Structure Optimization For Natural Draft Wet Cooling Tower Of Large Scale Unit

Based on the theory of natural draft counter flow wet cooling tower, analyze theflow field in tower with the help of CFD. Mesh the grid with GAMBIT and iterate theequation with FLUENT. Use different numerical study models in these zones for thecharacteristics of heat and mass transfer are different in rain zone, spray zone and fillzone in tower. In fill zone, Poppe model was applied to simulate water drops film flowand transfer heat and mass with air. UDF could describe it correctly. In spray zone andrain zone, DPM was provided to describe the heat and mass transfer between water dropand air.Build a numerical simulation model to analyze the thermal performance based on alarge cooling tower of1000MW generating unit existing in a power plant in North China.Expand the computing area to demonstrate the influence of the surrounding. Confirm theaccuracy of the numerical model by the teat data of outlet water temperature of the tower.Results means the numerical model is accurate enough and the deviation is low. Maxrelative error was1.71%.To solve the problem that deterioration of heat transfer occurs in the center ofcooling tower, verify the effect of two solutions: apply central catheter pipes anddouble-decker inlet. Results elucidated that the two solutions both can enhance thecooling effect and make the outlet water temperature decrease: central catheter pipes by0.433℃on average and double-decker inlet by1.41℃on average.In different seasons and different wind speed, verify inlet height of huge coolingtower to be applied in nuclear generate unit in the inland provinces. Analyze thetemperature field, Merkel number, outlet water temperature and the asymmetry leaded bycrosswind. Conclude that the best height is12m to supply the most electric power.