基于流动型定压比热容测量方法，本文设计了一套适用于高压低温的碳氢燃料定压比热测量系统，温度测量范围： 233.45~313.65 K，最高压力达到10 MPa，测量定压比热容的扩展相对不确定度为1.24%~2.20%（置信因子k=2）。实验在通过纯物质正己烷和质量比1:1正庚烷-正辛烷二元混合物对测量系统可靠性进行验证的基础上，测试了3种碳氢燃料A、B、C压力：0.7、1.5、3和6 MPa，温度：233.45~313.65 K的比热值，结果表明：3种燃料在4种压力下，定压比热分别随温度的增加而增加；在低温区，燃料A、B受温度的影响程度要小于燃料C；压力基本不影响碳氢燃料低温定压比热。该低温高压比热测量系统的建成为进一步开展碳氢化合物及其混合物低温定压比热的研究创造了条件。

Based on the flow type measurement method of isobaric specific heat, a new measurement system for isobaric specific heat of hydrocarbon fuels at low temperature and high pressure was designed in this paper. The tested temperature range was from 233.45 to 313.65 K and the pressure was up to 10 MPa. The relative expanded uncertainty of isobaric specific heat measurement was identified as 1.24% to 2.20% (the coverage factor k=2). Firstly, the pure substance n-hexane and the binary mixture of n-heptane and n-octane with the mass ratio 1:1 were used to calibrate the isobaric specific heat measuring system. Then three kinds of hydrocarbon fuels were tested at pressure 0.7 MPa, 1.5 MPa, 3.0 MPa and 6.0 MPa and temperature from 233.45 to 313.65 K.The results showed that isobaric specific heat of the three kinds of hydrocarbon fuels increases with the temperature. In the low temperature region, the temperature influence on fuel A and B is less than that on fuel C. Pressure marginally affects the low temperature isobaric specific heat of hydrocarbon fuels. The presented measurement system is believed to serve as steppingstone for the further study of isobaric specific heat of hydrocarbons and their mixtures at low temperature.

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基金项目：青年科学基金项目（21306147）；国家博士后科学基金项目（2013M532044）