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Pool boiling on horizontal tube, evaluation of ten correlations

Baki Touhami, Sahel Djamel

Archive of Mechanical Engineering

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2023

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LXX, nr 4

481--495

EN

The heat transfer coefficient during the pool boiling on the outside of a horizontal tube can be predicted by correlations. Our choice was based on ten correlations known from the literature. The experimental data were recovered from the recent work, for different fluids used. An evaluation was made of agreement between each of the correlations and the experimental data. The results of the present study firstly showed a good reliability for the correlations of untsov [10], Stephan and Abdeslam [11] with deviations of 20% and 27%, respectively. Also, the results revealed acceptable agreements for the correlations of Kruzhlin [6], Mc Nelly [7] and Touhami [15] with deviations of 26%, 29% and 29% respectively. The remaining correlations showed very high deviations from the experimental data. Finally, improvements have been made in the correlations of Shekriladze [12] and Mostinski [9], and a new correlation was proposed giving convincing results.

2

New analysis of experimental data of the hydrodynamic liquid film around jet zone on horizontal plate

Elmahi Abdelbaki, Baki Touhami, Tebbal Mohamed

Archive of Mechanical Engineering

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2021

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LXVIII, nr 4

435--448

EN

Optimization of cooling systems is of major importance due to the economy of cooling water and energy in thermal installations in the industry. The hydrodynamic study of the film is a prerequisite for the study of the intensity of the heat transfer during the cooling of a horizontal plate by a liquid film. This experimental work made it possible to quantify the hydrodynamic parameters by a new approach, a relation linking the thickness of the film to the velocity was found as a function of the geometrical and hydrodynamic characteristics of the sprayer. A new statistical approach has been developed for the measurement of the velocity, the liquid fluid arriving at the edge of the plate and having velocity V is spilled out like a projectile. The recovering of the liquid in tubes allowed us to quantify flow rates for different heights positions relative to the plate, statistical processing permitted us to assess the probable velocity with a margin of error.

3

Investigations on pool boiling of refrigerant R141b outside a horizontal tube

Baki Touhami, Aris Abdelkader, Tebbal Mohamed

Archive of Mechanical Engineering

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2021

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LXVIII, nr 1

77--92

EN

Boiling produces vapor with a phase change by absorbing a consistent amount of heat. Experimentation and modeling can help us better understand this phenomenon. The present study is focused on the heat transfer during the nucleate pool boiling of refrigerant R141b on the surface of a horizontal copper tube. The results of the experiment were compared with four correlations drawn from the literature, and the critical heat flux was examined for different pressures and also compared with the predicted values. Simulating boiling with two-phase models allowed us to infer the plot of the temperature distribution around the tube and compared it to results from other work.

4

Survey on the nucleate pool boiling of hydrogen and its limits

Baki Touhami

Journal of Mechanical and Energy Engineering

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2020

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Vol. 4, No 2

157--166

EN

Nucleate pool boiling is a very efficient transfer regime with low temperature gradients, bounded between two heat flux values and which border transitions to other regimes, this phenomenon is well framed with correlations. Our study aims to clarify the applicability of this regime to liquid hydrogen and to develop reliable correlations for a useful and qualitative agreement. An exhaustive review on the nucleate pool boiling of hydrogen and the limits of this regime, whether are the onset nucleate boiling (ONB) and the critical heat flux (CHF) was made, allowing the collection of more than 1400 points from experimental setups, highlighting a variety of parameters. Five predictive correlations were drawn from the literature, graphical and statistical comparisons were made, two in five reveal acceptable results. After analysis of the experimental data, new correlations were developed and compared with the data collected, convincing results were obtained and discussed. A simple form was expressed for the heat flux (...), shows better predicted values; convincing results of the (CHF) have been found on modified correlation, and the CHF value reaches a maximum of 148×103 W/m² for a reduced pressure at 0.35. A nucleate boiling correlation suitable for hydrogen has been developed.