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风扇磨煤机润滑系统的传热机理分析及改进设计
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作者 刘效洲 惠世恩 +3 位作者 徐通模 李战国 李萍 金宇锋 《热能动力工程》 CAS CSCD 北大核心 2001年第1期49-50,82,共3页
通过介绍风扇磨煤机润滑系统的改进设计方案、相应的计算方法以及润滑系统改进前、后效果的对比 ,证明了改造后的润滑系统具有明显的优越性。
关键词 风扇磨煤机 润滑系统 肋片管冷却器 热传机理
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Boiling Heat Transfer in an Acoustic Cavitation Field 被引量:1
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作者 周定伟 刘登瀛 《Chinese Journal of Chemical Engineering》 SCIE EI CAS CSCD 2002年第5期625-629,共5页
An experimental study has been carried out investigatesystematically the effects of acoustic cavi- tation parameters andfluid subcooling on boiling of acetone around a horizontal circulartube. The experimental results... An experimental study has been carried out investigatesystematically the effects of acoustic cavi- tation parameters andfluid subcooling on boiling of acetone around a horizontal circulartube. The experimental results show that acoustic cavitation enhancedremarkably the boiling heat transfer and decreased the incipientboiling superheat and that cavitation bubbles effect on boiling heattransfer reduced with cavitation distance. For boiling curves in aform of h-q', elevated cavitation distance shift nucleate boilingcurves to the right of the cor- responding ordinary pool boilingcurve. The associated mechanism of heat transfer enhancement isanalyzed with the consideration of cavitation bubble influence onvapor embryo. 展开更多
关键词 acoustic cavitation boiling heat transfer HYSTERESIS
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The Mechanism of Interfacial Mass Transfer in Gas Absorption Process 被引量:2
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作者 马友光 冯惠生 +1 位作者 徐世昌 余国琮 《Chinese Journal of Chemical Engineering》 SCIE EI CAS CSCD 2003年第2期227-230,共4页
Based on the method of molecular thermodynamics, the mass transfer mechanism at gas-liquid interface is studied theoretically, and a new mathematical model is proposed. Using laser holographic interference technique, ... Based on the method of molecular thermodynamics, the mass transfer mechanism at gas-liquid interface is studied theoretically, and a new mathematical model is proposed. Using laser holographic interference technique, the hydrodynamics and mass transfer characteristics of CO2 absorption are measured. It is shown that the calculated results are in good agreement with the experimental data. 展开更多
关键词 laser holographic interference mass transfer gas-liquid interface ABSORPTION
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OpenMP-Based PCG Solver for Three-Dimensional Heat Equation
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作者 Dandan Li Qun Wang 《Computer Technology and Application》 2011年第12期963-968,共6页
As one of the most important mathematics-physics equations, heat equation has been widely used in engineering area and computing science research. Large-scale heat problems are difficult to solve due to computational ... As one of the most important mathematics-physics equations, heat equation has been widely used in engineering area and computing science research. Large-scale heat problems are difficult to solve due to computational intractability. The parallelization of heat equation is available to improve the simulation model efficiency. In order to solve the three-dimensional heat problems more rapidly, the OpenMP was adopted to parallelize the preconditioned conjugate gradient (PCG) algorithm in this paper. A numerical experiment on the three-dimensional heat equation model was carried out on a computer with four cores. Based on the test results, it is found that the execution time of the original serial PCG program is about 1.71 to 2.81 times of the parallel PCG program executed with different number of threads. The experiment results also demonstrate the available performance of the parallel PCG algorithm based on OpenMP in terms of solution quality and computational performance. 展开更多
关键词 Three-dimensional heat equation preconditioned conjugate gradient compiler directives OpenMP.
