发动机电控节气门瞬态流动过程三维数值模拟与研究
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摘要
以某型号发动机电控节气门为研究对象研究了其基本结构和工作原理。按照节气门实际结构,利用计算流体力学(CFD)的方法结合运动网格技术及用户自定义编程方法,实现了节气门由关闭向全开位置转动时空气瞬态流动过程的三维数值模拟。研究了节气门运动对空气流动过程的影响,重点分析了节气门处于不同转角时刻空气速度场、压力场及流动噪声的变化规律。计算结果表明:在节气门转动初期,节气门后侧流动区域有气旋形成,在节气门前后两侧的压力发生了陡降,在节气门上止点和下止点附近产生流动噪声区,节气门开度在40°附近时声功率峰值达到最大。随着节气门开度的逐渐增加,节气门后侧的气旋逐渐减弱,节气门前后两侧的压力陡降幅度也逐渐减小,流动噪声则是先增大后减小,噪声峰值始终存在于节气门后侧,出现流动噪声峰值的位置也逐渐远离节气门中心。当节气门接近全开时,空气速度场、压力场和流动噪声也逐渐接近稳定。
Bases on the basic structure and operating function of engine throttle,according to the actual structure of a throttle,a 3-dimensional simulation of air transient flow in the course of throttle being rotated from closed position to the full opening position was realized by using CFD together with the moving mesh technology and user defining program.The influence of the throttle movement on air flow process was studied.The velocity field,pressure field and flow noise field were analyzed at different rotational angles of the throttle.The numerical simulation results show that at the beginning period of throttle rotation,eddy appears in the flow field behind the throttle and air pressure drop between the front and back of throttle is sharp,the flow noise field appears near the top and bottom position of throttle and the maximum value of acoustic power appears when the throttle opening is near 40 degrees.With the increase of the throttle rotational angle,the eddy weakens gradually,the air pressure drop between the two sides of throttle becomes small,the flow noise firstly increases and then decreases,the maximum value of acoustic power appears behind the throttle all the time and its position is gradually away from the throttle axes.The velocity field,pressure field and flow noise become steady gradually when throttle opens completely.
Bases on the basic structure and operating function of engine throttle,according to the actual structure of a throttle,a 3-dimensional simulation of air transient flow in the course of throttle being rotated from closed position to the full opening position was realized by using CFD together with the moving mesh technology and user defining program.The influence of the throttle movement on air flow process was studied.The velocity field,pressure field and flow noise field were analyzed at different rotational angles of the throttle.The numerical simulation results show that at the beginning period of throttle rotation,eddy appears in the flow field behind the throttle and air pressure drop between the front and back of throttle is sharp,the flow noise field appears near the top and bottom position of throttle and the maximum value of acoustic power appears when the throttle opening is near 40 degrees.With the increase of the throttle rotational angle,the eddy weakens gradually,the air pressure drop between the two sides of throttle becomes small,the flow noise firstly increases and then decreases,the maximum value of acoustic power appears behind the throttle all the time and its position is gradually away from the throttle axes.The velocity field,pressure field and flow noise become steady gradually when throttle opens completely.
引文
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[5]张安伟,刘巨江,林思聪,等.基于节气门开度的进气模型研究[J].小型内燃机与摩托车,2012,41(5):41-44.ZHANG A W,LIU J J,LIN S C,et al.Research on engine charge model based on throttle plate position[J].Small Internal Combustion Engine and Motorcycle,2012,41(5):41-44.
[6]唐琦军,刘敬平,易鹏,等.增压汽油机泵气损失影响因素分解及共性规律研究[J].内燃机工程,2016,37(4):126-134.TANG Q J,LIU J P,YI P,et al.Research on the decomposition of influencing parameters and general trends of pumping losses in GTDI engines[J].Chinese Internal Combustion Engine Engineering,2016,37(4):126-134.
[7]祖炳锋,周仁杰,徐玉梁,等.米勒循环在小型增压汽油机典型工况的应用研究[J].内燃机工程,2017,38(6):125-130.ZU B F,ZHOU R J,XU Y L,et al.The application of Miller cycle on the typical working conditions of turbocharged downsizing gasoline engine[J].Chinese Internal Combustion Engine Engineering,2017,38(6):125-130.
[8]NAKASE Y,KANEHARA K,OHARA K,et al.Flow noise reduction upon quick opening the throttle[C/OL].SAE Paper,2001,2001-01-1429.[2001-04-30].http://papers.sae.org/2001-01-1429/.