NUMERICAL SIMULATION OF THE THERMAL STATE OF AN ELECTRONIC UNIT IN A COUPLED FORMULATION
V.Ya. Modorskii, S.L. Kalyulin, N.V. Vladimirov, I.E. Cherepanov, M.A. Seregina, A.V. Babushkina
Perm National Research Polytechnic University, Perm, Russia
Keywords: electronic unit, unmanned aerial system, numerical simulation, conjugate heat transfer, convection
Abstract
A mathematical model of conjugate heat transfer and a numerical method for estimating the temperature distribution in a model electronic unit of an unmanned aerial system filled with hydrogen and exposed to external airflow are presented. The three-dimensional mathematical model for the external aerodynamics and internal gas dynamics is based on the Reynolds-averaged Navier-Stokes equations, closed by the ideal-gas equation of state (for both air and hydrogen), the SST turbulence model, and appropriate initial and boundary conditions. The thermal state of the unit is described by the heat conduction equation. The two problems are solved in a coupled manner, thereby implementing a conjugate heat-transfer model between the external air and the internal hydrogen through the solid walls, whose thermophysical properties (heat capacity, thermal conductivity, and density) are specified as functions of temperature. The heat dissipation from the circuit boards of the model electronic unit is prescribed as a thermal boundary condition on the surfaces of the heat-generating components. Temperature distributions in various cross sections of the structure are obtained.
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