IMPACT OF INCLINATION ON POOL BOILING HEAT TRANSFER ON A PARTIALLY ANNULAR TUBE WITH CLOSED BOTTOM INLET

An experimental study was conducted to investigate the effect of inclination angle on the pool boiling heat transfer of a stainless steel tube immersed in saturated water at atmospheric pressure. In this setup, the lower fluid inlet passage into the annular space was closed, and the annular space constituted 56% of the total heated length. The study found that increasing the inclination angle generally decreased the heat transfer coefficient. At an inclination angle of 95°, the critical heat flux was observed at 60kW/m2. The formation of bubble clusters inside the annular space and the generation of pulsating flow were identified as the main mechanisms driving heat transfer. Based on the experimental data, a new correlation was developed to predict the heat transfer coefficient as a function of inclination angle and heat flux, with a predictive accuracy within ±5%.