to debris and late-time target expansion. Estimates of blast loading are compared to experimental observations of damage.

  19. FINAL REPORT FOR THE DIII-D RADIATIVE DIVERTOR PROJECT

    Energy Technology Data Exchange (ETDEWEB)

    O' NEIL, RC; STAMBAUGH, RD

    2002-06-01

    OAK A271 FINAL REPORT FOR THE DIII-D RADIATIVE DIVERTOR PROJECT. The Radiative Divertor Project originated in 1993 when the DIII-D Five Year Plan for the period 1994--1998 was prepared. The Project Information Sheet described the objective of the project as ''to demonstrate dispersal of divertor power by a factor of then with sufficient diagnostics and modeling to extend the results to ITER and TPX''. Key divertor components identified were: (1) Carbon-carbon and graphite armor tiles; (2) The divertor structure providing a gas baffle and cooling; and (3) The divertor cryopumps to pump fuel and impurities.

  20. Fabrication and test of a diamond-turned mirror suitable for a spaceborne photometric heliospheric imager

    Science.gov (United States)

    Buffington, Andrew; Bach, Kirk G.; Bach, Bernhard W.; Bach, Erich K.; Bisi, Mario M.; Hick, P. Paul; Jackson, Bernard V.; Klupar, Peter D.

    2009-08-01

    We have fabricated a diamond-turned low-mass version of a toroidal mirror which is a key element for a spaceborne visible-light heliospheric imager. This mirror's virtual image of roughly a hemisphere of sky is viewed by a conventional photometric camera. The optical system views close to the edge of an external protective baffle and does not protrude from the protected volume. The sky-brightness dynamic range and background-light rejection requires minimal wideangle scattering from the mirror surface. We describe the manufacturing process for this mirror, and present preliminary laboratory measurements of its wide-angle scattering characteristics.

  1. Patterns of ELM impacts on the JET wall components

    Science.gov (United States)

    Ghendrih, Ph.; Sarazin, Y.; Bécoulet, M.; Huysmans, G.; Benkadda, S.; Beyer, P.; Figarella, C.; Garbet, X.; Monier-Garbet, P.; JET Team

    2003-03-01

    Numerical analysis of the images in visible light from the JET tangential camera show that the edge localised mode (ELM) events are characterised by impacts on the low-field side components. The increase of emission is not restricted to the components closest to the plasma. One finds also that the deposition on the low-field side components does not exhibit any poloidal or toroidal symmetry and varies from ELM to ELM. Conversely the increase of emission on the divertor baffles, or the top protection tiles, is close to axisymmetric.

  2. PIV Experimental Investigation on the Flow in a Model of Closed Pump Sump

    Institute of Scientific and Technical Information of China (English)

    MANSA Kante; ZHANG Botao(张波涛); LI Xiaoming(李小明); LI Yong(李永); WU Yulin(吴玉林)

    2003-01-01

    Vortices in the flow of a pump sump present an important problem in pump station operation. In the present study, the flow patterns in two model pump sumps with specially designed structures are analyzed using the particle image velocimetry (PIV) technique. The data is analyzed to reveal a number of parameters including the internal flow field with velocity distribution, the streamline distribution, and the turbulent kinetic energy. The analysis certifies that a modified pump with added T-type baffle below the sump exhibits good performance for realistic working conditions.

  3. Experimental study of particle size distribution in suspension polymerization

    International Nuclear Information System (INIS)

    Particle size distribution is an important characteristic in suspension polymerization. Special condition must satisfy for achievement of an appropriate particle size distribution This condition is studied for some systems. In this work the effect of parameters affecting the suspension polymerization system of styrene was studied and then the approximate optimum range was determined to obtain narrow particle size distribution mainly in the range of 200 to 400 microns. The studied parameters are: position of impeller, impeller type, impeller speed, baffles, stabilizer concentration, initiator concentration and divinylbenzene concentration as cross-linking agent

  4. An ion source based on the cathodic arc

    Energy Technology Data Exchange (ETDEWEB)

    Sanders, D.M.; Falabella, S.

    1992-12-31

    This invention is comprised of a cylindrically symmetric arc source to produce a ring of ions which leave the surface of the arc target radially and are reflected by electrostatic fields present in the source to a point of use, such as a part to be coated. An array of electrically isolated rings positioned in the source serves the duel purpose of minimizing bouncing of macroparticles and providing electrical insulation to maximize the electric field gradients within the source. The source also includes a series of baffles which function as a filtering or trapping mechanism for any macroparticles.

  5. Plasma facing components design of KT-2 tokamak

    International Nuclear Information System (INIS)

    The vacuum vessel of KT-2 tokamak is protected from high thermal loads by various kinds of plasma facing components (PFC): outer and inner divertors, neutral baffle, inboard limiter, poloidal limiter, movable limiter and passive plate, installed on the inner wall of the vessel. In this report the pre-engineering design of the plasma facing components, including design requirements and function, structures of PFC assemblies, configuration of cooling systems, calculations of some mechanical and hydraulic parameters, is presented. Pumping systems for the movable limiter and the divertor are also discussed briefly. (author). 49 figs

  6. Samsung Galaxy S6 for dummies

    CERN Document Server

    Hughes, Bill

    2015-01-01

    Explore the capabilities of your Samsung Galaxy S 6 with this definitive guide! Learning to use a new phone can be both difficult and frustrating. With confusing documentation and baffling support, the references provided by phone manufacturers can be intimidating. Enter Samsung Galaxy S 6 For Dummies! This extensive yet practical guide walks you through the most useful features of your new Samsung Galaxy S 6-and it shows you all the best tricks to getting the most out of your device. With an accessible and fun, yet informative writing style, this is a text that you'll refer to again and agai

