可变截面涡轮增压器喷嘴叶片小开度流动特性
|
摘要
利用NUMECA三维仿真软件对某款可变截面增压器(variable geometry turbocharger,VGT)分别在50%开度和10%开度和140 000 r/min工况下,各选取5各工况点进行仿真计算,通过对导叶周围速度场、压力场等宏观现象的分析,探究其在小开度下涡端效率低的原因。结果表明:小开度下流体经过导叶时的加速程度较大,整体速度偏高;导叶沿叶高方向上,压力损失系数较大;这些变化主要是由于导叶出口气流角和叶端间隙泄漏流的综合影响造成的,并且在小开度下叶端间隙泄漏流对主流道的干涉程度较大,对流动损失的影响权重较大。
By using NUMECA three-dimensional simulation software in a certain type of variable geometry turbocharger( VGT) at in 50% and 10% opening cases respectively,and the working condition of 140 000 r/min,five operating point were selected to simulating calculated. Through the analysis of the guide vane such as the velocity field and pressure field,the reasons for the low efficiency under the small opening degree were explored.The results show that the acceleration of the fluid under the small opening is larger and the overall velocity is higher. The pressure loss coefficient is greater along the direction of the blade. It' s mainly due to the comprehensive influence of the outlet flow angle and the tip clearance leakage flow. And under the small opening degree the leakage flow of the tip clearance has great influence on the mainstream channel,and flow loss.
By using NUMECA three-dimensional simulation software in a certain type of variable geometry turbocharger( VGT) at in 50% and 10% opening cases respectively,and the working condition of 140 000 r/min,five operating point were selected to simulating calculated. Through the analysis of the guide vane such as the velocity field and pressure field,the reasons for the low efficiency under the small opening degree were explored.The results show that the acceleration of the fluid under the small opening is larger and the overall velocity is higher. The pressure loss coefficient is greater along the direction of the blade. It' s mainly due to the comprehensive influence of the outlet flow angle and the tip clearance leakage flow. And under the small opening degree the leakage flow of the tip clearance has great influence on the mainstream channel,and flow loss.
引文
[1]邢世凯.非均匀布置可调导叶向心涡轮性能研究[D].北京:北京理工大学,2015.
[2]HAYAMI H,SENOO Y,HYUN Y I.Effects of tip clearance of nozzle vanes on performance of radial turbine rotor[J].Transactions of the ASME,1990(112):58-63.
[3]田永祥,刘云岗,王志明,等.喷嘴叶片形状的改善对涡轮增压器效率的影响[J].汽车工程,2007,29(4):328-332.
[4]詹志胜.可变喷嘴涡轮增压器喷嘴环设计及非定常流场分析[D].北京:北京理工大学,2015.
[5]陈榴,戴韧,陈康民,等.带有可调导叶的径流涡轮气动特性的研究[J].燃气轮机技术,2011,24(1):35-39.
[6]于舰.变几何涡轮可转导叶损失控制研究[D].哈尔滨:哈尔滨工程大学,2012.
[7]刘莹,马国玲,葛炜等.向心涡轮喷嘴出口气流角的数值研究[J].车用发动机,2014,(4):7-11.
[2]HAYAMI H,SENOO Y,HYUN Y I.Effects of tip clearance of nozzle vanes on performance of radial turbine rotor[J].Transactions of the ASME,1990(112):58-63.
[3]田永祥,刘云岗,王志明,等.喷嘴叶片形状的改善对涡轮增压器效率的影响[J].汽车工程,2007,29(4):328-332.
[4]詹志胜.可变喷嘴涡轮增压器喷嘴环设计及非定常流场分析[D].北京:北京理工大学,2015.
[5]陈榴,戴韧,陈康民,等.带有可调导叶的径流涡轮气动特性的研究[J].燃气轮机技术,2011,24(1):35-39.
[6]于舰.变几何涡轮可转导叶损失控制研究[D].哈尔滨:哈尔滨工程大学,2012.
[7]刘莹,马国玲,葛炜等.向心涡轮喷嘴出口气流角的数值研究[J].车用发动机,2014,(4):7-11.