Optical Fiber IR Thermometry and its Use within Gas Turbines
ADAM COOKE and PETER CHILDS
Thermo-Fluid Mechanics Research Centre (TFMRC)
School of Science & Technology, Department of Engineering & Design
University of Sussex
UK
Abstract: - Fiber optic infrared thermometers offer an alternative to traditional temperature measurement
techniques for use within gas turbines – particularly for use on rotating components. This paper addresses the
area of fiber optic infrared thermometry and its use for both surface and gas flow temperature measurements
within such gas turbines. Infrared fundamentals and thermometry operations are described before discussing
various types of fiber optic infrared thermometers. The paper ends with a look at possible near term future
developments for this technology.
Key-Words: - infrared thermometry, optical fiber, gas turbine
1 Introduction
The continual quest for ever better thermal
efficiencies within gas turbine engines almost
inevitably means higher temperatures throughout
the engine. These higher temperatures lead to a
more severe measuring environment, especially for
the turbine components. It is an essential part of
engine testing to measure the surface temperatures
of various internal components and the temperature
of air and gas flows.
Component surface temperatures have traditionally
been carried out using “contact” measurement
techniques, the most common of which is the use of
surface mounted thermocouples. The conventional
way of using such thermocouples is to machine a
groove in the component to insert a small diameter
thermocouple cable. The thermocouple can then be
secured in place in the groove using a high
temperature cement, welded in place or constrained
using shim straps which are spot welded to the
surrounding surface. However, these techniques
have a number of disadvantages and limitations
including: [1]

The machining of the grooves can introduce
undesirable stressing within the component.

The insertion of the groove and thermocouple
will inevitably alter the heat transfer and
temperature
distribution
within
the
component.

The temperature field is distorted by the
presence of the thermocouple and its method
of constraint.

The machining of the grooves and insertion of
the thermocouples is very labour intensive and
therefore expensive.

Thermocouple devices are limited in their
maximum measurable temperature, response,
accuracy and stability and can also be affected
by electromagnetic interference.

The
requirement
to
incorporate
instrumentation slip-ring unit.
an
The measurement of air and gas flow temperatures
has traditionally been made by immersing a
thermocouple or resistance temperature detector
directly into the flow. The actual device will
depend on the required temperature range to be
measured. Sometimes the sensor will require
protection from the local environment, often using
a protection tube or a thermowell. The main
disadvantage of this method is that high gas
velocities can give rise to dynamic heating with an
immersed probe and due allowance must be made
for this effect. Conduction of heat along any probe
and/or protective sleeve is also a prominent
problem. [23]
An alternative to contact temperature measurement
techniques are “non-contact” techniques, the most
prominent of which is Infrared (IR) thermometry.
IR thermometry makes use of the physical
electromagnetic phenomena whereby all objects
above 0 K emit radiant energy. This radiant energy
can then be used to infer the temperature of an
object.
-1-
2 Background to IR
Heat transfer between two entities can occur by
means of three mechanisms: conduction,
convection and radiation. It is with the process of
radiation with which infrared thermometry is
concerned. A typical IR measurement system
comprises the source or target (whose temperature
is desired), the transmission medium through which
radiant energy is transmitted, usually a gas, and the
measuring device. The measuring device may
include an optical system, a detector and a control
and analysis system.
C2 = the second radiation constant = 0.01438769 m
K
T = absolute temperature (K)
Fig.2 is a plot of spectral emissive power against
wavelength for the main infrared region of the
electromagnetic spectrum for a range of
temperatures.
The electromagnetic spectrum extends from
gamma rays, with wavelengths in the order of 10-5
μm, up to radio waves with wavelengths of
hundreds of meters. IR thermometry is concerned
with the section of this spectrum ranging from
approximately 0.1 μm to 100 μm. [2]. See Fig.1

Fig.2 Spectral emissive power
Fig.1 The electromagnetic spectrum (from 23])
Emissive power is the term used to describe the
amount of thermal radiation which leaves the
surface of an object. The emissive power of an
object is expressed relative to that of a blackbody.
A blackbody is a theoretical surface which is said
to absorb all incident radiation, emit more energy at
any given wavelength and temperature than any
other surface, and whose emitted radiation is
independent of direction. The spectral emissive
power for a blackbody can be determined using
Planck’s Law as follows:
C1
E  ,b 

