高效热管传热工质的热力学研究

用精密绝热量热法测量了高效热管传热工质在78～320 K温区内的热容.结果表明，在78.41～245.19 K， Cp/(J?K－1?g－1)=0.5369T＋0.07279.在274.08～318.51 K， Cp/(J?K－1?g－1)=3.403±0.020.在245～274 K， 高效热管传热工质发生固液相变.其相变温度、相变焓和相变熵分别是271.21 K、353.6 J?g－1，和1.304 J?K－1?g－1.根据热容与温度的定量关系和热力学函数之间的关系，得到了以标准温度298.15 K为基准的高效热管传热工质的热力学函数.

Thermodynamic Investigation of the High Efficient Working Fluid Used for a Heat Pipe

The heat capacities of the high efficient working fluid used for a heat pipe(Cp) were measured by a low temperature adiabatic calorimeter over the range from 78 to 320 K. No thermal anomaly was observed in the range from 78 to 245 K and 274 to 320 K. The functions of Cp vs T were established based on the measured heat capacity data by least-square fitting method to be Cp/(J?K－1?g－1)=0.5369T＋0.07279 in the range of 78.41～245.19 K. The freezing point, freezing enthalpy and freezing entropy of it were determined to be 271.21 K, 353.6 J?g－1 and 1.304 J?K－1?g－1, respectively. The heat capacities of it are near a constant to be Cp/(J?K－1?g－1)=3.403±0.020 in the range 274 K≤T≤320 K. According to the relationship of thermodynamic functions, the thermodynamic function values of the working fluid were calculated in the temperature range of 280～320 K with 5 K intervals.