Water tunnel flow velocity measurement method based on PVDF piezoelectric diaphragm

Abstract

The invention provides a water tunnel flow velocity measurement method based on a PVDF piezoelectric diaphragm. The method comprises the steps of: (1) mounting a PVDF piezoelectric diaphragm on the inner wall of a water tunnel, connecting an output end to a data collector, and connecting the data collector to a computer; (2) injecting water into the water tunnel, and collecting a spectrogram output by the PVDF piezoelectric diaphragm at a current flow rate by a data collector; (3) summing the voltage output of the PVDF piezoelectric diaphragm under different frequencies, and taking a logarithmto obtain a total voltage level; and (4) acquiring the flowing velocity of current water flow according to the corresponding relation between the total voltage level and the flow velocity. Turbulentpulsating pressure is generated when water flow flows through the PVDF piezoelectric diaphragm. According to the flow velocity measurement method, the water flow velocity is obtained by measuring thevoltage output of the PVDF piezoelectric diaphragm under the excitation of the turbulent pulsating pressure. The problem that the traditional flow velocity measurement method influences the flowing state of water flow in the water tunnel is solved, and the method has the advantages of low cost, high sensitivity, simple structure and the like.

Description

technical field [0001] The invention relates to a method for measuring flow velocity, in particular to a method for measuring the velocity of water flow in a water tunnel. Background technique [0002] The water tunnel is a necessary device for the study of fluid mechanics, which can provide water flow with controllable pressure and flow rate. This equipment is widely used in hydrodynamic experiments, and is suitable for researches related to phenomena such as boundary layer, wake, turbulence, hydrodynamic noise, and hydroelasticity. Before any ship model is actually put into production, it is necessary to conduct simulation research on water tunnels. [0003] Since the flow velocity is a key physical quantity in the water tunnel experiment, the measurement of the water flow velocity inside the water tunnel is particularly important. At present, the most widely used velocity measuring devices on the market are impeller flowmeters and Doppler velocity measuring instruments,...

AI Technical Summary

Problems solved by technology

PVDF sensors have been used for the measurement of river flow velocity. The patent literature (CN204214888U) uses a new type of equipment bracket and guide rail to install PVDF piezoelectric sensors, and uses the corresponding relationship between the pressure of the water flow on the front of the sensor and the flow velocity to measure the flow velocity of the river. This measurement The method will affect the flow state of water and cannot be applied in water tunnels

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