Heat transfer and thermo-mechanical analyses of W/CuCrZr monoblock divertor in subcooled flow boiling

It is necessary to take effective cooling methods from the divertor which can sustain one-sided high heat fluxes. In order to ensure the reliability and security of the divertor in fusion reactor, the heat transfer and thermo-mechanical assessment of W/CuCrZr monoblock divertor were conducted. In this paper, the heat transfer enhancements of the subcooled flow boiling in the vertically upward screw tubes, the tubes with twisted tape inserts and the plain tubes were examined by the Fluent software. Then, the thermo-mechanical analyses of the three cooling tubes were performed in this paper. The 3S(m) rule, Bree-diagram rule, fatigue, pipe material temperatures and the assessment of critical heat flux (CHF) were compared and analyzed for the three kinds of cooling tubes, which can guide the optimum for the heat transfer and structural analyses of the monoblock divertor. As a result, compared with the screw tube and plain tube, the tube with twisted tape inserts can enhance the heat transfer. Among the three kinds of cooling tubes, secondary stress of tungsten and CuCrZr in the tube with twisted tape inserts were the smallest. Thermal fatigue analyses of the tube with twisted tape inserts were calculated and the tube owned a fatigue life of approximately 0.427 years under the current working conditions.