Heat transfer studies of surface synthesized by chemical vapor deposition

In this paper, heat transfer characteristics of nickel coating over aluminium and mild steel are examined using jet impingement cooling. A rectangular sheet of dimension 10 cm x 3.5 cm x 0.1 cm taken as the test piece is coated with 4 g nickel acetate tetrahydrate precursor in the chemical vapor deposition (CVD) process for 85 mins. Heat transfer characteristics are studied on three layers of nickel coating (no coating, first coating, and second coating) with an impinging air-jet velocity of 3.5 ms(-1)and 6 ms(-1). The effect of Reynolds number, the thickness of the coating, jet velocity, distance from the stagnation point, and nozzle diameter on the heat transfer coefficient are investigated. The results show an increase in convective heat transfer characteristics with the Reynolds number, the thickness of the coating, and the nozzle diameter and a substantial decrease with deviation from the stagnation point.