Status of EVOLVE boiling flow regime experiments

Transcription

1 Status of EVOLVE boiling flow regime experiments M.H. Anderson M.L. Corradini J. Murphy I. Sviatoslavsky M. Sawan APEX TASK IV APEX ELECTRONIC MEETING August 9, 2001

2 Questions the experiment will answer. 1. hat is the integral vapor fraction and vapor distribution within the pool? 2. Do we produce a stable nucleate boiling regime (simulated by gas injection) and form vapor channels in the conductive pool as expected? 3. Can we keep the temperature of the tungsten within design limits? (i.e., is critical heat flux avoided?). Does the B field result in a gas layer between the pool and bottom plate.

3 How do we answer these questions: From previous data magnetic field does not seem to inhibit formation of vapor. This suggest ability to do Cold experiments assuming selective boiling sites for vapor formation. Cold Experiments with gas injection: Perform tests to visualize fluid mechanics: i.e., flow regimes and CHF within a magnetic field This can be done with bubbling a light gas through a pool of molten metal, should preserve Jg*, density ratio, electrical conductivity, Re and possibly other dimensionless parameters. Answers question of magnetic field effect to promote film boiling and ability to achieve a stable flow as predicted Answers questions on bubble movement in pool with and without MHD

4 Conceptual picture of experimental system 6 T superconducting solenoid magnet X-ray sensitive screen X-ray source Helium injected into NaK B=6T 6 T superconducting solenoid magnet

5 Schematic Diagram of test section 3/16 swage vent/vac instrument ports 3"L X1" X 2"H alumina/ss vessel 3/16 swage injector port

6 Top View of test section Gas exhaust Pressure tap window Gas injection lines

7 Individual Parts Injector holes Top plate splash guard Anodized Al chamber

8 X-ray setup Scintillation screen and camera system Support Rails for cryogenic chamber Test section X-ray Generator

9 Horizontal clear bore cryo-vessel and magnet Power stack American Magnetics A Central field 60KG Clear bore 8.0 inches Overall Length 12 inches LN Inches LHe S.C. Magnet Inches Horizontal Clear bore 6.00 Inches Inches

10 Initial X-ray images of water air injection Raw picture of the test section with a static pool of water Raw picture of gas injection through a single nozzle at a flow rate of 3.4 SCFH. (V jet =13.51 m/s, Jg* 1x1 =0.24 ) Measured Void fraction of 14% is seen with the evidence of a jet plume of air.

11 Contour Maps of Images 2.2 SCFM, V jet =8.74m/s, Jg* 1x1 =0.16 Possible problem with liquid metal carry over at high superficial gas velocities. From vapor production estimates the Evolve design will have much higher Jg* (>10 times).

12 Schedule of experimental activity e have completed the tasks shown in the green and are at the stage of preliminary experiments and tuning of the x-ray system to view the injection. The cryogenic system has been designed and is under construction by Precision Cryogenics and is scheduled completion time is estimated some time in Oct. Find S.C. Magnets Power supplies and other necessary equipment Task Design Experiment And Perform scaling analysis Construction of test section Design and construction of cryogenic LHe chamber for S.C. Magnet Perform Preliminary experiments with air/water Perform Experiments ith NaK and helium Initial MHD experiments ith NaK and Helium in ~7T field Review MHD literature Dec-00 Jan-01 Feb-01 Mar-01 Apr-01 May-01 June-01 July-01 Aug-01 Sept-01 Oct-01 Nov-01 Time Line

13 Summary: Experimental test section has been built and we are in the process of setting up the system. Preliminary x-ray images have been obtained for water/air injection and after we have tuned the system we will move to NaK The horizontal clear bore cryogenic chamber has been designed and is under construction at Precision Cryogenics Inc. and is expected sometime in Fall.