U型花瓣螺纹管中超临界航空煤油换热数值分析OA

In order to design high-performance air-fuel heat exchangers,the U-shaped petal-ribbed tube is proposed.Nu-merical study on heat transfer of supercritical RP-3 aviation kerosene is conducted.The distributions of wall tempera-ture and heat transfer coefficient along the flow direction are analyzed,and the non-uniform heat transfer is analyzed through the temperature,velocity,mass flow velocity,secondary flow,and turbulent kinetic energy distributions.The swirl effect generated by the coupling of ribbed structure and bend structure is investigated.The comprehensive heat transfer performance is evaluated,and the relationship between Nusselt number and secondary flow intensity is estab-lished.Results indicate that the weak secondary flow caused by ribbed swirl effect and the symmetric heat transfer in petal layers are observed in the upstream vertical section.The asymmetric secondary flow and petal-layer heat transfer appear in the bend section due to the centrifugal force,and the centrifugal force has a certain distortion impact on sec-ondary flow and heat transfer in the downstream vertical section.The centrifugal force significantly enhances the heat transfer in the bend section,with a maximum heat transfer coefficient of 35.75 kW/(m2·K).The comprehensive heat transfer coefficient is in the range of 1.0～1.7,which has a prominent enhanced heat transfer effect compared to ordinary U-shaped circular tubes.Decreasing the operating pressure and increasing the petal number all play a role in enhancing the secondary flow.