Differential type laminar flow rate measuring method and device

Abstract

The invention discloses a differential type laminar flow rate measuring method and device and belongs to the technical field of flow rate measurement. The measuring device is provided with a measuringpipeline; the measuring pipeline comprises a first laminar flow element, a second laminar flow element, a first differential pressure sensor and a second differential pressure sensor; the length of the first laminar flow element is different from the length of the second laminar flow element; the first differential pressure sensor measures the differential pressure deltaP1 of two sides of the first laminar flow element; the second differential pressure sensor measures the differential pressure deltaP2 of two sides of the second laminar flow element; the first laminar flow element and the second laminar flow element comprise the same number of capillary tubes of the same diameters; the length of the capillary tubes in the first laminar flow element is L1, and the length of the capillary tubes in the second laminar flow element is L2; if L2 is larger than L1, deltaP2 is larger than deltaP1, and a differential pressure difference value deltadeltaP can be obtained according to an equationthat deltadeltaP=deltaP2-deltaP1; if L2 is smaller than L1, deltaP2 is smaller than deltaP1, and the differential pressure difference value deltadeltaP can be obtained according to an equation that deltadeltaP=deltaP1-deltaP2; and the differential pressure difference value deltadeltaP is proportional to volumetric flow flowing through the measuring pipeline. With the method and device adopted, high-accuracy measurement and a larger range can be realized easily.

Description

technical field [0001] The invention relates to the technical field of flow measurement, in particular to a differential laminar flow measurement method and device. Background technique [0002] For the fully developed laminar flow in the pipe, when other parameters remain unchanged, the pressure loss of the fluid flowing through a section of the pipe is proportional to the volume flow rate, which is in line with the Hagen-Besueuille law. According to this principle, a laminar flow meter can be designed. [0003] To ensure that the flow is laminar, the Reynolds number must be less than the critical value, and generally requires a small diameter, so capillary tubes are usually used to make laminar flow components. The flow rate of a single capillary is very small. In order to achieve a large flow measurement, multiple capillary tubes can be connected in parallel. Whether it is a laminar flow element made of a single or multiple capillaries in parallel, generally two pressur...

AI Technical Summary

Problems solved by technology

The capillary length-to-diameter ratio of the laminar flowmeter generally used will not be so large. The second is to use the flow coefficient correction method, but it is difficult to achieve a good correction result, and the data processing model is relatively complicated.

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