 C2  
  1
 T  
5 exp 

Where:
E,b = spectral emissive power for a blackbody
(W/m3)
C1= the first radiation constant = 3.74177498 x 1016
W m2
 = wavelength (m)
From Fig.2 it can be seen that the magnitude of
spectral emissive power decreases as the
wavelength increases and that for each wavelength
it has a maximum value. Wien’s Displacement
Law defines the relationship between wavelength
and temperature and is as follows:
maxT = 0.028978 m K
Integrating Planck’s Law over all wavelengths
gives the total emissive power for a blackbody as
follows:
Eb  
C1
d
 C  
5 exp  2   1
  T  
Resulting in:
Eb  T 4
Where:
 = Stefan-Boltzmann constant = 5.67 x 10-8 W/
m2 K4
3 Fiber Optic Infrared Thermometers
-2-
The development of fiber optic infrared technology
has removed the need for IR thermometers to
require a clear line of sight between the target and
the sensor components. This means that IR
thermometry can now be used in even less
accessible areas and, due to the much reduced size
of fiber optics over conventional pyrometers, they
are much less intrusive to the surrounding area.
The use of fiber optic cables also allows the
detector and electronics to be located well away
from the measurement area and any possible risks
associated with it. Another feature of fiber optic
systems is the ability of the cables to withstand
extreme and hostile measuring environments.
There are two main types of fiber optic infrared
thermometer: a blackbody system and an optical
lens system. These two devices are similar but are
used for two very different applications.
A
blackbody fiber optic system is used to measure air
flow temperatures or gas temperatures whilst an
optical lens system is used to measure component
surface temperatures.
transmission properties of the core material which
determines the wavelength range of radiation which
can be measured. The cladding is usually made of
the same material as the core but with a slightly
lower index of refraction. Finally, the outer coating
surrounds the core and cladding and provides them
with protection from the physical environment.
This outer cladding is usually made from numerous
coats of plastic and/or metal sheaths with the exact
material being governed by the environment in
which the cable is to be used.
The difference in refractive index between the core
and the cladding results in the occurrence of total
internal reflection. A material’s index of refraction
is the ratio of light in a vacuum to the speed of light
in the material. When a beam of light or radiant
energy passes from one material to another with a
different index of refraction, the beam is bent (or
refracted) at the boundary of the two materials.
The law of refraction is described by Snell’s Law as
follows:
N1SinA = N2SinB
The working principle of the two systems is very
similar as it is only at their “measuring” end where
the two systems differ and this will be discussed in
later sections. Common to both systems is the
inclusion of a fiber optic cable. This cable is used
to channel the thermal radiation from the source, be
it a gas temperature or a surface temperature, to the
detector.
Where N1 and N2 are the indices of refraction of the
materials through which the beam of energy is
passing and A and B are the angles of incidence
and refraction respectively, see Fig.4
In simple terms, the two systems work as follows:
thermal radiation enters the fiber optic cable at its
measuring end and is then transported along its
length to the detector by way of total internal
reflection. This process obviously relies heavily on
the transmission characteristics of the cables.
All fiber optic cables have 3 basic elements: the
core, the cladding and the outer coating. See Fig.3
Outer Coating
Fig.4 Angles of refraction
If the angle of incidence is greater than the critical
angle for the interface (typically about 82 º for fiber
optic cables) then the beam of energy is reflected
back into the core without any loss and this is the
process termed total internal reflection, see Fig.5
[3]
Outer
Coating
Cladding
Beam
Core
Core
Fig.3 A typical fiber optic cable
The core is the main part of the cable through
which the radiation energy travels. It is the
Cladding
Fig.5 Total internal reflection
The main disadvantage of early fiber optic cables
was that they had very high transmission losses, or
-3-
were limited in wavelength coverage, this made
them unpractical for use, see Fig.6
Fig.7 Transmission losses of selected fiber optic
cables (from [7] )
Examples of, and more detail about fiber optic
cables and their properties can be found in
references 4 - 14.
4 Blackbody Fiber Optic System
A blackbody fiber optic system is used to measure
air flow, or gas, temperatures and consists of three
basic elements: a blackbody cavity, a fiber optic
cable, or cables, and a detector assembly, see Fig.8
Fig.6 Historical cable transmission losses (from
[21] )
However, recent developments have resulted in a
number of fiber optic cables with suitably low
transmission losses. These cables can be classified
into three categories: glass cables, crystal cables
and hollow waveguides. Table 1 is a summary
table of the different categories.
Category
Glass
Crystal
Hollow
waveguides
Sub-category
Heavy metal
fluoride
(HMFG)
Chalcogenide
Polycrystalline
(PC)
Single crystal
(SC)
Metal/dielectri
c film
Examples
ZBLAN (ZrF4BaF2-LaF3AlF3-NaF)
GeO2-PbO
AgBrCl
Sapphire
Hollow glass
waveguide
Hollow sapphire
Table 1 Different fiber optic cable materials
