EFFECTS OF HEAT SOURCE POWER ON HIGH-SPEED FLOW STRUCTURE AND WALL HEAT TRANSFER IN A CHANNEL
I. R. Vasnev, N. N. Fedorova
Khristianovich Institute of Theoretical and Applied Mechanics, Siberian Branch of the Russian Academy of Sciences, Novosibirsk, Russia
Keywords: numerical simulation, high-speed flow, turbulence, conjugate heat transfer, heat source, separated flow
Abstract
This paper presents numerical simulation results for supersonic turbulent airflow in a planar channel with a backward-facing step, incorporating a volumetric heat source that simulates the heat release from chemical reactions. The simulations account for conjugate heat transfer between the flow and copper plates mounted into the channel walls, which act as heat flux sensor elements. The results show that the heat source reduces the flow velocity and causes an upstream shift of the supersonic wave structure. Increasing the source power enlarges the subsonic zone transversely, induced by flow separation at the shock impingement location. A localized subsonic region forms in the flow core, isolated from the near-wall subsonic zone by a narrow supersonic jet, confining the thermal plume to the core flow. A sharp flow restructuring is triggered when the local separation zone merges with the recirculation zone downstream of the backward-facing step, allowing for the gas (warmed up by the heat source) to penetrate the enlarged separation bubble. This narrows the effective flow region, causing a compression wave, rather than an expansion wave, to form at the step edge. Consequently, the core flow temperature decreases while wall heat fluxes increase substantially.
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