Isobaric specific heat capacity measurements of n-decane at super-critical pressures

In order to measure the isobaric specific heat capacity(c_p)of hydrocarbon fuels at high temperature and high pressure conditions accurately, a new experimental method and device were developed based on the relation between c_p and enthalpy. The influence of heat loss on the measurement accuracy can be reduced significantly based on this method. The relative uncertainty of the method for isobaric heat capacity measurements is 3.7% in the temperature range of 300K to 800K according to the uncertainty analysis. Validation experiments were conducted by measuring the c_p of n-decane(3MPa and 5MPa, 312~797K). The test results indicate that the average absolute deviation(AAD)is below 1.8%, and the maximum absolute deviation(MAD)is 4.3%, excluding the pseudo-critical region where the MAD is 7.6% due to sharp variations of isobaric heat capacity. Test results are tabulated in the temperature range of 675K to 797K on 3MPa and 5MPa, which extended the data range of existing data. This method can be also applied to other fluids in similar operating conditions.