Abstract:  The energy recovery turbine plays an important role in reducing the energy consumption of seawater desalination systems. In order to solve the problem of low performance of energy recovery turbines, the flow field and pressure pulsation characteristics inside a centrifugal energy recovery turbine were studied. Firstly, the velocity streamline distribution characteristics of key components under multiple operating conditions were calculated and analyzed based on SST k-ω turbulence model. Then, the performance curves of the turbine under multiple operating conditions were tested through experiments. Finally, the pressure pulsation characteristics inside the turbine were studied. The research results indicate that the high-efficiency zone of the turbine is located in the operating conditions of 1.0 Qd ~1.2 Qd. At rated operating conditions, the interaction between the fluid and the blade is weak, resulting in the lowest energy loss. Under the 1.2 Qd operating condition, there are vortices on both the inlet pressure surface and suction surface of the blade. The vortices on the pressure surface are generated by the collision between the fluid and the blade, while the vortices on the suction surface are generated by the separation phenomenon of the fluid. The maximum amplitude of pressure fluctuation at the inlet of the impeller P11m is 0.019. It can be seen that the high-efficiency zone of the turbine is biased towards high flow conditions, so the design should be appropriately biased towards low flow conditions, which is conducive to efficient operation under multiple operating conditions.
Key words:  centrifugal energy recovery turbine; SST k-ω turbulence model; large flow condition; distribution characteristics of vortex; pressure fluctuation; performance curves