Experimental study on the onset of flow instability in small horizontal tubes at supercritical pressures

Yang, Zhuqiang; Shan, Yafei

doi:10.1016/j.applthermaleng.2018.02.092

Cited by 28 publications

(2 citation statements)

References 32 publications

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“…Wang et al Yang et al [21] conducted an experimental study to develop a correlation that can accurately predict the OFI of a cooling tube with a small diameter in order to prevent flow excursion accidents in regenerative cooling systems. Accordingly, they conducted an experiment to evaluate the OFI of cooling tubes with diameters of 1 and 2 mm under the conditions of a pressure of 4.5-5.5 MPa, an inlet bulk temperature of 30 °C-70 °C, and a heat flux of 158-450 kW m −2 .…”

Section: Introductionmentioning

confidence: 99%

Experimental study of thermal limits with one-side heated smooth channel for plasma facing component safety

Lim

Park

2021

Eng. Res. Express

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In order to stably operate the equipment inside the tokamak, which is loaded with a heat flux of several MW/m2 under the one-side heating condition, it is necessary to thoroughly prepare for various thermal engineering limits that may occur under the high heat flux load condition. In this study, we have experimentally explored critical heat flux (CHF) and onset of flow instability (OFI), which are considered potential threats in a DEMO fusion power plant. Specifically, the effect of system parameters on CHF was investigated. The results indicate that with an increase in subcooling and mass flux, the CHF increased, as it induced a faster bubble condensation near the CHF. As the system pressure increased, the CHF also increased. This is because the bubble size reduction effect was dominant in the pressure range of 1–10 bar. Most of the existing CHF correlations could evaluate the CHF with reasonable accuracy of within 25%; especially, the Boscary CHF correlation yielded the highest accuracy with an average error of 12%. Similar to CHF, OFI, which is a measure of the sudden fluctuations in the system pressure caused by a large amount of vapor generated due to the high heat flux, tended to increase as the subcooling, mass flow rate, and system pressure increased. Most of the existing OFI correlations yielded large error rates (more than 135%) as these correlations were primarily developed for micro-channels. Therefore, in this study, a new OFI correlation was developed using a Python code, in combination with an artificial intelligence (AI) regression method. The developed correlation can be used in the cooling system design of tokamaks, which involve a high-heat load condition on one-side of the reactor.

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Section: Introductionmentioning

confidence: 99%

Experimental study of thermal limits with one-side heated smooth channel for plasma facing component safety

Lim

Park

2021

Eng. Res. Express

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“…A number of investigations have been devoted to the supercritical heat transfer for various fluids [14][15][16][17]. However, while most of these studies were aimed at supercritical water and CO 2 [18][19][20][21], few studies have been devoted to the heat transfer of supercritical kerosene.…”

Section: Introductionmentioning

confidence: 99%

Experiments on Heat Transfer of Supercritical Pressure Kerosene in Mini Tube under Ultra-High Heat Fluxes

et al. 2020

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Heat transfer of supercritical-pressure kerosene is crucial for regenerative cooling systems in rocket engines. In this study, experiments were devoted to measure the heat transfer of supercritical-pressure kerosene under ultra-high heat fluxes. The kerosene flowed horizontally in a mini circular tube with a 1.0 mm inner diameter and was heated uniformly under pressures of 10–25 MPa, mass fluxes of 8600–51,600 kg/m2 s, and a maximum heat flux of up to 33.6 MW/m2. The effects of the operating parameters on the heat transfer of supercritical-pressure kerosene were discussed. It was observed that the heat transfer coefficient of kerosene increases at a higher mass flux and inlet bulk temperature, but is little affected by pressure. The heat transfer of supercritical-pressure kerosene is classified into two regions: normal heat transfer and enhanced heat transfer. When the wall temperature exceeds a certain value, heat transfer is enhanced, which could be attributed to pseudo boiling. This phenomenon is more likely to occur under higher heat flux and lower mass flux conditions. In addition, the experimental data were compared with several existing heat transfer correlations, in which one of these correlations can relatively well predict the heat transfer of supercritical-pressure kerosene. The results drawn from this study could be beneficial to the regenerative cooling technology for rocket engines.

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Analysis of Supercritical Hydrocarbon Fuel as a Coolant for Improved Thermal Performance of Scramjet

Rathan Babu,

Gudıkandula,

Sai Puravardhan

et al. 2024

Advances in Science, Technology &Amp; Innovation

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Experimental study on the onset of flow instability in small horizontal tubes at supercritical pressures

Cited by 28 publications

References 32 publications

Experimental study of thermal limits with one-side heated smooth channel for plasma facing component safety

Experimental study of thermal limits with one-side heated smooth channel for plasma facing component safety

Experiments on Heat Transfer of Supercritical Pressure Kerosene in Mini Tube under Ultra-High Heat Fluxes

Analysis of Supercritical Hydrocarbon Fuel as a Coolant for Improved Thermal Performance of Scramjet

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