For all the cable types the transmission losses vary
for differing wavelengths and so the choice of cable
is predominantly made by matching the
transmission characteristics with the wavelength of
thermal radiation which is to be measured, see
Fig.7
Blackbody Cavity
Fiber Optic Cable
Lens
Detector
Wavelength Filter
Detector Sensitive
Area
To Detector
Electronics
Fig.8 A schematic of a black body fiber optic
system
The black body cavity is typically a thin (3 to 5
μm) platinum (or iridium) film sputtered onto the
tip of the fiber optic cable. The most commonly
used cable type is sapphire because it is transparent
and non-emitting in the visible and near infrared
range up to its melting point of 2070 ºC. At the
fiber tip the surface is then coated with a protective
thin film of aluminium oxide. The response of the
thin film of aluminium oxide to the temperature
changes of the surrounding circumstances is
expected to be rapid because of the low thermal
conductivity of the sapphire cable [15]. Yabin Yu
[15] reported that the emissivity of the blackbody
cavity is not the ideal constant of 1, but is a
function of wavelength and temperature. For
example, the change in emissivity of a cavity (with
a length to diameter ratio of 2) is less than 0.01 for
λ from 0.5 to 0.7 μm and T from 600 to 1300 ºC.
Blackbody radiation is emitted from the blackbody
cavity as its temperature varies. A portion of this
radiation is then transmitted along the length of the
cable where it reaches the detector assembly.
The detector assembly typically contains a light
gathering lens to focus the radiation onto the
detector, an appropriate wavelength filter to filter
the radiation to the required wavelength and a
detector to convert the radiation energy to an
electrical signal for processing.
The most
commonly used detectors are photon (or quantum)
detectors such as InAs, Ge, ZnS and HgCaTe.
-4-
During the transmission of the thermal radiation
from the source to the detector assembly there are
inevitably some losses. These losses include small
amounts of reflection at the fiber ends, slight
misalignment of any cable couplings used and low
levels of absorption within the cable itself. All
these factors need to be taken into account when
processing the signal. This is usually done by the
use of a correction factor at the post processing
stage.
Blackbody fiber optic systems are finding more and
more uses for the measurement of gas temperatures
within gas turbines, especially in the hot sections of
the turbine. Tregay [16] reported a durable
blackbody fiber optic sensor for this purpose. This
device had a thermally emissive insert embedded
inside a sapphire cable and was reported to be able
to operate above the melting point of nickel based
super alloys. The device was installed between the
first stage rotor and second stage nozzle of a
General Electric MS7001B turbine with the
measuring tip located 1.5 inches into the hot gas
stream.
Over 2000 hours of testing were
accumulated at temperatures near 900 ºC. Dils [17]
developed a high temperature blackbody fiber optic
device which was capable of measuring gas
temperatures from 600 to 2000 ºC. This device
consisted of a small blackbody cavity sputtered on
the end of a sapphire fiber, a connecting low
temperature glass fiber and a conventional optical
detector assembly.
Tregay [16] reported the
development of a blackbody fiber optic device for
measuring gas temperatures within gas turbine
engines in the region 600 to 1900 ºC.
Whilst blackbody fiber optic systems have all the
advantages mentioned above they also have some
disadvantages. The main disadvantage is that the
blackbody cavity can be easily contaminated and
corroded by impurities whilst working under harsh
environment conditions [15].
5 Optical Lens Fiber Optic System
An optical lens fiber optic system is used to
measure surface temperatures and differs from a
blackbody system in that it has a collimating (or
focusing lens) at its measuring end instead of a
blackbody cavity. The principle of operation
however remains the same as for the blackbody
type systems described above.
The detected emission of thermal radiation comes
directly from the surface being measured. The
lenses are made from suitable IR transmitting
materials such as CaF2, KRS-5, or ZnSe. The
design and geometry of the lens dictates the size of
the spot on the target being measured and also the
field of view of the instrument. By varying the
design of this lens it is possible to measure either a
very small point temperature or a larger regional
temperature. By designing the lens in such a way
that allows the end of the cable to be positioned a
distance away from the target, it is possible to use
cables which do not have to be able to survive such
high temperatures. Fig.9 shows a schematic of a
typical optical lens fiber optic system.
Lens
Lens
Detector
Lens Holder
Fiber Optic Cable
Detector Sensitive
Area
To Detector
Electronics
Wavelength
Filter
Fig.9 A schematic of an optical lens fiber optic
system
The absorption and reflectance of the transmission
medium for this type of system is an important
factor and care needs to be taken to avoid
wavelengths with high levels of absorption.
Optical lens systems are offered by many
commercial
companies
including
LAND
Instruments, IMPAC Infrared, Omega and Raytek.
6 Advantages of Optical Fiber
thermometry
Detailed below are the main advantages that fiber
optic thermometers have over conventional
measuring methods [15, 18]:


