A two-way visual CHF research visualization experimental device in a narrow rectangular channel

Abstract

The invention belongs to the field of flow boiling visualization research, in particular to a two-way visual CHF research visualization experiment device in a rectangular narrow channel. The experimental device includes fastening bolts, graphite gaskets, flanges, heating plates, wide-side quartz glass, wide-side pressure plates, fluororubber gaskets, narrow-side quartz glass, narrow-side pressure plates, shells, substrates and support column. The three sides of the experimental device adopted in the present invention are all quartz glass, so as to observe the behavior of bubble generation, aggregation, growth and detachment on the heating surface from the side, and measure parameters such as bubble layer and liquid film thickness. The heating plate is slightly narrower than the substrate, avoiding the rectangular shape. Runner corner effect, the heating plate is axially shorter than the base body, eliminating the import and export effect, the base body is made of insulating ceramic materials, so that the heating plate is completely insulated from other parts of the experimental section, and three support columns are welded on the heating plate to fix the base body to avoid high temperature. The expansion and deformation of the heating plate can change the channel gap by changing the thickness of the gasket between the wide-side quartz glass and the housing.

Description

technical field [0001] The invention belongs to the field of flow boiling visualization research, in particular to a two-way visual CHF research visualization experiment device in a rectangular narrow channel. Background technique [0002] The critical heat flux CHF is the heat transfer limit of flow boiling. Accurately predicting the critical heat flux value is of great significance for reactor design and operation under accident conditions. Plate-type fuel assemblies with rectangular narrow channel features are widely used in research and experimental reactors and integrated reactors because of their compact structure, low fuel pellet temperature, and large heat transfer area. Some of the existing empirical relations for predicting the critical heat flux in narrow rectangular channels are all fitted based on their own experimental data. The accuracy depends strongly on the similarity of the experimental conditions and cannot be extended to other conditions. Therefore, the...

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Problems solved by technology

During the installation process, it is impossible to ensure that all the bolts are screwed to the same degree, which results in different clearances at different sections of the rectangular flow channel.

Secondly, the traditional rectangular channel experimental device can only photograph the aggregation behavior of the bubbles from the front, and cannot observe the growth of the bubbles and some important parameters that affect the critical heat flux from the side, such as the thickness of the bubble layer and the thickness of the liquid film.

Finally, the channel gap of the above-mentioned experimental device is fixed, so it is impossible to study the influence of the gap effect on the flow

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