Experimental Study On Tube Bundle Flow Resistance And Heat And Mass Transfer Of Evaporative Condenser

In today’s society,the problem of energy shortage is becoming more and more serious,especially in the industries of high energy consumption,such as power,metallurgy and petrochemical.In addition,in recent years,China has vigorously developed energy-saving and environment-friendly economy,so it is of great significance to find a kind of efficient energy-saving heat exchange equipment.Evaporative condenser,which adopts indirect evaporative cooling technology,has the advantages of energy saving,compact structure and convenient maintenance.Therefore it has a broad application prospect and is worthy of further research on its performance.This paper seted up the tube bundle resistance and heat and mass transfer performance test bench of evaporative condenser.The influence of spray density and on-stream wind velocity on the tube bundle resistance and heat and mass transfer performance of counter flow evaporative condenser with 1.6d tube spacing was studied,and the resistance and performance of evaporative condenser under the conditions of parallel and counter flow,1.3D tube spacing and1.6D tube spacing were also compared through experimental study.The experimental conclusions are as follows:(1)The tube bundle resistance of counter flow evaporative condenser increases with the increase of on-stream wind velocity,and the growth rate shows an upward trend,and slowly increases with the increase of spray density.The effect of on-stream wind velocity on the tube bundle resistance is significantly greater than that of the spray density.Under the experimental conditions of this paper,the tube bundle resistance in the counter flow is 4.8% larger than that in the parallel flow,and in the 1.3D tube spacing is 18.6% larger than that in the 1.6D tube spacing.(2)The spray density and on-stream wind velocity have significant effects on the heat and mass transfer performance of evaporative condenser.The heat transfer rate,sensible heat transfer coefficient and mass transfer coefficient all increase first and then tend to be flat with the increase of spray density and on-stream wind velocity.Under the experimental conditions of this paper,the optimal spray density and on-stream wind velocity are 0.093kg/(m·s)and3.51m/s.(3)Compared with the parallel flow evaporative condenser,the heat transfer rate,sensible heat transfer coefficient and mass transfer coefficient of the counter flow evaporative condenser increase by 5.1%,17.7% and 10.2% on average.The comprehensive heat and mass transfer performance of the counter flow evaporative condenser is better.Compared with the evaporative condenser with 1.3d tube spacing,the heat transfer rate of the evaporative condenser with 1.6d tube spacing increases by 10.3% on average,the sensible heat transfer coefficient decreases by 13.3% on average,and the mass transfer coefficient increases by26.1% on average.The comprehensive heat and mass transfer performance of the evaporative condenser with 1.6d tube spacing is better.This paper provides reliable reference data for future research on the system performance of evaporative condenser,and the research results also have certain guiding significance for the design and optimization of evaporative condenser.