To investigate the alternative application characteristics of 3D printed regenerative-cooling channels in the thrust chamber of liquid rocket engines,3D printed stainless steel 304 rectangular minichannels with sinusoidal wave internal surface structures and varying roughness levels are developed.These minichannels feature a cross-sectional dimension of 2.0 mm×2.0 mm,with specified roughness values of 6.3,25.0,and 100.0μm,while the measured actual roughness(Ra)values are 11.88,12.70,and 17.53 µm,respectively.By utilizing a combination of the high-temperature resistivity method and pixel method,the actual inner diameters and wall thicknesses of three types of 3D printed channels are acquired.This process corrects the internal wall temperature and heat flux density associated with the flow of rocket kerosene.Subsequently,an experimental research method is developed to investigate the heat transfer characteristics of rocket kerosene within 3D printed rough channels.Experimental parameters include a pressure range of 15-20 MPa,mass flow rates between 12 450 and 24 900 kg·m-2·s-1,heat flux densities from 5 to 15 MW·m-2,and fluid temperatures from ambient to-150℃.The research indicates that the heat transfer characteristics of rocket kerosene flow are influenced by heat flux density,fluid temperature,and mass flow rate.The heat transfer coefficient increases by approximately 25％-33％for fluid temperatures ranging from 50 to 135℃.With heat flux densities varying from 5.0 to 15.0 MW·m-2,the heat transfer coefficient increases by 8.3％.Additionally,for mass flow rates within the range of 12 450-24 900 kg·m-2·s-1,the heat transfer coefficient shows a significant increase of 60.2％.Enhancing roughness improves the heat transfer of rocket kerosene flow,with an increase in roughness from 11.88 μm to 17.53 μm resulting in over a 20％enhancement in heat transfer.
3D printingrectangle channelheat transferroughnessrocket kerosene
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