Research On The Characteristics Of Heat Transfer And Flow In The Corrugated Plate Evaporative Cooler

Evaporative cooling is a technology that uses water evaporation for heat absorbing.Compared with the traditional mechanical vapor compression refrigeration system,evaporative cooling does not need the compressor and chemical refrigerant.It has many advantages,such as energy saving,environmental protection,high efficiency,economy and so on.In this paper,the counter flow dew point indirect evaporative cooler is studied focusing on the enhancement of heat transfer and the falling film flow outside the plate.The main works and conclusions as follows:(1)The counter flow corrugated plate dew point indirect evaporative cooler is proposed and the heat transfer characteristics is numerically investigated.In this paper,the influence of corrugated baffle,the channel length,the gas channel height and the working channel height on the cooler performance are investigated.The results show that the corrugated structure plays a significant role in heat transfer enhancement,and its maximum performance can be up to 15.8% compared with the flat plate dew point evaporative cooler.With the range of study,the wet-bulb effectiveness and dew-point effectiveness increases with the increase of the channel length,decreases with the increase of the gas channel height.When the height of the working channel is between 2mm and 10 mm,the wet-bulb effectiveness first increases and then decreases with the increase of working channel height,and the optimal wet-bulb effectiveness can be obtained when the working channel height is around 5 mm.(2)The influence of the external conditions on the cooling efficiency of the indirect evaporative cooler with counter current corrugated baffle is studied numerically.The results show that the dew-point indirect evaporative cooler can achieve higher wet-bulb effectiveness with lower relative humidity and lower air velocity.Under different conditions of relative humidity,inlet air temperature and velocity,the wet-bulb effectiveness is 93.93-154.04% and the dew-point effectiveness is 45.43-91.83%.With the increase of working to product air flow ratio(W/P),the wet-bulb effectiveness and the dew-point effectiveness decrease.Considering the air supply,the efficiency of the cooler and the energy consumption,it is suggested that the W/P should be between 0.8-1.6.(3)The experimental paltform of falling film flow is established.The effect of water film flowing form and the heat transfer characteristics of plate are investigated under the different spray water flow and velocity.The results showthat the thickness of water film increases with the increase of the spray water flow.When the flow rate of spray water is lower,the “dry sports”phenomenon has produced on the plate.However,the splash of water film appeared in the some type of plate with the larger of spray water flow.Under the same operation conditions,the heat transfer performance increases first and then decreases with the increase of the spray water flow rate,and decreases with the increas e of the wind speed.In the range of study,the heat transfer performance of the semicircle corrugated plate is best.