Heat Transfer Coefficients in ITER Vacuum Vessel Cooling Channels


Completed orders:

ITER Team (Garching, Germany) - International Thermonuclear Experimental Reactor


The presented work describes the results of thermal-hydraulic tests with single rectangular vacuum vessel (VV) channel models which were performed to measure heat transfer coefficients under typical VV fluid conditions. The experiments have been carried out using the thermal-hydraulic facility developed in Central Boiler & Turbine Institute (CBTI) for wide-range tests of Power Plant equipments. This facility comprises a water loop 30 m in height designed for the full-scale study of nuclear reactor passive cooling. The VV test element is a rectangular channel 0.2 m in width, 3 m in total length, 2.48 m in heated length. The channel height (dch) is variable, i.e. dch=12.5, 25 or 50 mm. As the results of the experiments, the heat transfer coefficients have been obtained as a function of flow rate, channel height, model inclination and heating power.

The experimental study has been made to define the heat transfer coefficients for a wide-range of the operational parameters of the Vacuum Vessel cooling system. On the whole 361 experiments were made.

On the basis of the analysis of the experimental results the completing correlations were developed describing the heat transfer coefficient (h) at the parameters described in Tables 1- 2. Thus, for the heat releasing surfaces of the Vacuum Vessel cooling channels it is recommended to define h values by the following correlations:

- correlations for the vertical channels;

- correlations for the horizontal channels and for the surfaces cooled from above (lower heating surfaces) by choosing the highest out of the obtained h values;

- correlation for the horizontal channel and for the surfaces cooled from below (upper heating surface);

- for horizontal channels no more than 12 mm in height the water temperature stratification is absent, if the water velocity therein exceeds the value corresponding to the condition hforced=1,3hNC, where hforced and hNC are to be calculated by correlations (2 and 3), respectively. With this condition fulfilled, h is to be calculated by common formula (3) for the upper and lower heating surfaces;

- correlations for inclined channels and for the lower heating surface at hforced/hNC<1.0 and formula (3) (with the introduced additional correction factor equal to 0.913).at hforced/hNC>1.0;

- correlation for the inclined channels and for the upper heating surface.



Read the article »





Germany (headquarters): Alphysica GmbH. Unterreut, 6, D-76135, Karlsruhe, Germany,
Phone: +49 (0)163 904-85-61, Fax: +49 (0)7219 444-26-55, E-mail: info@alphysica.com

USA: Alphysica Inc. 414, Jackson street, San Francisco, CA 94111, USA,
Phone/Fax: +1 415.230.23.63, E-mail:usa@alphysica.com

Russia: Alphysica Ltd. 55, ul. Mayakovskogo, 191025, St.Petersburg, Russia,
Phone/Fax: +7 (812) 335-95-04, E-mail: russia@alphysica.com

Copyright © 1994-2010