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08:25
Measurements of Local Instantaneous Convective Heat Transfer in a Pipe - Single and Two-phase Flow
Published on: April 30, 2018
Measuring heat flux beyond Fourier's law
E R Smith1, P J Daivis2, B D Todd3
1Department of Mechanical Engineering, Imperial College London, Exhibition Road, South Kensington, London SW7 2AZ, United Kingdom.
The Journal of Chemical Physics
|February 17, 2019
Summary
Shear flow significantly impacts heat flux in fluids. This study quantifies these effects, revealing strain rate dependent components crucial for understanding thermal transport under flow conditions.
Area of Science:
- Thermodynamics
- Fluid Dynamics
- Computational Physics
Background:
- Understanding heat transport in flowing systems is crucial for various engineering applications.
- Traditional models often simplify or neglect the influence of shear flow on thermal conductivity.
Purpose of the Study:
- To investigate the effect of shear flow on heat flux in a simple fluid using nonequilibrium molecular dynamics.
- To quantify the additional components of heat flux parallel and normal to the walls induced by shear flow.
- To validate computational methods for calculating heat flux in flowing systems.
Main Methods:
- Nonequilibrium molecular dynamics simulations of a fluid in a channel.
- Comparison between temperature-driven and wall-driven Couette flow systems.
- Application and comparison of different formulations of the Irving-Kirkwood equations for heat flux calculation.
Main Results:
- Fourier's law thermal conductivity was recovered in the absence of flow, agreeing with experimental data.
- Heat flux in the flow direction was found to vary linearly with strain rate.
- Additional strain rate dependent components of heat flux normal to the wall were quantified.
Conclusions:
- Shear flow introduces additional, quantifiable components to the heat flux.
- The study provides experimentally testable terms for the thermal conductivity tensor under shear flow.
- The employed computational methods are validated for analyzing heat transport in flowing fluids.
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