Experimental And Theoretical Study On Spray Cooling To Enhance Heat Transfer

Spray cooling technology has many advantages,such as higher heat transfer,less fluid inventory,smaller heat resistance and so on.The application effects of two different forms of spray cooling technology are experimentally tested and simulation analysis based on the air cooled heat pump modular chiller and STEG.After the additional spraying device is installed in the air-cooled unit,the power consumption is reduced,the cooling capacity is increased and the overall energy efficiency coefficient is increased.The higher the ambient temperature,the more obvious is the spray cooling advantage.At the same time,Most of the droplets evaporate and some do not evaporate droplets impact and adhere to the surface of the unit.After addition of the spray device in thermoelectric power systems,the net output power of the system increases and the heat transfer coefficient of the cold side increases with the increase of the spray flow rate.At the same time,the power consumption increases and the optimal spray flow.In order to study the evaporative heat transfer process of the adherent liquid droplets on the hot surface,a visualization experiment platform was set up.After the spray liquid droplets impacted the hot surface,the liquid droplets showed a concave distribution with low tip temperature and high edge temperature.A circle of low temperature spot is formed on the surface,which strengthens the internal heat conduction process of the heating plate.The higher the hot surface temperature,the larger the droplet evaporation rate,the more droplet heat absorbed per unit time,and the higher the heat flux inside the hotplate.In this paper,a spray jet cooling test bench was set up to study the effects of spray height,spray pressure and heating power on the heat transfer enhancement of hot surface spray.The heat surface heat transfer coefficient increases with the increase of spray pressure.When the spray pressure is greater than 1bar,the spray power consumption is improved significantly,but the influence of spray pressure on the surface heat transfer coefficient is reduced.The best spray pressure is given to the power consumption and heat transfer performance.Considering the power consumption and heat transfer performance,there is a best spray pressure.The optimum height of the spray cooling is related to the spray pressure.Different spray pressures correspond to different optimum spray heights.The results of this paper have theoretical significance for the popularization and application of spray cooling technology.