Session: 06-09 Hybrid Electric Propulsion

Paper Number: 152670

Strut-Based Porous Media Heatsinks for High-Performance Power Electronics Thermal Management in Electrified Aircrafts 

Efforts to fly net zero by 2050 have promoted innovations in aircraft and
system designs. With the onset of electrification and advanced propulsion tech-
nologies, electric aircrafts require efficient, reliable, and power-dense power elec-
tronics (PE) systems. The choice of the converter topology is crucial and is,
therefore, under intense discussion. Multi-level inverters are one promising so-
lution. The emergence of these converter topologies with a larger number of
switches makes reliable forced and even natural convection air cooling a feasible
option for PE in aircraft. Electrified propulsion systems however, are challenged
with high heat load in electrical components and their thermal management. At
the limit of applicability, conventional heatsink structures may not show suffi-
cient performance, necessitating the exploration of alternative cooling struc-
tures. The need for high heat dissipation rate, robust design and lightweight
heatsinks has led to the development of strut-based porous media structures for
forced air cooling. Advancements in metal 3D printing makes it an even viable
option to manufacture complex periodic open cellular structures (POCS) effi-
ciently and cost-effectively. Since cooling systems contribute significantly to the
overall mass and volume of a PE system, carefully optimized cooling structures/
heatsinks are required to ensure efficient and safe operation in aviation. In this
work, various POCS geometries such as Simple Cubic (SC), Kelvin, Octet, and
Cody-Centered Cubic (OCC and BCC) are investigated based on their thermo-
hydraulic performance using Computational Fluid Dynamics (CFD) methods
by varying the cell size and porosity. POCS heatsinks are compared against a
commercially available conventional plate fin heatsink. CFD results from the
conjugate heat transfer (CHT) simulations are validated against the experimen-
tal results of multiple configurations i.e., forced-air cooling using conventional
aluminium heatsink and the 3D-printed AlSi10Mg heatsinks. POCS structures
with porosities ranging from 50-90% are considered with 2mm, 5mm, and 10mm
unit cell sizes for numerical simulations. Empirical correlations driven by this
work and also supported by the information in literature are fed to a 0D sim-
ulation tool developed in-house in MATLAB Simulink/ Simscape to facilitate
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precise and computationally effective simulations. Initial studies with the 0D
thermal resistance network predict the CFD results within ±5% range. The ex-
perimental results for one of the POCS heatsinks showed an absolute deviation
of nearly 2% when compared to the CHT simulations. Based on the numerical
results, it was found that for a similar cell size and porosity, Kelvin cell heatsink
geometry exhibits the best thermal performance. At the same time, the pressure
drop is lowest with the BCC strut geometry. In terms of overall effectiveness
based on lowest junction temperature and weight, SC heatsink outperforms all
the other designs.

Presenting Author: Dikshant Sharma Chair of Aeroengine Design, Brandenburg University of Technology Cottbus-Senftenberg

Presenting Author Biography: Dikshant Sharma received the bachelor's degree in mechanical engineering from Panjab University, Chandigarh, India in 2019 and a master's degree in power engineering from BTU Cottbus-Senftenberg, Germany in 2022. He is currently working as a Research Associate/ PhD student at the Chair of Aeroengine Design, BTU Cottbus-Senftenberg. His primary research includes thermal design of components for electrified aircrafts and innovative heatsink studies for battery and power electronics cooling.

Authors:

Dikshant Sharma Chair of Aeroengine Design, Brandenburg University of Technology Cottbus-Senftenberg
Lukas Radomsky Institute for Electrical Machines, Traction and Drives, Technische Universität Braunschweig
Akilan Mathiazhagan Chair of Aeroengine Design, Brandenburg University of Technology Cottbus-Senftenberg
Ghaieth Hammami Institute for Electrical Machines, Traction and Drives, Technische Universität Braunschweig
Karunakar Reddy Konda Chair of Aeroengine Design, Brandenburg University of Technology Cottbus-Senftenberg
Majid Asli Chair of Aeroengine Design, Brandenburg University of Technology Cottbus-Senftenberg
Klaus Höschler Chair of Aeroengine Design, Brandenburg University of Technology Cottbus-Senftenberg
Regine Mallwitz Institute for Electrical Machines, Traction and Drives, Technische Universität Braunschweig