  7. Castings for stainless steel primary piping in PWR nuclear power plant

    International Nuclear Information System (INIS)

    Primary piping steel of Z3CN20-09M for nuclear power plant is melted by combination of electric furnace and AOD furnace, ferrite content of Z3CN20-09M are adjusted based on the compute result of Scharffler. Measures by enlarging the wall thickness of shell, decreasing inside diameter of the baffle, selecting greater g value and increasing machining allowances of internal surface, etc, in centrifugal casting process, sample of primary piping are cast. Measure results show that various performance of sample of primary piping the needs of RCC-M are without exception meet

  8. A numerical study of a vertical solar air collector with obstacle

    Science.gov (United States)

    Moumeni, A.; Bouchekima, B.; Lati, M.

    2016-07-01

    Because of the lack of heat exchange obtained by a solar air between the fluid and the absorber, the introduction of obstacles arranged in rows overlapping in the ducts of these systems improves heat transfer. In this work, a numerical study using the finite volume methods is made to model the dynamic and thermal behavior of air flow in a vertical solar collector with baffles destined for integration in building. We search essentially to compare between three air collectors models with different inclined obstacles angle. The first kind with 90° shows a good performance energetic and turbulent.

  9. Internal dust recirculation system for a fluidized bed heat exchanger

    Science.gov (United States)

    Gamble, Robert L.; Garcia-Mallol, Juan A.

    1981-01-01

    A fluidized bed heat exchanger in which air is passed through a bed of particulate material containing fuel disposed in a housing. A steam/water natural circulation system is provided in a heat exchange relation to the bed and includes a steam drum disposed adjacent the bed and a tube bank extending between the steam drum and a water drum. The tube bank is located in the path of the effluent gases exiting from the bed and a baffle system is provided to separate the solid particulate matter from the effluent gases. The particulate matter is collected and injected back into the fluidized bed.

  10. Enrichment of carbon monoxide utilising microorganisms from methanogenic bioreactor sludge

    OpenAIRE

    Pereira, Ana Luísa; Stams, A.J.M.; Alves, M. M.; Sousa, D.Z.

    2015-01-01

    Conversion of CO is the rate limiting step during anaerobic conversion of syngas (a gaseous mixture mainly composed of CO, CO2 and H2). In this work we study the microbial diversity in anaerobic sludge submitted to extended contact to syngas in a multi-orifice baffled bioreactor (MOBB). Methane was the main product resulting from syngas conversion in the MOBB. Enrichment cultures started with this sludge produced methane as final product, but also acetate. 16S rRNA gene analysis revealed a pr...

  11. Empirical Formulation of Flow Characteristics in Trapezoidal Channels

    Science.gov (United States)

    Gandhi, S.; Singh, R. P.

    2016-05-01

    Empirical relations for hydraulic jump characteristics, viz. sequent depth ratio (Y2/Y1), efficiency of jump (E2/E1) and relative length of jump (Lj/Y1) in trapezoidal channel with/without appurtenances are developed by introducing dimensionless Reynolds number, and neglecting the frictional effect for approach Froude number (varied between 2 and 10 under different conditions). Developed empirical models were also validated and compared with acquired experimental data as well as with literature data. Close fitness of the empirical models with appurtenances under varying dimensions, positions of baffle blocks provides accurate prediction of same for higher value of Froude number.

  12. Particulate residue separators for harvesting devices

    Science.gov (United States)

    Hoskinson, Reed L.; Kenney, Kevin L.; Wright, Christopher T.; Hess, John R.

    2010-06-29

    A particulate residue separator and a method for separating a particulate residue stream may include a plenum borne by a harvesting device, and have a first, intake end and a second, exhaust end; first and second particulate residue air streams which are formed by the harvesting device and which travel, at least in part, along the plenum and in a direction of the second, exhaust end; and a baffle assembly which is located in partially occluding relation relative to the plenum, and which substantially separates the first and second particulate residue air streams.

  13. Methods of separating particulate residue streams

    Science.gov (United States)

    Hoskinson, Reed L.; Kenney, Kevin L.; Wright, Christopher T.; Hess, J. Richard

    2011-04-05

    A particulate residue separator and a method for separating a particulate residue stream may include an air plenum borne by a harvesting device, and have a first, intake end and a second, exhaust end; first and second particulate residue air streams that are formed by the harvesting device and that travel, at least in part, along the air plenum and in a direction of the second, exhaust end; and a baffle assembly that is located in partially occluding relation relative to the air plenum and that substantially separates the first and second particulate residue air streams.

  14. Time a traveler's guide

    CERN Document Server

    Pickover, Clifford A

    1998-01-01

    ""Bucky Fuller thought big,"" Wired magazine recently noted, ""Arthur C. Clarke thinks big, but Cliff Pickover outdoes them both."" In his newest book, Cliff Pickover outdoes even himself, probing a mystery that has baffled mystics, philosophers, and scientists throughout history--What is the nature of time? In Time: A Traveler's Guide, Pickover takes readers to the forefront of science as he illuminates the most mysterious phenomenon in the universe--time itself. Is time travel possible? Is time real? Does it flow in one direction only? Does it have a beginning and an end? What is eternity? P

  15. Soil separator and sampler and method of sampling

    Science.gov (United States)

    O'Brien, Barry H [Idaho Falls, ID; Ritter, Paul D [Idaho Falls, ID

    2010-02-16

    A soil sampler includes a fluidized bed for receiving a soil sample. The fluidized bed may be in communication with a vacuum for drawing air through the fluidized bed and suspending particulate matter of the soil sample in the air. In a method of sampling, the air may be drawn across a filter, separating the particulate matter. Optionally, a baffle or a cyclone may be included within the fluidized bed for disentrainment, or dedusting, so only the finest particulate matter, including asbestos, will be trapped on the filter. The filter may be removable, and may be tested to determine the content of asbestos and other hazardous particulate matter in the soil sample.

