Abstract: For the new ITER-like wall at JET, two new infrared diagnostics (KL9B, KL3B) have been installed. These diagnostics can operate between 3.5 and 5 μm and up to sampling frequencies of ∼20 kHz. KL9B and KL3B image the horizontal and vertical tiles of the divertor. The divertor tiles are tungsten coated carbon fiber composite except the central tile which is bulk tungsten and consists of lamella segments. The thermal emission between lamellae affects the surface temperature measurement and therefore KL9A has been upgraded to achieve a higher spatial resolution (by a factor of 2). A technical description of KL9A, KL9B, and KL3B and cross correlation with a near infrared camera and a two-color pyrometer is presented.

Abstract: Thermal barrier coatings are used to reduce the actual working temperature of the high pressure turbine blade metal surface and hence permit the engine to operate at higher more efficient temperatures. Sensor coatings are an adaptation of existing thermal barrier coatings to enhance their functionality, such that they not only protect engine components from the high temperature gas, but can also measure the material temperature accurately and determine the health of the coating e.g. ageing, erosion and corrosion. The sensing capability is introduced by embedding optically active materials into the thermal barrier coatings and by illuminating these coatings with excitation light phosphorescence can be observed. The phosphorescence carries temperature and structural information about the coating. Accurate temperature measurements in the engine hot section would eliminate some of the conservative margins which currently need to be imposed to permit safe operation. A 50K underestimation at high operating temperatures can lead to significant pre-mature failure of the protective coating and loss of integrity. Knowledge of the exact temperature could enable the adaptation of the most efficient coating strategies using the minimum amount of air. The integration of an on-line temperature detection system would enable the full potential of thermal barrier coatings to be realised due to improved accuracy in temperature measurement and early warning of degradation. This in turn will increase fuel efficiency and reduce CO2 emissions. Application: This paper describes the implementation of a sensor coating system on a Rolls-Royce jet engine. The system consists of three components: industrially manufactured robust coatings, advanced remote detection optics and improved control and readout software. The majority of coatings were based on yttria stabilized zirconia doped with Dy (dysprosium) and Eu (europium), although other coatings made of yttrium aluminium garnet were manufactured as well. Coatings were produced on a production line using atmospheric plasma spraying. Parallel tests at Didcot power station revealed survivability of specific coatings in excess of 4,500 effective operating hours. It is deduced that the capability of these coatings is in the range of normal maintenance schedules of industrial gas turbines of 24,000 hours or even longer. An advanced optical system was designed and manufactured permitting easy scanning of coated components and also the detection of phosphorescence on rotating turbine blades (13k RPM) at stand-off distances of up to 400mm. Successful temperature measurements were taken from the nozzle guide vanes (hot), the combustion chamber (noisy) and the rotating turbine blades (moving) and compared with thermocouple and pyrometer installations for validation purposes.Copyright © 2012 by ASME

Abstract: This paper focuses on the study of the relationships between brake disc surface temperatures and disc distortion for various high-energy stop-braking conditions. An original thermal metrology method combining an infrared camera and a fibre-optic two-colour pyrometer was used to record the spatial and temporal variation in disc surface temperature during braking. Disc distortion was investigated in situ by means of a high-frequency displacement sensor. In addition, an optical trigger kept track of disc revolutions and enabled the synchronization of the IR camera, two-colour pyrometer and displacement sensor measurements. This experimental set-up was successfully used to determine the surface temperature and investigate thermal localization and waviness distortion during braking. The results were correlated with each other in relation to the level of energy dissipation. It was shown that the highest temperature was reached in the hot spot regions at an early stage of stop-braking. By contrast, the greatest disc distortion appeared much later, during the last stage of stop-braking.

