Numerical simulation on the three kinds of water droplet diameter treatments in rain zone of wet cooling towers

摘要

Numerical simulation is an important means to study the thermal and resistance characteristics of natural draft wet cooling towers. The treatment method of droplet diameter distribution in the rain zone directly affects the accuracy of the numerical model, which becomes a key problem in the numerical simulation at present. In this paper, to provide an appropriate treatment method of droplet diameter, three kinds of droplet diameter distribution treatment models for the numerical simulation are studied and compared, including equivalent diameter method (EDM), Gaussian distribution method (GDM), and diameter distribution method based on field test (FTDM), and the influences of each treatment method on the simulation results are presented respectively, which provide references for the subsequent numerical simulation. It is found that each method can reasonably simulate the thermal characteristics of the cooling tower by determining their key parameters, but the temperature drop calculated by FTDM is the most accurate with a relative error of 0.58%. Additionally, FTDM can most accurately simulate the pressure drop with a relative error of 4.18% and the motion trajectory of the water droplets, so the FTDM should be given priority under the premise of known the droplet diameter distribution data of the tower.