Slide 1

Thermal-hydraulics Flows with TransAT - PTS - January 2014 ASCOMP ; ASCOMP Inc. USA www.ascomp.ch lakehal@ascomp.ch

Slide 2

Co-current condensing steam Experiment of Lim et al., J. Heat Transfer, 1984 Horizontal co-current steam water flow Comparison with NEPTUNE (Coste & Lavielleville, NURETH13) OpenMP parallel 3D computation: 3h on a Linux PC cluster Both using the SD model (Lakehal et al., J.Heat Transfer, 2008) Case K L (m 2 /s 2 )K G (m 2 /s 2 ) Smooth3.10 -4 0.36 Intermittent1.5.10 -4 0.915 Wavy3.10 -4 0.915 Click on movie to play

Slide 3

Steam-mass flow rate decrease

Slide 4

PTS: COSI Exp. (AREVA) During a hypothetical SB-LOCA, cold water is injected into the cold leg to limit the RPV lifetime (Emergency Core Cooling, ECC). The injected water mixes with the hot fluid in the cold leg and the mixture flows towards the downcomer, leading to excessive thermal stresses on the RPV walls. Courtesy from Yadigaroglu and Bestion, ICAPP07

Slide 5

ECC injection of cold water (296 K) in saturated water. Steam at saturation temperature (485 K). Pressure 20 bars 1.IST Grid (tubes immersed in a Cartesian grid) 2.Conjugate heat transfer, with two-phase flow 3.Level set technique for interface evolution 4.MPI parallel computation: 15h on 8 CPU Linux PC cluster IST /BMR grid

Slide 6

Temperature mixing Click on movie to play

Slide 7

Rate of condensation (new results) Click on movie to play

Slide 8

Cross-section interface & temperature (new)

Slide 9

Temperature average results