A study on heat transfer characteristics by impinging jet within a few amounts of mist

Abstract

• Heat transfer coefficient distribution. • Jet temperature distribution with and without mist. • Amount of heat evaporate in the main flow. • Temperature behavior on the heated plate. Jet impingement is used for cooling, drying purposes; typical applications include cooling turbine blades and electrical equipment, drying of textiles and other wetted surfaces and cooling of metal plates. The flow dynamics and heat and mass concentration in the turbulent boundary layer on the flat heated plate have been used to improve the heat transfer coefficient. Wide range of factors that have an effect on heat and mass concentration at several patterns which are X/D = 4, 7, 9 and velocity 15 m/ are analyzed. The experimental results indicate that, the heat transfer coefficient rate improved by 21% and 32% in case of M = 3 mg/s and 6 mg/s respectively, compared with the case without addition of mist. The amount of heat evaporates in the main air flow is almost twice, in case of M = 3 mg/s, ∆ Q = 8.81 W and when M = 6 mg/s, ∆ Q = 15.39 W at constant velocity distribution 6 m/s.