| The integrated prefabricated pumping station has the advantages of small land area,low environmental pollution and low construction cost,which are widely used in engineering,but the internal flow pattern of integrated prefabricated pumping station is poor and unclear,and the use efficiency is not high,which seriously affects the safe,stable and efficient operation of pumping station and limits the further development of integrated prefabricated pumping station technology,so it is necessary to carry out relevant research.In this paper,based on the SST k-ω turbulence model to numerically simulate the axial flow prefabricated pump station,the internal flow characteristics of single-pump prefabricated pump station and double-pump prefabricated pump station under different operating conditions are analyzed,and model tests are carried out for the double-pump prefabricated pump station,and finally the axial flow prefabricated pump station is optimized,and the following conclusions are finally drawn.(1)The internal flow pattern of single-pump prefabricated pumping station and double-pump prefabricated pumping station increase with the flow rate,the internal vortex range also increases,the more chaotic the flow line,the double-pump prefabricated pumping station has a low-speed zone between the two pumps,and the low-speed zone produces a shift to the right with the increase of flow rate.The efficiency of single pump prefabricated pumping station increases with the flow rate and then decreases,and the highest efficiency is 31.37% when the flow rate is 1.4m/s.The head decreases with the increase of flow rate and then increases and then decreases,and the uniformity of outlet flow rate increases with the increase of flow rate,and when the flow rate reaches 1.4m/s,the change of uniformity of outlet flow rate is smaller,and with the increase of flow rate,the outlet velocity weighted average angle increases first and then decreases with the increase of flow rate.(2)The efficiency of the double pump prefabricated pumping station increases and then decreases with the increase of flow rate,and the highest efficiency is 32.16% under the condition of flow rate of 2.0m/s.The head of the double pump prefabricated pumping station gradually decreases with the increase of flow rate,and the uniformity of flow rate of outlet 2 is better than that of outlet 1 under each condition,and the uniformity curves of flow rate of outlet 1 and outlet 2 change similarly,both increase and then decrease with the increase of flow rate,and finally level off.The velocity uniformity curves of outlet 1 and outlet 2 are similar,both increase and then decrease with the increase of the flow rate,and finally become stable,and reach the optimum at the flow rate of 2.0m/s.The curve of velocity weighted average angle of outlet 1 and outlet 2 is basically the same,which increases and then decreases with the increase of flow rate and reaches the maximum at the working condition of flow rate of 1.2m/s.The model test of double-pump prefabricated pumping station obtains similar results as the numerical simulation.(3)The change of inlet height has a great influence on the pumping station efficiency,with the increase of inlet height,the efficiency curve decreases first and then increases,the head change curve is basically the same as the efficiency change curve,and the efficiency is the highest when the inlet height is 1.4D.With the increase of inlet height,the internal flow pattern of pumping station also deteriorates,and the flow pattern is the best at 1.4D.The change of pump spacing has little effect on the efficiency of the prefabricated pumping station,but has a greater effect on the flow velocity of the water inside the pumping station,and the large flow velocity range inside the pumping station is larger when the pump spacing is 2.0D.The change of center distance has a big influence on the efficiency of prefabricated pumping station,when the center distance of the pump is near the negative half-axis of the inlet,the efficiency is significantly reduced,when the center distance of the pump is far from the positive half-axis of the inlet,the efficiency is higher,and the efficiency is the highest at 0.6R.The inlet diameter has a large impact on the efficiency of the prefabricated pumping station,and the head and efficiency of the prefabricated pumping station increase with the increase of the inlet diameter.Numerical simulation of the optimal solution under multiple flow conditions,the analysis shows that the efficiency curve increases and then decreases with the increase of flow,and the head decreases and then increases and then decreases with the increase of flow,and the highest efficiency point is shifted after optimization,and the highest efficiency is 75.65% at the flow rate of 2.8m/s.The internal flow pattern is better,the flow line is smooth and the vortex is less. |
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