Experimental researches of the effect of environmental wind on thermal recirculation under the tower of direct air cooled system

The reasons of thermal recirculation formed in air cooled system of power plant and its hazards were analyzed so as to present the evaluation criteria of quantitative analysis for thermal recirculation. The hot water with constant temperature flows inside the model of direct air cooled system to form the circulating system. Then the model was put into the low velocity wind tunnel to carry out the experimental research on heat effect. The effect under the variation of inflow velocity of environmental wind and its direction on the recirculation ratio under air cooled tower was searched by calculating the recirculation ratio based on the air temperature measured at each point of fan's inlet and fined tube's outlet with different inflow conditions. It was found that the mean recirculation ratio under the air cooled tower grows higher with increasing of the inflow velocity within the range of testing wind velocity. The trends of the mean recirculation ratio under the air cooled tower varying with the wind direction angle under different inflow wind velocity are basically the same. The mean recirculation ratio under the air cooled tower reaches the highest value with the testing wind direction angle of β = 0°.