Heat transfer characteristics of RP-3 kerosene at supercritical pressure in a vertical circular Tube

This paper experimentally investigates the heat transfer characteristics of Chinese RP-3 kerosene in the critical condition in a vertical tube. During the experiment, the inlet Reynolds number of the fuel changes from 3 × 10 ³ to 4 × 10⁴, and the Prandtl number changes from 2.8 to 9. Under constant pressure (5 MPa), the heat transfer characteristics of Chinese RP-3 kerosene in the critical condition were measured. The results showed that under constant heat flux (100 to 500 kW/m²), a fixed mass flow rate (7.2 kg/h), and a fixed inlet temperature (400 ± 3 K), the heat transfer characteristics of RP-3 kerosene are different for the upward flow and the downward flow; the heat flux and flow direction both influence the heat transfer characteristics. The pseudocritical temperature is a critical parameter to determine heat transfer enhancement under corresponding conditions. The results also show that the buoyancy effect still influences the heat transfer characteristics when the values of Gr/Re^2.7 and Bo ^*are lower than 10^-5 and 6 × 10^-6 for the latter part of the test section, respectively, and the effect of flow acceleration can be ignored under the experimental conditions. Based on the experimental data, a reliable heat transfer correlation has been proposed to calculate the Nu number for the normal and enhanced heat transfer process of supercritical fuel in a vertical tube.