Ghidersa, Bradut-Eugen

Starflinger, Jörg

Stieglitz, Robert

Wen, Wen

Wolfgang, Hering

English

KITopen

KIT – The Research University in the Helmholtz AssociationBasic Concept• Divertor target made out of parallel cylindrical Heat Pipes installed in a water cooling channel. The HP rods form a staggered structure (HP condenser). • The Heat Pipes penetrate the plasma facing side of the cooling channel, having a hexagon W-armor at that particular end (HP evaporator side). • HP has cylindrical body with outside diameter 15mm, while the vapor space is 12mm in diameter;• HP material: CuCrZr• HP total length is 230mm, the length of the evaporator and adiabatic part being 7mm and, respectively 23mm. • Orientation 7.8º depends on divertor target. Design StudiesPower removal system: assumed to have the same mass flow rate and conditions (4MPa, 130°C) as the EU-DEMO divertor baseline. HP working medium is water: design that has a vapor temperature around 200°C (best performance for water-based heat pipes) and does not exceed 250°C (rapid fall of performance). Find the optimal condenser length (𝒍𝒄)Four options for the capillary structure have been considered:-HP1: grooves for condenser and adiabatic zone and mesh for the evaporator               -HP2: grooves for condenser and adiabatic zone and sinter porous material forevaporator-HP3: mesh for capillary structures inside -HP4: sinter for capillary structures inside • HP1 and HP2 options can operate at vapor temperatures below 250°C when condenser length is more than 200mm • Capillary limit: HP2 has lager driving capillary pressure against pressure losses allowing for higher operational power.• Entrainment limit: using open groove it limits the power level; adding mesh screen between groove and vapor increases that limit.Heat Pipe technology based Divertor Plasma Facing Component concept for European DEMOWen Wena, Bradut-Eugen Ghidersaa, Hering Wolfganga, Jörg Starflingerb, Robert StieglitzaTemperature levels ( in °C) needed to transfer 5.6kW into the cooling circuit (lc with unit m)ObjectivesInvestigate the possibility of using water-based heat pipes in conjunction with a new divertor concept including:• dimensioning a variable conductance heat pipe that should be capable of dealing with heat fluxes as high as (at least) 20MW/m2• analysis the integration of the HP in the divertor targetConclusions• Solution: A water based heat pipe 230mm long made out of CuCrZr, from which the condenser should be at least 200mm long, should be capable  for peak heat flux of 20MW/m2. Futures works• The operating limits here using engineer formulas need to be validated experimentally. • The first experiment focus on evaporator is under preparation.Individual Heat PipeDesign option HP1 HP2 HP3 HP4Number of grooves Na 80 80Width of groove w [mm] 0.3 0.3Height of groove h [mm] 1 1Mesh/Wire Diameter dm [mm] 0.1 0.1Mesh width wm [mm] 0.5 0.5Sinter particle radius rp[mm] 0.05 0.05Porosity ε 0.74 0.5 0.74 0.5Variation of the maximum driving capillary pressure difference with temperature levels𝒍𝒄[mm]Vapor Temperature [ºC]Capillary limit [kW]Entrainment limit HP1/HP2 [kW]HP1 HP2 No mesh screenWith mesh screen150 277 1.6 5.57 5.7 16200 245 2.2 7.5 5.7 16220 234 2.5 7.9 5.6 15.6250 226 2.6 8.3 5.4 15.2300 212 2.8 8.5 5.1 14.5a: Institute for Neutron Physics and Reactor Technology, Karlsruhe Institute of Technology , Karlsruhe, Germanyb: Institute of Nuclear Technology and Energy Systems , University of Stuttgart, Stuttgart, GermanyInstitute for Neutron Physics and Reactor Technology (INR) Karlsruhe Institute of Technology (KIT), Campus NordHermann-von-Helmholtz-Platz 176344 Eggenstein-Leopoldschafen, Germanyhttp://www.inr.kit.edu/W-armor  HP Evaporator end with porousDivertor cassette assembly with a Heat Pipe-based targetHeat pipes arrangement (cooling channel side)Condenser: groovesEvaporator: Sintered Porous structureFlow DirectionGroovesSintered Porous

Heat Pipe technology based Divertor Plasma Facing Component concept for European DEMO

https://publikationen.bibliothek.kit.edu/1000124859/90220906

Heat Pipe technology based Divertor Plasma Facing Component concept for European DEMO

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