蜂窝状空气滤清器的流场分析及结构优化
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摘要
基于多孔介质理论,采用标准k-?湍流模型对不同结构的宏观蜂窝状空气滤清器的内部流场和阻力特性进行数值模拟,从而进行结构优化,提高其性能。采用的模型为相同滤芯(褶高h=5mm),壳体进出口形状分别为圆形与圆形(方案1)、圆形与椭圆形(方案2)、椭圆形与圆形(方案3)和椭圆形与椭圆形(方案4)的组合;优化得到的壳体结构与褶高分别为5, 10, 15 mm的蜂窝状滤芯组合,研究其过滤性能。结果表明,方案2的流场分布更均匀;压降随流量变大近似呈线性增长,当流量小于额定流量的60%时,4种方案的压降大致相等,大于额定流量的60%时,方案2的压降比方案1, 3和4小,方案2的壳体结构较合理。方案2滤芯褶高对空气滤清器流场分布有一定影响,且在研究的褶高范围内压降先降低后增加,存在最佳褶高使空气滤清器的压降最小。
Air filter as the heart of the car filtering the dirty air entering the engine which plays a key role in protecting the engine. In this work, because the performance of the air filter has a direct impact on the engine's power performance and economy, a standard k-? turbulence model was used to simulate the internal flow field and resistance characteristics of macrohoneycomb air filters with different structures based on the theory of porousmedia, thus to optimized the structure and improved its performance. The model adopted the same filter element(pleat height h=5 mm), while the series of combinations of the inlet and outlet shapes of the housing were round and round(scheme 1), round and ellipse(scheme 2), ellipse and round(scheme 3), ellipse and ellipse(scheme 4), respectively. Then the optimized housing was combined with honeycomb filter element with pleat heights of 5, 10 and 15 mm. The results showed that the flow field distribution of scheme 2 was more uniform than that of schemes 1, 3 and 4, and the pressure drop increased approximately linearly with the increase of flow rate. When the flow rate was less than 60% of the rated flow, the values of pressure drop of these four schemes were approximately equal. However, the pressure drop of scheme 2 was smaller than that of schemes1, 3 and 4 when the flow rate was greater than 60% of the rated flow. Therefore, the housing of scheme 2 was more reasonable. For this structure, the difference in the pleat height of the filter element had a certain influence on the flow filed distribution of the air filter. Furthermore, the pressure drop decreased firstly and then increased in the range of pleat height studied. Therefore, there was an optimal pleat height to minimize the pressure drop of the honeycomb air filter, which provided theoretical guidance for the optimal design of air filter.
Air filter as the heart of the car filtering the dirty air entering the engine which plays a key role in protecting the engine. In this work, because the performance of the air filter has a direct impact on the engine's power performance and economy, a standard k-? turbulence model was used to simulate the internal flow field and resistance characteristics of macrohoneycomb air filters with different structures based on the theory of porousmedia, thus to optimized the structure and improved its performance. The model adopted the same filter element(pleat height h=5 mm), while the series of combinations of the inlet and outlet shapes of the housing were round and round(scheme 1), round and ellipse(scheme 2), ellipse and round(scheme 3), ellipse and ellipse(scheme 4), respectively. Then the optimized housing was combined with honeycomb filter element with pleat heights of 5, 10 and 15 mm. The results showed that the flow field distribution of scheme 2 was more uniform than that of schemes 1, 3 and 4, and the pressure drop increased approximately linearly with the increase of flow rate. When the flow rate was less than 60% of the rated flow, the values of pressure drop of these four schemes were approximately equal. However, the pressure drop of scheme 2 was smaller than that of schemes1, 3 and 4 when the flow rate was greater than 60% of the rated flow. Therefore, the housing of scheme 2 was more reasonable. For this structure, the difference in the pleat height of the filter element had a certain influence on the flow filed distribution of the air filter. Furthermore, the pressure drop decreased firstly and then increased in the range of pleat height studied. Therefore, there was an optimal pleat height to minimize the pressure drop of the honeycomb air filter, which provided theoretical guidance for the optimal design of air filter.
引文
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[11]唐刚志,张力,邓涛,等.发动机用平板型空滤器流动阻力特性分析和改进[J].重庆大学学报,2015,38(4):18-23.Tang G Z,Zhang L,Deng T,et al.Analysis and improvement on flow resistance characteristics of planar air filter for engines[J].Journal of Chongqing University,2015,38(4):18-23.
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[14]Théron F,Joubert A,Coq L L.Numerical and experimental investigations of the influence of the pleat geometry on the pressure drop and velocity field of a pleated fibrous filter[J].Separation and Purification Technology,2017,182(56):69-77.
[15]王伟,王仁人,张良.基于CFD的内燃机空气滤清器内气固两相流数值模拟[J].德州学院学报,2010,26(2):77-81.Wang W,Wang R R,Zhang L.Numerical simulation of gas-solid two-phase flow in air filter of internal combustion engine based on CFD[J].Journal of Dezhou University,2010,26(2):77-81.
[16]Wu H W,Brunberg J,Altimira M,et al.Semi-empirical CFDtransient simulation of engine air filtration systems[J].SAEInternational Journal of Passenger Cars Mechanical Systems,2016,9(1):310-320.
[17]Tronville P,Sala R.Minimization of resistance in pleated-media air filter designs empirical and CFD approaches[J].HVAC&RResearch,2003,9(1):95-106.
