Study on Influence of Position and Diameter of Throttled Orifice on Impedance Characteristics and Three-dimensional Flow Field of Surge Tank with Long Connecting Pipe
The impedance characteristics of a surge tank with a long connecting pipe can be enhanced by setting a throttled orifice smaller than its diameter in the connecting pipe.In order to study the influence law of the position and di-ameter of the throttled orifice in the long connection on the impedance characteristics of such a surge tank,the head loss coefficient and flow coefficient were taken as optimization objectives,and the position and diameter were taken as optimi-zation variables.Based on the orthogonal optimization design method and CFD numerical simulation software,the varia-tion law of the impedance coefficient of the surge tank and the three-dimensional flow field under each combination scheme was calculated and analyzed.The results show that the turbulence intensity increases obviously before and after the im-pedance hole,and the closer the distance between the two ends of the connecting pipe,the greater the influence on the flow field in the surge tank well and pipeline system is.When the impedance hole is located at the connection between the top of the connecting pipe and the big well of the surge tank,the impedance effect of the impedance hole can be maxi-mized.Taking the 0.8 diameter ratio of the impedance hole to the connecting pipe as an example,the water head loss co-efficient increases by about 30%.The maximum floating range of local flow field pressure in the surge tank can be effec-tively reduced by increasing the diameter of the connecting pipe.When the impedance hole is located near the top of the connecting pipe and not at the big well joint,the overall turbulence intensity of the connecting pipe and the downstream tunnel is smaller and the flow field is more stable when the water flows out of the surge tank.
long connecting pipethrottled surge tankthrottled orifice locationorthogonal optimization designthree-dimensional flow field
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