Pressure drop, void fraction and shear stress measurements in an adiabatic two-phase flow in a coiled tube

Czop, V.; Barbier, D.; Dong, Siwei

doi:10.1016/0029-5493(94)90298-4

Cited by 50 publications

(26 citation statements)

References 10 publications

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“…It is evident that the available pressure drop data in usable form on water-steam flows through helically coiled tubes are rather limited, so that more experimental studies are clearly welcome. Since the present study is specifically targeting water-steam two-phase flows, available data generated with fluids other than water-steam [7,9,10,[14][15][16][17][18]21] are not taken into account.…”

Section: Experimental Pressure Drop Databankmentioning

confidence: 99%

“…Available void fraction measurements in helical coils [7,9,10,14,16,18] suggest that curvature effects on the void fraction are small and negligible, so that straight tube void fraction prediction methods can be extrapolated to helically coiled tubes, at least in first approximation. Therefore, the void fraction prediction method of Woldesemayat and Ghajar [51] was used here, as this is one of the most accurate general purpose void fraction correlations currently available for straight tubes [50].…”

Section: Comparison With Existing Correlationsmentioning

confidence: 99%

“…Due to its practical relevance, two-phase flow pressure drop in helically coiled tubes has been investigated quite extensively [6][7][8][9][10][11][12][13][14][15][16][17][18][19][20][21][22][23]. Notably, several authors found straight tube prediction methods appropriate to predict the pressure drop in helical coils.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Two-phase pressure drop prediction in helically coiled steam generators for nuclear power applications

Cioncolini

Santini

2016

International Journal of Heat and Mass Transfer

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This study considers the prediction of the pressure gradient with water-steam two-phase flows through helically coiled steam generator tubes, focusing in particular on the operating conditions of low-medium pressure, low mass flux and low heat flux typical of once-through steam generators with in-tube boiling adopted in small modular nuclear reactor systems. Twenty-five widely used empirical correlations have been tested against an experimental pressure drop databank drawn together in this study containing 980 data points. Since no existing correlation is capable of collapsing and satisfactorily fitting the collected databank, a new pressure drop prediction method for helically coiled tubes is proposed. This new prediction method is very simple to implement, as it is based on the homogeneous flow model, is asymptotically consistent with straight tube twophase flows and is largely superior in accuracy to existing prediction methods (mean absolute error of 7.3%, and 9 points out of 10 captured to within ±15%). The new prediction method is applicable for operating pressures in the range of 0.75-9.0 MPa, mass fluxes from 400 kg/m 2 s to 1191 kg/m 2 s, heat fluxes up to 750 kW/m 2 , tube diameters within 5-20 mm and coil to tube diameter ratio above 32.4. Curvature effects on the pressure gradient in helical coil two-phase flows can be significant, particularly with high velocity flows in tight curvature coils where the centrifugal force is intense.2

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Section: Experimental Pressure Drop Databankmentioning

confidence: 99%

Section: Comparison With Existing Correlationsmentioning

confidence: 99%

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Two-phase pressure drop prediction in helically coiled steam generators for nuclear power applications

Cioncolini

Santini

2016

International Journal of Heat and Mass Transfer

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“…They found out the thickness of water film on the wall of the coil at different points around the circumference experimentally. Czop et al (1994) carried out experiments on water-SF 6 flow through a helically coiled tube of 19.8 mm id with 1170 mm coil diameter. It has been observed that the two-phase pressure drops are very much different from those calculated with Lockhart-Martinelli correlation but are in fairly good agreement with the Chisholm correlation.…”

Section: Heat Transfer In Single-phase Flowmentioning

confidence: 99%

“…The values of Martinelli parameter, , is calculated using the pressure drop relations provided by Czop et al (1994). Fig.…”

Section: Correlation For Estimation Of Two-phase Heat Transfer Coeffimentioning

confidence: 99%

Helically Coiled Heat Exchangers

Jayakumar¹

2012

Heat Exchangers - Basics Design Applications

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Numerical study on heat transfer and pressure drop characteristics of fluid flow in an inserted coiled tube type three fluid heat exchanger

Mohapatra

Ray

Sahoo

et al. 2019

Heat Trans. Asian Res.

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The paper presents numerical investigations of a three fluid heat exchanger (TFHE), which is an improvement on the double pipe heat exchanger, where a helical tube is inserted in the annular space between two straight pipes. The helical tube side fluid, that is, hot water continuously transfers heat to the outer annulus side fluid and innermost tube side fluid. The heat transfer and pressure drop characteristics of the TFHE are assessed for different flow rates and inlet temperatures. With an increment in the volumetric flow rate of the helical tube side fluid and outer annulus side fluid, the overall heat transfer coefficient increases, and the effectiveness decreases for heat transfer from the helical tube side fluid to outer annulus side fluid in both parallel flow and counter flow configurations. It is also observed that with increment in the helical tube side fluid inlet temperature, the overall heat transfer coefficient and effectiveness increases for heat transfer from the helical tube side fluid to outer annulus side fluid in both flow configurations. The parameter, JF factor, has been proposed to evaluate the thermohydraulic behavior of the TFHE, where it is obtained that the behavior of the TFHE is better at a lower helical tube side fluid velocity and higher outer annulus side fluid velocity.

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Pressure drop, void fraction and shear stress measurements in an adiabatic two-phase flow in a coiled tube

Cited by 50 publications

References 10 publications

Two-phase pressure drop prediction in helically coiled steam generators for nuclear power applications

Two-phase pressure drop prediction in helically coiled steam generators for nuclear power applications

Helically Coiled Heat Exchangers

Numerical study on heat transfer and pressure drop characteristics of fluid flow in an inserted coiled tube type three fluid heat exchanger

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