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ISSN Online: 2377-424X

ISBN Print: 978-1-56700-421-2

International Heat Transfer Conference 15
August, 10-15, 2014, Kyoto, Japan

Behavior and Optimization of Spray Humidification inside Air-Cooled Condenser of Power Generating Unit

Get access (open in a dialog) DOI: 10.1615/IHTC15.fcv.008736
pages 3227-3238

Abstract

Output limit of direct air-cooled condenser (ACC) at high environmental temperature in summer is a common problem for air-cooling power generating units. Spray humidification to the air flow is a necessary approach to enhance the cooling capacity of ACC cells, despite of the additional water consumed. However, researches on mechanism of spray cooling are still incomplete till now. This study intends to reveal the behavior of water spray inside the ? frame of ACC cell with consideration of influences of operating axial flow fan, and in further, investigates the influence of spray humidification on the performances of air-cooled condenser. The analysis indicates that the working principle of spray humidification consists of three parts. Firstly, the droplets mix with air and evaporate in the process of movement, which reduces the dry bulb temperature of air. Secondly, it also increases the specific heat of air. Lastly, the residual droplets are attached to the finned bundles, which enhance heat transfer further by surface evaporation. Based on the above observations, the optimal design of spray humidification system is proposed according to the characteristics of air flow field inside ACC. The CFD simulating results show that the efficiency of heat exchange increases obviously, as well as spraying water can be saved to a great extent. The results may benefit the safe and high efficiency operation of direct air-cooling power generating units.