The Research Of The Characteristic Of Nutural Draft Wet Cooling Tower Under Low Circuration Water Flow Rate

In thermal power plants,the cold end equipment is an important auxiliary equipment that affects the operation economy of the unit,and in the cold end equipment,the cooling tower is the most common and the most critical equipment,in order to improve the efficiency of the generator unit.In this paper,the performance of the natural ventilation cooling tower under the special condition of low circulating water quantity during the peak load load of the thermal power unit is studied,and the corresponding optimization scheme is put forward based on the actual operation of the thermal power unit.Firstly,based on the theory of heat and mass transfer and the design principle of cooling tower,a mathematical and physical model of natural ventilation cooling tower was established.Then,combined with the mathematical and physical model of cooling tower,a numerical simulation model of cooling tower based on CFD method was established,and a reasonable and effective numerical simulation scheme and solution strategy was proposed.The validity of the numerical simulation model is verified by the test data of a wet cooling tower in a thermal power plant.Then based on the thermal characteristics of the cooling tower for cooling tower core cooling unit,water spray packing performance under low cycle water conditions simulated,compared the different kinds of water spray packing under low cycle water conditions,performance by simulation study found that at low water conditions,double oblique wave and S wave packing has high cooling capacity,In addition,the performance of non-uniform packing arrangement under the condition of low water volume was also studied.The results show that the non-uniform packing still has the characteristics of improving cooling effect under the condition of low circulating water volume.Finally,combining with the practical engineering problems,of a low power plant circulating water cooling tower under the condition of the problem of low efficiency of the simulation analysis,and combining with the results of the analysis and thermal characteristics of cooling tower,puts forward the working condition of low water wet cooling tower peripheral water distribution operation mode optimization scheme,the scheme can make the cooling tower in the circulation of water is lower,the lower water temperature 0.43 ℃.For the 300 MW thermal power unit,the annual fuel cost can be reduced by 873,000 yuan and260,900 yuan.The results obtained in this paper have a certain reference significance for the actual operation of thermal power plants.