Transient Calculations of Pump Performance Parameters

The oscillations of pump performance parameters like head and power corresponding to a wide range of flow-rate values are investigated in the present paper. A centrifugal double suction industrial pump is studied with comparison of test, steady state and averaged transient results. Different turbulence closure models, such as k-ω, and k-ω SST were used. The oscillation behavior of the head and the power of pump is studied for three different pump geometries. The pump model consists of suction, impeller and discharge parts which are meshed and calculated together. This, for instance, naturally permits the effects of non uniformity of velocity distribution on the impeller eye and on the inlet of the discharge segment to be taken into account. The commercial code Fluent 6.3.26 is used for the CFD computations. The results show much better agreement of the test data with averaged transient calculations compared with steady state calculations, especially far away from best efficiency point on the performance curve. Besides, an interesting transient effect, doubling of the frequency of pump parameters oscillations (compared with the blade passing frequency w = n*N) is observed.