An Advanced Mixing Tee Mock-Up Called “The Skin of the Fluid” Designed to Qualify the Numerical LES Analyses Applied to the Thermal Evaluation

Abstract

Nowadays, the LES (Large Eddy Simulation) models have reached an advanced stage in the thermal hydraulic numerical analyses. Particularly, in the mixing tee geometry, the LES allows the thermal, temperature fluctuations cartography — both in amplitude and frequency — to be evaluated. However, for the purpose of mechanical studies a better determination of the fluctuation temperature which impacts the wall would be of significant interest, magnitude of the fluctuation being directly linked to the lifetime of the Tee. This demand steps of experimental qualifications based on cartographic comparisons between numerical and experimental results, not compatible with basic current experiments proposing only local measurements. A mixing tee mock-up (␀ 50 mm) called “the skin of the fluid” was designed to show the real time observation of the temperature fluctuations in the mixing area with a digital infrared device. With its low Biot number the mock-up is quasi permeable to the fluctuation and does not attenuate the temperature amplitude at high frequency, consequently, the infrared image represents the temperature fluctuations which impacts the wall. An existent LES numerical analysis performed with the TRIO U code (developed by the CEA) on the same geometry is shown for a first comparative approach.