Pressure drop performance of rod bundles in hexagonal arrangements

Rehme, K.

doi:10.1016/0017-9310(72)90143-3

Cited by 125 publications

(34 citation statements)

References 19 publications

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“…Except for the extreme position, in which the rods contact each other, there is excellent agreement between the calculated and the experimental data. The same applies to the studies conducted by the author on rod bundles in hexagonal channels with rod distance ratios P/D equal to the wall distance ratios W/D [39,40] for different rod distance ratios and rod numbers, as is shown in Figs. 12-14. Also for other wall distances there is good agreement between experiment and theory.…”

Section: Comparison Between Calculated and And Measured Datamentioning

confidence: 69%

Simple method of predicting friction factors of turbulent flow in non-circular channels

Rehme

1973

International Journal of Heat and Mass Transfer

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115

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Abstract-On the basis of friction factor relationships of a simple model a method is developed which allows the prediction of friction factors for turbulent flow in non-circular channels if only the geometry factor of the pressure drop relationship for laminar flow is known. The proposed method of calculation is tested with numerous experimental results from the literature with respect to non-circular channels such as triangular shaped ducts, eccentric annuli and rod bundles in hexagonal and square arrays in circular tubes, hexagonal and square channels. It turns out that the proposed method provides an excellent description of all the experimental data at hand.channel wall and rods; annular zone parameter; wall distance; dimensionless wall distance y+ =

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Section: Comparison Between Calculated and And Measured Datamentioning

confidence: 69%

Simple method of predicting friction factors of turbulent flow in non-circular channels

Rehme

1973

International Journal of Heat and Mass Transfer

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115

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“…Rehme 4) carried out systematic investigations on the single phase friction loss using around 60 types of tight-lattice rod bundles. He pointed out that the single-phase friction loss coefficient in the bundles is smaller than that in the circular tube when the ratio of a pitch to diameter is smaller than 1.08, and his indication results from the nonuniform velocity and wall shear stress distributions and also from the fact that the hydraulic diameter does not take into account these irregularities.…”

Section: Resultsmentioning

confidence: 99%

“…The RMWR core consists of triangular and distorted flow channels, and the ratio of a pitch to diameter in the bundle is small (about 1.1). Rehme 4) pointed out that the coefficient of the single-phase friction loss in the bundles is smaller than that in the circular tube when the ratio of a pitch to diameter is small, and his indication results from the nonuniform velocity and wall shear stress distributions and also from the fact that the hydraulic diameter does not take into account these irregularities. Few correlations are therefore applicable to the evaluation of the pressure drop in the RMWR core without any verification.…”

Section: Introductionmentioning

confidence: 99%

Pressure Drop Experiments using Tight-Lattice 37-Rod Bundles

Tamai

Kureta

Ohnuki

et al. 2006

J. Nucl. Sci. Technol.

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In order to design a Reduced-Moderation Water Reactor (RMWR) core from a thermal-hydraulic point of view, an evaluation method on the pressure drop in a tight-lattice rod bundle is required. In this study, axial pressure drops in tight-lattice 37-rod bundles were measured under conditions of 2-9 MPa in exit pressure and 200-1,000 kg/(m 2 Ás) in mass velocity. The measured pressure drops were compared with calculated ones by the evaluation method with the Martinelli-Nelson's correlation. The comparison shows that a single-phase friction factor can be applied not only to a circular tube but also to a tight-lattice bundle except for an extremely small gap width. Then two-phase friction loss is a dominant component and accounts for about 60% of the pressure drop under an RMWR nominal operating condition. The evaluation method can evaluate effects of the flow area configuration (rod number, rod diameter, gap width) and axial power distribution under a wide range of flow conditions, and it can yield a good prediction of the pressure drop in a tight-lattice bundle.

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“…Rehme (16) carried out systematic investigations on the friction loss in a single-phase flow on about 60 types of rod bundles. He pointed out that the coefficient of the pressure loss decreases to approximately 60% of the circular tube with decreasing the ratio of a pitch to diameter in the bundles.…”

Section: Friction Loss At Tight-lattice Configurationmentioning

confidence: 99%

Pressure Drop Characteristics in Tight-Lattice Bundles for Reduced-Moderation Water Reactors

Tamai¹,

Kureta²,

Yoshida³

et al. 2004

JSME international journal. Ser. B, Fluids and thermal engineer

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The reduced-moderation water reactor (RMWR) consists of several distinctive structures; a triangular tight-lattice configuration and a double-flat core. In order to design the RMWR core from the point of view of thermal-hydraulics, an evaluation method on pressure drop characteristics in the rod bundles at the tight-lattice configuration is required. In this study, calculated results by the Martinelli-Nelson's and Hancox's correlations were compared with experimental results in 4 × 5 rod bundles and seven-rod bundles. Consequently, the friction loss in two-phase flows becomes smaller at the tight-lattice configuration with the hydraulic diameter less than about 3 mm. This reason is due to the difference of the configuration between the multi-rod bundle and the circular tube and due to the effect of the small hydraulic diameter on the two-phase multiplier.

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Pressure drop performance of rod bundles in hexagonal arrangements

Cited by 125 publications

References 19 publications

Simple method of predicting friction factors of turbulent flow in non-circular channels

Simple method of predicting friction factors of turbulent flow in non-circular channels

Pressure Drop Experiments using Tight-Lattice 37-Rod Bundles

Pressure Drop Characteristics in Tight-Lattice Bundles for Reduced-Moderation Water Reactors

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