They are non-contact and so can be used to
measure the temperature of moving
components much more easily.
The materials from which fiber optic cables
are made are typically good electrical
insulators.
Since they do not conduct
electricity, the probes themselves cannot
introduce electrical shorting. Likewise, they
do not absorb significant levels of
electromagnetic radiation or become heated by
such fields. In addition to this, stray fields
cannot induce electrical noise in fibers and so
the probes exhibit a very high level of
electromagnetic immunity.
-5-

The part of a typical blackbody fiber optic
thermometer which is inserted into the
measurement area is essentially no bigger than
the fiber optic cable itself and so requires very
little access space.
The small size of the fiber and its electrical,
chemical and thermal inertness allow for longterm location of the sensor deep inside
complex equipment and thereby provide
access to locations which are difficult to
address, where the monitoring of temperature
may be of interest.
of a blade averaging process. The measurement of
the temperature of the gas flowing through the
turbine is desirable in order to monitor operating
conditions. [19]

Most fiber optic sensors require no electrical
power at the sensor end of the system. They
generate their own optical signal or they are
“powered” remotely by radiation from a light
source located within the instrument.

The small size of the fiber optic cable and its
electrical, chemical and thermal inertness
allow semi-permanent location of the sensor
deep inside complex and hard to reach
equipment and thereby provide access to
difficult to address locations where
temperature may be of interest.
Access is most commonly achieved by the use of a
sighting tube and mounting flange. The mounting
flange is attached to the outer casing of the turbine
and then the fiber optic cable is inserted into a sight
tube which provides it with protection. If required,
cooling air can also be pumped down the sighting
tube. To assist with keeping the fiber end clean
and free from contamination, it is good practise to
point the device downstream of the flow. A typical
turbine blade access system is shown below in
Fig.10

