Performance Analysis Of Installing Windbreak Net In Air Cooled Island Of Direct Air Cooling Unit

Because of the advantage of saving water, direct air cooling unit is developped rapidly in China, especially for the area of rich in coal but poor in water. In high temperature season, the load of direct air cooling (DAC) unit is often limited by the wind, therefore installing windbreak net in air cooling island is proposed to increase the performance of heat transfer.Take a 330MW DAC unit as a case, the numerical model of installing windbreak was built, and the performance of heat transfer of air cooling island without net, with wing net, with upright net, was analyzed respectively. The results show that heat transfer efficiency of air cooling island is decreased with the increment of wind speed, and the higher wind speed is, the lower heat transfer efficiency is. It is found that heat transfer efficiency of air cooling island is increased by installing windbreak net.For different wind speed and wind direction, the structure parameters of wing net and upright net were optimized. For side-direction wind of 6m/s, the optimal opening ratios for wing net and upright net are respectivelly 0 and 30%; the optimal height for wing net and upright net are respectivelly 5m and 17m. For 6m/s wind from boiler side, the optimal opening ratios for wing net and upright net are respectivelly 0 and 15%; the optimal height for wing net and upright net are respectivelly 5m and 10m.Based on numberical results, the calculation model of exhaust pressure, considering the influence of wind, was built by translate calculation scale from air cooling island to cell, which make the result more accurate. The results show that exhaust pressure is increased with the increment of wind speed. What is more, the higher the wind speed is, the greater the effect of wind on exhaust pressure is. Exhaust pressure can be decreased by installing windbreak net, and the effect of wind from boiler side on exhaust pressure is greater than that of side-direction wind.The work of the paper afford the reference for windbreak net reform.