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High mixing effectiveness lobed nozzles and mixing mechanisms 被引量:3
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作者 SHENG ZhiQiang CHEN ShiChun +1 位作者 WU Zhe HUANG PeiLin 《Science China(Technological Sciences)》 SCIE EI CAS CSCD 2015年第7期1218-1233,共16页
For a circular lobed nozzle with the exit plane displaced from the center body,adding a central plug at exit or replacing the nozzle with an alternating-lobe nozzle can improve the mixing effectiveness.In this study,n... For a circular lobed nozzle with the exit plane displaced from the center body,adding a central plug at exit or replacing the nozzle with an alternating-lobe nozzle can improve the mixing effectiveness.In this study,numerical investigations of jet mixing in the lobed nozzles with a central plug and alternating-lobe nozzles in pumping operation were conducted.The effects of the central plugs with the wake ranging from attached to separated flow on the mixing were analyzed,along with the mechanism of improving the mixing performance in a"sword"alternating-lobe nozzle.The simulation results reveal that the large-scale mixing rate,which is dominated by streamwise vortices,is related to the intensity of the attainable heat and mass transfer in the streamwise vortices.The effects of the streamwise vortices on the normal vortex ring are virtually a manifestation of the heat and mass transfer/mixing process of the streamwise vortices.The simulation results also show that the central plug with the attached rear-flow performs better in improving the mixing effectiveness and pumping performance;on the contrary,if the rear-flow is separated,more pressure loss will be induced.In particular,a completely separated flow over the rear of the central plug will severely degrade the attainable heat and mass transfer in the streamwise vortices.For the sword alternating-lobe nozzle,wider sword deep troughs help to increase the flux of the secondary stream around the core region and delay the confluence of the primary stream in the region between the deep and shallow troughs.Thus,the mixing is improved in the middle and posterior segments.Compared to the lobed nozzle with a central plug,the improved sword alternating-lobe nozzle can achieve a higher mixing effectiveness with much less pressure loss,which is preferred in situations when the power loss of the engine is restricted. 展开更多
关键词 jet mixing lobed nozzle mixing effectiveness streamwise vortices heat and mass transfer
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Blowup mechanism for viscous compressible heat-conductive magnetohydrodynamic flows in three dimensions 被引量:3
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作者 WANG YongFu DU LiLi LI Shan 《Science China Mathematics》 SCIE CSCD 2015年第8期1677-1696,共20页
We investigate initial-boundary-value problem for three-dimensional magnetohydrodynamic (MHD) system of compressible viscous heat-conductive flows and the three-dimensional full compressible Navier-Stokes equations.... We investigate initial-boundary-value problem for three-dimensional magnetohydrodynamic (MHD) system of compressible viscous heat-conductive flows and the three-dimensional full compressible Navier-Stokes equations. We establish a blowup criterion only in terms of the derivative of velocity field, similar to the Beale^Kato-Majda type criterion for compressible viscous barotropic flows by Huang et al. (2011). The results indicate that the nature of the blowup for compressible MHD models of viscous media is similar to the barotropic compressible Navier-Stokes equations and does not depend on further sophistication of the MHD model, in particular, it is independent of the temperature and magnetic field. It also reveals that the deformation tensor of the velocity field plays a more dominant role than the electromagnetic field and the temperature in regularity theory. Especially, the similar results also hold for compressible viscous heat-conductive Navier-Stokes flows, which extend the results established by Fan et al. (2010), and I-Iuang and Li (2009). In addition, the viscous coefficients are only restricted by the physical conditions in this paper. 展开更多
关键词 blow up compressible magnetohydrodynamic flows compressible Navier-Stokes equations strong solutions
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Condensation heat transfer enhancement mechanism for vertical upflows by the phase separation concept at small gravity 被引量:3
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作者 Qicheng Chen Dongliang Sun 《Science Bulletin》 SCIE EI CAS CSCD 2015年第20期1759-1767,共9页
In the field of aerospace, minimum and seal of equipments cause the increase in the thermal loading sharply. Due to the lack of driving force, the performance of conventional condenser deteriorates greatly under the s... In the field of aerospace, minimum and seal of equipments cause the increase in the thermal loading sharply. Due to the lack of driving force, the performance of conventional condenser deteriorates greatly under the small gravity environment, which leads to reduction in the service life of equipments. In this study, a passive condenser, developed on basis of the phase separation concept,is utilized to improve the performance of the condensation heat transfer under the small gravity environment. As a result of the limitation of experiments, the mechanisms of heat transfer enhancement of the phase separation condenser tube are revealed through numerical simulation based on the volume-of-fluid(VOF) method. The following conclusions could be obtained:(1) A novel phase distribution of ‘‘gas near the tube wall and liquid in the tube core'' is formed. The thin liquid film is indeed created after the flow pattern modulation by inserting mesh cylinder.(2)The condensation quantity for single bubble in the annular region increases about 16 times greater than that in the bare tube region in the case of Jl= 0.0574 m/s and Jg= 0.0229 m/s.(3) Gas volume fraction affects the parameters of liquid film thickness, bubble length and liquid bridge length. The increase in the gas volume fraction results in the decrease in the evaluation index from21.56 to 12.82. The evaluation index is defined as the ratio of the condensation quantities per unit tube length of the annular region and the bare tube region. 展开更多
关键词 Condensation heat transfer PHASESEPARATION Small gravity Liquid film thickness
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