Publication

A study of gravitational effects on single elongated vapor bubbles

John Richard Thome, Mirco Magnini
2016
Journal Articles

Abstract

An experimental study was completed on the heat transfer induced by a single elongated vapor bubble rising in vertical, upward, co-current flow at various accelerations. The bubble shape and behavior were also studied under those conditions. Tests were conducted using a flow boiling rig which coupled flow visualization with measurements of the heat transfer and liquid film thickness. The bubble drift velocity was shown to dictate the bubble shape as well as the relative influences of thin film evaporation and turbulent wake heat transfer. When present, vortices shed behind the bubble tail created peaks in the heat transfer coefficient whose magnitude decreased with increasing liquid Reynolds number and acceleration. The vortex frequency was found to be linearly dependent on plunging velocity. A criteria for vortex incipience was proposed. (C) 2016 Elsevier Ltd. All rights reserved.

Official source

https://infoscience.epfl.ch/entities/publication/6c604f2c-783c-4977-826b-8ed933086937

About this result

This page is automatically generated and may contain information that is not correct, complete, up-to-date, or relevant to your search query. The same applies to every other page on this website. Please make sure to verify the information with EPFL's official sources.

John Richard Thome, Mirco Magnini
2016
Journal Articles

Abstract

Official source

https://infoscience.epfl.ch/entities/publication/6c604f2c-783c-4977-826b-8ed933086937

About this result

Related concepts (32)

Heat transfer coefficient

In thermodynamics, the heat transfer coefficient or film coefficient, or film effectiveness, is the proportionality constant between the heat flux and the thermodynamic driving force for the flow of heat (i.e., the temperature difference, ΔT ). It is used in calculating the heat transfer, typically by convection or phase transition between a fluid and a solid. The heat transfer coefficient has SI units in watts per square meter per kelvin (W/m2/K).

Heat transfer

Heat transfer is a discipline of thermal engineering that concerns the generation, use, conversion, and exchange of thermal energy (heat) between physical systems. Heat transfer is classified into various mechanisms, such as thermal conduction, thermal convection, thermal radiation, and transfer of energy by phase changes. Engineers also consider the transfer of mass of differing chemical species (mass transfer in the form of advection), either cold or hot, to achieve heat transfer.

Convection (heat transfer)

Convection (or convective heat transfer) is the transfer of heat from one place to another due to the movement of fluid. Although often discussed as a distinct method of heat transfer, convective heat transfer involves the combined processes of conduction (heat diffusion) and advection (heat transfer by bulk fluid flow). Convection is usually the dominant form of heat transfer in liquids and gases. Note that this definition of convection is only applicable in Heat transfer and thermodynamic contexts.

Related publications (28)

Computational fluid dynamics simulations of the heat transfer properties of graphene-based nanolubricants and application to hydrodynamic lubrication

Roberto Guarino

In this paper, we consider experimental data available for graphene-based nanolubricants to evaluate their convective heat transfer performance by means of computational fluid dynamics (CFD) simulations. Single-phase models with temperature-dependent prope ...

Aip Publishing2024

Stability of a liquid layer draining around a horizontal cylinder: Interplay of capillary and gravity forces

François Gallaire, Shahab Eghbali, Simeon Vladimirov Djambov

We study the drainage of a viscous liquid film coating the outside of a solid horizontal cylinder, where gravity acts vertically. We focus on the limit of large Ohnesorge numbers Oh, where inertia is negligible compared to viscous effects. We first study t ...

Amer Physical Soc2024

Plasmoid drift and first wall heat deposition during ITER H-mode dual-SPIs in JOREK simulations

Mengdi Kong

The heat flux mitigation during the thermal quench (TQ) by the shattered pellet injection (SPI) is one of the major elements of disruption mitigation strategy for ITER. It's efficiency greatly depends on the SPI and the target plasma parameters, and is ult ...

IOP Publishing Ltd2024