Calculation Of Turbine Runner Size And Study On Its Internal Flow Character Ristics And Force Characteristics Of Hydraulic Energy Recovery Turbines

Hydraulic energy recovery turbines are effective equipment for energy recovery in high-pressure flows. The pressure of the liquid components can be converted to mechanical energy to drive the movement of machines like pumps and blowers or for generating electricity. The study of the hydraulic energy recovery turbines is quite under scrutiny at present. Pumps as turbines is a main alternative, there are single and multi stage for pumps as turbines. Other kinds of turbines such as turbines based on reverse pump-turbine can be found also. Be aimed of the problems and shortcomings of pumps as turbines and others, including mode selection, and turbines operation is unstable and its design theoretical void. The author mainly studies 4 key aspects of hydraulic energy recovery turbine and to get related conclusions.The SLTP540-220 is taken as research object, a method to evaluate the turbine runner size was presented, which including hub diameter d_h, inlet diameter D₁ , blade inlet angleβ_b1, blade inlet width b₁ , outlet diameter D₂and blade number Z. especially studying on D₁ , b₁ ,β_b1. 8 schemes were determined according to different turbine runner size. Performance prediction was performed for turbines by using software FLUENT 6.1. It was shown by the computation result that the scheme Db performance parameters meet the design requirement by this method, meanwhile a higher efficiency. Reasonably, this method is practicable, The study also found turbine inlet shockness is obvious.In order to research on the performance of hydraulic energy recovery turbine with different blade shape, 3 kinds of blade shape with different inlet angles and wrap angles were designed for turbines. Numerical simulation was performed for these turbines by using FLUENT 6.1, it was shown by the result that turbines with different blade shape have different internal flow and performance characteristics. The first blade was the best model among 3 blades, the best efficiency of turbine with blade 1 was 1% and 2% better than blade 2 and 3 approximately, its velocity and pressure distribution also better than turbines with blade 2 and 3. Some phenomena such as relative eddy within turbine blade passage, secondary flow including flow separation and reverse flow and cross flow on pressure surfaces near the turbine inlet, low-pressure area on suction surface near the blade outlet and hub were found.The study illustrates 3 modifications of the edges, which involves rounding of the blade inlet, rounding both of the blade inlet and hub/shroud in the inlet of the turbines and non-rounding. Numerical simulation was performed for these turbines, and the result was shown that rounding of blade and hub/shroud did not make the flow state at turbine inlet better, and turbine efficiency did not improved. The force characteristic of turbines was analyzed, the radial force and its genesis was researched especially. It was found that the radial force was existing especially in design condition, this is not exist in theory indeed. The radial force of turbines increase with flow rate, the area on which the forces acted was about 130°¹80°from volute tongue along the flow direction. The radial force was smaller in turbines with single volute than with double volute.