Measuring method and measuring device for liquid drop particles in wet-steam region

Abstract

The invention relates to a measuring method and a measuring device for liquid drop particles in a wet-steam region. An ultrasonic excitation signal acquires ultrasonic signals with three different frequencies by adopting a mode of superposing waves; the processing and analyzing process of the ultrasonic signals in a computer comprises the following steps: performing fast Fourier transform on the obtained signals to obtain ultrasonic signal amplitudes with three frequencies, and calculating to obtain sound attenuation coefficients; obtaining particle diameter values of the liquid drop particles according to the relationship between the measured particle diameter values of the liquid drop particles and the ratio of the sound attenuation coefficients with three frequencies; likewise, obtaining a volume concentration value according to the relationship between the volume concentration value and the sound attenuation coefficients, and obtaining a humidity value of wet steam according to the conversion relationship between the volume concentration and the humidity. The measuring device is simple in structure and low in cost; compared with the measuring method for the wet steam by adopting other principles, the measuring method disclosed by the invention has the advantages that ultrasonic waves have strong penetrating power; an ultrasonic transducer can normally work in a severe environment; online measurement of particles sizes, volume concentration and humidity of the liquid drop particles in the wet steam region with higher concentration at the final stage of a low-pressure cylinder can be realized without precision correction.

Description

technical field

[0001] The invention relates to a wet steam measurement, in particular to a method and a device for measuring the particle size, volume concentration and humidity of liquid droplet particles in a wet steam area by an ultrasonic attenuation method under superimposed wave excitation. Background technique

[0002] In the power industry, petrochemical industry and other fields, wet steam is usually used, and the particle size, volume concentration and humidity of the droplet particles in the wet steam area need to be determined for process control or energy evaluation. In thermal power plants, the last stages of the low-pressure cylinder of large condensing steam turbines, pressurized water reactor nuclear power units, and all or most stages of steam turbines for nuclear-powered ships work under wet steam conditions. In the flow part of the nuclear power steam turbine, the humidity of the new steam entering the high-pressure cylinder is 0.25% to 0.5%, and the hum...

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