Research article
Wireless sensing using acoustic signals
for measurement of dynamic pressure
and temperature in harsh environment
Alfin Leo
Department of Mechanical & Industrial Engineering, Concordia University, Montreal, Canada
Gino Rinaldi
DRDC-AVRS, Department of National Defence, Ottawa, Canada, and
Ion Stiharu and Rama Bhat
Department of Mechanical & Industrial Engineering, Concordia University, Montreal, Canada
Abstract
Purpose – It is currently difficult to measure temperature and pressure in harsh environments. Such measurements are limited by either the ability of
the sensing element or the associated electrical wiring to withstand the operating environment. This is unfortunate as temperature and pressure are
important measurands in various engineering structures as they provide critical information on the operating condition of the structure. Hence, there is a
need to address this shortcoming. Such a sensor in place would enhance the operating efficiency thereby reducing the pollution burden and its impact
on the environment. The purpose of this paper is to present theoretical and preliminary experimental results for a co-integrated pressure and
temperature sensor for harsh environments.
Design/methodology/approach – This work describes a co-integrated pressure-temperature wireless sensing scheme. The approach presented
herein provides the possibility of measuring dynamic pressure and temperature within an enclosed volume using acoustic signals. Resonance tube
physics is exploited for the temperature sensing. A microphone is used to obtain the acoustic signal whose frequency is a function of the temperature
and the tube geometry.
Findings – The dynamic pressure is measured from the calibrated amplitude of the pressure wave signal measured by the microphone. The
temperature can be measured through the shift of the standing wave frequency with a resolution of ,18C. The resonance tube can be fabricated using
any material that resists harsh environments. The geometry of the tube can be tailored for any specific frequency range, as the application warrants.
Also, this provides a means for accurate temperature compensation of pressure sensor data from high temperature environments. A Matlab/Simulink
model is developed and presented for the acquisition of acoustic signals through the wall of an enclosed volume. For these applications the standing
wave signal transmitted through the enclosure wall becomes a function of the wall material and wall thickness. Preliminary experimental results are
presented in which a DC fan is used for generating the dynamic pressure in a varying temperature environment.
Research limitations/implications – The major issue is the separation of the noise from the signal. As various applications yield specific signal noise,
the problem needs detailed data to be addressed.
Practical implications – Temperature and dynamic pressure could be recorded/monitored in very harsh environment conditions such as chemical
reactors.
Originality/value – This work demonstrates thepossibility of employing a co-integrated acousticsensingscheme in which both pressure and temperature
are measured simultaneously with a sole sensor. The major advantage with acoustic sensing is the wirelesstransmission of data. This allows for non-invasive
measurement from within enclosedsystems. Direct real-time temperature compensationis possible that does not require any compensation circuitry. Hence,
pressure and temperature data may be obtained from caustic operating environments whose access is otherwise not feasible.
Keywords Sensors, Condition monitoring, Temperature, Pressure, Co-integrated sensing, Harsh environment, Resonance tube, Standing wave,
Acoustic impedance
Paper type Research paper
Introduction
The evolution of sensor technology is driven by the parallel
needs to address sensing improvements for current sensor
applications, and needs to develop new sensing materials and
methodologies for new applications. Also, an important benefit
of sensor evolution is that it allows for the development of new
products and/or novel applications with unique features
The current issue and full text archive of this journal is available at
www.emeraldinsight.com/0260-2288.htm
Sensor Review
32/2 (2012) 142– 148
q Emerald Group Publishing Limited [ISSN 0260-2288]
[DOI 10.1108/02602281211209437]
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