Ultrasonic Waveguide Sensor’s Thermal Simulation Study for

Temperature Sensing
A dissertation report submitted in partial fulfillment
of the requirements in 4th year 1st semester for the degree in
Bachelor of Technology
Mechanical Engineering
by

Name Roll number

Tarun Gadde 203267

S Sai Nisshith 203255

Shailesh Suran 203260

Kiran Tej 203154

Under the supervision of

Suresh Periyannan

Sign with name of Guide

Assistant/Associate/ Professor, Mechanical Engineering
Department of Mechanical Engineering

National Institute of Technology

Warangal
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 ABSTRACT
This report presents a novel method of temperature sensing using ultrasonic waveguide-based
sensing and Internet of Things (IoT). The use of ultrasonic guided waves has several advantages
including remote measurements, multi-modal nature allowing for measurement of different
parameters, small footprint, low cost, multi-point measurements on the same waveguide and most
importantly robustness. These inherent qualities of ultrasonic waveguide-based sensing are
particularly useful in industrial applications.

At present, few studies have explored the use of FEM simulations based on ultrasonic guided
waves for measuring high temperatures. The fundamental concept involved here is that the
propagation of the ultrasonic wave is dependent on the material properties like density and Young’s
modulus through which it is traveling. Those properties in turn depend on the temperature thus
giving a relation between the temperature and the wave propagation (time of flight difference has
been considered). Moreover, the effect of thermal expansion of the waveguide on the received
signal is also considered, as it influences the ultrasonic wave propagation.

This project also aims at a temperature monitoring system utilizing ultrasonic waveguides and IoT
technologies. The hardware setup employs ultrasonic sensors for non-invasive temperature sensing,
connecting to an IoT device for data transmission. The software stack includes ExpressJS, EJS, and
MongoDB for creating a dynamic dashboard displaying real-time and historical temperature data.
The IoT integration, planned post-experimental setup, aims to enable remote monitoring and
control. The modular design ensures scalability and adaptability, making it applicable across
various environments. This project contributes to the advancement of smart systems for
environmental monitoring, offering insights into sensor integration and IoT connectivity.

Keywords: Waveguide, Ultrasonic transducers, Piezoelectric transducer, Thermal expansion

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 CONTENTS

1. Abstract……………………………………………………….……………………….2
2. Chapter 1 Introduction and Literature ………………….………..……...…………….3
1.1 Introduction 3
1.2 Literature Review 4
1.3 Literature Gaps 6
1.4 Objectives 6
3. Chapter 2 Methodology……………………………………………………..…………..7
2.1 Experimental Setup 7
1. Piezoelectric Transducer 7
2. Pulser/Receiver 8
3. Picoscope Oscilloscope 9
4. Thermocouple and DAQ 10
2.2 Simulation Methodology 12
2.3 Simulation Procedure 12
4. Chapter 3 Results and Discussion…………………………..……………...…………13
3.1 Results 13
3.2 Material properties used for simulations 17
5. Chapter 4 Conclusions and future work……………………………..………..………18
4.1 Conclusions 18
4.2 Future Work 19
6. References…………………………………………...……………………..….............21

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 LIST OF FIGURES

Figure Description Page no

Figure 2.1 Experimental Setup 8

Figure 2.2 Piezoelectric Transducer​ 9

Figure 2.3 JSR DPR300 Pulser/receiver 10

Figure 2.4 Picoscope Oscilloscope 11

Figure 2.5 Thermocouple and DAQ 12

Figure 2.6 Module for simulating wave 13

propagation

Figure 2.7 Couples modules for thermal 13

study

Figure 3.1 Application of Hanning pulse 14

Figure 3.2 Wave propagation simulation 14

at 22°C

Figure 3.3 Temperature distribution 15

when one face maintained at
22°C and other end at 1000°C
after thermal expansion
(constant coefficient of
thermal expansion of 1.2E-05
/°C)​

Figure 3.4 Wave propagation simulation 15

at 22°C

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 Chapter 1

INTRODUCTION AND LITERATURE REVIEW

1.1 INTRODUCTION

Many industrial processes that require precise temperature control (such as nuclear, steel, and glass
plants) motivate the development of an ultrasonic temperature sensor. In a high-temperature
environment, especially where access is restricted, it is important to monitor temperature at various
points using dependable methods. Thermocouples, Resistive Temperature Devices (RTD), and
Radiation Pyrometers are typical temperature sensors used in industries. These temperature
diagnostic tools have accuracy problems due to sensor drift for long-term operation.
Thermocouples are prone to reliability issues (at the hot junction) while being used in hostile
elevated temperature environments.

