Numerical Simulations And Experimental Studies Of The Evaporative Cooling Heat Exchanger

Evaporative Cooling Technologies is widely used in air conditioning and electric and chemical industry. The advantage of Evaporative cooling technologies is that it makes use of cooling by water evaporation in unsaturated moist air absorbing. Evaporative cooling heat exchanger can be divided into different type according to the method of use different. Direct evaporative cooling heat exchanger and indirect evaporative cooling heat exchanger are abroad used of those types.the heat exchanger effect are affected by its geometry size and fluid parameters, This paper dealt with numerical prediction of mixed convention heat and mass transfer in direct evaporative cooling heat exchanger and indirect evaporative cooling heat exchanger using CFD and numerical heat transfer technologies, Mathematics model were developed for the fluid flow and the heat and mass transfer processes with simplifying assumptions, the dimensionless method was utilized to gain the dimensionless variable of the governing equation, Physical process of the two exchangers were simulated by using the FLUENT software. Predicted results about the flow field, temperature field and concentration field were presented.Based on the numerical simulation, this paper analyzed the direct evaporative cooling heat exchanger performance with different mass flow rate ratio of air to water,the dimensionless temperature of air inlet, the Re number of air inlet and the length-width ratio of the passage,the indirect evaporative cooling heat exchanger performance with different mass flow rate ratio of the secondary air to water, the Re number of the secondary air inlet, the dimensionless temperature of the secondary air inlet, the length-width ratio of the secondary air passage, the length-width ratio of the primary air passage and the Re number of the primary air inlet. Through the regressive analysis of the numerical experimental data, Correlations for average Nusselt and Sherwood numbers were developed of direct evaporative cooling heat exchanger and indirect evaporative cooling heat exchanger. The correlation of indirect evaporative cooling heat exchanger was verified by experiments, the research has references effect for the design of falling film evaporation heat exchanger.