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Main Authors: Bureš, Lubomír, Nilsson, Per
Format: Preprint
Published: 2025
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Online Access:https://arxiv.org/abs/2507.08515
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author Bureš, Lubomír
Nilsson, Per
author_facet Bureš, Lubomír
Nilsson, Per
contents In molten-salt-fuelled reactor systems, the fluid may experience substantial volumetric heat generation in addition to heat removal from surrounding structures. To quantify these effects, we investigate developed channel flow with internal heating using a systematic multi-scale approach comprising Direct Numerical Simulation (DNS), Large Eddy Simulation (LES), and a semi-analytical solver (SAS). First, DNS and LES are compared in a turbulent parallel-plate configuration at different Prandtl and Reynolds numbers, demonstrating excellent agreement in flow and thermal fields, with the SAS method showing acceptable accuracy. Building on this benchmarking, the SAS tool is then employed to explore a broad parameter space, offering insights into how internal heat deposition modifies the temperature distribution across Reynolds and Prandtl numbers. Comparisons are also drawn against the canonical wall-heating scenario, revealing that volumetric heating often remains a secondary effect in turbulent regimes but can become more pronounced at lower Reynolds numbers, higher Prandtl numbers, or when nearly all heat is deposited in the fluid. These findings establish guidelines for reduced-order modeling in liquid-fuel reactor analyses and highlight conditions under which internal heating warrants particular attention. The paper concludes by outlining ongoing and future research directions, including refinements for variable fluid properties and complex geometry extensions.
format Preprint
id arxiv_https___arxiv_org_abs_2507_08515
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Impacts of internal heating on temperature distribution in channels
Bureš, Lubomír
Nilsson, Per
Fluid Dynamics
Computational Physics
In molten-salt-fuelled reactor systems, the fluid may experience substantial volumetric heat generation in addition to heat removal from surrounding structures. To quantify these effects, we investigate developed channel flow with internal heating using a systematic multi-scale approach comprising Direct Numerical Simulation (DNS), Large Eddy Simulation (LES), and a semi-analytical solver (SAS). First, DNS and LES are compared in a turbulent parallel-plate configuration at different Prandtl and Reynolds numbers, demonstrating excellent agreement in flow and thermal fields, with the SAS method showing acceptable accuracy. Building on this benchmarking, the SAS tool is then employed to explore a broad parameter space, offering insights into how internal heat deposition modifies the temperature distribution across Reynolds and Prandtl numbers. Comparisons are also drawn against the canonical wall-heating scenario, revealing that volumetric heating often remains a secondary effect in turbulent regimes but can become more pronounced at lower Reynolds numbers, higher Prandtl numbers, or when nearly all heat is deposited in the fluid. These findings establish guidelines for reduced-order modeling in liquid-fuel reactor analyses and highlight conditions under which internal heating warrants particular attention. The paper concludes by outlining ongoing and future research directions, including refinements for variable fluid properties and complex geometry extensions.
title Impacts of internal heating on temperature distribution in channels
topic Fluid Dynamics
Computational Physics
url https://arxiv.org/abs/2507.08515