Remote measurements in areas that are hard to reach or dangerous can be done using
ultrasonic-guided waves. The waves can go far along the waveguide, so they can be created at one
end of the waveguide with ultrasonic transducers, and the measurement area can be at the other
end.

In general, ultrasonic waveguide sensors measure changes in waveguide velocity due to the
variations in its material properties (α, E, G and ρ). By comparing the ultrasonic waves at room
temperature, the changes in time of flight, velocity, and phase shift can measure the changes in
physical properties of the waveguide material and the media around it. The ultrasonic waveguide
sensor has many advantages, such as the waveguide can have different shapes like wire, rod, or
strip, and can be chosen and adjusted based on the access and the measurement needs, including the
special distribution of the sensors.

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In the contemporary landscape of technological integration, our project introduces a transformative
approach to temperature monitoring by seamlessly combining ultrasonic waveguide sensors and
IoT capabilities. The utilization of ultrasonic sensors offers an innovative, non-invasive method for
accurate temperature measurement. The software infrastructure, featuring ExpressJS, EJS, and
MongoDB, orchestrates a dynamic dashboard presenting real-time temperature updates and
insightful historical trends. Beyond immediate utility, our project outlines a future integration of
IoT, allowing for remote accessibility and control. This forward-thinking extension aligns with the
paradigm of smart systems, promising not only user convenience but also laying the foundation for
automated and intelligent applications. This project not only caters to the pressing need for
effective temperature monitoring but also positions itself as a pioneer in the evolving landscape of
environmental sensing and IoT-connected solutions.

1.2 LITERATURE REVIEW

The literature review encompasses a thorough examination of ultrasonic waveguide sensors,

delving into their wide-ranging applications spanning temperature, wall thickness monitoring,
equipment monitoring, rheological properties measurement, and simultaneous temperature and
viscosity measurements. The following summaries encapsulate key insights from each reviewed
paper:

1. Yunlu Jia, Vasiliy Chernyshev, Mikhail Skliar (2016):

This study introduces an innovative method for ultrasound-based measurements of segmental

temperature distribution within solids, including a rigorous validation of the technique at elevated
temperatures. The research contributes valuable insights into temperature sensing within solid
materials using ultrasound.

2. F. B. Cegla, P. Cawley, J. Allin, J. Davies (2011):

The focus of this paper lies in the realm of high-temperature wall thickness monitoring (>500°C)
utilizing dry-coupled ultrasonic waveguide transducers. It presents techniques crucial for
monitoring structural integrity under extreme temperature conditions.

3. Zuoyu Liao, Xin Zhang, Tianyang Liu, Jiuhong Jia, Shan-Tung Tu (2020):

4
 The paper discusses the characteristics of high-temperature equipment monitoring using
dry-coupled ultrasonic waveguide transducers, providing practical insights into their application in
extreme temperature environments.

4. K. Balasubramaniam et al. (1999, 2002, 2008):

Spanning multiple years, this research underscores the utility of ultrasonic waveguide sensors for
measuring the rheological properties of fluids, presenting a resilient and cost-effective solution.

5. Suresh Periyannan, Prabhu Rajagopal, Krishnan Balasubramaniam (2016):

The study introduces a torsional mode ultrasonic helical waveguide sensor designed for
re-configurable temperature measurement, showcasing innovative sensor designs in the realm of
temperature sensing.

6. Nishanth Raja, Krishnan Balasubramaniam, Suresh Periyannan (2019):

Investigation into ultrasonic waveguide-based level measurement using the flexural mode F(1,1)
expands the application scope of waveguide sensors to include level measurements in addition to
fundamental modes.

7. Jinrui Huang, Fredric Cegla, Andy Wickenden, Mike Coomber (2021):

The study explores simultaneous measurements of temperature and viscosity for viscous fluids
using an ultrasonic waveguide, demonstrating the sensor's versatility in providing multiple
measurements concurrently.

