Investigation of combined free and forced convection in a 2 x 6 rod bundle. [LMFBR]

Quigley,; McMonagle, C.A.; Bates, J.M.

doi:10.2172/7088966

Cited by 4 publications

(8 citation statements)

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“…Quigley, McMonagle, and Bates (1977) report on similar problems with LOA measurements in heated flows. It should be noted that for the particular signal processor and optical arrangement used in the LOA setup of the earlier study, Quigley et ale were unable to get complete velocity traverse data at all axial levels for bundle bulk temperature rises of 33°F at Re = 480.…”

Section: 1mentioning

confidence: 90%

“…The correlations for friction factor and Nusselt number for the rodcoolant interface were taken from the work of Quigley, McMonagle, and Bates (1977), who tried several friction factor correlations before determining that the most appropriate correlation was the maximum of smooth tube laminar and turbulent friction factors (Table 6.1).…”

Section: Cobra-we Code Inputmentioning

confidence: 99%

“…7.2 * and 9 (Z = 0.875 and 1.00, respectively), where Quigley, McMonagle, and Bates (1977) were unable to make reliable velocity measurements. These velocity profiles are presented in Figures 7.2 and 7.3, with the corresponding Case 1 isothermal profileS.…”

mentioning

confidence: 97%

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Investigation of combined free and forced convection in a 2 x 6 rod bundle during controlled flow transients

Bates¹,

Khan²

1980

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An experimental study was performed to obtain local fluid velocity and temperature measurements in the mixed (combined free and forced) convection regime for specific flow coastdown transients. A brief investigation of steady-state flows for the purely free-convection regime was also completed. The study was performed using an electrically heated 2 x 6 rod bundle contained in a flow housing. In addition a transient data base was obtained for evaluating the COBRA-We thermal-hydraulic computer program (a modified version of the COBRA-IV code).The objective of the study was to develop an understanding of the thermalhydraulic phenomena at low flows in a rod bundle subjected to lateral power skews. Test conditions included 500-, 300-, 150-and 45-second flow coastdown transients, a Reynolds number range of -90 to -1300, and power skews of 1:0, 2:1, 3:1, and 4:1. The dimensionless group Gr*/Re 2 , which represents the ratio of buoyancy to inertial forces, was varied in the range 0.0 to 2.4 at selected lateral power skews. Flow recirculation zones were detected in the bundle during transient conditions at large ratios of buoyancy to inertial forces as indicated by the measurements of downward flow in the colder subchannels and upward flow in the hotter subchannels. No flow recirculation was detected in the bundle at steady-state conditions except at extremely low Reynolds numbers where heat loss and/or hydraulic effects of the discharge geometry become important. The length of the recirculation zone in the axial direction was observed to be dependent on rod power level, the lateral power skew, and the total flow rate.The data were compared to predictions obtained with the COBRA-We computer code. COBRA-We satisfactorily predicted the measured bundle subchannel velocity and temperature histories. At Reynolds numbers below 450 an improvement in the turbulent mixing model in COBRA-We was required to satisfactorily predict experimental results. This improvement was necessary because as the magnitude of the buoyancy forces increased, thermal plumes grew laterally as they moved axially upward. When adjacent thermal plumes interacted, turbulence was v generated which appeared to promote lateral mlxlng between subchannels. A model incorporating the enhanced turbulent mixing due to the thermal plume interactions was used to improve the COBRA-We predictions at large ratios of Gr*/Re 2 . The enhanced turbulent mixing parameter was correlated as a function of Grashof and Reynolds numbers (Gr/Re 2 ) and the ratio of local heat generating rate to the bundle average heat generation rate.vi ACKNOWLEDGMENTS

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Section: 1mentioning

confidence: 90%

Section: Cobra-we Code Inputmentioning

confidence: 99%

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Investigation of combined free and forced convection in a 2 x 6 rod bundle during controlled flow transients

Bates¹,

Khan²

1980

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“…Spacer grid locations are provided in Figures 6,7,8,and 11. Assembly types 0-1, 0-2, 0-3, and 1 use the lantern-type spacer grid shown in Figure 16.…”

Section: Ctf Modelmentioning

confidence: 99%

CTF Validation and Verification: Version 4.4

Salko, Jr.,

Wysocki,

Toptan

et al. 2023

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“…The CTF model contained 12 rods and 21 subchannels arranged as shown in Figure 3.19. The numbering from the steady-state test reference [7] was used, in contrast to that in the transient test reference [8], where the subchannel numbering began in the middle row. The axial meshing of the test section is shown in Figure 3.20.…”

Section: Pnnl 2x6mentioning

confidence: 99%

CTF 4.0 Validation and Verification

Salko¹,

Wysocki²,

Toptan

et al. 2019

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Coolant-Boiling in Rod Arrays-Two Fluids (COBRA-TF) is a thermal/hydraulic (T/H) simulation code designed for Light Water Reactor (LWR) analysis. It uses a two-fluid, three-field (i.e. fluid film, fluid drops, and vapor) modeling approach. Both sub-channel and 3D Cartesian forms of nine conservation equations are available for LWR modeling. The code was originally developed by Pacific Northwest Laboratory in 1980 and has been used and modified by several institutions over the last several decades. COBRA-TF is also used at the Pennsylvania State University (PSU) by the Reactor Dynamics and Fuel Modeling Group (RDFMG) and has been improved, updated, and subsequently became the PSU RDFMG version of COBRA-TF (CTF). One part of the improvement process includes validating the methods in CTF.This document seeks to provide a certain level of certainty and confidence in the predictive capabilities of the code for the scenarios it was designed to model-rod bundle geometries with operating conditions that are representative of prototypical Pressurized Water Reactor (PWR)s and Boiling Water Reactor (BWR)s in both normal and accident conditions. This is done by modeling a variety of experiments that simulate these scenarios and then presenting a qualitative and quantitative analysis of the results that demonstrates the accuracy to which CTF is capable of capturing specific quantities of interest.

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Investigation of combined free and forced convection in a 2 x 6 rod bundle. [LMFBR]

Cited by 4 publications

References 1 publication

Investigation of combined free and forced convection in a 2 x 6 rod bundle during controlled flow transients

Investigation of combined free and forced convection in a 2 x 6 rod bundle during controlled flow transients

CTF Validation and Verification: Version 4.4

CTF 4.0 Validation and Verification

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