scholarly journals Study on mist cooling for heat exchangers. (2nd report Liquid film flow and heat transfer on a horizontal cylinder)

1986 ◽  
Vol 52 (482) ◽  
pp. 3554-3562
Author(s):  
Yujiro HAYASHI ◽  
Akira TAKIMOTO ◽  
Osamu MATSUDA
Keyword(s):  
Heat Transfer ◽  
Liquid Film ◽  
Heat Exchangers ◽  
Film Flow ◽  
Horizontal Cylinder ◽  
Flow And Heat Transfer ◽  
Liquid Film Flow ◽  
Mist Cooling

Non-Uniform Heat Source/Sink Effect on Liquid Film Flow of Jeffrey Nanofluid over a Stretching Sheet

2017 ◽  
Vol 11 ◽  
pp. 72-83 ◽  
Author(s):  
K. Avinash ◽  
N. Sandeep ◽  
Oluwole Daniel Makinde
Keyword(s):  
Heat Transfer ◽  
Heat Source ◽  
Liquid Film ◽  
Film Flow ◽  
Fluid Model ◽  
Jeffrey Fluid ◽  
Flow And Heat Transfer ◽  
Uniform Heat ◽  
Liquid Film Flow ◽  
Source Sink

The heat transfer in nanofluids plays a major role in solar energy, nuclear reactors, aerodynamics, etc. By keeping this in view, in this study, we investigated the flow and heat transfer nature of liquid film flow of ethylene glycol (EG)-Cu nanofluid in the presence of non-uniform heat source/sink. We considered the Jeffrey fluid model to investigate the flow and heat transfer behavior. The governing equations are transformed as ordinary differential equations with the aid of similarity variables. Numerical results are carried out by employing bvp5c Matlab package. The influence of pertinent parameters on velocity and temperature profiles along with the reduced Nusselt number is discussed with the help of graphs and tabular results. It is observed that the rising value of the non-uniform heat source/sink parameter acts like heat generators and regulates the thermal field. Rising the film thickness enhances the heat transfer rate.

Theoretical and Experimental Analysis of Turbulent Liquid Film Flowing down a Vertical Surface

2009 ◽  
Vol 15 ◽  
pp. 3-8
Author(s):  
Stasys Sinkunas ◽  
Jonas Gylys ◽  
Algimantas Kiela
Keyword(s):  
Heat Transfer ◽  
Liquid Film ◽  
Analytical Study ◽  
Film Flow ◽  
Convex Surface ◽  
Local Heat Transfer ◽  
Local Heat ◽  
Vertical Surface ◽  
Momentum And Heat Transfer ◽  
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.

Annular Liquid Film Flow Under Local Heating in Microchannel

2005 ◽  
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.

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

2017 ◽  
Vol 139 (6) ◽  
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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