Thermal Analysis on Mono-Block Type Divertor Based on Subcooled Flow Boiling Critical Heat Flux Data against Inlet Subcooling in Short Vertical Tube

Abstract

The subcooled flow boiling critical heat fluxes (CHFs) and the heat transfer coefficients (HTCs) data for the tube length, L, of 49, 99 and 149 mm with 9-mm inner diameter were applied to thermal analysis on the Mono-block type divertor of LHD. Incident CHFs for the divertor with the cooling tube diameter, d, of 10 mm and the carbon armor outer diameter, D, of 26 and 33 mm were numerically analyzed based on the measured CHFs and HTCs at the inlet pressure of around 800 kPa. The numerical solutions were also compared with those for the Flat-plate type divertor, which were numerically analyzed for the divertor with the cooling tube diameter d=10 mm and the divertor width, w, ranging from 16 to 30 mm. It is confirmed that the ratio of the one-side heating CHF data, q cr,inc , to the uniform heating CHF data, q cr,sub , can be represented as the simple equation based on the numerical solutions. The values of the q cr,inc for L=50, 100 and 150 mm were estimated with various D/d and w/d at higher pressures.

Steady and transient forced convection heat transfer for water flowing in small tubes with exponentially increasing heat inputs

“…Knowledge of transient forced convection heat transfer of water is important for the design of cooling devices such as the divertor of fusion reactors and hybrid/electric/ fuel cell vehicles [1,2]. For fusion reactors, there is high heat flux at the divertor on plasma disruption.…”

Influence of Test Tube Material on Subcooled Flow Boiling Critical Heat Flux in Short Vertical Tube

“…The incident CHF, q cr,inc , for the Flat-plate type divertor with the cooling tube diameter, d, of 10 mm and the plate width, w, ranging from 16 to 30 mm and for the Mono-block type divertor with the cooling tube diameter, d, of 10 mm and the carbon armor outer diameter, D, of 26 and 33 mm were numerically analyzed based on the measured steady state CHFs, q cr,sub,st , and HTCs with the test tube inner diameter, d, of 9 mm and the heated length, L, of 48 to 149 mm for the SUS304 test tube. And the ratio of the one-side heat loading data, q cr,inc , to the uniform heat loading data, q cr,sub,st , has been represented as the simple equation based on the numerical solutions (24)- (26) . However, the divertor for a nuclear fusion facility will be made of copper alloy tube or copper alloy block for the most part, not of stainless steel ones.…”

Icone15-10035 Turbulent Heat Transfer for Heating of Water in a Short Vertical Tube

“…For many years, we have already measured the quasi-steady state CHF to transient one by exponentially increasing heat inputs, (Q 0 exp(t/τ), τ=19 ms to 33.3 s) for the SUS304 test tubes with the wide range of experimental conditions to establish the database for designing the divertor of a helical type fusion experimental device, which is Large Helical Device (LHD) located in National Institute for Fusion Science, Japan. And, we have given the steady state and transient CHF correlations against outlet and inlet subcoolings based on the effects of test tube inner diameter (d), flow velocity (u), outlet and inlet subcoolings (ΔT sub,out and ΔT sub,in ), ratio of heated length to inner diameter (L/d) and non-dimensional exponential period [u/{σ/g/(ρ l -ρ g )} 0.5 ] on CHF (Hata et al, 2002(Hata et al, , 2003a(Hata et al, , 2003b(Hata et al, , 2004a(Hata et al, , 2004b(Hata et al, , 2004c(Hata et al, , 2004d(Hata et al, , 2005a(Hata et al, , 2005b(Hata et al, , 2006a(Hata et al, , 2006b(Hata et al, , 2006c(Hata et al, , 2006d(Hata et al, , 2006e, 2006f and 2007. However, more widely and precisely predictable correlation of turbulent heat transfer for heating of water in a short vertical tube has been desired to clarify the onset of subcooled nucleate boiling, subcooled boiling heat transfer and DNB for the SUS304 test tubes.…”