Analysis and experiment of the hypervapotron mock-up for the EAST upgrade
During the EAST upgrade, the peak heat flux applied on the first wall components will be 2 MW/m2, which requires powerful cooling concept to decrease the component temperature, in order to simplify the material requirement and armor/heat sink module design. Hypervapotron is a promising method for high heat transfer coefficient, which bases on sub cooling boiling phenomenon, and has the potential to support the demand in several years (up to 20 MW/m2 with strong armor), and is chosen to be a candidate. The design contains a copper heat sink and uses water as coolant, a series of CFD analyses are performed to optimize the design, and a mock-up based on this optimization is assembled on a high heat flux test facility which employs electromagnetic induction heating and high speed photography; during the experiment under the required working conditions, the flowing status and thermal parameters are recorded. The analysis and experiment confirm the performance of the hypervapotron concept and the feasibility of the use in the EAST upgrade project.
Experimental optimisation of a hypervapotron® concept for ITER plasma facing components
Abstract Historically developed for cooling of klystron electronic tubes, metallic hypervapotron® prototypes with different width were manufactured for high heat flux plasma facing components (PFC) applications. They were critical heat flux (CHF) tested on the European 200 kW electron beam facility (FE200), the 54 measured values have shown their good performances—up to 25–30 MW/m2 at low axial velocities (2–6 m/s)—interesting for ITER divertor dome and vertical target design. An important conclusion is that CHF decreases when the width increases.
An experimental investigation of the Post-CHF enhancement factor for a prototypical ITER divertor plate with water coolant
In an off-normal event, water-cooled copper divertor plates in the International Thermonuclear Experimental Reactor (ITER) may either experience heat loads beyond their design basis, or the normal heat lends may be accompanied by low coolant pressure and velocity. The purpose of this experiment was to illustrate that during one-sided heating, as in ITER, a copper divertor plate with the proper side wall thickness, at low system pressure and velocity can absorb without failing an incident heat flux, q/sub i/, that significantly exceed the value, q/sub i//sup CHF/, which is associated with local CHF at the wall of the coolant channel. The experiment was performed using a 30 kW electron beam test system for heating of a square cross-section divertor heat sink with a smooth circular channel of 7.6 mm diameter. The heated width, length, and wall thickness were 16, 40, and 3 mm, respectively. Stable surface temperatures were observed at incident heat fluxes greater than the local CHF point, presumably due to circumferential conduction around the thick tube walls when q/sub i//sup CHF/ was exceeded. The Post-CHF tube walls when enhancement factor, /spl eta/, is defined as the ratio of the incident burnout heat flux, q/sub i//sup BO/, to q/sub i//sup CHF/. For this experiment with water at inlet conditions of 70/spl deg/C, 1 m/s, and 1 MPa, q/sub 1//sup CHF/ and q/sub i//sup BO/ were 600 and 1 100 W/cm/sup 2/, respectively, which gave an /spl eta/ 1.8.