8. Nishanth Raja, Krishnan Balasubramaniam, Suresh Periyannan (2018):

This paper presents an ultrasonic waveguide-based multi-level temperature sensor designed for
confined space measurements, offering insights into temperature sensing in complex environments.

9. Periyannan Suresh and Krishnan Balasubramaniam (2015):

Investigation into simultaneous moduli measurement of elastic materials at elevated temperatures

using an ultrasonic waveguide method contributes to understanding material characterization at
high temperatures.

10. Vimal V Shah, Krishnan Balasubramaniam (2000):

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 The paper discusses the measurement of Newtonian viscosity from the phase of reflected
ultrasonic shear waves, providing valuable insights into viscosity measurement techniques using
ultrasonic waveguides.

In conclusion, this literature review underscores the adaptability and advancements in ultrasonic
waveguide sensors, emphasizing their pivotal role in high-temperature environments, rheological
properties measurement, and simultaneous temperature and viscosity measurements across various
applications.

1.3 LITERATURE GAPS

1. Limited research has been reported for high temperature measurement using different
configurations of waveguides and reflectors.

2. Limited research in high temperature measurement using FEM based simulations based on
ultrasonic waves.

1.4 OBJECTIVES

1. To study heat transfer and wave propagation through the cylindrical waveguide containing
notches using finite element analysis.

2. To design an experimental setup and perform experimental study to validate with the simulation
results.

3. Designing a dashboard for automatic data collection using IOT.

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 Chapter 2

METHODOLOGY

2.1 EXPERIMENTAL SETUP

The experimental setup consists of an Ultrasonic shear transducer (Olympus, 0.5 MHz, 1 in),
Pulser-receiver (JSR DPR 300), Picoscope 3205D, Thermocouples and a Personal Computer. The
connection between these devices is shown in the below Fig 2.1.

Figure 2.1 Experimental Setup

Each device mentioned above has been used for different purposes and has its significance in
experimentation. We can not conduct any experiments in case of the absence of any of the devices.
The brief information about some of the devices:

1. Piezoelectric Transducer: A piezoelectric PZT (lead zirconate titanate) crystal transducer is a

type of sensor that is commonly used in various industrial applications. The transducer is made up
of a piezoelectric material that generates an electrical charge when subjected to mechanical stress
or vibrations. The crystal has a unique property that allows it to convert electrical energy into
mechanical energy and vice versa.

The PZT crystal transducer is used in a variety of applications such as acoustic emission testing,
ultrasonic testing, vibration monitoring, and strain gauging. In acoustic emission testing, the
transducer is used to detect the sound waves generated by the materials during deformation,
cracking or failure. In ultrasonic testing, the transducer is used to produce high-frequency sound
waves to detect internal flaws in materials such as cracks, voids or inclusions.

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 Figure 2.2 Piezoelectric Transducer

In vibration monitoring, the PZT crystal transducer is used to measure the mechanical vibrations in
structures, machines, and equipment. The transducer can detect the slightest changes in vibrations
and alert the operators to avoid any anomalies or potential issues. In strain gauging, the transducer
is used to measure the deformation or strain in materials such as metals, plastics, and composites.

The PZT crystal transducer has many advantages over other types of sensors. It has high sensitivity,
excellent linearity, and a wide frequency range. It is also highly durable and can withstand high
temperatures, pressures, and harsh environments. The transducer is small in size and can be easily
integrated into different systems and devices.

In conclusion, the PZT crystal transducer is a versatile and reliable sensor that has many
applications in different industries. Its unique properties make it an essential tool for various types
of testing, monitoring, and measurement.

2. Pulser/Receiver: JSR DPR300 Pulser/receiver is a high-performance instrument used in Non

Destructive Testing (NDT) and Structural Health Monitoring (SHM) applications. It is designed to
produce and receive high-frequency ultrasonic waves, which are used to detect and measure
internal flaws or defects in materials, such as metals, plastics, and composites.

The JSR DPR300 Pulser/receiver is equipped with advanced features such as programmable pulse
shapes, digital filtering, and adjustable gain, which allows for precise control over the ultrasonic
signal. It also features a data acquisition system that can capture and process signals in real-time,
enabling accurate and reliable measurements.

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 Figure 2.3 JSR DPR300 Pulser/receiver

The instrument is commonly used in a variety of industries including aerospace, automotive, and
manufacturing, for applications such as flaw detection, thickness measurement, and material
characterization. It is also widely used in research and development for studying material properties
and developing new testing methodologies.