  16. Biogas generation in anaerobic wastewater treatment under tetracycline antibiotic pressure

    OpenAIRE

    Meiqing Lu; Xiaojun Niu; Wei Liu; Jun Zhang; Jie Wang; Jia Yang; Wenqi Wang; Zhiquan Yang

    2016-01-01

    The effect of tetracycline (TC) antibiotic on biogas generation in anaerobic wastewater treatment was studied. A lab-scale Anaerobic Baffled Reactor (ABR) with three compartments was used. The reactor was operated with synthetic wastewater in the absence of TC and in the presence of 250 μg/L TC for 90 days, respectively. The removal rate of TC, volatile fatty acids (VFAs), biogas compositions (hydrogen (H2), methane (CH4), carbon dioxide (CO2)), and total biogas production in each compartment...

  17. An extension to artifact-free projection overlaps

    International Nuclear Information System (INIS)

    Purpose: In multipinhole single photon emission computed tomography, the overlapping of projections has been used to increase sensitivity. Avoiding artifacts in the reconstructed image associated with projection overlaps (multiplexing) is a critical issue. In our previous report, two types of artifact-free projection overlaps, i.e., projection overlaps that do not lead to artifacts in the reconstructed image, were formally defined and proved, and were validated via simulations. In this work, a new proposition is introduced to extend the previously defined type-II artifact-free projection overlaps so that a broader range of artifact-free overlaps is accommodated. One practical purpose of the new extension is to design a baffle window multipinhole system with artifact-free projection overlaps. Methods: First, the extended type-II artifact-free overlap was theoretically defined and proved. The new proposition accommodates the situation where the extended type-II artifact-free projection overlaps can be produced with incorrectly reconstructed portions in the reconstructed image. Next, to validate the theory, the extended-type-II artifact-free overlaps were employed in designing the multiplexing multipinhole spiral orbit imaging systems with a baffle window. Numerical validations were performed via simulations, where the corresponding 1-pinhole nonmultiplexing reconstruction results were used as the benchmark for artifact-free reconstructions. The mean square error (MSE) was the metric used for comparisons of noise-free reconstructed images. Noisy reconstructions were also performed as part of the validations. Results: Simulation results show that for noise-free reconstructions, the MSEs of the reconstructed images of the artifact-free multiplexing systems are very similar to those of the corresponding 1-pinhole systems. No artifacts were observed in the reconstructed images. Therefore, the testing results for artifact-free multiplexing systems designed using the

  18. MBT - skoen der sælger sig selv Branding og dens rolle i moderne markedsføring

    OpenAIRE

    Tengberg, Niels

    2013-01-01

    Despite the time and money spent on market reearch through focus group and questionnaires, 60 to 80 % of all new products and services fail. Why do consumers often say one thing to marketers, yet do something entirely different in the market? The aim of this thesis is to: - Penetrate the mystery that baffles marketers in every industry: why customers don´t buy proucts and services that they instist they want. - Understand how a customer´s buying decision is influenced by the complex interacti...

  19. Samsung Galaxy S For Dummies

    CERN Document Server

    Hughes, Bill

    2011-01-01

    Colorful guide to getting more out of your Galaxy S smartphone!Now that you've got your new Galaxy S smartphone, you've got to figure out how to use it! If you're baffled by the technology and the documentation, this book can help. Written in the fun but clear and thorough For Dummies style, this book answers all your questions. You'll find out how to do all the fun stuff: texting, social networking, using the camera, how to watch movies, and more. And you'll also learn how to handle the "housekeeping": synching your phone with your PC, using business applications, downloading apps, accessin

  20. Induced natural convection thermal cycling device

    Science.gov (United States)

    Heung, Leung Kit

    2002-08-13

    A device for separating gases, especially isotopes, by thermal cycling of a separation column using a pressure vessel mounted vertically and having baffled sources for cold and heat. Coils at the top are cooled with a fluid such as liquid nitrogen. Coils at the bottom are either electrical resistance coils or a tubular heat exchange. The sources are shrouded with an insulated "top hat" and simultaneously opened and closed at the outlets to cool or heat the separation column. Alternatively, the sources for cold and heat are mounted separately outside the vessel and an external loop is provided for each circuit.

  1. Development and Testing of Active Groundwater Samplers

    DEFF Research Database (Denmark)

    Nilsson, Bertel; Jakobsen, Rasmus; Andersen, Lars Jørgen

    numerical modelling and controlled laboratory experiments. Active groundwater sampling techniques can be used for remedial pumping optimization and in obtaining hydraulic data and represent a fast operational and reliable sampling tool, also under heterogeneous and low permeability conditions....... Baffle System (PBS). The methodology and design of the two systems is presented and the operational application is demonstrated by examples from full-scale field experiments. The methods are validated and their sensitivity to the well construction and the hydrogeological environment is assessed based on...

