倾角及充液率对并联式脉动热管传热性能的影响

以超纯水为工质，在不同的充液率（35%、50%、70%）和倾角（60°、90°）下，对并联式脉动热管的传热特性进行实验研究，分析在不同加热功率下充液率和倾角对并联式脉动热管壁面温度、加热端与冷凝端温差、传热量及传热热阻的影响，并对传热热阻进行不确定度计算。实验结果表明，充液率和倾角对脉动热管的传热特性影响显著。倾角为90°时，3种充液率条件下，充液率为35%和50%时的壁面温度脉动稳定性要优于充液率为70%的情况，并且充液率为50%的传热热阻最小，加热端与冷凝端温差最小，充液率为70%的传热热阻最大，加热端与冷凝端温差最大。充液率为50%，倾角为60°和90°时，在相同的加热功率下，倾角为60°的壁面温度的脉动幅度较大，传热热阻较高，传热极限变窄，传热效果明显差于倾角为90°的情况。

Effect of inclination angle and liquid filling ratio inclination on heat transfer characteristics of parallel type pulsating heat pipe

With ultrapure water as working medium, the heat transfer characteristics of parallel type pulsating heat pipe with three different liquid filling ratios (35%, 50% and 70%) and two different inclination angles (60°and 90°) were investigated experimentally and analytically. On the basis, the effect of liquid filling ratio and inclination angle with different heating powers on the properties of parallel type pulsating heat pipe, namely wall temperature,temperature difference of heating section and condensing section, heat transfer quantity and thermal resistance were studied. Meanwhile, the uncertainty of thermal resistance was also calculated. The experimental results show that liquid filling ratio and inclination angle can effectively influence heat transfer characteristics of pulsating heat pipe. When the inclination angle was 90°, on the condition of different liquid filling ratios, pulsation stability of wall temperature with liquid filling ratios of 35% and 50% were superior to that of 70%. When the liquid filling ratio was 50%, the thermal resistance and temperature difference of heating section and condensing section were the smallest. On the contrary, when the liquid filling ratio was 70%, the corresponding thermal resistance and temperature difference were the largest. In addition, with liquid filling ratio of 50% and inclination angle of 60° and 90°, pulsation range of wall temperature and thermal resistance with 60° were large, and the corresponding heat transfer limitation became narrow with the same heating power comparedwith inclination angle of 90°. Therefore, heat transfer effect with liquid filling ratio of 60° was obviously worse than that with liquid filling ratio of 90°.