Thermo-Structural Analysis and Deformation Prediction of Airfoil Fin Printed Circuit Heat Exchangers

Airfoil fin Printed Circuit Heat Exchangers (PCHEs) offer significant advantages in reducing flow resistance, promoting turbulence, and enhancing heat transfer performance due to their discrete fin configuration. However, compared with conventional continuous-channel structures, the geometric discontinuities and sharp trailing edges introduced by discrete fins tend to induce severe stress concentration at the fin roots, resulting in a more complex structural response. In this study, a PCHE core with NACA0020 airfoil fins is investigated. Finite element analysis combined with a sequential one-way thermo-structural coupling approach is conducted to characterize the fins’ stress and deformation behavior under high temperature and pressure. The plate region is evaluated based on the linear elastic stress criteria specified in ASME Boiler and Pressure Vessel Code Section III, while localized yielding regions such as the fin roots are assessed using an equivalent plastic strain indicator. Results indicate that the structural response of the PCHE core is dominated by pressure loading under the investigated operating conditions with ΔT = 18 °C and ΔP = 12.05 MPa, whereas thermal stress caused by constrained thermal expansion mainly modifies local stress distributions and has a limited effect on global deformation. Owing to the discontinuous support provided by discrete airfoil fins, the fin roots act as the primary load-transfer path and sustain higher stress levels. The maximum von Mises stress is observed at the trailing edge of the fin root on the high-pressure side, while the largest deformation occurs in the unsupported plate region and is governed by bending. Parametric analysis indicates that, within the investigated parameter range, a fully staggered fin arrangement promotes more uniform load distribution and exhibits the most favorable structural response. In contrast, increasing the fin chord length and relative thickness reduces the overall load-carrying capacity of the core. Finally, a power-law predictive correlation for the maximum total plate deformation was developed, showing that the parameter influence on plate structural response follows the order horizontal pitch (Lh) > vertical pitch (Lv) > channel etching depth (Le) > staggered pitch (Ls). In contrast, normalized sensitivity analysis of the maximum fin-root von Mises stress shows the order staggered pitch (Ls) > horizontal pitch (Lh) > vertical pitch (Lv) > channel etching depth (Le), indicating that global plate deformation and local fin-root response are governed by different structural mechanisms.