Research on heat transfer characteristics of kerosene at supercritical pressure in circular tubes

Understanding the heat transfer characteristics of supercritical kerosene is significant for the corresponding engineering design, and the special properties of supercritical fluids make the heat transfer more complicated. In this article, the heat transfer characteristics of kerosene under the condition of supercritical pressure, high heat flux and high velocity were investigated and analyzed. The experimental results show that with the increase of flow velocity and inlet temperature at supercritical pressure, the heat transfer coefficient of kerosene increases and the pressure has little effect on the heat transfer coefficient. Experiment shows that when the inlet temperature is high, coking phenomenon may occur to affect heat transfer. Considering the particularity of the properties of supercritical kerosene and its violent changes of physical parameters in the flow space, dynamic viscosity and thermal conductivity were introduced to modify the traditional kerosene heat transfer correlation. Simultaneously taking the changes of the physical properties of kerosene in time dimension into consideration, the temperature probability density function (PDF) was introduced to obtain the time average physical property from the perspective of probability and statistics. The results show that when the inner wall temperature exceeds 400 degrees C, the kerosene heat transfer correlation with radial correction factors can reduce the predicted average error to 13%. With the proper selections of the standard deviation, the PDF model can reduce prediction error of 6% to 11% at high wall temperature. The results of this article provide reliable support for the reasonable design of the relevant equipment.