Abstract: A DARPA funded Multi-color Pyrometry (MCP) experiment was carried out on a government provided aircraft engine to study the nature of hot particulate bursts generated from the combustor at certain engine conditions. These bursts of hot particulates lead to intermittent high-voltage signal output from the line-of-sight (LOS) pyrometer which is ultimately detected and used by the onboard digital engine controller (DEC). The investigation used a high-speed MCP system designed to detect bursts and identify their properties. Results of the radiant temperature, multi-color temperature and apparent emissivity are presented. The results indicated that the apparent emissivity calculated during the signal burst was lower than that of the blade. The root cause for the signal burst was identified as soot particles generated as by-product of combustion under certain conditions. This conclusion was drawn based on both experimental and simulation results. Technical strategies to separate, reduce or remove the burst signal are proposed.Copyright © 2012 by ASME

Abstract: Kawasaki Heavy Industries, Ltd (KHI) have developed a new industrial gas turbine, L30A. The turbine section composed of two-stage high pressure turbine and three-stage low pressure turbine. In the development period, a commercial pyrometer system was employed to measure blade temperatures under real engine condition. The pyrometer was equipped with an updated detector module and could measure lower temperature compared to the conventional one. Thus it could be used to measure all stages of blades with one pyrometer. The validity of the result was demonstrated by comparing the result with data obtained with other conventional techniques. With the pyrometer system the temperature distribution on the blade surface was easily available and cooling capabilities of blades were evaluated without taking much time.This paper describes the detail of measurement and evaluation process.© 2012 ASME

Abstract: Epitaxy is a process strongly dependent on wafer temperature. Unfortunately, the performance of the pyrometers in charge of sensing wafer temperature deteriorate with the usage. This represents the major maintenance issue for epitaxy process engineers who have to frequently calibrate pyrometers emissivity coefficient. At the present state the change of the emissivity coefficient is heuristically based on fab tradition and process engineers experience. We present a statistical tool to map the relationship between change in the temperature readings and emissivity adjustments. The module has been tested on real industrial dataset.

Abstract: We describe a new method that improves upon temperature measurement by optical pyrometry. The main uncertainty in the traditional pyrometry technique is the surface emissivity, which is generally unknown and hard to measure. A common approach to deal with this problem is to measure the thermal emission at multiple wavelengths - an approach called multi-wavelength pyrometry. However, this technique can still result in a level of uncertainty in the surface temperature that is unsatisfactory for scientific applications, such as a measurement of equation of state of warm dense matter. In contrast to the conventional multi-wavelength technique, in the polarization pyrometry approach described herein, p- and s-polarization components of thermal radiation at multiple-angles are used to deduce the temperature. This paper describes the concept and the results of an initial proof-of-principle static experiment with an electrically heated tungsten ribbon. It was found that in the same experiment, the accuracy of the polarization pyrometry measurement was substantially greater than that achieved using conventional multi-wavelength pyrometry.

Abstract: By adapting existing thermal barrier coatings a sensor coating has been developed to enhance their functionality, such that they not only protect engine components from the high temperature gas, but can now also measure the material temperature accurately and the health of the coating eg ageing, erosion and corrosion The sensing capability is introduced by embedding optically active materials into the thermal barrier coating and by illuminating these coatings with excitation light phosphorescence can be observed The phosphorescence carries temperature and structural information about the coating Knowledge of the exact temperature could enable the design of advanced cooling strategies in the most efficient way using a minimum amount of air The integration of an on-line temperature detection system would enable the full potential of thermal barrier coatings to be realized due to improved accuracy in temperature measurement and early warning of degradation This in turn will increase fuel efficiency and reduce CO2 emissionsApplication: The work carried out included the successful implementation of a sensor coating system on a Rolls-Royce Viper engine The system consists of three components: industrially-manufactured robust coatings, advanced remote detection optics and improved control and readout software The majority of coatings were based on yttria stabilized zirconia doped with Dy, although other coatings made of yttrium aluminium garnet were manufactured as well Coatings were produced on a production line using atmospheric plasma spraying Parallel tests at Didcot power station revealed the durability of specific coatings in excess of 4,500 effective operating hours It is expected that the capability of these coatings is in the range of normal maintenance schedules of industrial gas turbines of 24,000hrs or even longer An optical energy transfer system was designed and developed permitting scanning of coated components and also the detection of phosphorescence on rotating turbine blades (13,000 RPM) at probe-to-target distances of up to 400mm The online measurement system demonstrated precision (around ±5K) comparable to commercial thermocouples and has shown calibration accuracy of ±4K Transient temperatures were tracked at maximum at 8Hz which is fast enough to follow a typical power generation gas turbine Repeatable measurements were successfully taken from the nozzle guide vanes (hot), the combustion chamber (noisy) and the rotating turbine blades (moving) and compared with thermocouple and pyrometer installationsCopyright © 2012 by ASME

