Assessment of heat transfer enhancement technique in flow boiling conditions based on entropy generation analysis: twisted-tape tube

Holagh, Shahriyar Ghazanfari; Abdous, Mohammad Ali; Shamsaiee, Masood; Saffari, Hamid

doi:10.1007/s00231-019-02705-y

Cited by 17 publications

(3 citation statements)

References 32 publications

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“…The operating conditions were taken into consideration as well. It can be found from experimental studies that [25][26][27][28] the results obtained in the experiments are precise, but the laws acquired in this research are not universal at different operating conditions. In addition, the influence of the flow patterns, such as vapor-liquid distribution, on the local entropy generation, cannot be directly acquired due to the limitations of experimental techniques.…”

Section: Introductionmentioning

confidence: 74%

“…The entropy generation during flow boiling in a in a micro-fin tube was investigated by Revellin and Bonjour [27] to explore the optimal structure of the tunnel with a certain heat flux. Experimental research was conducted by Shahriya [28] to characterize the entropy generation during the flow boiling in a twisted-tape tunnel. The operating conditions were taken into consideration as well.…”

Section: Introductionmentioning

confidence: 99%

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Entropy Generation Analysis of the Flow Boiling in Microgravity Field

Sun

Zhang

Wang

et al. 2022

Entropy

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Entropy generation analysis of the flow boiling in microgravity field is conducted in this paper. A new entropy generation model based on the flow pattern and the phase change process is developed in this study. The velocity ranges from 1 m/s to 4 m/s, and the heat flux ranges from 10,000 W/m2 to 50,000 W/m2, so as to investigate their influence on irreversibility during flow boiling in the tunnel. A phase–change model verified by the Stefan problem is employed in this paper to simulate the phase–change process in boiling. The numerical simulations are carried out on ANSYS-FLUENT. The entropy generation produced by the heat transfer, viscous dissipation, turbulent dissipation, and phase change are observed at different working conditions. Moreover, the Be number and a new evaluation number, EP, are introduced in this paper to investigate the performance of the boiling phenomenon. The following conclusions are obtained: (1) a high local entropy generation will be obtained when only heat conduction in vapor occurs near the hot wall, whereas a low local entropy generation will be obtained when heat conduction in water or evaporation occurs near the hot wall; (2) the entropy generation and the Be number are positively correlated with the heat flux, which indicates that the heat transfer entropy generation becomes the major contributor of the total entropy generation with the increase of the heat flux; (3) the transition of the boiling status shows different trends at different velocities, which affects the irreversibility in the tunnel; (4) the critical heat flux (CHF) is the optimal choice under the comprehensive consideration of the first law and the second law of the thermodynamics.

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Section: Introductionmentioning

confidence: 74%

Section: Introductionmentioning

confidence: 99%

Entropy Generation Analysis of the Flow Boiling in Microgravity Field

Sun

Zhang

Wang

et al. 2022

Entropy

View full text Add to dashboard Cite

show abstract

“…Due to the high heat transfer rate of boiling phenomenon, and similarly due to its complex nature, the study of flow boiling has been an interesting yet challenging field over the past five decades [1], particularly in enhanced heat exchangers [2]. Boiling phenomenon initiates when first bubbles form, and previous studies [3,4] reveal that the mechanisms of nucleation, growth, and departure of bubbles play a key role in boiling heat transfer and void fraction distribution.…”

Section: Introductionmentioning

confidence: 99%