The model of tip clearance leakage flow blockage in micro-scale centrifugal impellers was studied through theoretical analysis in combination with numerical simulations. Based on both low Reynolds number and high Mach number working condition of micro-scale rotating machinery

a model of tip clearance leakage flow blockage was established considering the compressibility and viscous loss. The features of micro-scale tip clearance leakage flow were analyzed and the viscous effect was explained with the help of numerical simulations. It is concluded that viscous effect is important in driving the tip clearance leakage flow

in agreement with differential pressure meanwhile resulting the increase of initial blockage of tip clearance flow. The verification of tip clearance leakage flow blockage model was carried out on a micro-scale centrifugal impeller. Tip clearance leakage flow blockage result extracted from numerical result was compared with model prediction results

and the result of improved tip clearance leakage flow blockage model shows more accurate evaluation and more suitable in micro-scale condition.