scholarly journals Accelerated thermal profiling of gas turbine components using luminescent thermal history paints

2018 ◽  
Vol 2 ◽  
pp. S3KTGK ◽  
Author(s):  
Silvia Araguás Rodríguez ◽  
Tomáš Jelínek ◽  
Jan Michálek ◽  
Álvaro Yáñez González ◽  
Fiona Schulte ◽  
...  
Keyword(s):  
Thermal History ◽  
Gas Turbines ◽  
Structural Changes ◽  
Material Selection ◽  
Measurement Techniques ◽  
Maximum Temperature ◽  
Material Structure ◽  
Limited Information ◽  
Measurement Capability ◽  
Component Design

Abstract Environmental requirements to reduce CO2 emissions and the drive towards higher efficiencies have resulted in increased operating temperatures in gas turbines. Subsequently, Original Equipment Manufacturer (OEMs) require improved component design and material selection to withstand the harsher conditions. This demands rapid evaluation of new components and their surface temperature to accelerate their market entry. Accurate temperature information proves key in the design of more efficient, longer-lasting machinery and in monitoring thermal damage. A number of traditional temperature measurement techniques are available, but can incur a number of limitations. Online temperature measurements, such as pyrometry or phosphor thermography, often require optical access to the component during operation and are therefore not suitable for inaccessible components. Other options including thermocouples can only provide point measurements and cannot deliver profiles across the surface. Offline techniques store temperature information that can be measured and analysed following operation. Several of these, however, are of destructive nature, can affect local thermal gradients and only provide point measurements. This article discusses an innovative offline measurement technique: luminescent Thermal History Paints (THPs). THPs are comprised of ceramic pigments in a binder matrix that can be applied to any hot component as a thin coating. These pigments are doped with optically active ions, which will phosphoresce when excited with a light source. The coating material experiences irreversible structural changes depending on the temperature it is exposed to. Changes in the material structure are reflected in its phosphorescent properties, which are measured with standard optical instrumentation at any surface location. Since the changes are permanent, the temperature information is stored in the coating and can be extracted after operation. Following calibration, it is therefore possible to relate phosphorescent behaviour to the past maximum temperature experienced at each location. This is done with Sensor Coating Systems Ltd. (SCS)’s portable instrumentation, which can provide rapid, automated and objective measurements across a component surface. Unlike the more traditional thermal paints, THPs are non-toxic, and provide a continuous measurement capability across the range 150°C–900°C with significantly improved durability. This article describes the underlying principles behind this novel technology and the advantages it provides over existing state-of-the-art methods. The benefits will be demonstrated through measurements on nozzle guide vanes (NGVs), with the view to compare and validate them against thermocouple measurements. The results show that the THP extends the limited information from thermocouples to provide a more complete view of the thermal processes on the component.

Validation of Surface Temperature Measurements on a Combustor Liner Under Full-Load Conditions Using a Novel Thermal History Paint

2016 ◽  
Author(s):  
Robert Krewinkel ◽  
Jens Färber ◽  
Martin Lauer ◽  
Dirk Frank ◽  
Ulrich Orth ◽  
...  
Keyword(s):  
Gas Turbine ◽  
Thermal History ◽  
Measurement Techniques ◽  
Combustion Process ◽  
Lanthanide Ions ◽  
Maximum Temperature ◽  
Oxide Ceramic ◽  
Ambient Conditions ◽  
Hot Gas ◽  
Wide Range

The ever-increasing requirements on gas turbine efficiency, which are at least partially met by increasing firing temperatures, and the simultaneous demand for reduced emissions, necessitate much more accurate calculations of the combustion process and combustor wall temperatures. Thermocouples give locally very accurate measurements of these temperatures, but there is a practical limit to the amount of measurement points. Thermal paints are another established measurement technique, but are toxic and at the same time require dedicated, short-duration tests. Thermal History Paints (THPs) provide an innovative alternative to the aforementioned techniques, but so far only a limited number of tests has been conducted under real engine conditions. THPs are similar in their chemical and physical make-up to conventional thermographic phosphors which have been successfully used in gas turbine applications for on-line temperature detection before. A typical THP comprises of oxide ceramic pigments and a water based binder. The ceramic is synthesized to be amorphous and when heated it crystallizes, permanently changing the microstructure. The ceramic is doped with lanthanide ions to make it phosphorescent. The lanthanide ions act as atomic level sensors and as the structure of the material changes, so do the phosphorescent properties of the material. By measuring the phosphorescence the maximum temperature of exposure can be determined through calibration, enabling post operation measurements at ambient conditions. This paper describes a test in which THP was applied to an impingement-cooled front panel from a combustor of an industrial gas turbine. Since this component sees a wide range of temperatures, it is ideally suited for the testing of the measurement techniques under real engine conditions. The panel was instrumented with a thermocouple and thermal paint was applied to the cold side of the impingement plate. THP was applied to the hot-gas side of this plate for validation against the other measurement techniques and to evaluate its resilience against the reacting hot gas environment. The durability and temperature results of the three different measurement techniques are discussed. The results demonstrate the benefits of THPs as a new temperature profiling technique. It is shown that the THP exhibited greater durability compared to the conventional thermal paint. Furthermore, the new technology provided detailed measurements down to millimeters indicating local temperature variations and global variations over the complete component.

