Session: 11-08-03: Fundamentals of Convection - Natural and Mixed Convection

Paper Number: 70129

Start Time: Monday, 05:40 PM

70129 - Numerical Simulation of Supercritical Rp-3 Aviation Kerosene Flow in a Circular Tube Under Different Gravity Conditions 

   A series of three-dimensional numerical simulations of the flow and heat transfer characteristics of RP-3 aviation kerosene in a circular tube under the condition of 0-15g gravity and supercritical pressure were carried out. The tube has an inner diameter of 1.8 mm, a wall thickness of 0.2 mm and a length of 300 mm. A uniform heat flow density equaling 400kW/m² is applied to the tube wall, neglecting the axial heat conduction inside the wall. The RP-3 aviation kerosene flows into the pipe at a fixed mass flow rate of 2.5g/s, an inlet temperature of 373K, and the inlet and outlet pressure of 5MPa.

  Results show that the difference in flow characteristics mainly exists in velocity and turbulent kinetic energy. The velocity increases along the length of the tube and is mainly affected by the level of gravity. When the level of gravity exceeds a certain critical value, the direction of gravity will begin to play a significant role. In horizontal flow, because the flow direction is perpendicular to the gravity and buoyancy, the velocity decreases with the increase of gravity level. When fluid flows vertically downward, the direction of flow is the same as the direction of gravity, which enhances the flow. The velocity increases as the level of gravity increases. In the vertical upward flow, although the buoyancy enhances the flow, the gravity hinders the flow, resulting in the vertical upward flow velocity slightly lower than the horizontal flow under the same gravity level. The turbulent kinetic energy of the fluid increases along the length of the pipe after the inlet region, the strength of which is mainly affected by the direction of gravity. Under the horizontal flow, the turbulent kinetic energy in different gravity levels is basically unchanged and larger than that of vertical flow. Under the vertical flow, the turbulent kinetic energy of downward flow is greater than that of upward flow. The higher the gravity level is, the greater the difference between the two will be. As for the heat transfer characteristics, the convective heat transfer intensity in the vertical flow is greater than that in the horizontal flow, because the temperature of the fluid in the vertical flow of the same section is higher than that in the horizontal flow. And this influence decreases with the length of the pipe. In the vertical downward flow, the buoyancy is opposite to the flow direction, which enhances the mixing of fluid microclusters with the surrounding fluid caused by the buoyancy and strengthens the heat transfer effect of the vertical downward flow. In the upward flow, the buoyancy is in the same direction as the flow, which limits the mixing of fluid microclusters with the surrounding fluid and weakens the heat transfer effect of the vertical upward flow, resulting in a lower heat transfer coefficient of the upward flow than that of the downward flow.

Presenting Author: Gu-Yuan Li Chongqing University

Authors:

Ke-Jie Ou Chongqing University
Ke-Fan Chen Chongqing University
Jia-Jia Yu Chongqing University
Jin Yu Chongqing Jiaotong University
Rui Chen Chongqing University
Gu-Yuan Li Chongqing University