Influence of Axial Vane on Inner Flow and Performance of a Molten-Salt Pump

A vertically installed two-stage pump transporting molten salt was studied. Axial vane diffuser was designed to relieve the effect of non-uniformity of circumferential pressure distribution near the impeller outlet. Performance test was carried out to evaluate the working ability and acquire the operation performance parameters of the designed pump. Numerical simulation was conducted to capture the variation of main flow parameters with time and space. Both steady and unsteady computations were performed and mediums of water and molten salt were defined in computation for comparative analysis. The results indicate that circumferential pressure distributions at different axial positions exhibit apparently different tendencies. Under the designed flow rate, energy loss in the rotor-stator interaction zone is relatively small, while under the condition of small flow rate, the loss can reach as high as 3.5% of the pump head. With impeller’s rotation, the flow pattern near blade outlet experiences drastic change. Dimension, shape and location of the typical flow structure change accordingly due to the interplay between rotating impeller and stationary axial vane.