涡轮增压器蜗壳形状对其喷嘴出口速度场的影响

用心形线表征了一种涡轮增压器无叶蜗壳梨形流道横截面轮廓，用有限差分法计算了涡轮增压器蜗壳流场，分析了无叶喷嘴出口气流速度和气流角的分布，经与测量结果比较，两者吻合较好。在此基础上，研究了三种不同蜗壳型线对喷嘴出口速度场的影响。结果表明，C型线蜗壳喷嘴出口的总速度v和气流角α分布均匀，A，B型线蜗壳喷嘴出口的总速度v和气流角α分布不均匀。

Influence of Turbocharger Scroll Case Geometry on Nozzle Outlet Velocity Field

The pear-shaped flow section contour of scroll of turbocharger is featured by heart-shaped line.Three-dimensional compressible turbulent flow in the scroll is simulated by using FDM,and the distributions of velocity and flow angle at nozzle outlet are analyzed.The computed results are consistent with those measured with IFA300 anemometer.The influences of scroll contours and nozzle width B on the flow field at nozzle outlet are investigated.It shows that the scroll with C contour has even velocity and flow angle distributions at nozzle outlet,but the scrolls with A and B contours have contrary results.With the B axial increase the a decreases gradually and its distribution tends even,but the velocity increases constantly and its distribution becomes worse.The flow field of nozzle outlet varies a little as the B decreases to some extent.As the B decreases linearly along the scroll circumference,the distribution of a is improved,but the velocity is improved a little.