基于湍流分布特征系数的消声器压力损失模型
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摘要
进行了消声单元压力损失流场数值计算,通过试验验证了计算方法的准确性.对比了不同边界条件下的湍动能分布特征,提出了湍流分布特征系数,建立了关于湍动能、密度和湍流分布特征系数的消声器压力损失模型,通过不同类型消声单元和不同气流进口速度验证了模型,以穿孔管消声单元为例建立了压力损失模型,并讨论了主要结构参数对压力损失的影响.结果表明:对不同结构参数消声单元压力损失模型计算的相对误差不超过8%,,不同气流速度下模型计算相对误差不超过7%,;穿孔管消声单元压力损失随穿孔率、穿孔部分长度的增大而减低,随腔体直径的增大而增加,穿孔直径则对压力损失几乎没影响.
Fluid numerical simulation of pressure loss on a muffler unit was performed and the accuracy of the model was verified by experiment.A turbulence distribution characteristic ratio was proposed after comparing the turbulent kinetic energy distribution under different boundary conditions.The simulation model of pressure loss of the muffler was then built,in which the turbulent kinetic energy,the flow density and the turbulence distribution characteristic ratio were considered.This model was confirmed by different muffler simulations and was applied here to analyze the influences of the main structure parameters of a perforated muffler on the pressure loss.The results show that the relative error of the pressure loss calculated under different structure parameters is no more than 8%,and the error is no more than 7% under different inlet velocities.The pressure loss of the perforated muffler unit decreases with the increase of the perforated rate and the perforated length,but it rises with the increase of the expansion length. Moreover,the perforated diameter has little effect on the pressure loss.
Fluid numerical simulation of pressure loss on a muffler unit was performed and the accuracy of the model was verified by experiment.A turbulence distribution characteristic ratio was proposed after comparing the turbulent kinetic energy distribution under different boundary conditions.The simulation model of pressure loss of the muffler was then built,in which the turbulent kinetic energy,the flow density and the turbulence distribution characteristic ratio were considered.This model was confirmed by different muffler simulations and was applied here to analyze the influences of the main structure parameters of a perforated muffler on the pressure loss.The results show that the relative error of the pressure loss calculated under different structure parameters is no more than 8%,and the error is no more than 7% under different inlet velocities.The pressure loss of the perforated muffler unit decreases with the increase of the perforated rate and the perforated length,but it rises with the increase of the expansion length. Moreover,the perforated diameter has little effect on the pressure loss.
引文
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[2]沙毅,宋德玉,段福斌,等.轴流泵变转速性能试验及内部流场数值计算[J].机械工程学报,2012,48(6):187-192.
[3]王喆,袁庆晴,马洪新,等.射流式挖沟机沟内流场数值计算与分析[J].哈尔滨工程大学学报,2015,36(3):292-296.
[4]王平,李昌平,陈泊松.基于CFD数值模拟的拉瓦尔喷管流场分析[J].航空计算技术,2012,42(4):60-62.
[5]刘胜吉,曾瑾瑾,韩维维,等.基于CFD及稳流式试验的柴油机进/排气系统的性能[J].内燃机学报,2016,34(1):68-73.
[6]谷芳,刘伯潭,李洪亮,等.基于CFD数值模拟的汽车排气系统结构分析[J].内燃机学报,2007,25(4):358-363.
[7]赵海军,邓兆祥.消声单元产生气流再生噪声的流场分布特征[J].内燃机学报,2011,29(4):378-383.
[8]王东,杨松枝.基于CFD仿真技术对某敞篷车外流场的优化[J].北京理工大学学报,2016,36(1):126-130.
[9]邓兆祥,向飞,李沛然,等.扩张比对扩张式消声器压力损失影响的分析[J].汽车工程,2011,33(3):231-235.
[10]Ozalp C,Pinarbasi A,Fakilar M S,et al.PIV measurements of flow through a sudden contraction[J].Flow Measurement and Instrumentation,2007,18(1):121-128.
[11]李秋实,徐飞,李志平.一种包含运动边界的高精度流场数值计算方法[J].航空学报,2014,35(7):1815-1824.
[12]Mak H,Balabani S.Near field characteristics of swirling flow past a sudden expansion[J].Chemical Engineering Science,2007,62(1):6726-6746.