JSR DPR300 pulser/receiver is a versatile and reliable instrument that offers high-performance and
precise control over ultrasonic signals. Its advanced features and capabilities make it an essential
tool in NDT applications, providing accurate and reliable results for a wide range of materials and
applications.

3. Picoscope Oscilloscope: PicoScope is a brand of high-performance oscilloscopes manufactured

by Pico Technology. These oscilloscopes are used in a variety of industries including automotive,
aerospace, defense, electronics design, and education. They offer advanced features and high
quality performance, equipped with a range of probes and accessories to enable users to measure
and analyze a wide range of signals, from low-level audio signals to high-speed digital signals.

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 Figure 2.4 Picoscope Oscilloscope

PicoScope oscilloscopes use advanced digital signal processing technology to provide high-quality
waveforms, high sampling rates, and deep memory storage. They also feature a user-friendly
interface and intuitive software, allowing users to easily capture, analyze, and share waveforms and
data. PicoScope oscilloscopes are highly versatile and can be used in a variety of applications such
as diagnosing and troubleshooting problems in electronic systems, measuring signals in research
and development, analyzing automotive signals, and testing and validating designs.

In conclusion, PicoScope oscilloscopes are high-performance, versatile, and user-friendly

instruments that are used in a wide range of industries and applications. They offer advanced
features, high-quality performance, and a range of probes and accessories to meet different needs
and requirements.

4. Thermocouple and DAQ: Thermocouples and Data Acquisition (DAQ) systems are two
important technologies that are widely used in temperature measurement and monitoring
applications. Thermocouples are temperature sensors that detect changes in voltage across two
different metals that are joined together. The voltage produced is proportional to the temperature
difference between the measurement point and the reference point, which allows for accurate
temperature measurement. They are used in various industries such as manufacturing,automotive,

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aerospace, and scientific research for applications such as temperature control, process monitoring,
and equipment maintenance.

DAQ systems are electronic devices used to capture and record data from multiple sensors,
including thermocouples, in real time. They consist of a computer, a signal conditioning module,
and a data acquisition card or module. The signal conditioning module conditions the signal from
the thermocouple to ensure accurate measurement, and the data acquisition card or module captures
the data and stores it in a digital format for further analysis. DAQ systems are widely used in
various industries to monitor and control the temperature of critical systems and equipment.

Figure 2.5 Thermocouple and DAQ

Together, thermocouples and DAQ systems provide an accurate and reliable means of temperature
measurement and monitoring. They are essential tools in many industries, including manufacturing,
aerospace, automotive, and scientific research. The accuracy, reliability, and versatility of these
technologies make them an integral part of temperature measurement and monitoring systems used
today.

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2.2 SIMULATION METHODOLOGY

In Ansys Software,

1. For simulating longitudinal mode wave propagation, Transient Structural module has been
chosen.
2. For simulating the effect of thermal expansion, three modules have been coupled.

i) Steady State Thermal module has been used to obtain temperature distribution along the
waveguide according to conditions specified.

ii) Static Structural module has been used to obtain the deformation of waveguide due to
temperature variation.

iii) Transient Structural module has been used to simulate wave propagation through the deformed
body.

2.3SIMULATION PROCEDURE
1.Cylindrical waveguide has been created with dimensions of 7 mm diameter and 1m length.
2.Simulation is started in the Steady State Thermal module by specifying Engineering Data.
3.Material is assigned to the waveguide - Structural Steel. Ansys Material Directory is used for
material properties.
4.Now initial conditions are specified - temperatures of the two end faces are given as input.
5.The solution of temperature distribution is obtained after solving the model. Now this solution is
coupled with the Setup of Structural module. A fixed support is applied at an end face and solution
of total deformation is obtained after solving the model.
6.Now the solution of the Static Structural module is coupled to the model of the Transient
Structural module to give the deformed body as starting geometry for simulation of wave
propagation.
7. Now in the transient structural module, Hanning pulse is applied at one end face. After solving
the model, we get directional deformation (along the longitudinal axis of the waveguide) as an
output signal at the same face where the Hanning pulse is applied.

