Microscale physics and macroscale convective heat transfer in supercritical fluids

Fuente: arXiv
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Main Authors: Li, Zhouhang, Banuti, Daniel T., Ren, Jie, Lyu, Junfu, Wang, Hua, Chu, Xu
Format: Preprint
Published: 2024
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author Li, Zhouhang
Banuti, Daniel T.
Ren, Jie
Lyu, Junfu
Wang, Hua
Chu, Xu
author_facet Li, Zhouhang
Banuti, Daniel T.
Ren, Jie
Lyu, Junfu
Wang, Hua
Chu, Xu
contents Driven by fundamental thermodynamic efficiency considerations, an emerging trend in the energy and propulsion systems is that the working fluid operates at a pressure above the critical pressure. Energy transport is thus accompanied by dramatic and strongly nonlinear variations of thermophysical properties, which cause abnormal heat transfer behavior and non-ideal gas effects. This situation raises a crucial challenge for the heat exchanger and turbomachinery design, overall energy and exergy efficiency. We aim to provide a multi-scale overview of the flow and thermal behavior of fluid above the critical point: microscopic physics and macroscopic transport. Microscopic physics, i.e. near-critical thermophysical properties, phase transition and fluid dynamics, are introduced. A particular focus will be on the supercritical pseudo boiling process, which is a generalization of classical liquid-vapor phase transitions to non-equilibrium supercritical states. These new perspectives lead to a revised view of the state space. Further, recent results demonstrated the possibility of stable supercritical fluid interfaces without surface tension. On the macroscale, recent progress on the modeling of turbulent flow and convective heat transfer of supercritical fluids are summarized. Direct numerical simulation is able to offer insights into the physics of thermal fluids. We start with a description of fundamental fluid mechanics problems related to supercritical fluids. In addition, the heat transfer deterioration in supercritical fluids is found to be closely connected to the flow relaminarization by the non-uniform body-force. Finally, various modeling approaches such as recently developed advanced Reynolds-averaged turbulence modeling as well as machine-learning methods are summarized.
format Preprint
id arxiv_https___arxiv_org_abs_2406_04119
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Microscale physics and macroscale convective heat transfer in supercritical fluids
Li, Zhouhang
Banuti, Daniel T.
Ren, Jie
Lyu, Junfu
Wang, Hua
Chu, Xu
Fluid Dynamics
Driven by fundamental thermodynamic efficiency considerations, an emerging trend in the energy and propulsion systems is that the working fluid operates at a pressure above the critical pressure. Energy transport is thus accompanied by dramatic and strongly nonlinear variations of thermophysical properties, which cause abnormal heat transfer behavior and non-ideal gas effects. This situation raises a crucial challenge for the heat exchanger and turbomachinery design, overall energy and exergy efficiency. We aim to provide a multi-scale overview of the flow and thermal behavior of fluid above the critical point: microscopic physics and macroscopic transport. Microscopic physics, i.e. near-critical thermophysical properties, phase transition and fluid dynamics, are introduced. A particular focus will be on the supercritical pseudo boiling process, which is a generalization of classical liquid-vapor phase transitions to non-equilibrium supercritical states. These new perspectives lead to a revised view of the state space. Further, recent results demonstrated the possibility of stable supercritical fluid interfaces without surface tension. On the macroscale, recent progress on the modeling of turbulent flow and convective heat transfer of supercritical fluids are summarized. Direct numerical simulation is able to offer insights into the physics of thermal fluids. We start with a description of fundamental fluid mechanics problems related to supercritical fluids. In addition, the heat transfer deterioration in supercritical fluids is found to be closely connected to the flow relaminarization by the non-uniform body-force. Finally, various modeling approaches such as recently developed advanced Reynolds-averaged turbulence modeling as well as machine-learning methods are summarized.
title Microscale physics and macroscale convective heat transfer in supercritical fluids
topic Fluid Dynamics
url https://arxiv.org/abs/2406.04119