The wall heat flux partitioning during the pool boiling of water on thin metallic foils

In this work a mechanistic model has been developed for the wall heat flux partitioning during subcooled flow boiling. The premise of the proposed model is that the entire energy from the wall is first transferred to the superheated liquid layer adjacent to the wall. A fraction of this energy is then utilized for vapor generation, while the rest of the energy is utilized for sensible heating of the bulk liquid. The contribution of each of the mechanisms for transfer of heat to the liquid—forced convection and transient conduction, as well as the energy transport associated with vapor generation has been quantified in terms of nucleation site densities, bubble departure and lift-off diameters, bubble release frequency, flow parameters like velocity, inlet subcooling, wall superheat, and fluid and surface properties including system pressure. To support the model development, subcooled flow boiling experiments were conducted at pressures of 1.03–3.2 bar for a wide range of mass fluxes 124-926kg/m2 s, heat fluxes 2.5-90W/cm2 and for contact angles varying from 30° to 90°. The model developed shows that the transient conduction component can become the dominant mode of heat transfer at very high superheats and, hence, velocity does not have much effect at high superheats. This is particularly true when boiling approaches fully developed nucleate boiling. Also, the model developed allows prediction of the wall superheat as a function of the applied heat flux or axial distance along the flow direction.

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Heat Transfer and Wall Heat Flux Partitioning During Subcooled Flow Nucleate Boiling—A Review

Journal of Heat Transfer ◽

10.1115/1.2349510 ◽

2006 ◽

Vol 128 (12) ◽

pp. 1243-1256 ◽

Cited By ~ 59

Author(s):

Gopinath R. Warrier ◽

Vijay K. Dhir

Keyword(s):

Heat Transfer ◽

Experimental Data ◽

Heat Flux ◽

Nucleate Boiling ◽

Wall Heat Flux ◽

Forced Flow ◽

Mechanistic Models ◽

Subcooled Flow ◽

Flux Partitioning ◽

Empirical And Mechanistic Models

In this paper we provide a review of heat transfer and wall heat flux partitioning models/correlations applicable to subcooled forced flow nucleate boiling. Details of both empirical and mechanistic models that have been proposed in the literature are provided. A comparison of the experimental data with predictions from selected models is also included.

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Simulation of pool boiling of nanofluids by using Eulerian multiphase model

Journal of Thermal Analysis and Calorimetry ◽

10.1007/s10973-019-09180-x ◽

2019 ◽

Vol 142 (1) ◽

pp. 493-505 ◽

Cited By ~ 5

Author(s):

Mohammed Saad Kamel ◽

Mohamed Sobhi Al-agha ◽

Ferenc Lezsovits ◽

Omid Mahian

Keyword(s):

Heat Flux ◽

Surface Modification ◽

Pure Water ◽

Classical Model ◽

Pool Boiling ◽

Pure Liquid ◽

Multiphase Model ◽

Two Phase ◽

Flux Partitioning ◽

Two Phases

AbstractIn the present work, a new simulation of nanofluid/vapor two-phase flow inside the 2-D rectangular boiling chamber was numerically investigated. The Eulerian–Eulerian approach used to predict the boiling curve and the interaction between two phases. The surface modification during pool boiling of silica nanofluid represented by surface roughness and wettability is put into the account in this simulation. New closure correlations regarding the nucleation sites density and bubble departure diameter during boiling of silica nanofluid were inserted to extend the boiling model in this work. Besides, the bubble waiting time coefficient which involved in quenching heat flux under heat flux partitioning HFP model was corrected to improve the results of this study. The numerical results validated with experimental works in the literature, and they revealed good agreements for both pure water and nanofluids. The results found that when improving the heat flux partitioning model HFP by considering the surface modification of nucleate pool boiling parameters, it will give more mechanistic sights compared to the classical model, which is used for predicting of boiling heat transfer of pure liquid.

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