A Calculation Model of Exhaust Pressure of Direct Air-cooled Units Considering the Effect of Environmental Wind

Environmental wind has obvious effect on the safe and economic operation of direct air-cooled unit.Key procedure of air-cooled condenser optimum operation is to forecast the exhaust pressure,especially under the operation condition of windiness.Take a certain 330 MW direct air-cooled unit as an example,numerical model of air-cooled condenser was built,and the inlet mean temperature and air volume flow of every air-cooled heat exchanger unit were obtained.The scale of calculating exhaust pressure was refined from air-cooled condenser to heat exchanger unit,and the calculation model of exhaust pressure,which considering the effect of environmental wind,was built.The results show that the air inlet mean temperature of downstream heat exchanger units and the air volume flow of upstream edge heat exchanger units,are both seriously affected by environmental wind.The exhaust pressure under the condition of windiness is higher than that of windless condition,and the wind of positive y-direction has a greater influence on exhaust pressure than the wind of positive x-direction.The dominant factor of causing the rise in exhaust pressure under the condition of windiness is the decrease in the air volume flow of heat exchanger unit.The model built in the paper can forecast the exhaust pressure of direct air-cooled unit under the operation condition of windiness.