COBRA-WC: a version of COBRA for single-phase multiassembly thermal hydraulic transient analysis. [LMFBR]

George, T.L.; Basehore, K.L.; Wheeler, C.L.; Prather, W.A.; Masterson, Robert E.

doi:10.2172/5167225

Cited by 11 publications

(8 citation statements)

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“…analysis codes, such as COBRA-We (George, Basehore, Wheeler, Prather and Masterson 1980) which are used for reactor design and safety analysis.…”

Section: Discussionmentioning

confidence: 99%

“…The time response of the temperature measurement system tended to time average small-scale fluid temperature fluctuation; however, the overall combined temperature fluctuation/system time response can be seen in Figures The COBRA-We computer program (George et al, 1980), a modified version of the COBRA-IV-I code (Wheeler et ale 1976) has been specifically developed for predicting core-wide steady-state and transient temperature and flow distributions in LMFBR assemblies on a subchannel basis. One of the basic objectives of this study was to evaluate and improve the COBRA-WC transient models at low-flow conditions and also to evaluate the flow recirculation model.…”

Section: 1mentioning

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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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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“…analysis codes, such as COBRA-We (George, Basehore, Wheeler, Prather and Masterson 1980) which are used for reactor design and safety analysis.…”

Section: Discussionmentioning

confidence: 99%

Section: 1mentioning

confidence: 99%

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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“…The code is also capable of resolving the flow and pressure fields for systems in which the net flow is zero. This calculational flexibility is a feature of the numerical solution method for the fluid equations that COBRA-SFS has inherited from its immediate predecessor, COBRA-WC (George et al 1980). In spent fuel assemblies and storage or shipping casks, the flow field may be fairly simple to obtain, but the strong coupling of the fluid energy equation and the heat transfer models for the solid structures presents special problems of stability and convergence rates.…”

Section: Numerical Solution Methodsmentioning

confidence: 99%

“…The COBRA-SFS code is derived from COBRA-WC (George et al 1980) and retains essentially the same structure. The main program COBRA, calls various routines to process the input and set up the problem, to perform the solution, and to process the output.…”

Section: Functional Hierarchy Of Cobra-sfsmentioning

confidence: 99%

COBRA-SFS: A thermal-hydraulic analysis code for spent fuel storage and transportation casks

Michener¹,

Rector²,

Cuta³

et al. 1995

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Printod inThis document presents a complete description of Cycle 2 of COBRA-SFS, and consists of three main parts. Part I describes the conservation equations, constitutive models, and solution methods used in the code. Part 11 presents the User Manual, with guidance on code applications, and complete input instructions. This part also includes a detailed description of the auxiliary code RADGEN, used to generate grey body view factors required as input for radiative heat transfer modeling in the code. Part I11 describes the code structure, platform dependent coding, and program hierarchy. Installation instructions are also given for the various platform versions of the code that are available.iii

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“…The code uses a lumped parameter finite-difference approach to predict flow and temperature distributions in spent fuel storage systems and fuel assemblies under forced and natural convection heat transfer conditions in both steady-state and transients. It is derived from the COBRA family of codes (Rowe 1973, Stewart et al 1977, George et al 1980, Khan et al 1981, which have been extensively evaluated against in-pile and out-of-pile data. COBRA-SFS retains all the important features of the COBRA codes for single-phase analysis, and extends the range of application to problems with two-dimensional radiative and three-dimensional conductive heat transfer.…”

Section: Cobra-sfs Code Descriptionmentioning

confidence: 99%

Verification and validation of COBRA-SFS transient analysis capability

Rector¹,

Michener²,

Cuta³

1998

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COBRA-WC: a version of COBRA for single-phase multiassembly thermal hydraulic transient analysis. [LMFBR]

Cited by 11 publications

References 0 publications

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

COBRA-SFS: A thermal-hydraulic analysis code for spent fuel storage and transportation casks

Verification and validation of COBRA-SFS transient analysis capability

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