Isobaric Specific Heat Capacity Measurement in the Trans-Critical Temperature Regions for Kerosene RP-3 under Pressures of 6–8 MPa

A new experimental method was proposed: the enthalpy difference method to measure the isobaric specific heat capacity of RP-3 at 6–8 MPa, 338.1–788.3 K. According to the calculation of the uncertainty of the relevant experimental apparatus, compared with the normal measurement method, the enthalpy difference method can reduce the uncertainty from 5.17 to 3.65%. The results were verified by using n-decane. The results showed that compared with National Institute of Standards and Technology (NIST), the average error of the experimental results of n-decane was 1.8%. Experimental results show that the measured peak isobaric specific heat capacity of RP-3 in this range is 3.93 kJ/kg (slightly less than the true value of the substance). As the pressure increases, its peak value gradually decreases until it becomes flat.