Study of Heat Transfer Enhancement for Water Heater

This paper aims to study the thermal efficiency of gas combustion for water heater. The water heater used in recreational vehicles comprises a combustion tube inserted in a water tank, in which the water is heated by the combustion heat of liquefied petroleum gases. The present study considers combustion reaction of propane gas and takes into account convective heat transfer of liquid water. An iterated boundary setting process is developed to solve gas combustion reaction and liquid water heat convection simultaneously. This investigation demonstrated the heat transfer augmentation of combustion tubes with embedded fins in the internal wall. The streamlines and temperature distributions of combustion gases and liquid water were both presented in this work. The present results indicated that the combustion tube with embedded fins have significant effects on thermal efficiency of the propane gas. By contrast, the affection of water flow rates and various arrangements of combustion tube, inlet and outlet in water tank are insignificant on the thermal efficiency.