Modeling of dry-out incipience for flow boiling in a circular microchannel at a uniform heat flux

Amen Younes, Ibrahim Hassan

Research output: Contribution to journalArticle

1 Citation (Scopus)

Abstract

Dry-out is an essential phenomenon that has been observed experimentally in both slug and annular flow regimes for flow boiling in mini and microchannels. The dry-out leads to a drastic drop in heat transfer coefficient, reversible flow and may cause a serious damage to the microchannel. Consequently, the study and prediction of this phenomenon is an essential objective for flow boiling in microchannels. The aim of this work is to develop an analytical model to predict the critical heat flux (CHF) based on the prediction of liquid film variation in annular flow regime for flow boiling in a horizontal uniformly heated circular microtube. The model is developed by applying one-dimensional (1D) separated flow model for a control volume in annular flow regime for steady, and sable saturated flow boiling. The influence of interfacial shear and inertia force on the liquid film thickness is taken into account. The effects of operating conditions, channel sizes, and working fluids on the CHF have been investigated. The model was compared with 110 CHF data points for flow boiling of various working fluids, (water, LN2, FC-72, and R134a) in single and multiple micro/minichannels with diameter ranges of (0:38 ≤ Dh ≤ 3:04 mm) and heated-length to diameter ratios in the range of (117.7 ≤ Lh/D ≤ 470). Additionally, three CHF correlations developed for saturated flow boiling in a single microtube have been employed for the model validation. The model showed a good agreement with the experimental CHF data with mean absolute error (MAE)=19.81%.

Original languageEnglish
Article number021502
JournalJournal of Heat Transfer
Volume137
Issue number2
DOIs
Publication statusPublished - 2015

Fingerprint

microchannels
Microchannels
boiling
Boiling liquids
Heat flux
heat flux
annular flow
Liquid films
working fluids
Fluids
separated flow
Heat transfer coefficients
Film thickness
Analytical models
liquids
predictions
heat transfer coefficients
inertia
film thickness
Water

Keywords

  • Annular flow regime
  • CHF
  • Liquid film
  • Saturated flow boiling

ASJC Scopus subject areas

  • Materials Science(all)
  • Condensed Matter Physics
  • Mechanics of Materials
  • Mechanical Engineering

Cite this

Modeling of dry-out incipience for flow boiling in a circular microchannel at a uniform heat flux. / Younes, Amen; Hassan, Ibrahim.

In: Journal of Heat Transfer, Vol. 137, No. 2, 021502, 2015.

Research output: Contribution to journalArticle

@article{0b9fa2500ac647ef9fae36b19063cbb3,
title = "Modeling of dry-out incipience for flow boiling in a circular microchannel at a uniform heat flux",
abstract = "Dry-out is an essential phenomenon that has been observed experimentally in both slug and annular flow regimes for flow boiling in mini and microchannels. The dry-out leads to a drastic drop in heat transfer coefficient, reversible flow and may cause a serious damage to the microchannel. Consequently, the study and prediction of this phenomenon is an essential objective for flow boiling in microchannels. The aim of this work is to develop an analytical model to predict the critical heat flux (CHF) based on the prediction of liquid film variation in annular flow regime for flow boiling in a horizontal uniformly heated circular microtube. The model is developed by applying one-dimensional (1D) separated flow model for a control volume in annular flow regime for steady, and sable saturated flow boiling. The influence of interfacial shear and inertia force on the liquid film thickness is taken into account. The effects of operating conditions, channel sizes, and working fluids on the CHF have been investigated. The model was compared with 110 CHF data points for flow boiling of various working fluids, (water, LN2, FC-72, and R134a) in single and multiple micro/minichannels with diameter ranges of (0:38 ≤ Dh ≤ 3:04 mm) and heated-length to diameter ratios in the range of (117.7 ≤ Lh/D ≤ 470). Additionally, three CHF correlations developed for saturated flow boiling in a single microtube have been employed for the model validation. The model showed a good agreement with the experimental CHF data with mean absolute error (MAE)=19.81{\%}.",
keywords = "Annular flow regime, CHF, Liquid film, Saturated flow boiling",
author = "Amen Younes and Ibrahim Hassan",
year = "2015",
doi = "10.1115/1.4029019",
language = "English",
volume = "137",
journal = "Journal of Heat Transfer",
issn = "0022-1481",
publisher = "American Society of Mechanical Engineers(ASME)",
number = "2",

