Numerical Study on Thermodynamic Performance of Shell-and-Tube and Compact Printed-Circuit Heat Exchangers for Aero-Engine Lubricating Oil System

To address the continuously increasing thermal load of aero-engines, fuel/lubricating oil heat exchangers are evolving toward higher heat transfer efficiency, lower flow resistance, and lighter weight. This paper numerically compares the thermo-hydraulic performance of a conventional shell-and-tube heat exchanger (STHE) and three typical types of printed-circuit heat exchangers (PCHEs) for aero-engine applications. The three PCHE configurations fall into two categories based on their flow channel geometries: continuous-rib structures (straight and Z channels) and a discontinuous-rib structure (airfoil channel). All models are established under identical core volume and equivalent diameter to ensure a fair comparison. The results show that the airfoil-channel PCHE achieves the best overall performance. Compared with the STHE, it increases the heat transfer rate by 63%, reduces flow resistance by 76%, expands heat transfer area by 125%, and reduces operating weight by 60%. Flow field analysis reveals that the airfoil channel enables efficient heat transfer without excessive flow resistance through three key mechanisms: leading-edge impingement, periodic boundary layer reconstruction, and uniform flow mixing. This study provides an important reference for the selection and optimization of high-efficiency compact heat exchangers in aero-engines.