Abstract:The heat transfer characteristics of steady state for single loop red copper-water pulsating heat pipe were investigated under the conditions of air-cooling and constant heating power. The characteristics of wall temperature distribution along tube length, and the variety rules of condenser and evaporator temperature rise or drop, heat transfer temperature difference and heat transfer thermal resistance with heat input power were discussed. The effects of charging ratio and pipe diameter on heat transfer performance were also analyzed. The results show that the heat transfer temperature difference and the average temperature of condenser and evaporator increase with the increasing of heat transfer power, while thermal resistance decreases. The effects of pipe diameter, charging ratio and heat power on thermal resistance are obvious for small heat input power. Reducing filling ratio or increasing internal diameter and heat power can reduce thermal resistance of heat pipe significantly. However, pipe