[18]王世峰.褶状式柴油滤清器滤芯的流阻研究分析[D].杭州:杭州电子科技大学,2016:4-6.Wang S F.Research and analysis of pleated diesel element[D].Hangzhou:Hangzhou Dianzi University,2016:4-6.
[19]袁惠新,刘明爽,吕浪,等.褶型筒式空气过滤器过滤压降的数值模拟[J].环境工程学报,2017,11(5):2946-2950.Yuan H X,Liu M S,LüL,et al.Numerical simulation of pressure drop of pleated air filter[J].Chinese Journal of Environmental Engineering,2017,11(5):2946-2950.
[2]韩青.空气滤清器内三维紊流数值计算与分析[D].济南:山东轻工业学院,2008:46-48.Han Q.Numerical simulation and analysis of three-dimensional turbulence in air filter[D].Jinan:Shandong Institute of Light Industry,2008:46-48.
[3]董贵杨,谭花,杨自双,等.CFD技术在汽车工程领域中的应用研究[J].机械工程与自动化,2013,(1):219-221.Dong G Y,Tan H,Yang Z S,et al.Application research of CFD in field of automobile engineering[J].Mechanical Engineering&Automation,2013,(1):219-221.
[4]Nagarajan G,Kumar S,Chowdhury D.CFD analysis of air filters for an off-highway vehicle[J].SAE Technical Paper,2007,26(13):48-50.
[5]李佳,刘震涛,刘忠民.空气滤清器流动过程仿真与试验分析[J].浙江大学学报(工学版),2012,5(2):327-332.Li J,Liu Z T,Liu Z M.Simulation and test of flow process in air filter[J].Journal of Zhejiang University(Engineering Science),2012,5(2):327-332.
[6]Saleh A M,Fotovati S,Tafreshi H V,et al.Modeling service life of pleated filters exposed to poly-dispersed aerosols[J].Powder Technology,2014,266(35):79-89.
[7]Hosseini S A,Tafreshi H V.Modeling particle-loaded single fiber efficiency and fiber drag using ANSYS-Fluent CFD code[J].Computer and Fluids,2012,74(21):157-166.
[8]Fotovati S,Pourdeyhimi B.A macroscale model for simulating pressure drop and collection efficiency of pleated filters over time[J].Separation and Purification Technology,2012,98(39):344-355.
[9]Saleh A M,Hosseini S A,Tafreshi H V,et al.3-D microscale simulation of dust-loading in thin flat-sheet filters:a comparison with 1-D macroscale simulations[J].Chemical Engineering Science,2013,99(27):284-291.
[10]付海明,朱静.圆筒状褶式机油滤清器的模拟与优化设计[J].交通运输工程学报,2009,9(3):60-65.Fu H M,Zhu J.Simulation and optimization design on cylindrical pleated lube oil filter[J].Journal of Traffic and Transportation Engineering,2009,9(3):60-65.
[11]唐刚志,张力,邓涛,等.发动机用平板型空滤器流动阻力特性分析和改进[J].重庆大学学报,2015,38(4):18-23.Tang G Z,Zhang L,Deng T,et al.Analysis and improvement on flow resistance characteristics of planar air filter for engines[J].Journal of Chongqing University,2015,38(4):18-23.
[12]何志霞,蒋兆晨,王硕,等.空气滤清器的空气动力学仿真及优化[J].中南大学学报(自然科学版),2012,43(3):1179-1184.He Z X,Jiang Z C,Wang S,et al.Aerodynamic simulation and structural optimization of air filter[J].Journal of Central South University(Science and Technology),2012,43(3):1179-1184.
[13]赵树恩,蒋艾伶.某发动机空滤器的CFD优化设计[J].机械设计与制造,2015,13(8):163-166.Zhao S E,Jiang A L.Optimization of an engine air filter by CFD[J].Machinery Design&Manufacture,2015,13(8):163-166.
[14]Théron F,Joubert A,Coq L L.Numerical and experimental investigations of the influence of the pleat geometry on the pressure drop and velocity field of a pleated fibrous filter[J].Separation and Purification Technology,2017,182(56):69-77.
[15]王伟,王仁人,张良.基于CFD的内燃机空气滤清器内气固两相流数值模拟[J].德州学院学报,2010,26(2):77-81.Wang W,Wang R R,Zhang L.Numerical simulation of gas-solid two-phase flow in air filter of internal combustion engine based on CFD[J].Journal of Dezhou University,2010,26(2):77-81.
[16]Wu H W,Brunberg J,Altimira M,et al.Semi-empirical CFDtransient simulation of engine air filtration systems[J].SAEInternational Journal of Passenger Cars Mechanical Systems,2016,9(1):310-320.
[17]Tronville P,Sala R.Minimization of resistance in pleated-media air filter designs empirical and CFD approaches[J].HVAC&RResearch,2003,9(1):95-106.
[18]王世峰.褶状式柴油滤清器滤芯的流阻研究分析[D].杭州:杭州电子科技大学,2016:4-6.Wang S F.Research and analysis of pleated diesel element[D].Hangzhou:Hangzhou Dianzi University,2016:4-6.
[19]袁惠新,刘明爽,吕浪,等.褶型筒式空气过滤器过滤压降的数值模拟[J].环境工程学报,2017,11(5):2946-2950.Yuan H X,Liu M S,LüL,et al.Numerical simulation of pressure drop of pleated air filter[J].Chinese Journal of Environmental Engineering,2017,11(5):2946-2950.