Experimental Investigation of Effect of Entrainment on the Heat Transfer Characteristics of Multiple Heated Impinging Jets

ABSTRACT

Heat transfer characteristics of isothermal multiple jets impinging onto a flat surface have been extensively studied in literature. However for heated impinging jets, entrainment effects can significantly affect the heat transfer characteristics and such data is scarce in literature. An experimental investigation of the convective heat transfer characteristics and entrainment effects of multiple heated air jets impinging onto a flat surface is reported here. The local distribution of Nusselt number with adiabatic wall temperature as the reference temperature has been obtained. The entrainment effects are reported in terms of a non dimensional temperature called the effectiveness. Effects of nozzle to plate distance, jet to jet spacing, and Reynolds number on the distribution of the Nusselt number and effectiveness are reported here. The Nusselt number obtained here is independent of jet temperature. The effectiveness is independent of the Reynolds number as well as the jet temperature. The Nusselt number can thus be used with a single effectiveness curve for performing heat flux calculations. Correlations have been developed for the stagnation and the average Nusselt number and effectiveness in terms of jet configuration parameters.

---

Full Text (PDF)

© 2010 Research Publishing Services