Thermal History Coatings: Part II — Measurement Capability up to 1500°C

2020 ◽  
Author(s):  
Marta Ferran-Marqués ◽  
Silvia Araguás-Rodríguez ◽  
Christopher Pilgrim ◽  
Kang Lee ◽  
Joël Larose ◽  
...  
Keyword(s):  
High Temperatures ◽  
Thermal History ◽  
Gas Turbines ◽  
Temperature Data ◽  
Metallic Alloys ◽  
Host Material ◽  
Maximum Temperature ◽  
Next Generation ◽  
Barrier Coatings ◽  
Optical Access

Abstract To improve the efficiency of gas turbines, the turbine inlet temperature needs to be increased. The highest temperature in the gas turbine cycle takes place at the exit of the combustion chamber and it is limited by the maximum temperature turbine blades, vanes and discs can withstand. A combination of advanced cooling designs and Thermal Barrier Coatings (TBCs) are used to achieve material surface temperatures of up to 1200°C. However, further temperature increases and materials that can withstand the harsh temperatures are required for next-generation engines. Research is underway to develop next-generation CMCs with 1480 °C temperature capability, but accurate data regarding the thermal load on the components must be well understood to ensure the component life and performance. However, temperature data is very difficult to accurately and reliably measure because the turbine rotates at high speed, the temperature rises very quickly with engine startup and the blades operate under harsh environments. At the operating temperature range of CMCs, typically platinum thermocouples are used, however, this material is incompatible with silicon carbide CMCs. Other temperature techniques such as infrared cameras and pyrometry need optical access and the results are affected by changes in emissivity that can take place during operation. Offline techniques, in which the peak temperature information is stored and read-out later, overcome the need for optical access during operation. However, the presently available techniques, such as thermal paint and thermal crystals cannot measure above ∼1400°C. Therefore, a new measurement technique is required to acquire temperature data at extreme temperatures. To meet this challenge, Sensor Coating Systems (SCS) is focused on the development of Thermal History Coatings (THC) that measure temperature profiles in the 900–1600 °C range. THC are oxide ceramics deposited via air plasma spraying process. This innovative temperature profiling technique uses optically active ions in a ceramic host material that start to phosphoresce when excited by light. After being exposed to high temperatures the host material irreversibly changes at the atomic level affecting the phosphorescence properties which are then related to temperature through calibration. This two-part paper describes the THC technology and demonstrates its capabilities for high-temperature applications. In this second part, the THC is implemented on rig components for a demonstration on two separate case studies for the first time. In one test, the THC was implemented on a burner rig assembly on metallic alloys instrumented with thermocouples, provided by Pratt & Whitney Canada. In another test, the THC was applied to environmental barrier coatings developed by NASA, as part of a ceramic-matrix-composite system and heat-treated up to 1500°C. The results indicate the THC could provide a unique capability for measuring high temperatures on current metallic alloys as well as next-generation materials.

Validation of Surface Temperature Measurements on a Combustor Liner Under Full-Load Conditions Using a Novel Thermal History Paint

2016 ◽  
Vol 139 (4) ◽  
Author(s):  
Robert Krewinkel ◽  
Jens Färber ◽  
Ulrich Orth ◽  
Dirk Frank ◽  
Martin Lauer ◽  
...  
Keyword(s):  
Gas Turbine ◽  
Thermal History ◽  
New Technology ◽  
Measurement Techniques ◽  
Combustion Process ◽  
Lanthanide Ions ◽  
Maximum Temperature ◽  
Oxide Ceramic ◽  
Ambient Conditions ◽  
Hot Gas

