Optimization Design Of Large-sized Indirect Cooling Tower

Indirect air-cooled system design is directly related to the safe operation of power plants and economic benefits, so it is very necessary to study the structure optimization of the indirect air-cooled tower.By use of the simulation software Fluent, this paper chose a600MW indirect air-cooled unit as research object. The influence on the tower air flow field generated by the environmental wind was investigated by a numerical simulation. The results show that the tower air flow field presents a uniform symmetry when there is no wind. However, when wind exists, the air flow field will deflect. And if the wind velocity is big enough, part of the air cannot flow out from the exit of the cooling tower,it is called "intrusion" phenomenon. At the same time, part of the air flows into the cooling tower from one side of the radiator in the bottom, and flow out from the other side, not flow out from the exit of the tower, forms through flow. The higher wind velocity is, the worse "intrusion" and "through flow" phenomena are. It will have a bad effect on the unit’s security and economy.Appling the thermal characteristics and resistance characteristics mathematical model of the indirect air-cooled system, a comprehensive analysis on optimizing the dimension of the air-cooled tower is given. By using the software VC++, the indirect air-cooled tower optimization program is developed, it was analyzed and studied with examples.The results showed that the larger the total air flow,the smaller the velocity when the air leaves the tower,this makes the "intrusion" phenomenon easy to happen.The cooling water temperature decreases with the increasing of the total air flow and cooling water flow, and the back pressure of the condenser decreases too, the units performance is better.The greater the cooling tower effective height,the greater the cooling tower pumping force and the velocity of the air out of the tower and the stability of the cooling tower. Due to the high investment and running costs of air-cooled heat exchanger and cooling water circulation pumps and other water equipment, it is recommended to select a tower with larger total air flow, minor amount of cooling water, smaller cooling triangular number n and higher cooling tower effective height.Combined with economic analysis, in Practical applications, it helps to seek the most technically reasonable and economical tower combination. It is of great practical value.