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 Chapter 3

RESULTS AND DISCUSSION

3.1 RESULTS
1. Simulation Of Wave Propagation at 22°C (Longitudinal Wave Mode) ( Material – Structural
Steel)​

Figure 3.1 Application of Hanning pulse

In the Transient Structural module after geometry and material properties are defined, a Hanning
pulse is applied at one end face. Mesh size of 5 mm is chosen and meshing is done. After solving
the model, directional deformation along the longitudinal axis of the waveguide is obtained as a
solution.(A-Scan signal)

Figure 3.2 Wave propagation simulation at

22°C

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2. Simulation Of Wave Propagation when one face maintained at 22°C and other end at 1000°C
after thermal expansion (constant coefficient of thermal expansion of 1.2E-05 /°C)​

Figure 3.3 Temperature distribution when one face maintained at 22°C and other end at
1000°C after thermal expansion (constant coefficient of thermal expansion of 1.2E-05 /°C)​

Simulation is started in steady state thermal where the conditions are applied and temperature
distribution is obtained. Then, using the static structural module total deformation is obtained.
Lastly, using transient structural module wave propagation is simulated in deformed body.

Figure 3.4 Total Deformation when one face maintained at 22°C and other end at 1000°C
after thermal expansion (constant coefficient of thermal expansion of 1.2E-05 /°C)​

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Figure 3.5 Wave propagation simulation when one face maintained at 22°C and other end at
1000°C after thermal expansion (constant coefficient of thermal expansion of 1.2E-05/°C)​

3. Comparison of signal at 22°C and signal when one face end is at 1000°C (constant thermal
coefficient of expansion)

Figure 3.6 Comparison of A-Scan Signals at 22°C and signal when one face end is at 1000°C
(constant thermal coefficient of expansion)

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4. Comparison of signal when variation in coefficient of thermal expansion is considered

Figure 3.7 Variation of coefficient of thermal expansion

➔ In this simulation the coefficient of expansion has been varied from 22°C to 1000°C.​
➔ The values used in this simulation are assumed values to check if the simulation model can
show the difference in reflected signal if coefficient of expansion is varied with respect to
temperature.​
➔ Simulation is performed for geometry whose faces are at 22°C and 1000°C with both varying
α and constant α and are compared.​

Figure 3.8 Comparison of A-Scan Signals for varying and constant coefficient of thermal
expansion

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3.2 MATERIAL PROPERTIES USED FOR SIMULATIONS

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 Chapter 4

CONCLUSIONS AND FUTURE WORK

4.1 CONCLUSIONS

The simulation of ultrasonic wave propagation through a waveguide under uniform room temperature
conditions has provided valuable insights into the behavior of reflected waves. However, in our
pursuit of a comprehensive understanding, we extended our study to include the impact of thermal
expansion caused by distributed temperatures along the waveguide.

Through meticulous simulation modeling, we successfully demonstrated that the reflected wave
undergoes significant alterations when subjected to higher temperatures. This phenomenon is
attributed to thermal expansion, which elongates the waveguide and subsequently increases the time
of flight for the reflected wave. The observed differences in the reflected wave at elevated
temperatures highlight the intricate interplay between temperature variations and ultrasonic wave
behavior.

The successful implementation of a user-friendly dashboard adds a practical dimension to our project.
Key features such as real-time temperature monitoring, temperature history, and a temperature vs time
graph enhance the usability of the simulation. These additions not only facilitate the visualization of
temperature trends but also contribute to a more comprehensive analysis of the reflected wave
behavior under varying thermal conditions.

In summary, our project not only advances the understanding of ultrasonic wave propagation but also
underscores the significance of considering thermal effects, specifically thermal expansion, in such
simulations. The developed simulation model, coupled with the intuitive dashboard, lays the
foundation for future research and practical applications in fields where precise control and
monitoring of ultrasonic waves in varying thermal environments are essential.

This project serves as a testament to the importance of interdisciplinary approaches in tackling

complex phenomena and opens avenues for further exploration in the realms of acoustics, materials
science, and temperature-dependent wave behavior.

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4.2 FUTURE WORK

1. Incorporating Material Properties in Simulation:

To enhance the fidelity of our simulation model, future work will focus on incorporating the
influence of material properties at different temperatures. This includes a detailed investigation into
how variations in temperature affect the acoustic properties of the waveguide material. By integrating
comprehensive material models, we aim to provide a more accurate representation of real-world
scenarios and further refine our understanding of the interplay between temperature, material
properties, and ultrasonic wave propagation.