  2. Advanced ultrasonic inspection system for the ID-inspection of reactor pressure vessels of BWRs

    International Nuclear Information System (INIS)

    A newly-developed, modular ultrasonic examination system has been developed by Siemens for the ID inspection of BWR RPV'S. It is based on the phased-array technique with hybrid probes using the latest in manipulator and control equipment technology to allow the often hard-to-access weld areas of older reactor pressure vessels in US BWR plants to be examined within a very short time and with minimal radiation exposure of the examination personnel. New NRC stipulations requiring almost complete ultrasonic examination of all RPV welds can be fully satisfied using this system for the ID inspection of all longitudinal and circumferential welds above the jet pump baffle plate

  3. Agaricus geesterani, spec. nov. A very remarkable agaric discovered in the Netherlands

    OpenAIRE

    Bas, C.; Heinemann, P.

    1986-01-01

    For several years now a very striking agaric is known to occur in the Netherlands that baffles every mycologist who has the luck to see it. As one of us (P.H.) never had this luck, the present study is based on thorough examinations of the material by the other author, while for the rather precarious taxonomic decisions both authors are to be held responsible. At first sight the present species resembles a large Agaricus bitorquis, but on closer examination the differences are obvious and man...

  4. A loss-free measurement of the beta-spectrum of 35S and the origin of the 17 keV neutrino signals

    International Nuclear Information System (INIS)

    We present measurements of the β-spectrum of 35S, using two energy sensitive silicon detectors in a 4π configuration. A 7 Tesla magnetic field guides the electrons to the detectors. Electrons which are backscattered in one detector are counted in the other detector. No baffles or collimators are needed. In the sum spectra all effects due to electron backscattering are eliminated. No evidence for heavy neutrinos is observed. When we remove the backscattering suppression, the data show a deviation from the usual electron spectrum that could be misinterpreted as an admixture of a heavy neutrino. (authors). 11 refs., 5 figs

  5. Flock Growth Kinetics for Flocculation in an Agitated Tank

    OpenAIRE

    R. Šulc; O. Svačina

    2010-01-01

    Flock growth kinetics was investigated in baffled tank agitated by a Rushton turbine at mixing intensity 40 W/m3 and kaolin concentration 0.44 g/l. The tests were carried out with a model wastewater (a suspension of tap water and kaolin). The model wastewater was flocculated with organic Sokoflok 56 A flocculant (solution 0.1 % wt.). The flock size and flock shape were investigated by image analysis. A simple semiempirical generalized correlation for flock growth kinetics was proposed, and wa...

  6. Electromagnetically induced transparency (EIT)-like transmission in side-coupled complementary split-ring resonators.

    Science.gov (United States)

    Guo, Yinghui; Yan, Lianshan; Pan, Wei; Luo, Bin; Wen, Kunhua; Guo, Zhen; Luo, Xiangang

    2012-10-22

    We investigate a plasmonic waveguide system based on side-coupled complementary split-ring resonators (CSRR), which exhibits electromagnetically induced transparency (EIT)-like transmission. LC resonance model is utilized to explain the electromagnetic responses of CSRR, which is verified by simulation results of finite difference time domain method. The electromagnetic responses of CSRR can be flexible handled by changing the asymmetry degree of the structure and the width of the metallic baffles. Cascaded CSRRs also have been studied to obtain EIT-like transmission at visible and near-infrared region, simultaneously. PMID:23187197

  7. Rushton桨搅拌槽中气液两相流动的全流场数值模拟%Numerical Simulation of Gas-Liquid Flow in a Stirred Tank with a Rushton Impeller

    Institute of Scientific and Technical Information of China (English)

    王卫京; 毛在砂

    2002-01-01

    The gas-liquid flow field in a stirred tank with a Rushton disk turbine, including the impeller region,was numerically simulated using the improved inner-outer iterative procedure. The characteristic features of the stirred tank, such as gas cavity and accumulation of gas at the two sides of wall baffles, can be captured by the simulation. The simulated results agree well with available experimental data. Since the improved inner-outer iterative algorithm demands no empirical formula and experimental data for the impeller region, and the approach seems generally applicable for simulating gas-liquid stirred tanks.

  8. Numerical Simulation of Gas—Liquid Flow in a Stirred Tank with a Rushton Impeller

    Institute of Scientific and Technical Information of China (English)

    WANGWeijing; MAOZaisha

    2002-01-01

    The gas-liquid flow field in a stirred tank with a Rushton disk turbine,including the impeller region,was numerically simulated using the improved inner-outer iterative procedure.The characteristic features of the strirred tank,such as gas cavity and accumulation of gas at the two sides of wall baffles,can be captured by the simulation.The simulated results agree well with available experimental data.Since the improved inner-outer iterative algorithm demands no empirical formula and experimental data for the impeller region,and the approach seems generally applicable for simulating gas-liquid stirred tanks.

  9. NUMERICAL SIMULATION BY COMPUTATIONAL FLUID DYNAMICS AND EXPERIMENTAL STUDY ON STIRRED BIOREACTOR WITH PUNCHED IMPELLER

    Institute of Scientific and Technical Information of China (English)

    WANG Yu; HE Pingting; YE Hong; XIN Zhihong

    2007-01-01

    Instantaneous flow field and temperature field of the two-phase fluid are measured by particle image velocimetry (PIV) and steady state method during the state of onflow. A turbulent two-phase fluid model of stirred bioreactor with punched impeller is established by the computational fluid dynamics (CFD), using a rotating coordinate system and sliding mesh to describe the relative motion between impeller and baffles. The simulation and experiment results of flow and temperature field prove their warps are less than 10% and the mathematic model can well simulate the fields, which will also provide the study on optimized-design and scale-up of bioreactors with reference value.

