LES analysis of jets in cross flow

U. Bieder (1) , P. Errante (1)

1 CEA-DES (ex-DEN) - CEA-Direction des Energies (ex-Direction de l'Energie Nucléaire)

Jets in cross flow are of fundamental industrial importance and play an important role in the validation of turbulence models. Two jet configurations are investigated with the TrioCFD code, the CFD reference code of the Nuclear Energy Division of CEA: • A tee junction of circular tubes where a hot jet discharges into a cold main flow, • A rectangular jet marked by a scalar discharging into a main flow in a rectangular channel. The $tee-junction$ configuration is very important for the phenomena of thermal fatigue. The OECD/NEA benchmark on the Vattenfall tee junction flow is analyzed. This test case is selected because, beside the experimental results, various calculation results with several turbulence modelling approaches have been published. A LES modelling and calculation strategy is developed and validated on this data for jets in crossflow under thermal fatigue conditions. The rectangular jet configuration is important for basic physical understanding and modelling and has been analyzed experimentally at CEA. The experimental work was focused on the turbulent mixing between a rectangular channel flow with grid turbulence exiting a heated jet into a confined grid turbulent crossflow, with both kinematic and passive scalar high quality measurements in order to characterize its statistical properties (energy spectra, Reynolds stresses (anisotropy), PdF). These experiments are analyzed for the first time with LES by applying the strategy developed for the Vattenfall configuration. The turbulent inlet boundary conditions are well controlled in both experiment and calculation(grid turbulence). Structured and unstructured tetrahedral grids are used to predict the measured mean values and turbulent fluctuations of the velocity and the temperature.

Mots clés: LES; jet; cross flow; turbulence

Domaines: Physique Nucléaire Expérimentale [nucl-ex]; Physique Nucléaire Théorique [nucl-th]

U. Bieder, P. Errante. LES analysis of jets in cross flow. NUTHOS-11 - The 11th International Topical Meeting on Nuclear Reactor Thermal Hydraulics, Operation and Safety, Oct 2016, Gyeongju, South Korea. ⟨cea-02438721⟩