A CFD study on design parameters acting in cavitation of positive displacement pump

A CFD test case of a positive displacement reciprocating pump is presented to demonstrate the capability and benefits which numerical analysis may bring to designers in terms of information on fluid dynamic fields useful to optimize the geometry of the discussed device in all the different operating conditions; even in the worst operating conditions when cavitation appears. The paper discusses the role of design parameters such as the inlet valve shape, mass and spring preload in full cavitating conditions. The comprehensive CFD model makes use of the Singhal et al.(1) cavitation algorithm in conjunction with an Eulerian multiphase model. User defined functions add a few more functionalities to the CFD solver such as the valve dynamics model and the compressibility of water. For each of the cases, the work presented shows the capability of the CFD technique to predict quantitative results such as the volumetric efficiency loss and amount of water vapour generated when cavitation arises. Providing pump designers with this information before the design process has come to an end would give them the possibility to improve the operational life of the device as well as its efficiency. It would also result in a more economic and competitive device on the market.