Computational characterization of millimetre-wave heat exchangers with an AlN:Mo susceptor of multiple cylindrical elements

Abstract

A concept for a millimetre-wave (MMW) heat exchanger (HX) featuring AlN:Mo ceramic composite structures as electromagnetic absorbing elements (susceptors) has been recently introduced as a receiving device in power beaming applications. Earlier computational studies of electromagnetic and thermal processes have shown reasonable energy efficiency and exceptional uniformity of MMW-induced temperature fields in a single cubic susceptor with concentration of Mo doping on the level of 3–4% by volume. As part of ongoing research, a MMW HX comprised of an array of cylindrical susceptors is proposed to potentially enable increased robustness against thermal stress and reduced manufacturing cost. In this paper, we computationally study the effects driven by such a change and demonstrate feasibility of the designs based on multiple cylinders. We present the output of electromagnetic and coupled electromagnetic-thermal simulations of a prospective physical prototype of a HX with five cylinders on a square metal base plate. Three alternative layouts with four, nine, and sixteen cylindrical elements that are suggested by the highest density packing of equal circles in a square are also analyzed. It is shown that, in comparison with the previously studied case of a single cubic susceptor, energy efficiency of all systems with Mo = 3–4% is down from 50–55% to 35–45%. While temperature distribution within each individual cylinder remains highly uniform, maximum temperatures of different cylinders may be different by up to 30–40 °C; when the angle of incidence deviates from normal, this difference further increases: e.g. when the angle is 10^°, in the sixteen-cylinder system, it may reach 120–130 °C.

Keywords:

• Ceramic susceptor
• electromagnetic heating
• energy efficiency
• millimetre-wave beaming
• packing problem
• temperature uniformity

Acknowledgment

The authors would like to thank Kevin Stern and Alex Zozulya for their interest in this study and fruitful discussions of its results.

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

CH and VY are grateful for the support from the Air Force Research Laboratory, via Leidos, Inc., Grant No P010200226. BH was funded by the Air Force Office of Scientific Research under FA9550-17RDCOR449 and the Operational Energy Capability Improvement Fund (OECIF). IR was supported by OECIF.

Notes on contributors

Catherine M. Hogan

Catherine Hogan received her BSc degrees in physics and mathematical sciences from Worcester Polytechnic Institute, Worcester, MA, USA in 2021. During her undergraduate studies, she completed research in multiphysics modeling, millimeter wave technology, and power beaming applications. Her current research interests include space exploration through the astrophysics and space science fields. She is currently a Systems Engineer at the MIT RE Corporation, Bedford, MA, USA.

Brad W. Hoff

Brad Hoff is a Senior Scientist at the Air Force Research Laboratory working in the area of high power electromagnetics. He obtained a PhD from the University of Michigan (Ann Arbor, MI, USA) in 2009.

Ian M. Rittersdorf

Ian M. Rittersdorf received the BSE, MSE, and PhD degrees in nuclear engineering and radiological sciences from the University of Michigan, Ann Arbor, MI, in 2008, 2010, and 2014, respectively. From 2014 to 2016 he was a National Research Council Post-Doctoral Fellow with the Naval Research Laboratory, Washington, DC, working with the Pulsed Power Physics Branch, Plasma Physics Division. His current research focus is on the development of numerical models for the evolution of electrode plasmas, high power microwaves, and the physics of high-power charged particle beam diodes for various applications.

Vadim V. Yakovlev

Vadim Yakovlev is an Associate Research Professor in the Department of Mathematical Sciences, Worcester Polytechnic Institute, Worcester, MA, USA. He is a head of the Industrial Microwave Modeling Group which he formed in 1999 as a division of the WP I’s Center for Industrial Mathematics and Statistics. He received his PhD degree in Radio Physics from the Institute of Radio Engineering and Electronics of the Russian Academy of Sciences, Moscow, Russia in 1991. His research interests include multiphysics modeling, microwave power engineering, microwave imaging, and power beaming applications.