Study of a Pump as Turbine for a Hydraulic Urban Network Using a Tridimensional CFD Modeling Methodology

Nowadays, the application of a PAT (Pump as Turbine) has been developed in several applications as pressure dropping valve. Generally, pump manufacturers do not provide the characteristic curves of their pump working as turbine and researchers have the objective of build a model to predict the turbine operation of pumps for energy recovery schemes. This paper shows a methodology based on a mathematical model of a centrifugal pump used as a PAT in an urban hydraulic network, to solve this kind of problem. The model was built up, starting from the real geometry, with a commercial tridimensional code, which is particularly suitable to simulate pumps and valves. The aim of this paper isthe investigation on the possibility to use a simulation methodologyto obtain the inverse characteristic of a commercial centrifugal pump. First, the model results were compared with the data declared by the pump manufacturer and after it was used to obtain the inverse characteristic (PAT mode). Furthermore, an experimental test bench was used to obtain the reverse mode pump characteristic, in terms of flow-rate/head. In both cases, the simulation model showed good accuracy, there is a low difference between simulated results and manufacturer/experimental data. The model results, which represents the first step of this activity, revealed that it is possibleto obtain the pump characteristic in reverse mode, which is not declared in the commercial pump datasheet.