A device and method for mass flow measurement of a fixed conductance element based on dynamic differential pressure decay

Abstract

The invention discloses a fixed conductance component mass flow rate measuring device and method based on dynamic differential pressure attenuation. The mass flow rate measurement of an AAO fixed conductance component is accurate, efficient and simple. The device provided by the invention comprises an inflator, a first valve, a container A, a first thermometer, a differential pressure transmitter,a second valve, a third valve, the AAO fixed conductance component, a second thermometer, a container B, a fourth valve and a vacuum pump set. When pressure difference drives experimental gas to flowthrough the AAO fixed conductance component, an exponential function is fitted according to the attenuation variation of the inlet and outlet dynamic differential pressure of the AAO fixed conductance component with time, and then the transient mass flow rate of the gas flowing through the fixed conductance component is calculated.

Description

technical field [0001] The invention relates to a mass flow measurement device and method of a fixed conductance element based on dynamic differential pressure attenuation, and belongs to the field of measurement technology. Background technique [0002] In recent years, with the development of microelectronic micromechanical systems (MEMS), microfluidic technology has received extensive attention, and many theoretical and experimental studies have been carried out to understand the physical phenomena related to flow. Among them, the measurement of the mass flow rate of rarefied gas has been a hot research topic. At present, there are three commonly used measurement techniques, namely droplet method, constant pressure method and constant volume method. The droplet method is a direct measurement technique, which measures the velocity of the droplet moving in the calibration tube through a low-power microscope or photoelectric sensor to obtain the change in mass flow rate; th...

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Problems solved by technology

The droplet method is a direct measurement technique, which measures the velocity of the droplet moving in the calibration tube through a low-power microscope or photoelectric sensor to obtain the change in mass flow rate; the constant pressure method and constant volume method are indirect measurement techniques, and the disadvantages of the constant pressure method are The piston moves slowly at a lower mass flow rate and is difficult to control accurately; the constant volume method can only measure mass flow rates in various quasi-stationary states

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