Heat transfer during cooling of high temperature spheres in subcooled water at different pressures

Yagov, V. V.; Zabirov, A R; Kaban’kov, O. N.; Minko, M. V.

doi:10.1016/j.ijheatmasstransfer.2017.03.029

Cited by 40 publications

(13 citation statements)

References 16 publications

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“…They found that the heat flux in stable MEB region was quasi‐stable and oscillated with a frequency of 0.8–2 kHz. Yagov et al studied microbubble boiling phenomenon occurred in cooling of hot mental spheres in a subcooled pool. Many tiny bubbles were observed near the vapor film around the sphere in this boiling process.…”

Section: Introductionmentioning

confidence: 99%

“…They deemed that the microbubble boiling was triggered in cooling process when heat supply of a heating surface was controlled with the metal thermal effusivity. Besides, according to the analysis of experimental results by Ando et al, Yagov et al also made a supposition that the oscillation of heat flux meant the potential influence of the thermal effusivity of the heater on the transition to MEB.…”

Section: Introductionmentioning

confidence: 99%

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Experimental investigation of transition process from nucleate boiling to microbubble emission boiling under transient heating modes

Tang

Sun

et al. 2019

AIChE Journal

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This study investigated the transition from nucleate boiling to microbubble emission boiling (MEB) on a small heating surface under transient heating modes. During the short unstable boiling process after critical heat flux with a rapid increase in wall temperature, capillary waves were observed over the vapor film at subcooling of 30–40 K. The visualization results in this process demonstrated that the partial collapse of vapor film induced strong jet toward the heating surface and therefore avoided complete dryout thereon. This mechanism certainly plays an important role in the transition to stable MEB. Further comparison between the wall temperature and boiling states indicates that the wall temperature at onset point of stable MEB is determined by the predominance of MEB mode over film boiling in the transition process. Effects of liquid subcooling and surface oxidation on the transition process were also investigated at the same time.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Experimental investigation of transition process from nucleate boiling to microbubble emission boiling under transient heating modes

Tang

Sun

et al. 2019

AIChE Journal

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“…It is found that in water subcooled by ΔT sub > 20-30 K, microbubble boiling occurs when the samples made of materials with very different properties (stainless steel, nickel, and copper) are cooled. As far as is known, the temperature of a cooled ball is measured in such experiments at the center and at several points on the surface rather than at one point only in [7][8][9][10][11][12][13]. The presence of several surface thermocouples enables us to determine reliably the temperature of occurrence of the intensive cooling mode, the velocity of the cooling front propagation over the surface, and the rate of the ball cooling.…”

Section: Heat and Mass Transfer And Physical Gasdynamicsmentioning

confidence: 99%

Effect of Coating by a Carbon Nanostructure on Heat Transfer with Unsteady Film Boiling

et al. 2019

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We present the results of an experimental study of heat transfer regimes during cooling in water of high-temperature, heated steel balls with a technically smooth and modified surface. The modification consisted of the application of a finely dispersed carbon coating to the surface followed by electron beam treatment. When the samples are placed in subcooled water, an intensive heat transfer regime occurs on the both samples; it appeared upon film boiling with heat fluxes on the surface up to 6 MW/m 2 . The heat flux values based on the initial cooling thermograms were obtained from a one-dimensional inverse heat conduction problem. The carboncoating leads to a decrease in the surface temperature, which corresponds to the transition to the intensive cooling mode, whereas the intensive cooling mode itself is identical for samples with the different surface treatments. Experimental results confirm the approximate model proposed for the conditions for the occurrence of the intensive cooling regime during film boiling of a subcooled liquid.

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“…Традиционные методы расчетов теплообменных аппаратов, построенные с применением уравнений теплового баланса и теплопередачи, не учитывают обратное перемешивание теплоносителей, т.е. справедливы при идеальном вытеснении потоков [1][2][3]. Такой подход допустим в расчетах теплообменников с гладкими поверхностями, без дополнительных устройств (перегородок, интенсификаторов и т.д.…”

Section: Introductionunclassified

Modeling of temperature profiles and efficiency of heat transfer equipment with intensifiers

Фарахов

Лаптев

2020

«Izvestiya vysshikh uchebnykh zavedenii. PROBLEMY ENERGETIKI»

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The problem of determination of temperature fields in the flow and efficiency of heat exchangers with intensification by metal chaotic packings is considered. Results of experimental studies of the heating of industrial oil with hot water in a "pipe-in-pipe" heat exchanger, where a chaotic packing of nominal size 6 mm is placed in the internal pipe, are presented. The packing, due to turbulence in the flow of oil, provides transition from the laminar to the turbulent regime and a significant increase in heat transfer coefficient (by 15-20 times). For calculating temperature profiles in channels, a cell model of the flow structure is written, where the main parameters are thermal number of transfer units and number of complete mixing cells. Expressions are given for calculating these parameters in pipes with chaotic packings. Results of calculating temperature profiles for various flowrates of the heated oil are presented and satisfactory agreement with experimental data is shown. The calculation of temperature fields makes it possible to take into account a change in thermophysical properties of flows along the length of the channels, which is especially important for hydrocarbon mixtures with high viscosity and large Prandtl numbers. The presented mathematical model allows to take into account the structure of heat carrier flows in apparatus with intensifiers and to calculate thermal efficiency of the processes of heating and cooling the media.

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Heat transfer during cooling of high temperature spheres in subcooled water at different pressures

Cited by 40 publications

References 16 publications

Experimental investigation of transition process from nucleate boiling to microbubble emission boiling under transient heating modes

Experimental investigation of transition process from nucleate boiling to microbubble emission boiling under transient heating modes

Effect of Coating by a Carbon Nanostructure on Heat Transfer with Unsteady Film Boiling

Modeling of temperature profiles and efficiency of heat transfer equipment with intensifiers

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