Heat transfer in a high temperature region of spray cooling interacting with liquid film flow

The purpose of the present study is to obtain a comprehension for the momentum and heat transfer developments in gravitational liquid film flow. Analytical study of stabilized heat transfer for turbulent film was performed. A calculation method of the local heat transfer coefficient for a turbulent film falling down a vertical convex surface was proposed. The dependence of heat flux variation upon the distance from the wetted surface has been established analytically. Experimental study of velocity profiles for turbulent liquid film flow in the entrance region is performed as well. Analysis of profiles allowed estimating the length of stabilization for turbulent film flow under different initial velocities.

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Annular Liquid Film Flow Under Local Heating in Microchannel

ASME 3rd International Conference on Microchannels and Minichannels, Part B cont’d ◽

10.1115/icmm2005-75253 ◽

2005 ◽

Cited By ~ 1

Author(s):

Elizaveta Ya. Gatapova ◽

Vladimir V. Kuznetsov ◽

Oleg A. Kabov ◽

Jean-Claude Legros

Keyword(s):

Heat Transfer ◽

Liquid Film ◽

Biot Number ◽

Gas Flow ◽

Film Flow ◽

Local Heating ◽

Local Heat Transfer ◽

Flow Region ◽

Local Heat ◽

Liquid Film Flow

In our previous investigations the formation of liquid bump of locally heated laminar liquid film with co-current gas flow was obtained [1,2]. The evaporation of liquid was left out of account. Heat transfer to the gas phase was approximately specified by a constant Biot number [2,3]. The aim of this work is an investigation of the evaporation effect, the hydrodynamics and the heat transfer of liquid film flow in a channel 0.2–1 mm height. The 2-D model of locally heated liquid film moving under gravity and the action of co-current gas flow with low viscosity in a channel are considered. The channel can be inclined at an angle with respect to horizon. It is supposed that the height of the channel is much less than its width. Surface tension is assumed to depend on temperature. The velocity profiles for gas and liquid regions are found from problem of joint motion of isothermal non-deformable liquid film and gas flow. Using the findings the joint solution of heat transfer and diffusion problem with corresponding boundary condition is calculated. Having the temperature field in the whole of liquid and gas flow region we find a local heat transfer coefficient on the gas-liquid interface and Biot number as a function of flow parameters and spatial variables.

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Convective heat transfer to shear-driven liquid film flow in a microchannel

International Journal of Heat and Mass Transfer ◽

10.1016/j.ijheatmasstransfer.2013.04.012 ◽

2013 ◽

Vol 64 ◽

pp. 42-52 ◽

Cited By ~ 11

Author(s):

Farzad Houshmand ◽

Yoav Peles

Keyword(s):

Heat Transfer ◽

Liquid Film ◽

Convective Heat Transfer ◽

Convective Heat ◽

Film Flow ◽

Liquid Film Flow

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Combined Dielectrophoretic and Electrohydrodynamic Conduction Pumping for Enhancement of Liquid Film Flow Boiling

Journal of Heat Transfer ◽

10.1115/1.4035709 ◽

2017 ◽

Vol 139 (6) ◽

Cited By ~ 5

Author(s):

Viral K. Patel ◽

Jamal Seyed-Yagoobi

Keyword(s):

Heat Transfer ◽

Liquid Film ◽

Film Flow ◽

Flow Boiling ◽

Nucleate Boiling ◽

Transport Systems ◽

Heater Surface ◽

Force Magnitude ◽

Boiling Heat Transfer Coefficient ◽

Liquid Film Flow

This paper extends previous liquid film flow boiling studies by including the effect of an additional electrohydrodynamic (EHD) force, namely, the dielectrophoretic (DEP) force. Rather than using only EHD conduction pumping of the liquid film to electro-wet the heater surface, a localized nonuniform electric field above the heater surface is established to generate a DEP force for improved vapor bubble extraction during the nucleate boiling regime. The effects of liquid film height and applied potential are studied as a function of heater superheat and heat flux. A brief analytical study is also used to estimate the expected DEP force magnitude to explain the results. All of the above studies are also used to quantify the enhancement in heat transfer that can be achieved when heat transport systems are driven or augmented by these two EHD mechanisms. The results show remarkable enhancement of up to 1217% in boiling heat transfer coefficient at a given superheat when both mechanisms are used simultaneously. The experimental data are important for applications in thermal management in terrestrial and space conditions.

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