Numerical simulation study on the heat transfer and flow characteristics of fuel/lubricating oil heat exchanger based on triply periodic minimal surface (TPMS)

Abstract

Lattice structures based on triple periodic very small surfaces (TPMS) have been widely studied in the field of heat transfer due to their complex geometries that offer the advantage of increasing the heat exchange area and enhancing convection phenomena. However, the influence of specific structural parameters of a particular TPMS structure type on the overall flow and heat transfer characteristics remains understudied. In order to investigate the relationship between the structural parameters and the heat transfer and flow properties to meet the thermal design requirements, this paper designs a heat exchanger based on a Gyriod-type TPMS structure according to the actual working conditions of fuel/lubricating oil heat exchanger in an aero-engine. Numerical simulations are carried out using the SST K-ω turbulence model, and the relationships between the three design parameters (uniform lattice size l, unidirectional lattice size lsingle, and hot/cold fluid porosity ratio εh/εc) and the key characteristics, such as the flow resistance and convective heat transfer coefficient, are calculated. Among them, the structural parameters l and lsingle are mainly used to improve the heat transfer effect by changing the heat transfer area of the heat exchanger, and the parameter εh/εc can largely improve the convective heat transfer coefficient and optimize the flow state by changing the distribution of the cold and hot fluid channels. In the studied range of structural parameters, the convective heat transfer coefficients of cold and hot fluids of the εh/εc = 2 model under the same working condition are 34 % and 26 % higher than those of the 10 mm model, and the average synergistic angle of the cold fluid surface on the XY center plane is 77.55 degrees.