Steady and unsteady simulations for annular internal condensing flows, part I: Algorithm and its accuracy

Naik, Ranjeeth R.; Narain, Amitabh; Mitra, Soumya Asimkumar

doi:10.1080/10407790.2016.1138802

Cited by 18 publications

(26 citation statements)

References 28 publications

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“…Pressure (or flow) pulsations were supplied to the inlet vapor flow at different frequencies, while at the liquid inlet a constant frequency flow pulsation (generated and supplied through a peristaltic pump) was imposed. Mostly, annular flow was achieved throughout the entire length of the heat transfer surface as ensured in previous experiments and simulations [1][2][3][4][5][6][7][8][9][10].…”

Section: Setupmentioning

confidence: 99%

“…), are needed for these critical applications. Although some experimental and computational works have been done, and their results reported [1][2][3][4][5][6][7][8][9][10], further experimental and computational evaluations are needed to enable these critical applications.…”

Section: Introductionmentioning

confidence: 99%

“…Past studies [1][2][3][4][5][6][7][8][9][10] focused on consideration of different flow regimes, flow control methods, and estimating heat transfer coefficient related to the particular flow regimes. Various methods of flow regime control have been proposed, such as actively controlled vapor re-circulation in flow condensers and vapor and liquid re-circulation in flow boilers.…”

Section: Introductionmentioning

confidence: 99%

“…shown in Fig. 1a and discussed in [1][2][3][4][5][6][7][8][9][10]. To achieve this, the inlet liquid flow rate was chosen based on the desired heat input of the flow boiler, and inlet vapor mass flow rate was chosen to lie within a range that provides annular boiling over the whole length of the boiler (The desired inlet mass flow rates of the vapor and liquid were obtained through numerical simulations discussed in [5,6,9].…”

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Heat-flux enhancement response for novel flow-boiler operations under resonant, sub-harmonic, and superharmonic imposition of vapor pulsation frequencies relative to a liquid flow-rate pulsation frequency

Koca

Kivisalu

2019

J Braz. Soc. Mech. Sci. Eng.

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This paper presents fundamental results from experimental investigations of shear/pressure-driven internal flow boiling of FC-72 in a horizontal test section of total flow channel length 1000 mm, gap height 2 mm, and width 15 mm. It compares effects of the frequencies of vapor and liquid pressure fluctuations (pulsations) on the experimentally measured heat-flux rates and heat transfer coefficients at a representative location within the flow boiler under a flow operation method in which re-circulating vapor maintains an annular flow regime over the entire length of the device. For liquid flow/pressure pulsations at 3.8-3.9 Hz, four externally imposed inlet vapor pressure fluctuation conditions were considered: (1) no externally imposed vapor pulsations and (2)-(4): high-amplitude externally imposed vapor pulsations at (2) the same, (3) half, and (4) double the inlet liquid pulsation frequency. Representative pressure differences within the flow boiler are also examined. Local time-averaged heat-flux and heat transfer coefficient responses of these flows are compared with previously published data at the same liquid pulsation frequency, but at a different inlet liquid flow rate, vapor quality, and pressure. The reported measurements, and the discussions and conclusions in this paper, enable better understanding of an established pulsationinduced heat-flux enhancement phenomenon which may be used in future cooling systems to significantly enhance average heat-flux values over the entire length of an annular flow boiler. The main conclusion is that, for the flow conditions investigated, optimal heat transfer efficiency occurs when vapor and liquid pulsations are imposed at the same frequency on the flow-boiler inlet.

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Section: Setupmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Heat-flux enhancement response for novel flow-boiler operations under resonant, sub-harmonic, and superharmonic imposition of vapor pulsation frequencies relative to a liquid flow-rate pulsation frequency

Koca

Kivisalu

2019

J Braz. Soc. Mech. Sci. Eng.

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“…At times, for channel flows, the channel height "h" is used as the characteristic length scale [16,20,21] [27], in the following forms:…”

Section: Traditional and Annular (Innovative) Flow-boiling/condensationmentioning

confidence: 99%

Assessment of Annular Flow Boiling in the Context of Computational Fluid Dynamics (Cfd) Simulations, Experiments, and Existing Correlations

Prasad¹,

Prasad²

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Internal Annular Flow Condensation and Flow Boiling: Context, Results, and Recommendations

Narain

Prasad

Koca

2018

Handbook of Thermal Science and Engineering

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Steady and unsteady simulations for annular internal condensing flows, part I: Algorithm and its accuracy

Cited by 18 publications

References 28 publications

Heat-flux enhancement response for novel flow-boiler operations under resonant, sub-harmonic, and superharmonic imposition of vapor pulsation frequencies relative to a liquid flow-rate pulsation frequency

Heat-flux enhancement response for novel flow-boiler operations under resonant, sub-harmonic, and superharmonic imposition of vapor pulsation frequencies relative to a liquid flow-rate pulsation frequency

Assessment of Annular Flow Boiling in the Context of Computational Fluid Dynamics (Cfd) Simulations, Experiments, and Existing Correlations

Internal Annular Flow Condensation and Flow Boiling: Context, Results, and Recommendations

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