Analysis of the pressure reduction mechanism in multi-stage counter-flow channels

In the construction and operation of supercritical units, valves are the most commonly used equipment in power plants. Cavitation erosion, turbulence and other phenomena usually occur in the valve, which seriously threaten the operation stability of the control system. In this paper, the energy dissipation characteristic parameters under different structural parameters are evaluated in order to achieve high pressure difference and high flow channel design. The results show that there is a significant increase in turbulence intensity at the exit due to the influence of flow passage mutation. The Q values of the first two stages are smaller than that of the last stage. The energy dissipation of the first two stages dominates the energy loss of the entire runner. Meanwhile the cavitation effect at the outlet is the most obvious. The U-groove of 3.5 mm, the outlet diameter of 15 mm and the equidistant distribution, are the optimal configuration in the optimization of multi-stage hedge runner for high pressure difference and high flow.