为了满足航空发动机换热器高换热特性、低阻力变化的设计要求,开展三重周期极小曲面(TPMS)换热器结构在航空发动机工作条件下的探索.本文选取了Gyroid,I-WP,Diamond,Primitive和Fischer-Koch S 5 种具有较大潜力的TPMS换热器结构展开研究,采用数值仿真的方法,研究在航空发动机工作条件下,5 种TPMS换热器的流动换热特性,分析质量流量变化对传热系数和压降的影响,总结出空气侧和燃油侧的摩擦系数和努塞尔数与雷诺数的关联式,并与螺旋套管(TTHC)换热器进行对比分析.结果表明:在传热性能方面,TPMS换热器传热系数沿结构横向呈周期性变化;在冷侧,TPMS换热器的努塞尔数由高到低排列顺序为Primitive,I-WP,Gyroid,Diamond,Fischer-Koch S;在阻力性能方面,I-WP换热器摩擦系数最低,压降损失最小.与TTHC换热器相比,5 种TPMS换热器流动情况更加复杂,努塞尔数和摩擦系数均得到提高,I-WP换热器摩擦系数提升得最低,提升值为0.705;Primi-tive换热器努塞尔数提升得最高,提升值为为833.66.
Study on Flow and Heat Transfer Characteristics of Air-fuel Heat Exchanger based on TPMS
In order to meet the design requirements of aero-engine heat exchanger with high heat transfer characteristics and low drag variations,the exploration of triple periodic minimal surface(TPMS)heat exchanger structure under aero-engine operating conditions was carried out.In this paper,five TPMS heat exchanger structures with high potential were selected for study,namely,Gyroid,I-WP,Diamond,Primitive and Fischer-Koch S.Numerical simulation was used to study the flow and heat transfer charac-teristics of the five TPMS heat exchangers under the operating conditions of the aero-engine,analyse the effects of mass flow change on the heat transfer coefficient and the pressure drop,summarise the friction coefficients of the air side and the fuel side and the correlations between Nusselt and Reynolds numbers,and make a comparative analysis with that of the tube-in-tube helical coil(TTHC)heat exchanger.The results show that the heat transfer coefficient of the TPMS heat exchanger varies periodically along the structure lateral distance;and the Nusselt number of the TPMS heat exchanger is ranked in the order Primitive>I-WP>Gyroid>Diamond>Fischer-Koch S on the cold side;the I-WP heat exchanger exhib-ites the lowest friction coefficient and pressure drop loss in terms of resistance performance.Compared with TTHC heat exchanger,the five TPMS heat exchangers have more complex flow conditions and im-prove Nusselt numbers and friction coefficients,in which the I-WP heat exchanger has the lowest friction coefficient enhancement of 0.705;the Primitive heat exchanger has the highest Nusselt number enhance-ment of 833.66.
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