Abstract: Temperature measurement in an extremely harsh environment, such as in a coal gasifier and gas turbine, presents significant challenges to any conventional temperature sensing technology, including thermocouples, IR camera, pyrometer, and blackbody radiation measuring methods. The commonly used fiber Bragg grating (FBG)-based temperature sensors have many advantages, making them very successful in structural health monitoring application. However, conventional FBGs have poor thermal stability and survivability when environmental temperature is beyond 500oC. A band-gap engineering method has been used to transform amorphous fiber material into tetrahedral dominated microstructures, and the mass density modulated grating structure has shown the same fundamental characteristics as conventional FBG but the tetrahedral dominated fiber material enables such grating structure more tolerable to extremely temperature without losing structure integrity. The developed tetrahedral fiber Bragg grating (TFBG) have been prototyped for coal gasification radial and axial distributed temperature measurements. The field validations have demonstrated these TFBG sensors can provide reliable temperature measurement under 1200oC harsh conditions.© (2012) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.

Abstract: In fusion devices like ITER, plasma facing components will be in metal, (Tungsten and Beryllium), with emissivity in the range of 0.1–0.4. Therefore, surface temperature monitoring by infrared system will become more challenging due to low emissivity and consequently non negligible reflected flux. The active pyrometry method proposed in this paper allows surface temperature measurements independently of reflected and parasitic fluxes. A local increase of the surface temperature (ΔT(t)~10 °C) introduced by a transient heating source (pulsed or modulated) results in an additional component of the flux collected by the detector. A filtering of the signal allows extracting a temporal flux proportional only to the variation of the emitted flux. The ratio of simultaneous measurements at two wavelengths allows solving the unknown emissivity (same as for classical bicolour pyrometry). In this paper, it is described how the active pyrometry method is adapted to the surface temperature measurements of metallic PFCs independently of the reflected fluxes. Experimental results for carbon and tungsten samples are reported. Finally, it is shown how, by using the active pyrometry, the overall 2D standard IR perturbed by a reflected flux is corrected to recover the full 2D surface temperature close to the real surface temperature.

Abstract: The CN violet system (B2Σ+ - X2Σ+) molecular emission spectrum is frequently observed in plasma sources containing hydrocarbons and nitrogen mixture. We have simulated the spectrum of (0,0) and (1,1) bands of this system for different rotational and vibrational temperatures. The influence of the noise to signal ratio has been studied, if the noise to signal ratio is about 10% we found an error of 6% at temperature 3000K and 10% at 6000K.

Abstract: Equations of state of metals are important issues in earth science and planetary science. A major limitation of them is the lack of experimental data for determining pressure-volume and temperature of shocked metal simultaneously. By measuring them in a single experiment, a major source of systematic error is eliminated in determining from which shock pressure release pressure originates. Hence, a non-contact fast optical method was developed and demonstrated to simultaneously measure a Hugoniot pressure-volume (PH-VH) point and interfacial temperature TR on the release of Hugoniot pressure (PR) for preheated metals up to 1000 K. Experimental details in our investigation are (i) a Ni–Cr resistance coil field placed around the metal specimen to generate a controllable and stable heating source, (ii) a fiber-optic probe with an optical lens coupling system and optical pyrometer with ns time resolution to carry out non-contact fast optical measurements for determining PH-VH and TR. The shock response of preh...

