Numerical Study on Heat Transfer of Inclined Jet Impingement With Explicit Crossflow

Abstract

Due to its high heat and mass transfer rate, especially near the stagnation region, jet impingement has been widely used in many applications, such as annealing of metal and plastic sheets, cooling of gas turbine blades and electronic components. However, the high heat transfer rate can be strongly affected by the crossflow coming from either the exhaust fluid in an array of jets or other sources. On the other hand, the inclination angle of injection also influences the jet impingement flow and heat transfer, and an inclined jet towards the crossflow may strengthen jet penetration. The combined effect of the crossflow and inclination angle on jet impingement heat transfer makes the problem even more complicated. This paper studied this effect numerically with various parameters, including the velocity ratio of jet to the crossflow, inclination angles, the crossflow temperature as well as the jet-to-target spacing. The heat transfer coefficient distribution and its peak value at the stagnation region are examined and compared. Results show that at small jet-to-target spacing the crossflow can enhance the heat transfer, while at large jet-to-target spacing the heat transfer is reduced due to the crossflow as well as inclination. In some cases jet impingement heat transfer can be higher with an inclined angle than that of a normal jet, given the same crossflow ratio.