Study On Structure Optimization Of Natural Draft Wet Cooling Tower Of 1000MW Unit

In order to optimize structure data of natural draft wet cooling tower(NDWCT)of inland nuclear power(INP)and the thermal performance under cross wind.According to the principle of heat and mass transfer in the NDWCT,a three-dimensional numerical calculation program of the NDWCT is established by using the FLUENT platform.The program uses a porous medium model processing air and water heat exchange within the packing layer;discrete phase model(DPM)is used to simulate in pour water zone and rain zone.The resistance between air and water uses a user's defined function(UDF).The accuracy of the program is verified by comparing the measured value with the calculated value of the outlet water temperature of the super large cooling tower in a 1000 MW Unit.Then the program is used to optimize the structure data of the NDWCT of a 1000 MW unit.The results show that the optimal throat height ratio is 0.8033 and optimal the throat radius ratio is 0.7.According to structure data of the NDWCT of the INP and the current standard is not the same phenomenon,throat height,throat radius and throat upper curvature of the NDWCT is optimized.The results show that when the throat height ratio is 0.8 and the throat radius ratio is 0.65 and the upper throat duct curvature is 0.19,the structure data is optimal.To improve air intake efficiency of the NDWCT,a case study of optimal the NDWCT of the INP,in the summer wind conditions,the deflectors is installed in the air inlet.The installation angle,quantity,length,arc type deflectors and distance between air inlet and deflector are studied.The results show that when the wind speed equals to 2.13m/s,the best installation angle of deflector is 45°;the optimal number is 20,the optimal plate length is 8m,optimal distance between arc type deflector peak point and chord length is 0.5m and optimal distance between arc type deflector and air inlet is 5m.When the wind speed equals to 2.13m/s,the outlet water temperature decrease is 0.642 ?;when the wind speed is 4m/s,the outlet water temperature decrease equals to 1.127?;when the wind speed is 6m/s,the outlet water temperature decrease is equivalent to 1.211?.