| At present when energy problems are becoming increasingly serious,energy saving and emission reduction have become one of the most important issues in the world,and China is actively and steadily promoting the work of "carbon peaking and carbon neutral".Therefore,it is of great importance to actively carry out research on energy-saving technologies and devices.In urban water supply and drainage systems,agricultural irrigation systems and many other processes,there is a large amount of liquid pressure energy,which can be recovered by using hydraulic turbine devices.Pump as Turbine(PAT)can be high-pressure liquid pressure energy into the mechanical energy of the rotating shaft,with simple structure,convenient maintenance,low cost and other characteristics,so the recovery of high-pressure liquid energy by pump inversion has a broad prospect.This paper will take an axial flow pump for hydraulic turbine as the research object,the main research content for the following 3 parts.In order to study the influence of different blade number and different guide vane number matching on the performance of axial-flow pump as turbine,the matching of 3different blade number and 4 guide vane blade number was numerically simulated by numerical calculation,and the external characteristics,internal flow field and energy loss under different matching schemes were analyzed.The results show that the 6 blade scheme has the highest efficiency under the condition of small flow rate,under the condition of large flow rate,the efficiency of 4 blade scheme is the highest,and with the increase of blade number,the pressure head and power of the turbine also increase.At the optimal operating point,the efficiency of the original design guide vane number scheme is the highest,while in the case of deviation from the optimal condition,the 8blade guide vane has higher efficiency.In order to study the influence of different front and rear guide vane stage matching on the turbine performance of axial-flow pump,four different matching schemes of front and rear guide vane stages were studied under different flow conditions by numerical calculation,and the external characteristics,outlet section loss and blade load of different schemes were analyzed.The results show that: Under the condition of large flow rate,the hydraulic efficiency of axial-flow pump as turbine can be improved by adding the rear guide vane,which can be increased by 16.01%.Moreover,under the condition of large flow rate,the loss of the rear guide vane scheme at the outlet section is obviously less than that of the scheme without rear guide vane,while the efficiency of the rear guide vane scheme is slightly lower than that of the non-rear guide vane scheme under the condition of small flow rate.In order to study the influence of fluid structure interaction characteristics of axial-flow pump as turbine on impeller blades,the deformation distribution and equivalent stress distribution of blades under different schemes were analyzed through fluid structure interaction calculation of the first two parts.The results show that: The total deformation distribution of the blade is basically uniform under different blade numbers,and the total deformation of the blade increases with the increase of the flow rate,and the deformation of the blade decreases with the increase of the number of blades,and the equivalent stress has a similar law;Axial flow turbine with front guide vane will increase the deformation of blade,due to the direct impact of liquid on the blade,the inlet angle of axial flow turbine without front guide vane changes greatly compared with that with front guide vane,so the blade deformation is relatively small. |
