| In winter,because the air temperature is too low,the natural draft cooling towers of power plants often experience icing,which affects the safe operation of the cooling towers.Windshields are usually used to prevent icing.After the icy period has passed,the windshields need to be removed in time.This not only increases labor costs,but also the working conditions of the disassembly and assembly workers are quite cold.The paper proposes an air intake regulating device arranged on the periphery of the cooling tower.Aiming at the proposed natural draft cooling tower’s air intake regulating device,the GAMBIT software is used to establish a three-dimensional model of the natural draft wet cooling tower under different baffle opening adjustments of the device,and simulate it with FLUENT software.The factors that affect the temperature of the cooling tower’s outlet water include external environmental factors,the internal structure of the cooling tower,etc.,Among them,external environmental factors are the main factors affecting icing.Therefore,the influence of different ambient temperature,transverse wind speed,and relative humidity on the performance of the cooling tower in winter when the device is fully opened is calculated,and design the windshield layout plan for icing conditions.At the same time,the influence of two different baffle opening directions on the decrease of the temperature of the circulating water out of the tower is discussed.Conclusion as below:(1)As the ambient temperature decreases,the minimum water temperature on the characteristic surface of the cooling tower decreases almost linearly.When the ambient temperature decreases from 270.15 K to 250.15 K,the minimum water temperature of the base ring surface,the upper surface of the air inlet,and the lower surface of the filler are reduced by 20.58 K,14.59 K,and 14.23 K respectively.As the transverse wind speed increases,the minimum water temperature on the characteristic surface first rises and then slowly decreases.When the wind speed increased from 1m/s to 3m/s,the minimum water temperature of the base ring surface,the upper surface of the air inlet,and the lower surface of the filler increased by 10.91 K,5.92 K,and 5.41 K respectively;When the wind speed increases from 3m/s to 5m/s,the minimum water temperature of the base ring surface,the upper surface of the air inlet,and the lower surface of the filler are reduced by 1.95 K,1.33 K,1.1K respectively.As the relative humidity increases,the minimum water temperature on the characteristic surface gradually rises.(2)In view of the icing phenomenon in the simulation process,by closing the air intake regulating device layer by layer,the appearance of icing in different degrees on the characteristic surface can be effectively prevented.When the ambient temperature is258.15 K,when the transverse wind speed is 2m/s,closing a layer of windshield can prevent icing,when the transverse wind speed is 1m/s,closing two layer windshields can prevent icing;When the ambient temperature is 255.15 K,icing can be prevented by closing two layer windshields;When the ambient temperature is 250.15 K,adjust the air intake regulating device to the fully closed state to prevent icing.(3)Rotating the air intake regulating device horizontally into an oblique upward flow guiding structure or longitudinally rotating into a side flow guiding structure can reduce the temperature of the water outlet from the tower.In this simulation scheme,the oblique upward diversion structure can reduce the tower water temperature by up to0.53 K,and the side diversion structure can reduce the tower water temperature by up to0.395 K.(4)The natural draft cooling tower’s air intake regulating device proposed in the paper can not only realize anti-icing in winter,but also in the case of high temperature in summer,the windshields can be adjusted to a suitable opening,so that the windshields become the external diversion structure of the cooling tower and reduce the temperature of the water outlet from the cooling tower... |
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