One of the most important things to consider with
turbine blade and turbine gas thermometry is the
issue of access to the target for the infrared
thermometer. The target will typically either be the
turbine blades themselves or the gas flowing
through the turbine and so the issue of access can
be dealt with in the same way.
To Detector Electronics
Sight Tube
Mounting Flange
Outer Casing
7 The use of Fiber Optic IR
Thermometry within Gas Turbines
Fiber Optic Cable
To date most fiber optic IR thermometry systems,
and indeed all types of IR thermometry systems,
within gas turbines have either been used to
measure the surface temperature of the turbine
blades or the temperature of the gas in the turbine
section. A small number of systems have been
used to measure the temperature of turbine disks.
For turbine blade measurements there are three
common basic requirements:
1. Blade profiling
2. Hot blade detection
3. Blade averaging
The objective of blade profiling is detailed thermal
mapping of individual blades which can then be put
together to create a thermal map of the entire array
of turbine blades. In hot blade detection the
objective is to identify and locate any blade, or
blades, which are running at higher temperatures
than the rest of the array. An average temperature
measurement of the entire blade array is the result
Inner Casing
Vane
Blade
Vane
Blade
Fig.10 Typical turbine blade access set-up
For more information on fiber optic IR
thermometry systems and specific examples of
their uses in gas turbines see references 1, 5, 13, 15
- 20, 22, 24 - 31 and 34 - 39.
When measuring the temperature of turbine disks,
the requirement is usually for an average
temperature as a function of disk radius, although
sometimes detailed data of temperature from the
area of blade roots is of particular interest. Disk
heating rates on engine start-up are also often of
interest.
-6-
8 The Future of Fiber Optic IR
Thermometry within Gas Turbines
The use of fiber optic IR thermometry within gas
turbines has changed little in recent years and is
still to significantly progress from use for just
turbine blade and gas measurements. Listed below
are a number of possible developments which may
be seen in the near future which will aid the
increase in use of fiber optic IR thermometry.
8.1 Range Expansion
Whilst the temperature measuring range of some
fiber optic IR thermometry systems is already
large, they tend to have a lower temperature limit
of around 200 or 300 ºC. This means that these
systems cannot be used to make measurements at
temperatures lower than this - which makes the
measurement of engine start-up temperatures
impossible. The cause of this “high” lower
temperature limit is the properties of the fiber optic
cable material used, specifically their low
transmission levels at longer wavelengths. This
limitation is being overcome by the development of
new chalcogenide and polycrystalline IR fiber
materials, CIR and PIR respectively. These cables
have much lower transmission losses over a wider
range of wavelengths and so can be used to
measure lower temperatures. For more information
see references 32 and 33.
8.2 Cost Reduction
The current high cost of specialist IR fiber optic
cables constitutes a barrier to their widespread use.
While some of the costs are unavoidable, much of
it stems from the limited volume of manufacture.
As more uses for these cables are found then
production volumes can be increased which should
lead to a decrease in these costs. [18]
optic cables in a linear array, all within a single
outer coating, and so with careful arrangement,
each individual cable can be set to measure the
temperature of a different disk radius.
8.3 Cable Flexibility
The typical “sight tube and mounting flange”
arrangement mentioned earlier is mounted on the
external casing of the gas turbine and so is limited
to access to the turbine blade area and cannot be
used to access other gas turbine components such
as the discs. Access to these areas will typically
involve feeding the cable through the turbine shaft,
then up into the disc cavities before finally fixing
them to adjacent stator components. This process
requires the cables to be bent, sometimes
significantly, and current fiber optic cables have
very definite minimum bending radii of typically
