Study On Optimal Operation Of Spray Humidification System In Direct Air-cooled Condenser And Flow And Heat Transfer Characteristics In Air-cooled Unit

The output in direct air-cooled power plants mey be reduced in Summer, the humidification system can efficiently increase the operational vacuum of the unit, consequently, saving water resource and increasing economic benefit. Direct air-cooled unit can be easily effectd by the wind velocity, the study on the velocity and temperature fields of the cooling air in the condenser cell is important.Through thermal calculation and thermal experiments of a typical 600MW power plant spray humidification system, the optimal operation of spray humidification was analyzed. It is indicated that the actual atomization effect is the percentage of 79 of the total water spray, in the same way of spray, the cost per hour increased with the increase of load, and the trend is also growing gradually, in the same load, the ecnonmy of spraying 1-6 rows first, then 78 rows is best, spraying 8 rows at the same time is worst.By way of CFD,the influence of wind velocity,wind direction,radiator installation angle and shapes of wind covers upon the flow and heat transfer of the cooling air was analyzed. It is concluded that at X direction, the wind speed add each lm/s, fan flow decreased by about 25m3/s,because of the wind on both sides of the wall, fan flow is least at the direction of 45°,as the wind speed increases, flow of 60°radiator installation angle declines fast; for installation of inlet cover of air-cooled unit, the shape of inlet cover has limit effect on the fan flow,increasing the inlet cover area has more beneficial to fan flow.The externa & internal velocity and temperature fields of the cooling air in the condenser cell with the flow guiding device were numerically studyed and the influence of layers and angles of the flow guiding device was analyzed. The conclusion is that the guiding device can efficiently decrease the negative influence of wind, when at the velocity of 9m/s, the fan flow increased by 32.4% after the guilding device installed compared to non-guiding device, the flow grows as the increase of guilding device layer, but the rate of increase gradually decreases, at the same wind velocity, the greater the device point, the more flow of the fan and the greater the recycle rate.The research is favor to the operation staff to analyze and compare various spray methods, and is instructively significant to design and optimize air-cooled unit as well.