Assessment of criteria for Onset of Flow Instability in vertical narrow rectangular channels with downward flow
Paper i proceeding, 2018
According to the global approach, the Whittle-Forgan and Stelling criteria only use global system parameters to predict OFI. Relatively good results can be obtained over the whole database. The local approach is based on the prediction of the Net Vapor Generation (NVG) along the channel. The standard Saha-Zuber correlation fails to capture OFI for Peclet numbers lower than 70000. On the other hand, the Saha-Zuber KIT correlation identifies OFI in all the experiments with uniform heat flux. In the case of a non-uniform heat flux along the width of the rectangular channel, the use of thermalhydraulic
parameters averaged over the cross section is not sufficient to predict the local onset of NVG. Nevertheless, this issue can be solved if a local estimate of the flow conditions is employed, so that the effect of the non-uniform heat flux can be accounted for. These results are consistent with the ones found
for upward flow in previous studies. No significant effect of the flow direction is therefore observed.
nuclear research reactor
downward flow
narrow rectangular channel
onset of flow instability
Författare
Alberto Ghione
Le Commissariat à l’Énergie Atomique et aux Énergies Alternatives (CEA)
Brigitte Noel
Le Commissariat à l’Énergie Atomique et aux Énergies Alternatives (CEA)
Paolo Vinai
Chalmers, Fysik, Subatomär fysik och plasmafysik
Christophe Demaziere
Chalmers, Fysik, Subatomär fysik och plasmafysik
12th International Topical Meeting on Nuclear Reactor Thermal-Hydraulics, Operation and Safety (NUTHOS-12)
Qingdao, China,
DEterministisk MOdellering av Jules HorowitzReaktorn (DEMO-JHR)
Vetenskapsrådet (VR) (2011-7747), 2012-01-01 -- 2016-12-31.
Ämneskategorier
Energiteknik
Annan fysik
Strömningsmekanik och akustik
Styrkeområden
Energi