排气管中二维非定常流动的试验研究

以MPC二维排气管模型为对象，对其二维非定常流动进行了研究。在柴油机倒拖时，测量了该模型排气管内6个截面的压力和速度分布的变化，研究了热线探头标定前的预处理、实测状态与标定状态差异引起的误差修正和流动方向判别对速度测量的影响。测量结果显示，同一截面不同测点的压力变化曲线非常接近；支管的速度分布曲线是不对称的，其峰值偏向支管的内壁面，进入总管后速度曲线呈偏向总管外壁面的不对称分布，随后渐渐变为对称分布。测量结果还可用于排气管二维非定常流动计算的边界条件和考核数据。

Experimental Investigation on Two-Dimensional Unsteady Gas Flow in an Exhaust Manifold

The gas flow in exhaust manifolds has much effect on scavenge,pumping loss and exhaust energy utilization of turbocharged diesel engines.This paper presents experimental investigation on two-dimensional usteady flow in MPC exhaust manifold model.The pressure and velocity distributions in six sections of the manifold model were measured when the diesel engine was motored.Effect of probe contamination,circumstance difference between measurement and calibration and flow direction differentiation on velocity measurement by HWA were studied.The experimental results show that velocity distributions vary with place and time,and the pressure traces at different points of the same section were not different obviously.