Numerical Simulation of Low Specific Speed American Petroleum Institute Pumps in Part-Load Operation and Comparison With Test Rig Results

A low specific speed centrifugal pump is investigated by means of numerical simulation, especially in deep part-load operation. The 3D computational fluid dynamics (CFD) model includes the front and back cavities, a 360 deg impeller and a double volute, as well as suction and pressure pipes. Stationary calculations show a strong clocking effect and lead to an overprediction of the head close to zero flow rate. A one-dimensional estimation of the head at the closed valve operation point is compared to the 3D CFD results and also a series of test rig results. In a second step, the whole head curve is calculated by a fully transient calculation using the shear stress transport–scale-adaptive simulation (SST–SAS) turbulence model. For the net positive suction head (NPSH) estimation, the histogram method is applied providing good correlation to the test rig measurement—as do the head curve and the efficiency.