10 mm. As cables develop they will need to have
smaller minimum bending radii which would allow
them access to ever more restrictive environments.
8.4 Multiple Instruments
As discussed earlier, a slightly different piece of
equipment is used to measure surface temperatures
than is used to measure gas temperatures. Future
systems could combine the two and be used to
measure blade surface temperatures and the
temperature of the gas flowing past them. Watari
M. et al [20] developed an optical fiber
thermometer which had 4 cables fed into a single
detector system. These cables could be separated
from the detector system in any combination. The
principle advantage of this system is that it allows
the cables to be individually replaced if they
become damaged or otherwise require replacing.
Future systems could see both a blackbody system
and a lens system being fed into a single detector
system.
8.3 Measurement Arrays
9 Conclusions
Whilst it is currently possible to use a small motor,
or similar movement device, in order to scan a
surface using a single probe, this process cannot
return simultaneous measurements – as only one
location can be measured at any one time.
However, it is often desirable to know
simultaneous surface temperatures e.g. turbine disk
temperatures at different radii at a given instance in
time. It is now possible to arrange several fiber
This paper discusses the current use of fiber optic
infrared thermometers for both surface and gas
flow temperature measurements within gas
turbines. Blackbody fiber optic systems can be
used to measure gas flow temperatures whilst
optical lens systems can be used to measure surface
temperatures. Both of these systems share many
common components, central to which is the fiber
optic cable itself. Recent developments have seen
-7-
the production of several types of fiber optic cable
which have a transmission range which is ideally
suited to the measurement of infrared radiation and
many systems are now being successfully used
within gas turbines.
References
[1] C. Bird, R. Shepherd, M.D.W. Smith and
H.M.L.
Watson,
“Surface
temperature
measurement in turbines”, AGARD PEP
Symposium,
on
Advanced
Non-Intrusive
Instrumentation for Propulsion Engines, Belgium,
1997.
[2] P.R.N. Childs, J.R. Greenwood and C.A. Long,
“Review of temperature measurement”, Review of
Scientific Instruments, Vol 71, pp 2959-2978,
2000.
[3] “Fiber Optics: Understanding the basics”, The
Photonics Handbook, 49th International Edition,
pp.132-135, Laurin Publishing, 2003
[4] V. Gopal and J.A. Harrington, “Deposition and
characterization of metal sulphide dielectric
coatings for hollow glass waveguides”, Optical
Society of America, Optics Express, 2003.
[5] M. Gottlieb and G.B. Brandt, “Temperature
sensing in optical fibers using cladding and jacket
loss effects”, Applied Optics, 1981, 20(22), pp
3867-3873.
[6] D.J. Haan and J.A. Harrington, “Hollow
waveguides for gas sensing and near-IR
applications”, Proceedings of the SPIE conference
on Speciality Fiber Optics for Medical
Applications, SPIE Vol. 3596, pp. 43-49, San Jose,
California, January 1999.
[7] J.A. Harrington, “Infrared Fiber Optics”,
Handbook of Optics, Vol.3, Second edition,
McGraw Hill, 1995.
[8] J.A. Harrington, “A review of IR transmitting
hollow waveguides”, Fiber and Integrated Optics,
Vol.19, pp 211-227, 2000.
[9] J.A. Harrington and C.D. Rabii, “Mechanical
properties of hollow glass waveguides”, Optical
Engineering Vol.38, No.9, pp 1490-1499,
September 1999.
[10] Y. Matsuura, T. Abel and J.A. Harrington,
“Optical properties of small-bore hollow glass
waveguides”, Applied Optics, Vol.34, No.30, pp
6842-6847, 20th October 1995.
[11] R.K. Nubling and J.A. Harrington, “Optical
properties of single-crystal sapphire fibers”,
Applied Optics, Vol.36, No.24, pp 5934-5940, 20th
August 1997.
[12] S. Sade, O. Eyal and A. Katzir, “Embedded
silver halide optical fiber temperature sensor”,
Proc. SPIE Vol. 4820, p. 646-652, Infrared
Technology and Applications XXVIII; Bjorn F.
Andresen, Gabor F. Fulop, Marija Strojnik; Eds,
Jan. 2003.
[13] S. Sade and A. Katzir, “Fiberoptic infrared
radiometer for real time in situ thermometry inside
an MRI system”, Magnetic Resonance Imaging,
Volume 19, Issue 2, February 2001, Pages 287290.
[14] J.S. Sanghera, L.B. Shaw and I.D. Aggarwal,
