根据优化前后叶轮上下端壁静压分布情况可知，轮盘和机匣的静压梯度均匀。主叶片吸力面前半部分压力梯度提高使得后半部分压力梯度降低，改善了吸力面出口压力梯度过高的现象。

According to the static pressure distribution of the upper and lower end walls of the impeller before and after optimization, the static pressure gradient of the wheel and the casing is uniform. The pressure gradient of the front part of the main blade suction decreases with the increase of the pressure gradient of the back part, and the pressure gradient of the outlet of the suction surface is too high.