Because of obvious water conversation, direct dry cooling system is widely used in coal-rich and water-deficient areas. The economical operation of axial flow fans is the important part for the economic performance of direct air-cooled unit, and also a key way to lower station service, so it is of great importance to optimize the operation of axial flow fans.By the base of the typical 2×600MW direct air-cooled plant in the paper, the variation of flow and heat transfer characteristic of air-cooled condenser and net power under different wind speed and direction is studied, which is following the fans speed in different region. The results show that the windard fans are susceptible to effects of environmental wind. With the fan speed 79rad/s as a reference, when improving windard fans speed average temperature of the fan entrance rises but cooling air mass flow doesn’t change much, therefore thermo-flow performances of air-cooled condenser deteriorate slightly. Reducing windard fans speed, the heat transfer effect of air-cooled units from the windard and the adjacent row goes bad, so the economy of power plant declines though fans consumptions lowers. When the wind which is small blows from the side of air-cooled condenser, the flow and heat transfer characteristic will be improved and the net power rises moderately, but the power will go down when the wind is larger. While speed of all fans except windard fans are elevated to 86.9rad/s, air mass flow rises, the heat transfer effect is better and net power of the unit is greater, that says the economy is improved. However, increase of the net power will be reduced when the wind becomes very large, and when wind speed is about 15m/s, heat transfer effect and net power are both going down. This study found that, when wind speed is not very large, we can improve the flow and heat transfer characteristics of air-cooled condenser and thus improve the economy of dircet air-cooled unit by elevating fans speed except the windard fans. |