The ever-increasing requirements on gas turbine efficiency and the simultaneous demand for reduced emissions, necessitate much more accurate calculations of the combustion process and combustor wall temperatures. Thermal history paints (THPs) is an innovative alternative to the established measurement techniques, but so far only a limited number of tests have been conducted under real engine conditions. A typical THP comprises oxide ceramic pigments and a water-based binder. The ceramic is synthesized to be amorphous and when heated it crystallizes, permanently changing the microstructure. The ceramic is doped with lanthanide ions to make it phosphorescent and as the structure of the material changes, so do the phosphorescent properties of the material. By measuring the phosphorescence, the maximum temperature of exposure can be determined, enabling postoperation measurements at ambient conditions. This paper describes a test in which THP was applied to an impingement-cooled front panel from a combustor of an industrial gas turbine. The panel was instrumented with a thermocouple (TC), and thermal paint was applied to the cold side of the impingement plate. The THP was applied to the hot-gas side of this plate for validation against the other measurement techniques and to evaluate its resilience against the reacting hot gas environment. The durability and temperature results of the three different measurement techniques are discussed. It is shown that the THP exhibited greater durability compared to the conventional thermal paint. Furthermore, the new technology provided detailed measurements indicating local temperature variations and global variations over the complete component.

scholarly journals FT8-55 Mechanical Drive Aeroderivative Gas Turbine: Design of Power Turbine and Full-Load Test Results

1994 ◽  
Author(s):  
E. Aschenbruck ◽  
R. Blessing ◽  
L. Turanskyj
Keyword(s):  
Gas Turbine ◽  
Gas Turbines ◽  
Material Selection ◽  
Measurement Techniques ◽  
Load Test ◽  
Civil Aviation ◽  
Test Results ◽  
Full Load ◽  
Highly Efficient ◽  
Power Turbine

A new, highly efficient 25-MW aero-derivative gas turbine, model FT8-55, has been developed for mechanical drive applications as a member of the FT8 gas turbine family which also includes two generator drive gas turbines, models FT8-30 and FT8-36, with power turbine speeds of 3000 rpm and 3600 rpm, respectively. For the new mechanical drive version FT8-55, the power turbine can be operated up to 5775 rpm at maximum continuous speed. All power turbines are equipped with gas generators, model GG8-1, which are derived from the most popular aero-engine in civil aviation, the JT8D. The first part of this paper describes design features, rotor dynamics, and material selection for the three-stage power turbine PT8-55. Rotor design permits unrestricted operation in the speed range from 2500 rpm up to maximum continuous speed. The first FT8-55 gas turbine was subjected to mechanical and performance workshop tests at different speeds and power outputs up to full-load. The second part of the paper deals with the description of the test stand arrangement for testing complete gas turbine packages as well as measurement techniques and data evaluation. Power was absorbed by a two-stage pipeline compressor, equipped with magnetic bearings and dry gas seals, which was operated in a closed loop. Thermodynamic and mechanical test results at various speeds and loads provide evidence of a highly efficient and mechanically robust gas turbine for mechanical drive applications.

Thermal History Coatings: Part I — Influence of Atmospheric Plasma Spray Parameters on Performance

2020 ◽  
Author(s):  
Silvia Araguás-Rodríguez ◽  
Marta Ferran-Marqués ◽  
Christopher C. Pilgrim ◽  
Spyros Kamnis ◽  
Jörg P. Feist ◽  
...  
Keyword(s):  
Thermal History ◽  
Gas Turbines ◽  
Gas Flow ◽  
Measurement Techniques ◽  
Luminescent Properties ◽  
Atmospheric Plasma ◽  
Steady Increase ◽  
Spray Parameters ◽  
Calibration Data ◽  
Particle Exposure

Abstract Firing temperatures in gas turbines have seen a steady increase over the years to allow for higher engine efficiencies and a decrease in hazardous emission levels. Conversely, these harsh conditions severely challenge the component lifetime, requiring a trade-off during the design process. Thus, it is crucial to understand temperature distribution across the majority of a component surface (>80%) to verify the design and component durability. While a range of temperature measurement techniques are available, these are primarily focused on lower temperatures, exhibit low durability (thermal paints), require line of sight (pyrometers), are destructive (thermal crystals) and only provide point measurements (thermocouples, thermal crystals). To overcome this challenge, Sensor Coating Systems (SCS) have developed Thermal History Coatings (THCs) to measure temperature profiles in the 900–1600°C range. This new temperature profiling capability records the past maximum exposure temperature in such a way that it can be determined once the component has already cooled down. THCs are comprised of oxide ceramics deposited via Atmospheric Plasma Spraying (APS) to create a robust coating. APS deposition employs several variable parameters; spray settings such as gun power, gas flow or scan rate can affect the particle exposure and thus, the microstructure of the coating and its temperature sensing performance. This two-part paper covers the THCs principles and demonstrates their capabilities for high-temperature applications. This first part shows, for the first time, the influence of APS parameters on luminescent measurements due to changes in the material microstructure. Extensive calibration data was used to develop a new model to relate the APS spray parameters to the luminescent properties in the as-deposited condition and consequent performance as a temperature sensor. The powder composition and the power and gas flow used during deposition were found to be the most influential parameters. The model identified the optimum spray parameters and was used to demonstrate THCs can achieve measurements in excess of 1600°C.

