Thermal characteristics of a premixed impinging flame at different impingement plate temperature

Experiments were carried out to investigate the heat transfer characteristics of a premixed LPG/air circular flame jet impinging upwards normally on a watercooled flat rectangular plate. The temperature of the cooling was maintained at 38°C, 58°C or 78°C so as to vary the impingement plate temperature. The effects of Reynolds number, equivalence ratio and nozzletoplate distance on the heat flux characteristics when the impingement plate was operating under different cooling water temperatures were examined. The selected Reynolds numbers were 500, 1000 and 1500 and the selected equivalence ratios were 0.9, 1.0, 1.1 and 1.2. The nozzletoplate distance was varied from 3d to 6d with an interval of 1d. The fireside impingement plate temperature was enhanced as the cooling water temperature was increased, whereas the difference between the fireside impingement plate temperature and the cooling water temperature was reduced. The heat flux received by the impingement plate was suppressed with the cooling water temperature was increased. The average heat flux was the highest at the cooling water temperature of 38oC, and the lowest was obtained when the cooling water temperature was increased to 78°C.