Experimental And Numerical Investigation Of The Heat Transfer Enhancement For High Heat Flux Components In Fusion Reactor

Fusion energy has attracted worldwide attention due to its cleanliness and abundant reserves.The International Thermonuclear Experimental Reactor(ITER)is an international super conducting tokamak experimental reactor built to verify the feasibility of controlled fusion technology.Plasma facing high heat flux components in ITER,such as the first wall(FW)of the blanket module and divertor,need endure high heat flux from high temperature plasma radiation and high power density nuclear beat of high energy neutron deposition.When the heat flux exceeds the allowable heat flux,the structural stress will exceed the allowable stress.Therefore,it is necessary to strengthen the heat transfer method to improve the heat transfer efficiency and reduce the maximum temperature and temperature gradient.This paper focuses on the important and difficult problems of heat transfer enhancement in high heat flux components of fusion reactor.Experiments and numerical simulation were carried out mainly for water-cooled HyperVapotron(HV)heat transfer enhancement and first wall heat transfer enhancement technology of helium cooled test blanket module(TBM).The heat transfer mechanism experiments of HV for different HV samples,flow parameters and input heat flux were carried out by the developed experimental loops of water-cooled HV.The formation,rupture,convergence and flow of bubbles in the HV phenomenon were observed by the high-speed photography(HSP),planar laser induced fluorescence(PLIF)and Particle image velocimetry(PIV)technology.The temperature distribution and vortex motion in the HV flow field were measured.The feasibility of non-contact measurement technology in the study of HV was verified.Numerical simulation model and methods for HV cooled boiling enhance heat transfer based on computational fluid dynamics(CFD)software was established,and the phase transformation process was loaded into the volume of fluid model(VOF)control equation through the user defined function(UDF).All the results of the numerical simulation were verified by the experimental results.Innovatively,the helium experiment system built with the method of"Filling-Evacuating".The pressure of the test section can be adjusted within the range from 3 to 8MPa and the maximum mass flow rate can reach up to 0.21kg/s.By using the developed high-pressure helium-cooled loop experiments,an appropriate experimental section has been processed to carry out an experimental study on high pressure helium enhance heat transfer technology.The experimental results show that the maximum temperature and temperature gradient of the structure can be effectively reduced and the CHF can be improved by setting the fin in the high temperature region of the structure.The results of different turbulence models and experimental results were verified.It is indicated that the results of smooth channels calculated by the Realizble Ks model had the minimum errors relative to the experimental results,and the results of more complex flow of the ribs in the flow channels calculated by the detached-eddy simulation(DES)model had the minimum errors compared with the experimental results.The numerical simulation of the heat transfer schemes of setting the transverse and V ribs in the first wall flow channels of Helium-Cooled Ceramic Blanket(HCCB)were carried out,and the optimal scheme for adding ribs to the HCCB helium cooled first wall flow channels was proposed.The feasibility study of the cooling performance and circulating power of ITER HCCB-TBM using He/CO2 binary mixtures gas as coolant was studied by numerical simulation method in order to improve the cooling capacity and efficiency of the first wall helium cooled and reduce the driving power and cost.A potential new method was provided for the high efficiency coolant of the first wall.