  10. Numerical Simulation of Macroscopic Mixing in a Rushton Impeller Stirred Tank

    Institute of Scientific and Technical Information of China (English)

    王正; 毛在砂; 沈湘黔

    2006-01-01

    The macroscopic mixing in a stirred tank with different tracer injection locations, impeller speeds and impeller positions is simulated numerically by solving the transport equation of the tracer based on the whole flow field in the baffled tank with a Rushton disk turbine numerically resolved using the improved inner-outer iterative procedure. Predicted mixing time is compared well with the literature correlations. The predicted residence time distribution of the stirred tank is very close to the present experimental results. The effect of the installation of a draft tube on the mixing time and residence time distributions is addressed.

  11. Treatment of agglomerates of solid particles in suspension in a liquid in order to obtain a circulating mixture without deposits

    International Nuclear Information System (INIS)

    The invention concerns a process and an installation for treating agglomerates of solid particles in suspension in a liquid in order to obtain a circulating mixture without deposits. This process is notably used for reprocessing spent fuel after its cutting up, its dissolution in nitric solution and its decantation in a clarifier. Particles are conducted to a transferring tank, then circulated in a loop including a pomp and a dilacerator. Finally, the disaggregated particles are sifted and transferred to a vitrification site. The sifter can be ultrasonic, the dilacerator can be ultrasonic with Venturi tube or with Venturi tube and baffled system. A previous dilaceration can be done inside the clarifier. 6 figs

  12. CPI,Cost of Living and Politics

    Institute of Scientific and Technical Information of China (English)

    赵忠德

    2000-01-01

    All economic decisions are made basedupon statistics,which are supposed to comefrom facts in real life.However,people aresometimes baffled by the conclusions drawnfrom different statistics,which present differ-ent pictures of our lives and society.Consumer Price Index(CPI),one of theprice indexes that government normally usesto judge the cost of living,measures the pricesof a fixed market basket of some 300 con-sumer goods and services purchased by a“typ-ical”urban consumer(McConnell & Brue,p.

  13. Quantum Einstein, Bohr and the great debate about the nature of reality

    CERN Document Server

    Kumar, Manjit

    2008-01-01

    For most people, quantum theory is a byword for mysterious, impenetrable science. And yet for many years it was equally baffling for scientists themselves. Manjit Kumar gives a dramatic and superbly-written history of this fundamental scientific revolution, and the divisive debate at its heart.  For 60 years most physicists believed that quantum theory denied the very existence of reality itself. Yet Kumar shows how the golden age of physics ignited the greatest intellectual debate of the twentieth century.  Quantum sets the science in the context of the great upheavals of the modern age. In 1

  14. Conceptual design study of the hylife lithium fall laser fusion chamber. FY 1979 annual report

    Energy Technology Data Exchange (ETDEWEB)

    1979-11-30

    In FY 1979, the basic configuration of FY 1978 was used as a reference point. Many studies were then made to either generate more design information concerning this design or to produce new concepts that would lead to a superior configuration. Among these activities were a detailed weight analysis, an assembly sequence, a chamber vibration analysis, a splash baffle stress study, and an analysis of first wall thermal stresses. Then some new concepts were introduced that pertained to the first wall, the lithium inlet nozzle, the chamber supports, the inlet piping, and pressure vessel.

  15. Radiotracers and CFD methods for wastewater treatment apparatus investigation

    International Nuclear Information System (INIS)

    Full text: Using Br-82 and La-142 radiotracers for labeling liquid and solid phases, respectively, the researches of apparatus for wastewater treatment were carried out. The clarifier-equalizer, aeration tanks and sediment settlers were investigated. The models of liquid phase flow were proposed. The parameters of sediment removal processes were determined. Computational fluid dynamic (CFD) methods are used for verification of proposed models in laboratory and industrial scale. Application of CFD methods is an effective tool for prediction of flow pattern changing in apparatus as a function of tank geometry (inflow and outflow localization, baffles etc.). (author)

  16. The fall of equalization myth - radiotracer investigations of the case

    International Nuclear Information System (INIS)

    The results of extensive radiotracer investigations of the PRTD (proportional residence time distribution) waste-water equalization basins are presented. The PRTD process is based on proportional residence time distribution of liquid streams. Different types of PRTD tanks have been built, among them some of circular. Two tanks, one with and another without baffles were investigated by means of radiotracer technique. For the first tank experiment was repeated after removing the dividing walls. The mathematical analysis of all investigated cases have clearly shown that obtaining the PRTD conditions in the big equalization tanks is rather impossible. The equalization effects are far away from the effects predictable form the theoretical models. (author)

  17. Procedure and equipment for the separation of isotopes for deuterium upgrading and for the production of heavy water

    International Nuclear Information System (INIS)

    The invention concerns a simple procedure for the separation of isotopes for the enrichment of deuterium and for the production of heavy water as well as the equipment necessary for carrying out the process. Methane is conducted over bacterial cultures oxidizing methane to water and carbon dioxide. An enrichment of deuterium takes place in non-oxidized methane. The bacterial cultures are placed on carriers that are arranged in oxidation columns as baffle plates. Several oxidation towers of this kind can be arranged in series. (orig./RW)

  18. A new Calculation Procedure for Spatial Impulse Responses in Ultrasound

    DEFF Research Database (Denmark)

    Jensen, Jørgen Arendt

    1999-01-01

    A new procedure for the calculation of spatial impulse responses for linear sound fields is introduced. This calculation procedure uses the well known technique of calculating the spatial impulse response from the intersection of a circle emanating from the projected spherical wave with the......-dimensional integration. The case of a soft baffle mounting of the aperture is also included. Specific solutions for transducer boundaries made from lines are given, so that any polygon transducer can be handled. Specific solutions for circles are also given. Finally, a solution for a general boundary is stated, and all...

