液氮中导线加热丝的沸腾传热特性研究

BOILING HEAT TRANSFER OF LIQUID NITROGEN AROUND A HEATING WIRE

本文以50μm的磷青铜丝作为加热丝和测温元件,采用控制热流密度的方式测量了0°-90°倾角下加热丝在液氮中的沸腾曲线,结果表明:核态沸腾在增加热流密度时存在滞后现象;Bromley公式能准确的预测出膜态沸腾换热曲线的斜率,Zuber模型和Kutateladze公式预测水平细加热丝的CHF误差在15%以内;对于Leidenfrost热流密度的预测,常温流体的计算模型并不适用;CHF随倾角的变化较大,且大于加热平面在相同倾角下的变化幅度。

Boiling heat transfer of liquid nitrogen were test around a heating phosphorous bronze wire under different inclination angles between 0?and 90? Hysteresis was found in nucleate boiling when increasing heat flux. Bromley formular was proven to be effective in predicting the slope of film boiling curves, and Zuber's model and Kutateladze's model could predict CHF with an error less than 15%. The results of the experiment also indicated that the relations used to predict Leidenfrost heat flux of normal fluid were ineffective for liquid nitrogen, and Vashinev's formula underestimated the variation of CHF under different inclination angles.