Abstract: The invention discloses a rapid heat-treatment temperature measuring and controlling system and a measuring and controlling method. The system comprises an infrared pyrometer, a standard K-shaped thermoelectric couple silicon wafer, a temperature signal processor, a thermoelectric couple thermodetector, a heating power regulator, an alternating current zero crossing detector, a timing counter, a controllable silicon control signal isolation amplifier, a controllable silicon heating source, a heating light set and a control computer. The connection relationships of the assemblies are shown as an attached drawing 1 and the whole system is uniformly coordinated by the control computer for controlling, wherein the heating power regulator is internally set in the program of the computer. The temperature measuring and controlling method comprises the steps of measuring and calibrating the temperature by using the standard thermoelectric couple, measuring the temperature by using the infrared pyrometer, controlling the adjustment of the heating power of light by using the timing counter, dividedly controlling the heating light, adjusting the distribution uniformity of the temperature andthe like. The invention can carry out self-adaptive PID adjustment on the temperature, has rapid adjustment and controlling reaction and can fully-automatically achieve the rapid temperature measuring and controlling functions.

Abstract: The temperature of post-detonation fireballs produced by advanced energetic formulations is commonly determined using optical methods such as pyrometry and spectral line fitting. These methods are noninvasive and provide an average temperature predominantly from the surface of the fireball. However, for many applications the ability to probe the internal temperature as well as temperature gradients within the fireball is highly desirable. One such method that has shown promise in providing this information is seeding micron to nano-sized temperature sensors into the fireball which can be collected post-detonation and analyzed to determine a temperature profile. In this work, disordered rare-earth-doped metal oxide nanoparticles were synthesized and subjected to various types of heat treatment, including furnace heating, T-Jump (fast pyroprobe), and explosive heating. The heat treatment leads to irreversible phase transitions which are monitored by optically active rare-earth dopants. Eu3+ in particularly is a well-known probe ion. Optical signatures are evaluated to monitor phase transitions (disorder-order) in the nanoparticles. For Y2O3:Eu, the peak position and peak width of the excitation spectra appear to be the most promising indicators for the temperature.

Abstract: This paper presents the monitoring and characterization of emissive properties of soot particles in heavy oil flames based on pyrometric imaging techniques. The soot temperature is derived from the relationship between the primary colors of flame images captured by a RGB camera. The emissivity of soot particles is then estimated by using the gray-level ratio of a primary color of the image to that of a blackbody source at the same temperature. The soot concentration is represented and estimated by KL factor, which is derived from the Hottel and Broughton's model once the emissivity is determined. The imaging system is calibrated using a blackbody furnace as a standard temperature source. The measurement accuracy is verified by applying the system to measure the true temperature of a tungsten lamp. The maximum relative error is about 0.9%. Experiments were conducted on a 9MW th industrial-scale combustion test facility to investigate the impact of the ratio of overfire air to total air, and the location of overfire air ports on the soot temperature, emissivity and concentration of a heavy oil flame.

Abstract: In this work, spectroscopic ellipsometry (SE) is demonstrated as a technique to calibrate growth temperature measurement devices (thermocouples and pyrometers) prior to real mercury cadmium telluride (HgCdTe) growth. A pyrometer is used to control the substrate temperature in molecular beam epitaxy (MBE) for the growth of HgCdTe-based material. It is known that a very narrow optimal growth temperature range exists for HgCdTe, typically ±5°C. A nonoptimal growth temperature will negatively impact on material quality by inducing growth defects, reducing composition uniformity, causing difficulty in controlling doping incorporation, promoting poor electronic properties, and having other adverse effects. Herein, we present a method for measuring and calibrating substrate temperature measurement equipment by using spectroscopic ellipsometry (SE) prior to real HgCdTe growth. This method is easy to implement, nondestructive, and reliable. The proposed method requires one substrate with a surface material with optical properties well known in the temperature range of interest, but not necessarily the same base material as the material to be grown. In the specific case of this work, we use epitaxial CdTe material on top of a Si substrate. This wafer was used to create a database of its optical properties as a function of temperature by using SE. From the collected optical parameters, a model is built and a fit is generated from the SE data collected. The temperature can then be determined by fitting the temperature-dependent SE measurements from this specific CdTe material. The angle offset and surface roughness parameters are also included in the model to account for changes in the average run-to-run angle variations and surface conditions over time. This work does not attempt to obtain an absolute temperature, but rather a reliable and repeatable relative temperature measurement.

