Prediction of two-phase condensation in horizontal tubes using probabilistic flow regime maps

Jassim, Emad W.; Newell, T.A.; Chato, J. C.

doi:10.1016/j.ijheatmasstransfer.2007.05.021

Cited by 71 publications

(9 citation statements)

References 15 publications

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“…To create the map the authors implemented a new criterion and called it a time fraction without analysis of the accuracy of its substantiation. Comparison between all the models and the experiments on seven refrigerants was analyzed in [64]. As seen, with the exception of the data on mixture R32/R125 60/40%, without doubt, more precise agreement with the experiments has simple the Dobson and Chato model [48] and the theoretical model submitted by Cavallini et al [8].…”

Section: Experimental Researchesmentioning

confidence: 78%

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Condensation inside smooth horizontal tubes: Part 1. Survey of the methods of heat-exchange prediction

Rifert

Sereda

2015

THERM SCI

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Survey of the works on condensation inside smooth horizontal tubes published from 1955 to 2013 has been performed. Theoretical and experimental investigations, as well as more than 25 methods and correlations for heat transfer prediction are considered. It is shown that accuracy of this prediction depends on the accuracy of volumetric vapor content and pressure drop at the interphase. The necessity of new studies concerning both local heat transfer coefficients and film condensation along tube perimeter and length under annular, stratified and intermediate regimes of phase flow was substantiated. These characteristics being defined will allow determining more precisely the boundaries of the flow regimes and the methods of heat transfer prediction.

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Section: Experimental Researchesmentioning

confidence: 78%

“…Comparison between different models for calculation of α is given in [64]. Here, the calculations by the models proposed by Thome et al [56], Cavallini et al [8], Dobson and Chato [48] and by the authors of the model using the eq.…”

Section: Experimental Researchesmentioning

confidence: 99%

Condensation inside smooth horizontal tubes: Part 1. Survey of the methods of heat-exchange prediction

Rifert

Sereda

2015

THERM SCI

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“…Using the flow regime probabilities will assure a proper weighing of the flow phenomena and result in a smooth transition. This can be an alternative for a full probabilistic heat transfer model for evaporating flow similar to the model developed by Jassim et al [12] under condensing conditions. The soft-clustering algorithm assigns a membership grade to each data point which can be interpreted as a flow regime probability.…”

Section: Applicabilitymentioning

confidence: 99%

“…Jassim et al [9] obtained probabilistic two-phase flow data of R134a and R410A in single horizontal smooth, adiabatic tubes (diameters D ranging from 1.74mm to 8mm) by using an automated image recognition technique. Jassim [10] also developed curve fits for this time fraction data, which were used by Jassim et al [11] for void fraction modeling and by Jassim et al [12] for heat transfer modeling during condensation. However, so far, it is not known how general such time fraction curve fits are [5].…”

Section: Introductionmentioning

confidence: 99%

Mapping of horizontal refrigerant two-phase flow patterns based on clustering of capacitive sensor signals

Canière

Bauwens

T’Joen

et al. 2010

International Journal of Heat and Mass Transfer

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A capacitive void fraction sensor was developed to study the objectivity in flow pattern mapping of horizontal refrigerant two-phase flow in macroscale tubes. Sensor signals were gathered with R410A and R134a in a smooth tube with an inner diameter of 8mm at a saturation temperature of 15°C in the mass velocity range of 200 to 500 kg/m²s and vapour quality range from 0 to 1 in steps of 0.025. A visual classification based on high speed camera images is made for comparison reasons. A statistical analysis of the sensor signals shows that the average, the variance and a high frequency contribution parameter are suitable for flow regime classification into slug flow, intermittent flow and annular flow by using the fuzzy c-means clustering algorithm. This soft clustering algorithm predicts the slug/intermittent flow transition very well compared to our visual observations. The intermittent/annular flow transition is found at slightly higher vapour qualities for R410A compared to the prediction of [Barbieri et al., 2008, Flow patterns in convective boiling of refrigerant R134a in smooth tubes of several diameters, 5th European Thermal-Sciences Conference, The Netherlands]. An excellent agreement was obtained with R134a. This intermittent/annular flow transition is very gradual. A probability approach can therefore better describe such a transition. The membership grades of the cluster algorithm can be interpreted as flow regime probabilities. Probabilistic flow pattern maps are presented for R410A and R134a in an 8 mm I.D. tube.

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“…Compared to the experimental tests, they found the accuracy of their condensation heat transfer model is within AE 20%. Then, Jassim et al 12 proposed another condensation heat transfer model based on flow regime map. Compared to the experimental data, they found that their model is accurate in the flow transition region.…”

Section: Introductionmentioning

confidence: 99%

Investigations on water condensation in the main steam pipe of a pressurized water reactor nuclear power station: Part I – Experimental tests

Yan

et al. 2014

Proceedings of the Institution of Mechanical Engineers, Part A:

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Experiments were conducted to measure the water condensation rates and to investigate the heat transfer characteristics in the main steam pipe of pressurized water reactor nuclear power plant during starting up and stable operation conditions. Through a series of electric control valves, two representative experimental tests were attempted to validate the proposed theoretical method (see Part II of this two-part paper). Reliability of the experimentations was checked and guaranteed by repeating the stable operation condition experiment. To reveal the steam temperature fluctuation in different operation conditions, two K-type sheathed thermocouples were installed at the pipe inlet and outlet to monitor the transient temperature fields through an NI data collection system. Apart from these, five sections of thermocouple-wires (NiCr–NiSi) were welded onto the pipe outer wall surface to obtain the time-dependent temperature. Results show that the measured and theoretically predicted water condensation rates agree well (0.5% deficiency) for the startup process, while for the stable operation condition, the deficiency between measurements and predictions were around 30%. Water condensation in the startup process is dominated by the heat capacities of the pipe and insulation layer, while water condensation in the stable operation process is determined by the radiation and natural convection heat transfers from the insulation layer. The accuracy of the predicted water condensation rate in the stable operation condition is mainly affected by the thermal conductivity of the insulation layer. The transient temperature on the piping outer wall surface shows non-uniformity along the circumferential direction. However, due to the mixing and turbulence effects of the flowing vapor, the non-uniform effect becomes weaker along the axial direction.

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Prediction of two-phase condensation in horizontal tubes using probabilistic flow regime maps

Cited by 71 publications

References 15 publications

Condensation inside smooth horizontal tubes: Part 1. Survey of the methods of heat-exchange prediction

Condensation inside smooth horizontal tubes: Part 1. Survey of the methods of heat-exchange prediction

Mapping of horizontal refrigerant two-phase flow patterns based on clustering of capacitive sensor signals

Investigations on water condensation in the main steam pipe of a pressurized water reactor nuclear power station: Part I – Experimental tests

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