Ceramic Stationary Gas Turbine Development Program: Sixth Annual Summary

1999 ◽  
Author(s):  
Jeffrey R. Price ◽  
Oscar Jimenez ◽  
Vijay Parthasarathy ◽  
Narendernath Miriyala
Keyword(s):  
Gas Turbine ◽  
Gas Turbines ◽  
Material Selection ◽  
Field Testing ◽  
Phase Iii ◽  
Engine Test ◽  
Component Design ◽  
Ceramic Components ◽  
Wall Ceramic ◽  
Engine Testing

The Ceramic Stationary Gas Turbine (CSGT) program is being performed under the sponsorship of the United States Department of Energy, Office of Industrial Technologies. The objective of the program is to improve the performance of stationary gas turbines in cogeneration through the selective replacement of cooled metallic hot section components with uncooled ceramic parts. This review summarizes the progress on Phase III of the program which involves field testing of the ceramic components at a cogeneration end user site and characterization of the ceramic components following the field test exposure. The Solar Centaur 50S engine, which operates a turbine rotor inlet temperature (TRIT) of 1010°C (1850°F), was selected for the developmental program. The program goals include an increase in the TRIT to 1121°C (2050 °F), accompanied by increases in thermal efficiency and output power. This will be accomplished by the incorporation of uncooled ceramic first stage blades and nozzles, and a “hot wall” ceramic combustor liner. The performance improvements are attributable to the increase in TRIT and the reduction in cooling air requirements for the ceramic parts. The “hot wall” ceramic liners also enable a reduction in gas turbine emissions of NOx and CO. The component design and material selection have been definitized for the ceramic blades, nozzles and combustor liners. Each of these ceramic component designs were successfully tested in short term engine tests in the Centaur 50S engine test cell facility at Solar. Based on the results of the engine testing of the ceramic components, minor redesigns of the ceramic/metallic attachments were conducted where necessary. Based on their performance in a 100 hour cyclic in-house engine test, the ceramic components are approved for field testing. To date, four field installations of the CSGT Centaur 50S engine totaling over 4000 hours of operation have been initiated under the program at an industrial cogeneration site. This paper discusses the component design and material selection, in house engine testing, field testing, and component characterization.

Reliable Temperature Measurement With Thermal History Paints: An Uncertainty Estimation Model

2019 ◽  
Author(s):  
David Peral ◽  
Daniel Castillo ◽  
Silvia Araguas-Rodriguez ◽  
Alvaro Yañez-Gonzalez ◽  
Christopher Pilgrim ◽  
...  
Keyword(s):  
Temperature Measurement ◽  
Thermal History ◽  
Gas Turbines ◽  
Operating Temperature ◽  
Uncertainty Estimation ◽  
Operating Conditions ◽  
Maximum Temperature ◽  
Estimation Model ◽  
Thermal Models ◽  
Uncertainty Model

Abstract The operating temperature of turbomachinery components are increasing the drive towards higher efficiency, lower fuel consumption and reduced emissions. Accurate thermal models are required to simulate the operating temperature of gas turbine components and hence predict service life or other qualities. These models require validation through measurement. Therefore, the quality of the models and prediction are dependent on the uncertainty of the measurements used to validate them. Currently available temperature measurement techniques have limitations in the harsh operating conditions inside gas turbines. Thermocouples are widely used, however, are practically very challenging to apply on rotating components and only provide point measurements. Furthermore, over 80% of the surface must be measured to validate complex thermal models. A new technique under development called thermal history paints (THP) and coatings (THC) overcomes some of these limitations. While the uncertainty estimation model described in this work is directly related to THP, the principles can be applied in general to thermographic phosphors. The paint comprises a proprietary phosphor powder and a water-based silicate binder. The paint is applied to the surface of the test component. When the component is operated the paint records the maximum temperature of exposure across the complete surface of the component. After operation, the paint is read-out using automated instrumentation. The measurements are related to temperature through calibration to deliver a high-resolution temperature profile. An uncertainty model has been developed and described for the first time. The model assesses the uncertainty sources related to the generation of the calibration data and the measurement of the component. It has been applied to determine the uncertainty of the THP in the temperature range 400–750 °C. The estimated uncertainty in this case was, for most samples, ±3–6 °C (67% confidence level). The maximum estimated uncertainty was ±6.3 °C or ±13 °C for 67% or 95% confidence levels respectively. This is believed to be well within the uncertainty of thermal models and the requirements for temperature measurements in harsh environments on gas turbines. These results combined with the fact that the THP can record the temperature at many locations demonstrates that it is a very useful tool for the validation of thermal models and lifing predictions. The uncertainty model was validated by measuring separate test samples and comparing the temperature measured from the THP with the thermocouple data from the heat treatment. The difference was within ±7 °C and the uncertainty bounds determined by the model.

