INVESTIGATION ON SUBCOOLED FLOW BOILING HEAT TRANSFER TO WATER-ETHANOL MIXTURE

2018 ◽  
Author(s):  
Pushkar Kumar ◽  
B. G. Suhas ◽  
Alangar Sathyabhama
Keyword(s):  
Heat Transfer ◽  
Boiling Heat Transfer ◽  
Flow Boiling ◽  
Subcooled Flow Boiling ◽  
Ethanol Mixture ◽  
Subcooled Flow ◽  
Flow Boiling Heat Transfer

scholarly journals Investigation of Forced Convective and Subcooled Flow Boiling Heat Transfer Coefficients of Water-Ethanol Mixture: Numerical Study

2021 ◽  
Vol 39 (2) ◽  
pp. 512-520
Author(s):  
Suhas Badakere Gopalakrishna ◽  
Ravi Lakkanna ◽  
Satyabhama Alangar
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Coefficient ◽  
Transfer Coefficient ◽  
Boiling Heat Transfer ◽  
Flow Boiling ◽  
Subcooled Flow Boiling ◽  
Ethanol Mixture ◽  
Subcooled Flow ◽  
Flow Boiling Heat Transfer ◽  
Boiling Heat Transfer Coefficient

The subcooled flow boiling is related to the operation of electronic devices, Hybrid electric vehicle (HEV) Battery module and small catalytic reactors. It is well known that the operational temperature must be maintained to avoid any malfunction of these heat dissipative devices. In this paper the forced convective and subcooled flow boiling heat transfer coefficients of water-ethanol mixture is determined numerically by Volume of fluid analysis (VOF). The interaction between liquid and local vapour is analysed by solving the bubble volume of fraction in the numerical study. Crank Nicolson implicit scheme is used for discretizing the scalar convection equation for bubble void fraction and transforming into algebraic equation. Thomas Algorithm is used to solve the algebraic equations of bubble void fraction. The corrector predictor equation method is used to solve for bubble void fraction when the value obtained is less than 0 or exceeds 1. The thermodynamic and Thermophysical properties are substituted in the x-momentum and energy equation to determine the values of pressure drop, velocity and temperature of the fluid. From the temperature values, the subcooled flow boiling heat transfer coefficient is obtained. It is found that the addition of ethanol to water decreases the forced convective and subcooled flow boiling heat transfer coefficient of the water-ethanol mixture. The numerically determined heat transfer coefficient of water ethanol mixture is compared with that of the experimental results. The average deviation between the experimentally determined and numerically determined subcooled flow boiling heat transfer coefficient of water ethanol-mixture is found to be 24.13%.

Subcooled Flow Boiling in Circumferentially Nonuniform and Uniform Heated Vertical Channels With Downward Flow

2000 ◽  
Vol 122 (3) ◽  
pp. 620-625 ◽  
Author(s):  
Q. Peatiwala ◽  
R. D. Boyd,
Keyword(s):  
Heat Transfer ◽  
Boiling Heat Transfer ◽  
Flow Boiling ◽  
Axial Flow ◽  
Subcooled Flow Boiling ◽  
Subcooled Flow ◽  
Single Side ◽  
Flow Boiling Heat Transfer ◽  
Higher Power ◽  
Heated Length

Results are presented for new experimental data for subcooled flow boiling heat transfer in circumferentially nonuniform (single-side) and uniformly heated tubes. Although the Liu-Winterton correlation had better agreement at low power levels and axial locations, Shah’s correlation had better agreement at higher power levels and at axial locations near the center of the heated length. Both correlations overpredicted the data near the exit. Therefore, additional correlational developmental work is needed for local (axial) flow boiling heat transfer in circumferentially nonuniform heated channels. [S0022-1481(00)00603-4]

scholarly journals Alumina Nanoparticle Pre-Coated Tubing Enhancing Subcooled Flow Boiling Critical Heat Flux

2009 ◽  
Author(s):  
Bao Truong ◽  
Lin-wen Hu ◽  
Jacopo Buongiorno ◽  
Thomas McKrell
Keyword(s):  
Heat Transfer ◽  
Heat Flux ◽  
Critical Heat Flux ◽  
Mass Flux ◽  
Boiling Heat Transfer ◽  
Flow Boiling ◽  
Subcooled Flow Boiling ◽  
Nanoparticle Deposition ◽  
Subcooled Flow ◽  
Flow Boiling Heat Transfer

Nanofluids are engineered colloidal dispersions of nano-sized particle in common base fluids. Previous pool boiling studies have shown that nanofluids can improve critical heat flux (CHF) up to 200% for pool boiling and up to 50% for subcooled flow boiling due to the boiling induced nanoparticle deposition on the heated surface. Motivated by the significant CHF enhancement of nanoparticle deposited surface, this study investigated experimentally the subcooled flow boiling heat transfer of pre-coated test sections in water. Using a separate coating loop, stainless steel test sections were treated via flow boiling of alumina nanofluids at constant heat flux and mass flow rate. The pre-coated test sections were then used in another loop to measure subcooled flow boiling heat transfer coefficient and CHF with water. The CHF values for the pre-coated tubing were found on average to be 28% higher than bare tubing at high mass flux G = 2500 kg/m2 s. However, no enhancement was found at lower mass flux G = 1500 kg/m2 s. The heat transfer coefficients did not differ much between experiments when the bare or coated tubes were used. SEM images of the test sections confirm the presence of a nanoparticle coating layer. The nanoparticle deposition is sporadic and no relationship between the coating pattern and the amount of CHF enhancement is observed.

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