Experimental Investigation and Empirical Correlations of Heat Transfer in Different Regimes of Air–Water Two-Phase Flow in a Horizontal Tube

Nada, S.A.

doi:10.1115/1.4034903

Cited by 12 publications

(2 citation statements)

References 19 publications

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“…That's why 'Heat Transfer Coefficient' (which is a mixture of fluid, flow and body geometry) increased with an increase flow rate. At the other hand, the turbulent flow raises the air resistance and noise levels; however, the turbulent flow also accelerates heat conduction and thermal mixing [29]. Increasing the coefficient of the heat transfer with increasing the air Re number at constant superficial velocity of the water has been depicted in Figure 7(b) as well.…”

Section: Comparing Experimental and Numerical Heat Transfer Coefficientmentioning

confidence: 85%

Experimental and CFD Analysis of Two-Phase Forced Convection Flow in Channels of Various Rib Shapes

Abed

Kareem

Majdi³

et al. 2020

ARFMTS

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This paper investigates numerically and experimentally heat transfer forced convective two-phase flow (i.e. air and water) over a rectangular ribbed channel with a vertical orientation. Three distinct rib–groove shapes have been examined. Ribs - groove shapes are; Triangle, Trapezoid, and Semi-Trapezoid ribs-groove. The present study has been performed with continuous heat flux through range of water and air superficial inlet velocity values between 0.105 – 0.316m/s, and 0.263 – 1.320 m/s, respectively. Continuity, momentum and energy calculations have been formulated using the Finite Volume Approach (FVM). Results indicate that the triangle rib-groove has the high heat transfer coefficient and lower temperature difference than other cases against a different number of Reynolds. The experimental data has been compared to numerical results for ribs –grooved channel with deviation of about 1.0% - 7.5%. The channel fitted with triangle ribs shows the highest heat transfer, which is about 59% higher than the smooth channel; 56% for trapezoidal rib, and 44% for channel fitted by semi-trapezoidal rib. Finally, the triangle rib-groove gives a better heat transfer improvement value in comparison with trapezoidal and semi trapezoidal rib-groove channel at constant pumping power.

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Section: Comparing Experimental and Numerical Heat Transfer Coefficientmentioning

confidence: 85%

Experimental and CFD Analysis of Two-Phase Forced Convection Flow in Channels of Various Rib Shapes

Abed

Kareem

Majdi³

et al. 2020

ARFMTS

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show abstract

“…This poses the question if the bubbles will reach the surface of the heat exchanger and result in influencing the heat transfer. Moreover, we aim to study this effect depending on the type of prevailing regime [2]. To address this challenge two approaches are targeted.…”

mentioning

confidence: 99%

Investigation Of Bubble Behaviour And Heat Transfer In The Cooling-Circuit Of The PEM-Electrolysis

Guesmi,

Unz,

Beckmann

2023

Proceedings of the 9th World Congress on Mechanical, Chemical, and Material Engineering

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Climate change, carbon neutrality and the future of mankind became part of the daily news feed. This led to an urgent need for the decarbonization of the economy. The production of hydrogen based on green electricity through upscaling of electrolysis systems is a very promising strategy to reach this goal in a cost-effective manner. The Polymer-Electrolyte-Membrane (PEM)-electrolysis is considered as one of the promising technologies thanks to its advantageous load charge behavior. Therefore, it can be easily combined with highly fluctuating power from wind and solar energy [1].The mechanism of PEM-electrolysis produces oxygen at the anode side according to the following chemical reaction 2𝐻𝐻 2 0 → 𝑂𝑂 2 + 4𝐻𝐻 + + 4𝑒𝑒 − [1]. The water streaming in the anode cycle is supersaturated, because the oxygen concentration in water exceeds its solubility. In the cooling circuit, the water flow experiences an ongoing bubble evolution due to many factors like the pressure or temperature change. In the cooling circuit a gas separation through a gas-liquid separator is realized. Thereafter, the flow enters the heat exchanger. At this stage the bubble behavior and its influence on the heat transfer gained great scientific interest.The scope of this research is to understand and investigate the bubble evolution in the cooling-circuit of the PEM-Electrolysis and to estimate the resulting effect on the heat transfer. Inside the heat exchanger several bubble phenomena occur such as nucleation, rise in the flow and coalescence. This poses the question if the bubbles will reach the surface of the heat exchanger and result in influencing the heat transfer. Moreover, we aim to study this effect depending on the type of prevailing regime [2]. To address this challenge two approaches are targeted. The first approach is to develop an empirical cell model for bubbly and stratified flow in a horizontal pipe. The model estimates the pressure drop and heat transfer. The second approach is a CFD investigation which can capture the phenomena cited above. The advantage of the first approach is a quick prediction compared to the numerically expensive CFD approach. The CFD approach will help investigate the evolution of bubbles in the pipe flow. In a further step, the results achieved will be validated experimentally. The experimental plant is already designed and it is currently under construction. It will enable the investigation of bubble evolution in pipe and rectangular flow channels. The two channels are made transparent to make the bubble evolution observable with a high-speed camera. Furthermore, heat transfer will be also experimentally studied.The main objective of this scientific work is to create an empirical and a CFD model that can predict the effect of oxygen gas in water on the heat transfer and give further details about the behavior of bubbles. This will help in the design and the improvement of the performance of heat exchanger for electrolysis plants.

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Two‐Component Gas–Liquid Heat Transfer

2021

Two‐Phase Heat Transfer

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Experimental Investigation and Empirical Correlations of Heat Transfer in Different Regimes of Air–Water Two-Phase Flow in a Horizontal Tube

Cited by 12 publications

References 19 publications

Experimental and CFD Analysis of Two-Phase Forced Convection Flow in Channels of Various Rib Shapes

Experimental and CFD Analysis of Two-Phase Forced Convection Flow in Channels of Various Rib Shapes

Investigation Of Bubble Behaviour And Heat Transfer In The Cooling-Circuit Of The PEM-Electrolysis

Two‐Component Gas–Liquid Heat Transfer

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