Two Wire Sensor for Measuring the Velocity of Non-Isothermal Flows.

Katarzyna Socha,Paweł Jamróz

doi:10.3390/s22010162

Abstract

Changes in the temperature of the medium significantly affect the static characteristics of hot-wire anemometry measuring wires, which causes errors in the results of flow velocity measurements. High temperatures of the medium make it necessary to additionally heat the sensor to even higher temperatures, which may lead to its damage due to wire burnout. The article proposes a solution to the problem of measuring the flow velocity in conditions of non-stationary temperatures with the use of the method of cross-correlation of signals from two-wire resistance thermometers. The main assumptions of the method and its experimental verification were presented.

Highlights

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Since the measurement of the flow velocity using the correlation method consists in determining the time shift between two recorded temperature signals, there is no need to determine the static characteristics of individual temperature sensors in advance, as in the case of classic hot-wire anemometry probes [13,14]
The advantage of this method is the ability to detect the sense of the velocity vector, which is impossible in case of the conventional hot-wire anemometry probe

Summary

Introduction

Wire Sensor for Measuring the Velocity of Non-Isothermal Flows. Publisher’s Note: MDPI stays neutral with regard to jurisdictional claims in published maps and institutional affiliations. Based on the analysis of the thermometer’s wires response, it is possible to determine the flow velocity based on the phase shift between the response signals of the thermometric sensors [5,6] Both of the presented methods (hot-wire anemometry and thermal waves), allowing for the measurement of low velocities, have limitations as they cannot be used to measure flows in the conditions of high temperature fluctuations of hundreds of degrees Celsius. Measurement in such conditions would require heating the measuring wire or the one generating the temperature wave well above the temperature of the medium, which would damage the wire. An attempt was made to develop a method for measuring low velocity values under conditions of non-isothermal flows

Correlative Method of Measuring Flow Velocity

Testing the Correlation Method of Velocity Measurement

Modification of the Measurement Algorithm

Findings

Conclusions