Realization of Constant Voltage Anemometer Using an Alternative Signal Conditioning Circuit
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RESEARCH PAPER
Realization of Constant Voltage Anemometer Using an Alternative Signal Conditioning Circuit V. Sivakami 1 & A. Pal 1 & B. Vasuki 1 Received: 23 October 2019 / Accepted: 11 May 2020 # The Society for Experimental Mechanics, Inc 2020
Abstract Anemometric method is the most accurate and reliable technique for air velocity measurement. In present work, a voltage follower based circuit is proposed, and a low-cost sensor (tungsten filament) is chosen to perform Constant Voltage Anemometer (CVA) operation for air velocity measurement. For performing the real-time experiment, a wind tunnel featuring a rectangular section (test section I) and a circular section (test section II) with a provision for low-cost sensors and a reference Hot Wire Anemometer (HWA) was fabricated. The measurement is repeated multiple times for various air velocities in the range of 3 m/s to 12 m/s. The estimated ‘pdr’ value (ratio of the power dissipated in the sensor, Pw to the difference between heated sensor resistance, Rw and the sensor resistance at ambient temperature, Ra), considered as new output voltage, is analogous with the output voltage (Vo) of the proposed circuit. The range of ‘pdr’ in test sections I and II is 0.033 mW/Ω to 0.867 mW/Ω and 0.0062 mW/ῼ to 0.1059 mW/Ω, respectively. Similarly, overheat ratio, OHR (ratio of the difference between heated sensor resistance, Rw and the sensor resistance at ambient temperature, Ra to the sensor resistance at ambient temperature, Ra) estimated, is also found to be analogous with the change in temperature (difference between the temperature of the heated sensor Tw and the ambient temperature Ta). The range of OHR in test sections I and II is 0.709 to 0.660 and 0.678 to 0.647, respectively. Uncertainty analysis is carried out for the proposed voltage follower based CVA measurement system and the expanded uncertainty with a 95% confidence level is obtained as 0.54 for the whole range of air velocity measurement. Keywords Constant voltage anemometer . Low-cost sensor . Voltage follower . Wind tunnel fabrication . Air velocity measurement . Uncertainty analysis
Introduction Flow measurement is an essential process parameter in the field of process industries. It is a continuously changing field concerning the requirement of industry needs. The flow measurement technique primarily depends on the nature of the flow, type of medium, and the steadiness of the medium.
* V. Sivakami [email protected] A. Pal [email protected] B. Vasuki [email protected] 1
Department of Instrumentation and Control Engineering, National Institute of Technology, Tiruchirappalli, India
The flow meters for flow measurement applicable to industries are listed as, obstruction type, inferential type, positive displacement flow meter, fluid dynamic, ultrasonic, anemometer, and mass flow meter. Out of all these, the anemometer technique has various advantages compared to other methods listed above. Table 1 shows the list of symbols used in this paper and their corresponding description. Hot Wire Anemomet
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