Under the same impeller outlet speed, the flow speed of blade diffuser is faster than the vaneless one. The average flow field at impeller outlet trends to uniform.
在相同叶轮出口速度下，叶片扩压器比无叶扩压器中气流速度下降迅速，叶轮出口处平均流场趋于均匀。
2
Sharp blade key: hand must keep horizontal motion, force must be uniform and owner. on back must be straight or round straight, nearly edge department can not have a little hunchback.