离心压气机进气流场研究及控制

对某车用增压离心压气机进行了三维数值模拟,研究了离心压气机设计点和不同转速下近喘振点进气流场,基于此提出了离心压气机进气轮盖导叶流场控制措施并进行了验证实验.研究表明:离心压气机近喘振点压力面与吸力面压力差异影响到进气流场,导致进气口轮盖附近出现与叶轮转向相反的切向速度;且从低转速到高转速,该与叶轮转向相反的切向速度逐渐增大;离心压气机设计点进气在叶片压力面和吸力面前分别形成与叶轮转向相反和相同的切向速度区域,该区域不限于轮盖附近.轮盖导叶的流动控制方法可以有效抑制近喘振点切向反速度,实验结果表明,轮盖导叶使得离心压气机整体性能得到了提高,在90 000r/min近喘振点压比提高了3.4%,效率提高了3.0%.

Investigation and control of centrifugal compressor inlet flow field

Three-dimensional numerical simulation was conducted on a turbocharger centrifugal compressor to study the inlet flow field of the design point and the points near surge at different rotating speeds; inlet guide vanes on the shroud of centrifugal compressor were presented as a flow control method based on the inlet flow field study and verified by experiment. Investigation shows that the pressure difference of the pressure side and suction side of the blade near surge leads to tangential velocity near shroud in the inlet flow field opposite to the impeller rotating direction, and the tangential velocity increases with the growing impeller speed; at the design point, there are two opposite tangential velocity areas before each blade pressure side and suction side and the area of tangential velocity opposite to the impeller rotating direction is not limited to the area near shroud. Inlet guide vanes on the shroud can decrease the tangential velocity opposite to the impeller rotating direction near surge effectively, and experimental result shows that the centrifugal compressor pressure ratio is improved by 3.4% and the efficiency by 3.0% at 90000r/min near surge. The overall performance is improved.