The influence of main-auxiliary combined indirect air-cooling tower at different ambient wind speeds and with different directions on flow heat transfer characteristics of the unit under normal working conditions in summer is investigated via numerical simulation. The results show that

as the ambient wind speed increases from 4 m/s to 16 m/s

the pressure in windward fan section of the main-auxiliary combined indirect air-cooling tower will increase

while the pressure on both sides of the fan section will decrease. The pressure on the inner side of the back fan section will increase and high-temperature zones which will decrease in quantity when the wind speed exceeds 8 m/s will form. The pressure on the outer side will decrease

and the pressure change in the upwind and backwind sections will be greater than that on both sides of the fan section. The total heat transfer in the main fan section will continue to decrease

while the auxiliary fan section will continue to increase slowly and be less affected by environmental wind. In different environmental wind directions

when the wind direction angle is 0° or 180°

the heat transfer of the blocked tower will increase significantly. When the wind direction angle is 45° or 135°

some fan sections between the two towers will be blocked

and the heat transfer of the blocked tower will decrease slightly. The maximum heat transfer of the main fan section occurs in the direction where the environmental wind is completely blocked

and the maximum heat transfer of the auxiliary fan section occurs at a 90° environmental wind direction angle

which is directly facing the auxiliary fan section.