  19. Conceptual design study of the hylife lithium fall laser fusion chamber. FY 1979 annual report

    International Nuclear Information System (INIS)

    In FY 1979, the basic configuration of FY 1978 was used as a reference point. Many studies were then made to either generate more design information concerning this design or to produce new concepts that would lead to a superior configuration. Among these activities were a detailed weight analysis, an assembly sequence, a chamber vibration analysis, a splash baffle stress study, and an analysis of first wall thermal stresses. Then some new concepts were introduced that pertained to the first wall, the lithium inlet nozzle, the chamber supports, the inlet piping, and pressure vessel

  20. UNDERSTANDING ACCOUNTS

    OpenAIRE

    Neha Birwal

    2014-01-01

    It's not just accountancy specialists who deal with spreadsheets, and figures, and the financial side of business. It's highly likely that, as a line manager or department head, you're going to have to analyze a spreadsheet at some point, or have some form of financial recording to do as part of your job description. However, if you feel baffled by balance sheets, or confused by cash flow statements, then read on. This article will take you through the basics of finance for...

  1. Computational fluid dynamic studies on gas entrainment in fast breeder reactors

    International Nuclear Information System (INIS)

    Primary sodium pools in fast reactors are covered with argon. There is strong potential for argon gas entrainment into sodium and associated reactivity perturbations if the free surface velocity is large. Basic CFD studies have been carried out on ideal models and the threshold value of free surface sodium velocity that avoids gas entrainment is arrived at employing the VOF method. Subsequently, 3-D CFD studies have been carried out for PFBR hot pool and the free surface velocity is estimated to be 1.14 m/s. To reduce this value below the threshold limit, a horizontal baffle device has been identified (author)

  2. Study of Pumping Capacity of Pitched Blade Impellers

    OpenAIRE

    I. Fořt; T. Jirout; R. Sperling; S. Jambere; Rieger, F.

    2002-01-01

    A study was made of the pumping capacity of pitched blade impellers in a cylindrical pilot plant vessel with four standard radial baffles at the wall under a turbulent regime of flow. The pumping capacity was calculated from the radial profile of the axial flow, under the assumption of axial symmetry of the discharge flow. The mean velocity was measured using laser Doppler anemometry in a transparent vessel of diameter T = 400 mm, provided with a standard dished bottom. Three and six blade pi...

  3. Pumping Capacity of Pitched Blade Impellers in a Tall Vessel with a Draught Tube

    OpenAIRE

    J. Brož; I. Fořt; R. Sperling; S. Jambere; M. Heiser; Rieger, F.

    2004-01-01

    A study was made of the pumping capacity of pitched blade impellers (two, three, four, five and six blade pitched blade impellers with pitch angles α = 35° and 45°) coaxially located in a cylindrical pilot plant vessel with cylindrical draught tube provided with a standard dished bottom. The draught tube was equipped with four equally spaced radial baffles above the impeller pumping liquid upwards towards the liquid surface. In all investigated cases the liquid aspect ratio H/T = 1.2 - 1.5, t...

  4. An Investigation of the Erosion Wear of Pitched Blade Impellers in a Solid-Liquid Suspension

    OpenAIRE

    T. Jirout; I. Fořt

    2008-01-01

    This paper reports on a study of the erosion wear mechanism of the blades of pitched blade impellers in a solid-liquid suspension in order to determine the effect of the impeller speed n as well as the concentration and size of the solid particles on its wear rate. A four-blade pitched blade impeller (pitch angle α = 30°), pumping downwards, was investigated in a pilot plant fully baffled agitated vessel with a water suspension of corundum. The results of  experiments show that the erosion we...

  5. CFD Simulation of Hydrodynamic Characteristics in Stirred Reactors Equipped with Standard Rushton or 45°-Upward PBT Impeller

    Institute of Scientific and Technical Information of China (English)

    未作君; 徐世民; 元英进; 许松林

    2003-01-01

    The hydrodynamic characteristics generated by the standard Rushton or 45°-upward pitched-blade-turbine (PBT) impellers in a baffled reactor are numerically simulated for different off-bottom clearances (C= 1/3H and 1/2H) and agitator speeds (100, 150, 200, 250 and 300r·min-1) by using FLUENT code (Version 5.4). The results are compared with the experimental and simulated data in the published papers and good agreement is observed. The shapes of the profile of mean velocities seem independent to the speed of agitators under the experimental conditions (100-300r·min-1).