Abstract: A new triple-wavelength spectral-ratio pyrometer that measures the true temperature of thermal radiation by minimizing the equivalent wavelength is described. An algorithm of the operation of the pyrometer and the results of its use in ferrous metallurgy are presented.

Abstract: In-flight particle measurements of the surface temperature and velocity are important for understanding of melting behavior of glass particles during in-flight melting by multi-phase AC arc plasma. However, the use of optical pyrometry for particle surface temperature has inevitable uncertainties due to non-thermal emissions signals from the plasma plume. This work presents spectroscopic measurements of the non-thermal signals which were found to be caused mainly by the plasma emissions scattered by the particles and the radiation emitted by vapor. After that, the accuracy of thermal radiation measurement was estimated and surface temperature of in-flight glass particle was corrected.

Abstract: Recording of a sequence of thermal-radiation spectra allows determination of a nonstationary temperature T(t) without using the data on the emissivity of an object. For a КЭФ-4.5 silicon single crystal heated with radiation from a continuous-wave Nd:YAG laser (λ = 1.064 μm), sequences of hundreds of emission spectra in wavelength ranges of λ = 350–760 nm and λ = 650–1000 nm were recorded at a signal storage time of a CCD array of τ = 15–35 ms and a frequency of recording spectra of f ≈ 30–66 Hz. The spectra were automatically processed, and the dependences of the crystal temperature on the time after the irradiation onset were obtained in the range T ≈ 1100–1450 K.

Abstract: Measurements of the temperature behavior in the zone of action of the laser-radiation on the molten metal have been performed using multichannel pyrometer. Measurements were carried out for test cutting of a 3-mm mild-steel plate with several values of cutting speed and pressure of assist gas (oxygen), using an 1800-watt Ytterbium fiber laser. It is shown that fluctuations of temperature are related to local melt's surface deformations due to unequal radiation absorption; thus the noise spectrum of temperature fluctuations reflects turbulent surface deformation caused by gas jet and capillary waves. The maximum density of turbulent energy dissipation e depends on cutting conditions: its value rises with increasing cutting velocity and oxygen pressure in a described range of parameters. The maximum of e is localized near depth of (1.2...1.5) mm along the cutting front. We can distinguish the specific radiation pulsation spectrum of laser cutting from other processes of radiation affection to the sample, including unwanted degrading of the quality of technological operations. The spectrum of capillary waves on the melt's surface is formed under the effect of assisted gas jet and has a function of ω −3 , ω is cycle frequency. The results of this investigation can be useful for the development of monitoring and quality-control systems for the laser-cutting process.

Abstract: The high temperature provided by a 12-phase AC arc plasma is beneficial to finish vitrification reaction in milliseconds. Another heating method called "hybrid plasma" combines multi-phase AC arc and oxygen burner are expected to improve glass quality and increase productivity with minimum energy consumption. In this study, recent works on the development of in-flight particle measurement in hybrid plasma system are presented. Two-colour pyrometry offers considerable advantages for measuring particle temperatures in flight. A high-speed camera equipped with a band-pass filter system was applied to measure the in-flight temperatures of glass particles. The intensity recorded by the camera was calibrated using a tungsten halogen lamp. This technique also allows evaluating the fluctuation of the average particle temperature within millisecond in plasma region.

Abstract: The invention relates to a method for improving the shearing accuracy of a flying shear on a hot-rolled thin plate production line. According to the technical scheme, the method comprises the following steps of: arranging a pyrometer (1) for detecting the temperature of band steel and a hot metal detector (2) in front of the flying shear (3); inputting a band steel temperature signal measured by the pyrometer into a control program of a hot metal detector signal; comparing the temperature signal with a threshold value; converting a real temperature signal into a hot metal detector Boolean signal; and when a pyrometer signal is greater than the threshold value, outputting a signal detected by an analog hot metal detector, namely outputting Boolean 1, and otherwise, outputting the Boolean 0. The invention has the advantages that: hot metal detectors and relative maintenance amount are reduced, so that multipurpose utilization of an instrument is realized, the accuracy and the stability of an output signal are ensured, the shearing accuracy of the flying shear is greatly improved, and the yield of a product is improved.