Influence of Leakage Flow through the Labyrinth Seal Gap on the Hydraulic Performance of a High-Head Two-Stage Centrifugal Pump

Two-stage centrifugal pumps are designed for high-head applications, which require higher pressure generation by the pump. The labyrinth seal is the primary mechanism for controlling the contact between rotating parts and stationary parts in a pump. A small, non-contacting radial clearance gap is maintained to allow for the rotary motion. Hence, leakage flow occurs through the labyrinth seal clearance gap, returning to a low-pressure region in the system. Numerical analysis is performed to evaluate the performance and internal flow variation of the labyrinth seal gap under varying flow conditions. The analysis shows efficiency reduction with an increase in the labyrinth seal gaps of 0.5 mm, 1 mm, and 2 mm.