For the streamline curvature inverse proposition design of a full three-dimensional centrifugal impeller
a new finite difference method is put forward to solve the S2m stream surface velocity gradient equation. In the difference scheme
forward difference is chosen for the relative velocity derivative along the quasi orthogonal curve; that along the streamline direction is decomposed into two items
forward difference is used for first item
backward difference for another
and forward difference for all other parameter derivatives. The scheme solves the difficulty to guarantee the matrix main diagonal elements being dominant in solving velocity field with simple forward difference or backward difference scheme
and has higher stability and convergence. The new finite difference scheme is taken to redesign Krain impeller. The CFD analysis shows that modified impeller efficiency is increased by 0.3%
CASEY M V, ROBINSON C. A new streamline curvature throughflow method for radial turbomachinery [J]. ASME Journal of Turbomachinery, 2010, 132(3): 031021.
王尚锦. 离心压缩机三元流动理论与应用 [M]. 西安: 西安交通大学出版社, 1991.
KRAIN H. Swirling impeller flow [J]. ASME Journal of Turbomachinery, 1988, 110(1): 122-128.
KRAIN H, HOFFMANN W. Verification of an impeller design by laser measurements and 3D-visous flow calculations, ASME 89-GT-159 [R]. New York, USA, ASME, 1989.