  6. Liquid sloshing in gravity driven water pool of Advanced Heavy Water Reactor - pool liquid under design seismic load and slosh control studies

    International Nuclear Information System (INIS)

    Sloshing phenomenon is well understood in regular cylindrical and rectangular liquid tanks subjected to earthquake. However, seismic behaviour of water in complex geometry such as a sectored annular tank, e.g., Gravity Driven Water Pool (GDWP) which is located in Advanced Heavy Water Reactor (AHWR) need to be investigated in detail in the view of safety significance. Initially, for validation of Computational Fluid Dynamics (CFD) procedure, square and four sectored square tanks are taken. Slosh height and liquid pressure are calculated over time through theoretical and experimental procedures. Results from theoretical and experimental approaches are compared with CFD results and found to be in agreement. The present work has two main objectives. The first one is to investigate the sloshing behaviour in an un-baffled and baffled three dimensional single sector of GDWP of AHWR under sinusoidal excitation. Other one is to study the sloshing in GDWP water using simulated seismic load along the three orthogonal directions. This simulated seismic load is generated from design basis floor response spectrum data (FRS) of AHWR building. For this, the annular tank is modelled along with water and numerical simulation is carried out. The sinusoidal and earthquake excitations are applied as acceleration force along with gravity. For the earthquake case, acceleration-time history is generated compatible to the design FRS of AHWR building. The free surface is captured by Volume of Fluid (VOF) technique and the fluid domain is solved by finite volume method while the structural domain is solved by finite element approach. Un-baffled and baffled tank configurations are compared to show the reduction in wave height under excitation. The interaction between the fluid and pool wall deformation is simulated using a partitioned fluid-structure coupling. In the earthquake case, a user subroutine function is developed to convert FRS in to time history of acceleration in three directions

  7. A new practical guide to the Luria-Delbrück protocol.

    Science.gov (United States)

    Zheng, Qi

    2015-11-01

    Since 2000 several review papers have been published about the analysis of experimental data obtained using the Luria-Delbrück protocol. These timely papers cleared much of the confusion surrounding various methods for estimating or comparing mutation rates. As a result, today the fluctuation test is more widely applied with much improved accuracy. The present paper provides guidelines on a few remaining problems that continue to baffle mutation researchers. Among the issues addressed are incomplete plating, relative fitness, and comparison of experiments where average final cell population sizes differ. It also offers a fresh view on the estimation methods that are based on the sample median. PMID:26366669

  8. Advancement in fuel design and manufacturing technologies of NFI

    International Nuclear Information System (INIS)

    NFI has two works manufacturing PWR fuel, BWR fuel and other types of fuel with a total capacity of 465 ton-U/year and has employees approx. 500. NFI is appreciated as a unique company for supplying both PWR fuel and BWR fuel with excelent quality and carrying out R and D work covering a wide range of areas. NFI has had no leak problem except tow occasions both caused by baffle flow in PWRs. As to BWR fuel, approx. 1,000 bundles have been manufactured by NFI and used to date and not a single case of failure has occurred. (author)

  9. 搅拌槽内液-固两相体系的数值研究(Ⅱ)临界搅拌转速的预测%Numerical Study of Solid-Liquid Two-Phase Flow in Stirred Tanks with Rushton Impeller(Ⅱ) Prediction of Critical Impeller Speed

    Institute of Scientific and Technical Information of China (English)

    王峰; 毛在砂; 沈湘黔

    2004-01-01

    The critical impeller speed, NJs, for complete suspension of solid particles in the agitated solid-liquid two-phase system in baffled stirred tanks with a standard Rushton impeller is predicted using the computational procedure proposed in Part I. Three different numerical criteria are tested for determining the critical solid suspension. The predicted NJS is compared with those obtained from several empirical correlations. It is suggested the most reasonable criterion for determining the complete suspension of solid particles is the positive sign of simulated axial velocity of solid phase at the location where the solid particles are most difficult to be suspended.

  10. Hacker's guide to Microsoft Excel (how to use Excel, shortcuts, modeling, macros, and more)

    CERN Document Server

    Hudson, Kimberly

    2012-01-01

    ABOUT THE BOOK Microsoft Excel is a user-friendly spreadsheet program that lets you organize data, create charts, program time-saving shortcuts, and make reports. It is part of the Microsoft Office Suite. There are multiple versions of Microsoft Excel out there, the latest being part of the Microsoft Office 2010 Suite. Although you may be baffled by Excel now, don't give up! Once you read what Excel can do, you will quickly use simple functions to answer questions, create charts, and increase productivity. MEET THE AUTHOR Kimberly Hudson is a professional writer who lives and works in Ma

  11. Characteristics of various confinement regimes obtained with EC and LH heating on the TdeV tokamak

    International Nuclear Information System (INIS)

    Steady-state H-modes in type III ELM regime on TdeV with electron cyclotron and lower hybrid heating are investigated with respect to lower hybrid wave coupling, threshold power, helium pumping and separation between separatrix and surrounding structures. Energy confinement is found to improve as the distance between separatrix and divertor baffle is reduced. With off-axis EC heating, reduced particle transport is observed inside the deposition zone, but no energy transport barrier is obtained. New measurements on compact toroid fuelling are reported which indicate that further optimization of the injector is required. (author)

  12. Predicted and measured velocity distribution in a model heat exchanger

    International Nuclear Information System (INIS)

    This paper presents a comparison between numerical predictions, using the porous media concept, and measurements of the two-dimensional isothermal shell-side velocity distributions in a model heat exchanger. Computations and measurements were done with and without tubes present in the model. The effect of tube-to-baffle leakage was also investigated. The comparison was made to validate certain porous media concepts used in a computer code being developed to predict the detailed shell-side flow in a wide range of shell-and-tube heat exchanger geometries

  13. Cooling performance of helium-gas/water coolers in HENDEL

    International Nuclear Information System (INIS)

    The helium engineering demonstration loop (HENDEL) has four helium-gas/water coolers where the cooling water flows in the tubes and helium gas on the shell side. Their cooling performance was studied using the operational data from 1982 to 1991. The heat transfer of helium gas on the shell was obtained for segmental and step-up baffle type coolers. Also, the change with operation time was investigated. The cooling performance was lowered by the graphite powder released from the graphite components for several thousand hours and thereafter recovered because the graphite powder from the components was reduced and the powder in the cooler shell was blown off during the operation. (orig.)

