المجلة الدولية للعلوم والتقنية

An experimental investigation is performed to study the effects of the plate angle, jet-to-plate spacing and Reynolds number on the local heat transfer distribution between an obliquely smooth flat plate and impinging circular air jet. In the tests, plate angles of 90°, 60°, and 45° were chosen, with 90° indicating a vertical stream. Depending on the nozzle situation jet-to-plate distance (L/D=2, 4, 6 and 8), its Reynolds number (1.2013E04,1.5E04 and 2.3016E04). Temperatures recorded from an infrared thermal imaging camera are used to assess the localized coefficients of heat transfer. The results show that the heat transfer coefficient, h is higher at the stagnation region and decreases gradually at the outlet region. The heat transfer coefficients increase with higher Reynolds numbers and a lower L/D ratio. In relation to the geometric impingement point, the displacement of the plate's minimum temperature point (region of maximal heat transfer coefficient) was measured. Results of experiments indicated that for a given position this displacement increases with increasing the plate angle (less than 90°), and the displacement occurred on the compression side of the plate. Keywords: Heat transfer .air impingement .Obliquely flat .Nozzle shape .Thermal imaging.