进气压力对真空发生器性能的影响
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摘要
为研究进气压力对真空发生器性能的影响,利用Fluent软件对真空发生器内部流场进行数值模拟。仿真范围内,通过对真空口处压强、引射效率、气体沿轴线的速度与压强,以及发生器失效的讨论分析,得到如下结论:真空口封闭的瞬态条件下,对真空口处压强而言,进气压力存在临界值与最优值,超过临界值后真空口处压强出现周期性震荡,达到最优值时,能以最优进气压力达到高于该压力所能维持的真空度;基于等压混合假设的稳态条件下,对引射流量、引射效率而言,分别存在相应的进气压力最优值,并于对应最优值时达到最大的引射流量与引射效率。
The flow field in the lab-built device,called vacuum "generator" and designed by modifying an ejector,was mathematically modeled and numerically simulated with Fluent software.The influence of the inlet-pressure on the entrainment rate,axial distributions of pressure/velocity,and the lowest pressure obtained was investigated.The simulated results show that the inlet-pressure has a major impact.For example,under the port-closed transient condition,there is a critical inlet-pressure;at the vacuum port,an optimized inlet pressure results in the lowest pressure,whereas an inlet-pressure higher than the critical one causes a periodic pressure fluctuation.Moreover,in steady-state isobaric mixing hypothesis,an optimized inlet pressure maximizes the entrainment flow and entrainment rate.We suggest that the simulated results be of some technological interest in design and application of the vacuum "generator."
The flow field in the lab-built device,called vacuum "generator" and designed by modifying an ejector,was mathematically modeled and numerically simulated with Fluent software.The influence of the inlet-pressure on the entrainment rate,axial distributions of pressure/velocity,and the lowest pressure obtained was investigated.The simulated results show that the inlet-pressure has a major impact.For example,under the port-closed transient condition,there is a critical inlet-pressure;at the vacuum port,an optimized inlet pressure results in the lowest pressure,whereas an inlet-pressure higher than the critical one causes a periodic pressure fluctuation.Moreover,in steady-state isobaric mixing hypothesis,an optimized inlet pressure maximizes the entrainment flow and entrainment rate.We suggest that the simulated results be of some technological interest in design and application of the vacuum "generator."
引文
[1] Yen R H,Huang B J,Chen C Y,et al.Performance Optimization for a Variable Throat Ejector in a Solar Refrigeration System[J].International Journal of Refrigeration,2013,36(5):1512-1520
[2] Bartosiewicz Y,Aidoun Z,Mercadier Y.Numerical Assessment of Ejector Operation for Refrigeration Applications Based on CFD[J].Applied Thermal Engineering,2006,26(5-6):604-612
[3] Besagni G,Mereu R,Chiesa P,et al.An Integrated Lumped Parameter-CFD Approach for Off-design Ejector Performance Evaluation[J].Energy Conversion and Management,2015,105:697-715
[4] Desevaux P,Marynowski T,Khan M.CFD Prediction of Supersonic Ejectors Performance[J].International Journal of Turbo & Jet Engines,2006,23(3):173-182
[5] Hemidi A,Henry F,Leclaire S,et al.CFD Analysis of a Supersonic Air Ejector.Part I:Experimental Validation of Single-Phase and Two-Phase Operation[J].Applied Thermal Engineering,2009,29(8):1523-1531
[6] Arun K M,Tiwari S,Mani A.Three-Dimensional Numerical Investigations on Rectangular Cross-section Ejector[J].International Journal of Thermal Sciences,2017,122:257-265
[7] Huang B J,Chang J M,Wang C P,et al.A 1-D Analysis of Ejector Performance[J].International Journal of Refrigeration,1999,22(5):354-364
