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Thermal-Hydraulic Analysis in Support to the Water Experiment Target Header Dimensioning. Presented by Vincent Moreau CRS4, Energy & Environment Program. EUROTRANS-DEMETRA WP 4.4 meeting FZK-Karlsruhe 08-03-2007. General features.
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Thermal-Hydraulic Analysis in Support to the Water ExperimentTarget Header Dimensioning Presentedby Vincent Moreau CRS4, Energy & Environment Program EUROTRANS-DEMETRA WP 4.4 meeting FZK-Karlsruhe 08-03-2007
General features • Support to the water free surface experiment • Propose Header pre-sizing • Check Header pre-sizing • Objective • Minimize deviation of flow axial-symmetry at the active region inlet • Avoid excessively huge pressure losses • Simple design • Design insensitive to small geometric perturbation (where possible) • Constraints • Header fed by an horizontal pipe of 82 mm Internal Diameter (ID) • Header internal diameter less than 183.4 mm • Header Height no more than 200 mm • Header annular outlet dimension fixed (internal 69.2mm, external 103.5)
Proposed Solution • Header ID 180 mm (limit 183.4mm) • Header Height 190 mm (limit 200 mm) • Horizontal pipe connecting the upper part of the Header to give more room for flow regularisation. • Flow enhanced regularisation obtained by insertion of a set of centred annular hollow plates.
Geometry: 3 variants Header without concentric plate Header with 2 plates Header with 3 plates
Computational features • StarCD V4.0 CFD code. • Steady State calculation with Standard k-e (also tested Chen and NRG variants without significant change) • About 160 000 polyhedral cells (Full 3D) with a 2 cells/1 mm (58.000) boundary layer.
Result Analysis • Relative annular dispersion of velocity in the outlet core (thus without considering a 1mm boundary layer) • Global pressure loss between computational domain inlet and outlet.
Flow arrangement Header without concentric plate Flow in the annular outlet channel clearly non uniform
Flow arrangement Header with 2 plates Flow in the annular channel much more uniform One global maximum in outlet
Flow arrangementHeader with 3 plates Flow in the annular channel still more uniform Flow in outlet with two local maxima
Concluding Note • Before entering the free surface region, the flow is expected to withstand about another 12000 Pa which is about 4 times the kinetic energy (1/2 ru2 ~3000 Pa). Therefore we expect the velocity dispersion to be at least one order lower and fall down below 1% for each configuration. • The 3 plate configuration gives the better result and would be the proposed solution if the pressure drop is readily available.