Numerical Study of Turbulent Convective Heat Transfer of Aviation Kerosene in Coiled Pipes

Turbulent flow and convective heat transfer of kerosene in coiled pipes with different wall boundary conditions and curvature radii of coiled pipes are numerically studied. The Reynolds-averaged Navier-Stokes equations are solved by finite volume method and the realizable k-epsilon model is applied for turbulence modeling. The fluid media is aviation kerosene with an inlet supercritical pressure of 3MPa and an inlet temperature of 400K. The present results provide temperature and velocity fields as well as distributions of turbulence kinetic energy and streamlines at different axial locations along the flow direction. The Nusselt number at the outer side of the pipe wall is higher than that at the inner side by 75%. Compared to a straight pipe with the same pipe radius of 6mm and inlet flow conditions, the coiled pipe with a curvature radius of 192.5mm can increase the averaged heat transfer coefficient by 28.5%. Meanwhile, it is found that when the curvature ratio increases, the effect of secondary flow in the cross section of pipe is more significant and the heat transfer effect at different locations of the pipe wall also changes significantly. In addition, the present results also reveal that heat transfer deterioration takes place for the kerosene flow in coiled pipe with an increased wall heat flux due to the state change of kerosene from liquid to supercritical