“Applications of chalcogenide glass optical fibers”,
Comptes Rendus Chimie,Volume 5, Issue 12 ,
December 2002, Pages 873-883.
[15] Y. Yu and W.K. Chow, “Review on an
Advanced
High-Temperature
Measurement
Technology: the Optical Fiber Thermometer”
[16] G.W. Tregay, P.R. Calabrese, M.J. Finney
and K.B. Stukey, “Durable, Fiber-Optic Sensor for
Gas Temperature Measurement in the Hot Section
of Turbine Engines”, Proceedings SPIE Vol. 2295,
pp. 156-163, Fly-by-Light, 1994.
[17] R.R. Dils, “High-temperature optical fiber
thermometer”, Journal of Applied Physics, 1983,
54(3), pp 1198-1201.
[18] K.A. Wickersheim, “Fiberoptic thermometry:
an overview”, Temperature: It’s Measurement and
Control in Science and Industry, Vol. 6, Part 2, pp.
711-714, 1992.
[19] T.G.R. Beynon, “Radiation thermometry
applied to the development and control of gas
turbine engines”, Temperature: It’s Measurement
and Control in Science and Industry, Vol. 5, Part 1,
pp. 471-477, 1982.
[20] M. Watari, T. Ueda and M. Yamamoto, “A
new two-colour pyrometer using optical fibers”,
Temperature: It’s Measurement and Control in
Science and Industry, Vol. 6, Part 2, pp. 751-755,
1992.
[21] T. Katsuyama and H. Matsumura, “Infrared
optical fibers”, IOP Publishing Ltd. , 1989.
[22] D.C. Amory and R.A. Hovan, “Improving
Gas Turbine Efficiency using Optical Pyrometry”,
Turbomachinery
International,
pp.
22-24,
January/February 2004.
[23]
P.R.N. Childs, “Practical temperature
measurement”, Butterworth-Heinemann, 2001.
[24] S. Clausen, “Local measurement of gas
temperature with an infrared fibre-optic probe”,
Measurement Science & Technology, 1996, 7(6),
pp 888-896.
[25] G.W. Tregay, P.R. Calabrese, P.L. Kaplin and
M.J. Finney, “Optical Fiber Sensor for
Temperature Measurement From 600 to 1900 ºC in
Gas Turbine Engines”, Proceedings SPIE Vol.
-8-
1589, pp. 38 – 47, Speciality Fiber Optic Systems
for Mobile Platforms, 1991.
[26] W.H. Atkinson and R.N. Guenard, “Turbine
pyrometry in aircraft engines”, IEE Electro
Conference, 1978, 33(3), pp 1-9.
[27] P.J. Kirby, “Some considerations relating to
aero engine pyrometry”, AGARD 67th Symposium
Propulsion and Energetics Panel on Advanced
Instrumentation for Aero Engine Components,
Philadelphia, US, May 19-23 1986.
[28] M. de Lucia, R. de Sabato, P. Nava and S.
Cioncolini, “Temperature measurements in a heavy
duty gas turbine using radiation thermometry
technique: error evaluation”, ASME 99-GT-311,
1999.
[29] S.L.F. Frank, “Surface temperature mapping
of gas turbine blading by means of high resolution
pyrometry”, International Symposium on Heat
Transfer in Gas Turbine Systems, 13-18 August
2000, Golden Dolphin Holiday Village Çeþme,
Turkey.
[30] R.W. Phillips and S.D. Tilstra, “Design of a
fiber optic temperature sensor for aerospace
applications”, Temperature: It’s Measurement and
Control in Science and Industry, Vol. 6, Part 2, pp.
721-724, 1992.
[34] J. Schwerman and J. Allen, “Special Topical
Review Temperature Measurement Techniques:
Full view infrared pyrometry”, GE Global
Research Technical Information Series, Report
number 2003GRC200, August 2003.
[35] J. Dixon, “Radiation Thermometry”, J. Phys.
E: Sci. Instrum. 21 (May 1988) pp. 425-436.
[36] H.L. Daneman, “Fiber-Optic Thermometers”,
Chapter 5 from Temperature Measurement, Bela
G.Liptak (editor in chief), 1993.
[37] B.E. Adams, “Optical fiber thermometry for
use at high temperatures”, Temperature: It’s
Measurement and Control in Science and Industry,
Vol. 6, Part 2, pp. 739-743.
[38] M. Saito and K. Kikuchi, “Infrared Optical
Fiber Sensors”, Optical Review, Vol. 4, No. 5
(1997), pp.527-538.
[39] Z. Houmin, W. Qiaoying and W. Zhe, “An
optical fiber two colour radiation thermometer
down to 400 ºC”, Temperature: It’s Measurement
and Control in Science and Industry, Vol. 6, Part 2,
pp. 735-738.
[31] O. Struß, “Transfer Radiation Thermometer
Covering the Temperature Range from -50 ºC to
1000 ºC”, Temperature: It’s Measurement and
Control in Science and Industry, Vol. 7, Part 2, pp.
565-570.
[32] V. Artiouchenko, V. Lobachev, M. Nikitin, T.
Sakharova, V. Sakharov and C. Wojciechowski,
“PIR-fiber sensing in 4-18 μm range for flexible IRimaging and process IR-spectroscopy”.
[33] V. Artiouchenko, G. Chekanova, I. Lartsev,
V. Lobachev and M. Nikitine, “New IR-detectors
pig-tailed with PIR-fibers”.
-9-