scholarly journals Feasibility of a Helium Closed-Cycle Gas Turbine for UAV Propulsion

2020 ◽  
Vol 11 (1) ◽  
pp. 28
Author(s):  
Emmanuel O. Osigwe ◽  
Arnold Gad-Briggs ◽  
Theoklis Nikolaidis
Keyword(s):  
Gas Turbine ◽  
Gas Turbines ◽  
Pressure Ratio ◽  
Low Noise ◽  
Closed Cycle ◽  
Propulsion Systems ◽  
Component Design ◽  
Readiness Level ◽  
Aerial Vehicle ◽  
Turbine Design

When selecting a design for an unmanned aerial vehicle, the choice of the propulsion system is vital in terms of mission requirements, sustainability, usability, noise, controllability, reliability and technology readiness level (TRL). This study analyses the various propulsion systems used in unmanned aerial vehicles (UAVs), paying particular focus on the closed-cycle propulsion systems. The study also investigates the feasibility of using helium closed-cycle gas turbines for UAV propulsion, highlighting the merits and demerits of helium closed-cycle gas turbines. Some of the advantages mentioned include high payload, low noise and high altitude mission ability; while the major drawbacks include a heat sink, nuclear hazard radiation and the shield weight. A preliminary assessment of the cycle showed that a pressure ratio of 4, turbine entry temperature (TET) of 800 °C and mass flow of 50 kg/s could be used to achieve a lightweight helium closed-cycle gas turbine design for UAV mission considering component design constraints.

Some Effects of Size on the Performances of Small Gas Turbines

2003 ◽  
Author(s):  
C. Rodgers
Keyword(s):  
Gas Turbine ◽  
Gas Turbines ◽  
Engine Performance ◽  
Lessons Learned ◽  
Rapid Expansion ◽  
Cycle Performance ◽  
Frictional Drag ◽  
Component Design ◽  
Turbine Component ◽  
Performance Development

By the new millennia gas turbine technology standards the size of the first gas turbines of Von Ohain and Whittle would be considered small. Since those first pioneer achievements the sizes of gas turbines have diverged to unbelievable extremes. Large aircraft turbofans delivering the equivalent of 150 megawatts, and research micro engines designed for 20 watts. Microturbine generator sets rated from 2 to 200kW are penetrating the market to satisfy a rapid expansion use of electronic equipment. Tiny turbojets the size of a coca cola can are being flown in model aircraft applications. Shirt button sized gas turbines are now being researched intended to develop output powers below 0.5kW at rotational speeds in excess of 200 Krpm, where it is discussed that parasitic frictional drag and component heat transfer effects can significantly impact cycle performance. The demarcation zone between small and large gas turbines arbitrarily chosen in this treatise is rotational speeds of the order 100 Krpm, and above. This resurgence of impetus in the small gas turbine, beyond that witnessed some forty years ago for potential automobile applications, fostered this timely review of the small gas turbine, and a re-address of the question, what are the effects of size and clearances gaps on the performances of small gas turbines?. The possible resolution of this question lies in autopsy of the many small gas turbine component design constraints, aided by lessons learned in small engine performance development, which are the major topics of this paper.

A Two-Dimensional Conjugate Heat Transfer Model for Forced Air Cooling of an Electronic Device

1989 ◽  
Vol 111 (1) ◽  
pp. 41-45 ◽  
Author(s):  
A. Zebib ◽  
Y. K. Wo
Keyword(s):  
Heat Transfer ◽  
Conjugate Heat Transfer ◽  
Electronic Device ◽  
Transfer Problem ◽  
Maximum Temperature ◽  
Transfer Model ◽  
Air Cooling ◽  
Two Dimensional ◽  
Component Design ◽  
Forced Air

Thermal analysis of forced air cooling of an electronic component is modeled as a two-dimensional conjugate heat transfer problem. The velocity field in a constricted channel is first computed. Then, for a typical electronic module, the energy equation is solved with allowance for discontinuities in the thermal conductivity. Variation of the maximum temperature with the average air velocity is presented. The importance of our approach in evaluating possible benefits due to changes in component design and the limitations of the two-dimensional model are discussed.

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