[8] Chang Y J,Chen Y M.Enhancement of a Steam-Jet Refrigerator Using a Novel Application of the Petal Nozzle[J].Experimental Thermal & Fluid Science,2000,22(3):203-211
[9] Hong W J,Alhussan K,Zhang H,et al.A Novel Thermally Driven Rotor-Vane/Pressure-Exchange Ejector Refrigeration System with Environmental Benefits and Energy Efficiency[J].Energy,2004,29(12-15):2331-2345
[10] Aphornratana S,Pianthong K,Seehanam W,et al.Investigation and Improvement of Ejector Refrigeration System Using Computational Fluid Dynamics Technique[J].Energy Conversion & Management,2007,48(9):2556-2564
[11] Zhu Y,Cai W,Wen C,et al.Numerical Investigation of Geometry Parameters for Design of High Performance Ejectors[J].Applied Thermal Engineering,2009,29(5):898-905
[12] RUSLY,AYE,Lu,et al.CFD Analysis of Ejector in a Combined Ejector Cooling System[J].International Journal of Refrigeration,2005,28(7):1092-1101
[13] Eames I W,Ablwaifa A E,Petrenko V.Results of an Experimental Study of an Advanced Jet-Pump Refrigerator Operating with R245fa[J].Applied Thermal Engineering,2007,27(17-18):2833-2840
[14] Varga S,Oliveira A C,Diaconu B.Numerical Assessment of Steam Ejector Efficiencies Using CFD[J].International Journal of Refrigeration,2009,32(6):1203-1211
[2] Bartosiewicz Y,Aidoun Z,Mercadier Y.Numerical Assessment of Ejector Operation for Refrigeration Applications Based on CFD[J].Applied Thermal Engineering,2006,26(5-6):604-612
[3] Besagni G,Mereu R,Chiesa P,et al.An Integrated Lumped Parameter-CFD Approach for Off-design Ejector Performance Evaluation[J].Energy Conversion and Management,2015,105:697-715
[4] Desevaux P,Marynowski T,Khan M.CFD Prediction of Supersonic Ejectors Performance[J].International Journal of Turbo & Jet Engines,2006,23(3):173-182
[5] Hemidi A,Henry F,Leclaire S,et al.CFD Analysis of a Supersonic Air Ejector.Part I:Experimental Validation of Single-Phase and Two-Phase Operation[J].Applied Thermal Engineering,2009,29(8):1523-1531
[6] Arun K M,Tiwari S,Mani A.Three-Dimensional Numerical Investigations on Rectangular Cross-section Ejector[J].International Journal of Thermal Sciences,2017,122:257-265
[7] Huang B J,Chang J M,Wang C P,et al.A 1-D Analysis of Ejector Performance[J].International Journal of Refrigeration,1999,22(5):354-364
[8] Chang Y J,Chen Y M.Enhancement of a Steam-Jet Refrigerator Using a Novel Application of the Petal Nozzle[J].Experimental Thermal & Fluid Science,2000,22(3):203-211
[9] Hong W J,Alhussan K,Zhang H,et al.A Novel Thermally Driven Rotor-Vane/Pressure-Exchange Ejector Refrigeration System with Environmental Benefits and Energy Efficiency[J].Energy,2004,29(12-15):2331-2345
[10] Aphornratana S,Pianthong K,Seehanam W,et al.Investigation and Improvement of Ejector Refrigeration System Using Computational Fluid Dynamics Technique[J].Energy Conversion & Management,2007,48(9):2556-2564
[11] Zhu Y,Cai W,Wen C,et al.Numerical Investigation of Geometry Parameters for Design of High Performance Ejectors[J].Applied Thermal Engineering,2009,29(5):898-905
[12] RUSLY,AYE,Lu,et al.CFD Analysis of Ejector in a Combined Ejector Cooling System[J].International Journal of Refrigeration,2005,28(7):1092-1101
[13] Eames I W,Ablwaifa A E,Petrenko V.Results of an Experimental Study of an Advanced Jet-Pump Refrigerator Operating with R245fa[J].Applied Thermal Engineering,2007,27(17-18):2833-2840
[14] Varga S,Oliveira A C,Diaconu B.Numerical Assessment of Steam Ejector Efficiencies Using CFD[J].International Journal of Refrigeration,2009,32(6):1203-1211