Effects of multiple-nozzle distribution on large scale spray cooling via numerical investigation

Abstract

Spray cooling has been widely employed in many applications due to its high flux removal ability. A previous study has been conducted to reveal the large scale spray cooling performance of an industrial used single nozzle. Continuously, influence of multiple-nozzle distribution has also been numerically investigated in present work. The mean heat flux and its standard deviation (STD) and uniformity are used to qualify the cooling performance. A flat wall with 1.6 m in length and 1.0 m in width has been taken as the research object. Effects of nozzle number, distance and offset have been parametrically compared. It is found that increasing nozzle number could promote mean heat flux, improve the uniformity of cooling patterns and enhance heat transfer performance. A best nozzle number of 10 could be obtained by an equation fitting. Decreasing nozzle distance turns out to be detrimental to heat transfer. The reason comes from the collisions and interactions of two too adjacent nozzles. Based on choices in real practice, two types of arrays i.e. perpendicular and skew array have been discussed and compared. It is concluded that the skew array could obtain higher heat flux with more uniform distribution.