Pressure pulsation and its reduction in annular linear induction pump

A sodium test was carried out to measure the double-supply-frequency pressure pulsation arising in an annular linear induction pump. The obtained result shows that the amplitude of the pressure pulsation increases with decreasing supply frequency and/or decreasing number of poles. The pressure pulsation was analyzed numerically by using a magnetohydrodynamic computer code developed by CRIEPI. The numerical result reveals that the pressure pulsation comes from a disturbance of the electromagnetic force occurring near the stator ends. Additional tests including a linear grading of coil winding were fulfilled. As a result, it is confirmed that the linear grading is an effective way to reduce the pressure pulsation. In addition, it is found that the linear grading improves the pump efficiency. The numerical result of the pressure pulsation agrees with the experimental result, which demonstrates the consistency of both results. (author)