Speaker
Sergej Gordeev
(Institute for Neutronic Physics and Reactor Technology)
Description
The configuration of the Early Neutron Source (ENS) is the IFMIF-DONES (DEMO Oriented Neutron Source) approach, based on an IFMIF-type neutron source. It aims providing an intense fusion-like neutron spectrum with the objective to qualify on an accelerated time scale structural materials to be used in the future DEMO fusion reactor. IFMIF-DONES is based on the interaction of single 40MeV 125mA deuteron beam impacting a flowing liquid lithium target to simulate DEMO like neutron flux spectrum for fusion material irradiation experiments.
The lithium free-surface flow providing the desired neutron flux and heat removal is operated in vacuum. Hence its operational performance determines the design of the target assembly and interfaces such as e.g. the quench tank. Since it is practically unfeasible to avoid geometrical discontinuities such as steps, obstacles or gaps in engineering designs, a realistic assessment in terms of magnitude and location of the potential cavitation risk in the lithium system components is needed.
The present work focuses on the numerical investigation of cavitation phenomena in the lithium flow at IFMIF-DONES relevant operation conditions. Calculations reproduce different cavitation processes depending on the kind of the wall surface discontinuity. In case of the flow over the lateral gaps, in the channel lithium gaseous phase generated within the gap remains stable and does not collapse. Simulations of the lithium flow over the backward-step show the generation of the gaseous lithium phase within the flow separation area and formation of a stable sheet cavity on the wall surface. The subsequent breakup of the sheet cavity in the flow reattachment region is accompanied by generation and collapse of unstable vapor structures downstream. The risk of cavitation induced erosion on the wall surface is assessed using a function based on the mean value of the time derivative of the local pressure.
Co-authors
Friedrich Groeschel
(Institute for Applied Materials, Karlsruhe Institute of Technology, Eggenstein-Leopoldshafen, Germany)
Sergej Gordeev
(Institute for Neutronic Physics and Reactor Technology, Karlsruhe Institute of Technology, Eggenstein-Leopoldshafen, Germany)