}

TY - JOUR

T1 - Modeling of dry-out incipience for flow boiling in a circular microchannel at a uniform heat flux

AU - Younes, Amen

AU - Hassan, Ibrahim

PY - 2015

Y1 - 2015

N2 - Dry-out is an essential phenomenon that has been observed experimentally in both slug and annular flow regimes for flow boiling in mini and microchannels. The dry-out leads to a drastic drop in heat transfer coefficient, reversible flow and may cause a serious damage to the microchannel. Consequently, the study and prediction of this phenomenon is an essential objective for flow boiling in microchannels. The aim of this work is to develop an analytical model to predict the critical heat flux (CHF) based on the prediction of liquid film variation in annular flow regime for flow boiling in a horizontal uniformly heated circular microtube. The model is developed by applying one-dimensional (1D) separated flow model for a control volume in annular flow regime for steady, and sable saturated flow boiling. The influence of interfacial shear and inertia force on the liquid film thickness is taken into account. The effects of operating conditions, channel sizes, and working fluids on the CHF have been investigated. The model was compared with 110 CHF data points for flow boiling of various working fluids, (water, LN2, FC-72, and R134a) in single and multiple micro/minichannels with diameter ranges of (0:38 ≤ Dh ≤ 3:04 mm) and heated-length to diameter ratios in the range of (117.7 ≤ Lh/D ≤ 470). Additionally, three CHF correlations developed for saturated flow boiling in a single microtube have been employed for the model validation. The model showed a good agreement with the experimental CHF data with mean absolute error (MAE)=19.81%.

AB - Dry-out is an essential phenomenon that has been observed experimentally in both slug and annular flow regimes for flow boiling in mini and microchannels. The dry-out leads to a drastic drop in heat transfer coefficient, reversible flow and may cause a serious damage to the microchannel. Consequently, the study and prediction of this phenomenon is an essential objective for flow boiling in microchannels. The aim of this work is to develop an analytical model to predict the critical heat flux (CHF) based on the prediction of liquid film variation in annular flow regime for flow boiling in a horizontal uniformly heated circular microtube. The model is developed by applying one-dimensional (1D) separated flow model for a control volume in annular flow regime for steady, and sable saturated flow boiling. The influence of interfacial shear and inertia force on the liquid film thickness is taken into account. The effects of operating conditions, channel sizes, and working fluids on the CHF have been investigated. The model was compared with 110 CHF data points for flow boiling of various working fluids, (water, LN2, FC-72, and R134a) in single and multiple micro/minichannels with diameter ranges of (0:38 ≤ Dh ≤ 3:04 mm) and heated-length to diameter ratios in the range of (117.7 ≤ Lh/D ≤ 470). Additionally, three CHF correlations developed for saturated flow boiling in a single microtube have been employed for the model validation. The model showed a good agreement with the experimental CHF data with mean absolute error (MAE)=19.81%.

KW - Annular flow regime

KW - CHF

KW - Liquid film

KW - Saturated flow boiling

UR - http://www.scopus.com/inward/record.url?scp=84993939801&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=84993939801&partnerID=8YFLogxK

U2 - 10.1115/1.4029019

DO - 10.1115/1.4029019

M3 - Article

AN - SCOPUS:84993939801

VL - 137

JO - Journal of Heat Transfer

JF - Journal of Heat Transfer

SN - 0022-1481

IS - 2

M1 - 021502

ER -