Investigation on thermal management for electrified aero engines using experiments in a modular air duct

Abstract

Effective thermal management is crucial for the development of future electrified aircraft propulsion sys�tems1 . Among the critical phases, take-off scenarios pose particularly high demands on cooling systems, whereas the aerodynamic drag during cruise flight has to be kept minimal. In this study, a novel experimental test stand designed specifically to investigate cooling ducts in such propulsion systems, with a focus on fuel�cell-based systems, is introduced. Given the versatility in designs of nacelle-integrated electrified aero engines, our approach provides for a high flexibility in cooling duct design. This encompasses aspects such as the po�sitioning and geometry of heat exchangers (HEX), inlet and outlet configurations, duct flow optimization for uniform guidance within the nacelle, and the integration of additional fans to enhance airflow. Various system components, including particle separators, grids, and filters, are incorporated to examine their thermal behavior within a controlled experimental environment, facilitating a fundamental understanding of their interactions. The experimental setup, depicted in Figure 1, consists of a modular air duct with a cross-sectional area of 20cm × 20cm. These modules allow for the study of heat and fluid flow dynamics in cooling ducts across a range of configurations, including straight and curved geometries, diverse HEX and fan configurations, and the incorporation of compressors. Module segments are designed to be ex- and interchangeable and made from acrylic glass to enable optical measurements of fluid flow, while additional short modules facilitate probe-based measurements. The study observes heat flux and pressure losses within these systems and conducts thorough fluid flow analysis. Furthermore, the experimental data serves as a valuable resource for validating numerical models of cooling ducts, enhancing the accuracy and reliability of future design iterations.