2. Designing an Experimental Setup:

To validate the results obtained from the simulation study, the development of a robust experimental
setup is crucial. This entails designing and implementing a controlled environment where temperature
variations can be systematically induced. The experimental apparatus will include the waveguide
material under investigation, temperature control mechanisms, and sensors for precise data
acquisition. The goal is to closely mimic the conditions simulated in the model and compare the
real-world results with the simulated predictions.

3. IoT Integration for Real-time Data Collection:

Leveraging Internet of Things (IoT) technology, we propose to enhance the data collection process
by implementing sensors and devices capable of real-time monitoring. Through IoT-enabled sensors
strategically placed within the experimental setup, we can continuously capture temperature variations
and corresponding wave characteristics. This real-time data stream will not only validate the
simulation results but also provide dynamic insights into the transient behavior of the wave under
changing temperature conditions.

4. Integration with the User Interface:

The existing user interface will be expanded to seamlessly integrate with the experimental setup.
This integration will enable the display of real-time data collected through IoT devices, providing
users with a comprehensive visualization of the correlation between temperature changes and

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ultrasonic wave behavior. The extended interface will include additional features such as live updates,
statistical analyses, and comparative displays between simulation predictions and experimental
observations.

In conclusion, these proposed avenues for future work aim to advance the current project by refining
the simulation model, validating its predictions through experimental studies, and incorporating
real-time data visualization for a more comprehensive analysis of temperature-dependent ultrasonic
wave behavior

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 REFERENCES
1) Yunlu Jia, Vasiliy Chernyshev, Mikhail Skliar, Ultrasound measurements of segmental
temperature distribution in solids: Method and its high-temperature validation, Ultrasonics, Volume
66,2016,Pages 91-102,ISSN 0041-624X

2) F. B. Cegla, P. Cawley, J. Allin and J. Davies, "High-temperature (>500°c) wall thickness

monitoring using dry-coupled ultrasonic waveguide transducers," in IEEE Transactions on
Ultrasonics, Ferroelectrics, and Frequency Control, vol. 58, no. 1, pp. 156-167, January 2011, doi:
10.1109/TUFFC.2011.1782.​

3) Zuoyu Liao, Xin Zhang, Tianyang Liu, Jiuhong Jia, Shan-Tung Tu, Characteristics of
high-temperature equipment monitoring using dry-coupled ultrasonic waveguide transducers,
Ultrasonics, Volume 108,2020,106236,ISSN 0041-624X.​

4) Periyannan Suresh, Prabhu Rajagopal, and Krishnan Balasubramaniam. “Torsional mode

ultrasonic helical waveguide sensor for re-configurable temperature measurement.” AIP Advances
6.6 (2016): 065116​

5) Suresh Periyannan, Prabhu Rajagopal, and Krishnan Balasubramaniam. “Torsional mode

ultrasonic helical waveguide sensor for re-configurable temperature measurement.” AIP Advances
6.6 (2016): 065116​

6) Nishanth Raja, Krishnan Balasubramaniam, Suresh Periyannan; Ultrasonic waveguide based

level measurement using flexural mode F(1,1) in addition to the fundamental modes. Rev. Sci.
Instrum. 1 April 2019; 90 (4): 045108.​

7) Jinrui Huang, Fredric Cegla, Andy Wickenden, Mike Coomber; Simultaneous Measurements
of Temperature and Viscosity for Viscous Fluids Using an Ultrasonic Waveguide. 2021, 21(16),
5543;
8) Nishanth Raja, Krishnan Balasubramaniam, Suresh Periyannan; Ultrasonic Waveguide-Based
Multi-Level Temperature Sensor for Confined Space Measurements. 2018,
10.1109/JSEN.2018.2843531

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9) Periyannan Suresh and Krishnan Balasubramaniam ;Simultaneous moduli measurement of
elastic materials at elevated temperatures using an ultrasonic waveguide method, Rev. Sci. Instrum.
86, 114903 (2015)
10) Vimal V Shah, Krishnan Balasubramaniam ; Measuring Newtonian viscosity from the phase
of reflected ultrasonic shear wave; Received 17 September 1999, Revised 24 April 2000.

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