  14. Predicted and measured velocity distributions in a model heat exchanger

    International Nuclear Information System (INIS)

    This paper presents a comparison between numerical predictions, using the porous media concept, and measurements of the two-dimensional isothermal shell-side velocity distributions in a model heat exchanger. Computations and measurements were done with and without tubes present in the model. The effect of tube-to-baffle leakage was also investigated. The comparison was made to validate certain porous media concepts used in a computer code being developed to predict the detailed shell-side flow in a wide range of shell-and-tube heat exchanger geometries

  15. The Application of Compulational Fluid Dynamics to Design of Vehicle Cooling Wind Tunnel

    Institute of Scientific and Technical Information of China (English)

    BI Xiao-ping; HUANG Xiao-hui

    2009-01-01

    A computational fluid dynamics (CFD) calculation model for the airflow and heat transfer in an armored vehicle cooling wind tunnel is established. A practical method to determine computation region outside power train compartment, produce grid and ensure grid quality is put forward. A commercial software FLUENT can be used to obtain solutions numerically in 3-D space. Precision of CFD calculation results is verified. The CFD model is used in designing a vehicle cooling wind tunnel, and air flow resistance of fan blast baffle is calculated. The calculated results show feasibility of the CFD model and the method.

  16. The realization of three special photovoltaic (PV) pilot projects. The roles and learning experiences of parties involved

    International Nuclear Information System (INIS)

    Experiences with the following three demonstration projects, carried out in the Netherlands, are inventorized and evaluated: (1) 16 private grid-connected PV-systems in existing houses within the framework of the project of the Organization for Renewable Energy (ODE, abbreviated in Dutch); (2) five private grid-connected roof-integrated PV-systems in renovated buildings in Leiden; and (3) the integration of PV in an acoustic baffle along the high-way A-27 near De Bilt. Attention is paid to the decision making processes, the most important actors, the management of the projects and what is learned from the experiences

  17. 读书(英文)

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    1 The Insider's Guide to Beijig《北京指南》Editor:Adam Pillsbury Publisher:True Run Media Beijing is an overwhelming place.The language barrier,urban sprawl,gridlock and culture shock combine to make expats'first weeks in the Chinese capital a baffling experience.How is a newcomer,who can't even direct a taxi driver to his apartment,supposed to find a block of cheese,a pair of shoes or a Western hairstylist in this metropolis? The answer is in the"Insider's Guide to Beijing."

  18. The long-term development of cold-water coral mounds in the NE-Atlantic

    OpenAIRE

    Eisele, Markus Hermann

    2010-01-01

    Cold-water corals are distributed all over the world's oceans where they form a high variety of ecosystems depending on their specific environment. This study is dealing with so called cold-water coral mounds that are mainly composed of fragments of cold-water corals and hemipelagic mud that is baffled in between the coral branches. Changes of the environment have a direct effect on coral growth and thus on mound growth. This study aims to unravel the environmental factors that influence moun...

  19. Vibration analysis of reactor assembly internals for Prototype Fast Breeder Reactor

    International Nuclear Information System (INIS)

    Vibration analysis of the reactor assembly components of 500 MWe Prototype Fast Breeder Reactor (PFBR) is presented. The vibration response of primary pump as well as dynamic forces developed at its supports are predicted numerically. The stiffness properties of hydrostatic bearing are determined by formulating and solving governing fluid and structural mechanics equations. The dynamic forces exerted by pump are used as input data for the dynamic response of reactor assembly components, mainly inner vessel, thermal baffle and control plug. Dynamic response of reactor assembly components is also predicted for the pressure fluctuations caused by sodium free level oscillations. Thermal baffle (weir shell) which is subjected to fluid forces developed at the associated sodium free levels is analysed by formulating and solving a set of non-linear equations for fluids, structures and fluid structure interaction (FSI). The control rod drive mechanism is analysed for response under flow induced forces on the parts subjected to cross flow in the zone just above the core top, taking into account FSI between sheaths of control and safety rod and absorber pin bundle. Based on the analysis results, it is concluded that the reactor assembly internals are free from any risk of mechanical as well as flow induced vibrations. (author)

  20. Final Technical Report for Grant DE-FG02-97ER54451

    International Nuclear Information System (INIS)

    VUV ultraviolet spectroscopy in DIII-D Divertor. The research carried out on this grant was motivated by the high power emission from the CIV doublet at 155 nm in the DIII-D divertor and to study the characteristics of the radiative divertor. The radiative divertor is designed to reduce the heat load to the target plates of the divertor by reducing the energy in the divertor plasma using upstream scrape-off-layer (SOL) radiation. In some cases, particularly in Partially Detached Divertor (PDD) operations, this emission accounts for more than 50% of the total radiation from the divertor. In PDD operation, produced by neutral gas injection, the particle flow to the target plate and the divertor temperature are significantly reduced. A father motivation was to study the CIV emission distribution in the lower, open divertor and the upper baffled divertor. Two Vacuum Ultra Violet Tangential viewing Television cameras (VUV TTV) were constructed and installed in the upper, baffled and the lower, open divertor. The images recorded by these cameras were then inverted to produce two-dimensional distributions of CIV in the poloidal plane. Results obtained with these cameras are summarized