Mass flow distribution characteristics of supercritical fuel oil in parallel tubes under non-uniform heating conditions

To study the flow distribution characteristics in parallel tubes under leaner non-uniform heating, a transient simulation of supercritical fuel oil RP-3 flowing through parallel tubes was conducted in this paper, and the influence factors and their mechanisms were studied. The influence of different uniform heating conditions on flow distribution characteristics was investigated by steady-state simulations with average heat flux in the range of 2.7−3.9 MW/m2 and heat flux growth rate in the range of 0.025−0.225. The results show that the influence factors include pseudo critical state, pyrolysis, heat conduction, and shunting resistance difference. The positive feedback of pseudo-critical state and pyrolysis would increase the difference in flow distribution between the two tubes. The flow distribution discrepancy will be lessened by the negative feedback of the shunting resistance differential and heat conduction. When the average heat flux remained constant at 3.7 MW/m2, the growth rate of the heat flux increased eight times, which resulted in an 11% rise in the relative standard deviation of mass flow. Non-uniform heating conditions mainly guide the flow distribution deviation and have a slight influence on the final flow distribution characteristics.