Tip clearance influence on the performance of high-speed micro-pumps

The fast-paced development of the aerospace and shipping industry is promoting the development of lightweight and high-speed transfer pumps. High-speed micro-pumps with semi-open impellers are highly sensitive to tip clearance (TC), which crucially influences the head and efficiency. This study proposes a new design for a high-speed micro-semi-open impeller centrifugal pump with a 19 000 rpm rotational speed and 30 m hydraulic head. The performance of the proposed centrifugal pump under different inlet corrosion allowances and different impeller TC ratios (0.05, 0.08, 0.11, and 0.14) is investigated through numerical simulations and experiments. The interaction process between the leakage and main flows in the tip gap is recorded with a high-speed camera and is numerically calculated. The stability of the internal flow field is optimal under smaller TCs. This study provides the optimal TC and guidance for designing high-speed micro-pumps.