计及前缘形状变化的离心式压气机流场分析

Flow-Field Analysis of Centrifugal Compressor Considering Leading Edge Shape Change

通过两种转速(120 000r/min和140 000r/min)下压气机性能试验与仿真结果对比分析得知其总体误差范围在5%左右,验证了ANSYS CFX软件在压气机性能模拟计算的可靠性;采用数值计算方法分别对具有圆形和椭圆形前缘的压气机叶轮与涡壳的组合性能进行计算,得到了相关转速下压气机特性曲线,分析了四种不同长短径之比(a/b=1、3、5、8)前缘的叶轮流道内的气体流动特性。研究结果表明:压气机特性随着前缘长短径比值的增大呈先增后减的趋势,最高压比LE5比LE1提高了5%,最大效率LE3比LE1提高了6.7%,且流量范围也有所增加;在一定范围内增大前缘长短径比可以抑制前缘分离流动,改善叶轮出口处流场。

Comparison of the compressor performance experiment result with simulation data under 2 speeds （120 000 and 140000 r/min ） exhibited that the error was about 5 %, thus the reliability of the software ANSYS CFX used was verified. Mated behaviors of impeller and volute of different leading edge shape were separately computed by numerical calculation, efficiency and pressure ratio curves under relevant speeds were obtained,air flow characteristics of 4 different ratios of major and minor axis （a/b= 1,3,5,8） of LE inside impeller tunnel was analyzed. Results show that as LE ratio increases, pressure ratio and efficiency exhibit increase-decrease shape trend, the highest pressure ratio of LE5 is 5 % higher than LE1, LE3 efficiency was 6. 7 % higher than LEl,and mass flow range also extends. Increasing LE ratio within certain range can inhibit flow separation of LE and improve flow field of impeller outlet.