Guide vane and guide vane wheel for multi-stage centrifugal pump, centrifugal pump and design method of guide vane and guide vane wheel

The invention discloses a guide vane for a multi-stage centrifugal pump, a guide vane wheel, a centrifugal pump and a design method of the centrifugal pump. The guide vane comprises a cover plate, and a through hole is formed in the cover plate; the first blades are arranged on the cover plate and arranged around the through hole, a first flow channel is formed between every two adjacent first blades, the end, facing the through hole, of each first flow channel is a first inlet, and the end, back to the through hole, of each first flow channel is a first outlet; the second blades are arranged on the first blades, the number of the second blades corresponds to that of the first blades, second flow channels are formed between the adjacent second blades, the ends, facing the through holes, of the second flow channels are second outlets, the ends, back to the through holes, of the second flow channels are second inlets, and the second inlets correspond to the first outlets; at least two third blades are arranged