Research On Injection Characteristics Of The Self-priming Venturi Tube

The self-priming Venturi scrubber is commonly used in the filtered containment venting system as the key component to removal radioactive products. It can filtrate the methyl iodide,aerosols and iodine when a serious accident happened in the nuclear reactor. The removal efficiency of self-priming Venturi scrubber is mainly decided by its liquid injection flow rate.By experiment method,the affection of structure parameters and system condition parameters on the liquid injection flow rate of Venturi scrubber was studied.In the aspect of structure parameters, this article adopts the method of control variables,under the condition of normal pressure, larger flow rate range to measure the injection quantity, summarized the influence law of various structural parameters on the liquid injection quantity. Results show that the angle can be chosen from 2°to 6°. The longer length of the mixing tube, the lower the injection flow rate will be. Area ratio has a very significant effect on self-priming Venturi scrubber injection features, the injection flow rate increase rapidly when the ratio of area increasing. In the region of big area ratio, the injection flow rate increases with the increase of laryngeal spacing. In the region of small area ratio, with the increase of laryngeal spacing, the injection flow rate first increases and then decreases. The spherical baffle set in the export of the venturi scrubber has no affection on the injection flow rate as long as it has a reasonable spacing.In the aspect of system condition parameters, this paper control the structural parameters ,under the conditions of different nozzle outlet gas velocity, different pressure of systems,different level, different ratio of steam , testing the quantity of liquid injection flow rate, get the influence regulation of the operation parameters. Results show that the liquid injection flow rate appears linearly rise with the increase of the gas velocity. System pressure can make the liquid injection flow rate rise. The affects of liquid level on the injection flow rate was divided into two situations, when the export of Venturi scrubber was not drown, improve the level of liquid level, the injection flow rate increased, when the export of Venturi scrubber was drown, increase the height of liquid level, the injection flow rate is almost the same.Local resistance of liquid suction mouth consumes most of the injection dynamic. The greater the share of steam in the working gas, the lower the injection flow rate will be.The liquid injection flow rate of self-priming venturi scrubber is directly related to the static pressure distribution. When designing a Venturi scrubber, the static pressure distribution at various points of the scrubber should to be studied. Results of this paper show that the temperature difference of the nozzle import and export was obverse, the single-phase gas acceleration process was comply with the principle of adiabatic process. The two phase flow characteristics comply with the principle of annular-mist flow model, and momentum exchange between gas and liquid exist. According to the research of the static pressure distribution, this paper established a self-priming venturi scrubber preliminary design calculation model. The calculation results agree well with the experimental value, and it can provide guidance for engineering design.