Use of Natural Fluctuations of Flow Parameters for Measurement of Velocity Vector

The main drawback of standard hot-wire anemometric methods consists of the difficulty in their employment and a considerable measurement uncertainty in the case of flows in which high-amplitude fluctuations of temperature or other physical quantities occur. It is caused by the interaction between these fluctuations and measurement signal. In this paper, we propose a method for the determination of 2- or 3-D velocity vector of fluids flow or gases based on the employment of several detectors of fluctuations of temperature, velocity, or other physical quantity propagating with the velocity equal to the velocity of flow of the medium or higher by a known value. By analyzing the signals obtained by the detectors, the times of flight required for flat isophase surface of fluctuation to travel between the detectors in the direction of velocity vector are determined. On their basis, the flow velocity vector is calculated using the system of equations of motion of flat isophase surface of fluctuation. In this paper, we present an idea of this measurement method, developed sensor and measurement system, algorithm for signal processing, examples of measurement signals, and we also show the potential area of applicability. Considering the fact that the proposed measurement method is based on measurement of the path and time of flight of a fluctuation, the system implements an absolute measurement of velocity vector and does not require any calibration to be carried out in the flow of known parameters. In addition, the measurement is insensitive to the change in the parameters of the flowing medium.

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