单回路脉动热管传热性能的试验

通过对单回路紫铜-水脉动热管在风冷方式和定热流加热条件下,稳定运行时的传热性能的试验研究,得到管壁温度沿管长的变化规律,冷热段均温和温降(或温升)、传热温差、传热热阻随传热功率的变化特性.分析了充液率和管径对热管传热性能的影响.结果表明:冷热段均温、传热温差随传热功率的增加而增大,传热热阻随传热功率的增加而减小；小传热功率时,传热热阻对传热功率、管内径和充液率的变化较为敏感；减小充液率,增大管内径,增加传热功率可明显降低热管的传热热阻；较高传热功率时,充液率、管内径和传热功率对传热热阻的影响较小,影响传热热阻的主要因素是冷却热阻,可通过增加管外径或改善冷却条件来降低传热热阻,提高传热性能.

Experiment on heat transfer characteristics of single loop pulsating heat pipe

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 tempe-rature 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 diameter,charging ratio and heat power have slight effect on thermal resistance for high heat input power.The main factor of thermal resis-tance is cooling thermal resistance.Increasing external diameter or improving cooling condition may reduce the thermal resistance of heat pipe and improve heat transfer performance of heat pipe.