一种离心压气机子午流道的优化成形方法

A METHOD FOR OPTIMIZING THE MERIDIONAL PASSAGE IN A CENTRIFUGAL COMPRESSOR

利用S_2反问题的数值计算,发展了一种通过合理调整压力分布来确定优化子午流道形式的实用方法。优化的两个原则是尽量减少附面层分离和减小作为引起二次流主要原因之一的子午流道内的法向压差。设计了两种自动生成优化流道的方案,并将相应的程序用于实际离心压气机的优化设计,比较了子午流遭轮毂轮整处的压力分布,表明所用的方法达到了予期的效果。

A method for optimizing the meridional passage of the rotor in a centrifugal compressor has been developed according to the theory of S1 and S2 stream filaments. Two optimization principles are introduced. First, the gradient of static pressure in stream line directon should be minimized as it is mainly responsible for the boundary layer separation at the hub and shroud. Second, the gradient of static pressure from hub to shroud should be lessened as possible for it is generally considered as the major reason for triggering the second flow in the passage. According to these two principles, a reasonable criterion has been set up. In order to optimize meridional passage automatically through computer programming, two practical approaches have been provided . In one approach, the passage is modified again and again by using formulas derived from the continuity equation and thermodynamic relations. In the other, a series of quadratic curves are introduced to form a series of meridional passages. In both these approaches, it is neccessary to predict the flow field by using 'S2 inverse problem' computer code many times. Then, according to the above-mentioned criterion, the optimized meridional passage can be distinguished. Two numerical examples are given in this paper. Their results are obtained from the two approaches respectively. The comparison of the static pressure distributions at hub and shroud between the original and optimized passages indicates that this method obtains access to the expected results.