A Conceptual Design Study for a New High Temperature Fast Response Cooled Total Pressure Probe

2008 ◽  
Vol 131 (2) ◽  
Author(s):  
Jean-François Brouckaert ◽  
Mehmet Mersinligil ◽  
Marco Pau
Keyword(s):  
High Temperature ◽  
Gas Turbines ◽  
Total Pressure ◽  
Fast Response ◽  
Pressure Probe ◽  
Piezoresistive Pressure Sensor ◽  
Industrial Gas Turbines ◽  
Aero Engines ◽  
Harsh Conditions

The present paper proposes a concept for a water-cooled high temperature unsteady total pressure probe intended for measurements in the hot sections of industrial gas turbines or aero-engines. This concept is based on the use of a conventional miniature piezoresistive pressure sensor, which is located at the probe tip to achieve a bandwidth of at least 40 kHz. Due to extremely harsh conditions and the intention to immerse the probe continuously into the hot gas stream, the probe and sensor must be heavily cooled. The short term objective of this design is to gain the capability of performing measurements at the temperature conditions typically found at high pressure turbine exit (1100–1400 K) and in the long term at combustor exit (2000 K or higher).

A Conceptual Design Study for a New High Temperature Fast Response Cooled Total Pressure Probe

2008 ◽  
Author(s):  
Jean-Franc¸ois Brouckaert ◽  
Mehmet Mersinligil ◽  
Marco Pau
Keyword(s):  
High Temperature ◽  
Gas Turbines ◽  
Total Pressure ◽  
Fast Response ◽  
Pressure Probe ◽  
Industrial Gas Turbines ◽  
Aero Engines ◽  
Harsh Conditions ◽  
Term Objective

The present paper proposes a concept for a water cooled high temperature unsteady total pressure probe, intended for measurements in the hot sections of industrial gas turbines or aero-engines. This concept is based on the use of a conventional miniature piezo-resistive pressure sensor, located at the probe tip to achieve a bandwidth of at least 40kHz. Due to extremely harsh conditions and the intention to immerse the probe continuously into the hot gas stream, the probe and sensor must be heavily cooled. The short term objective of this design is to gain the capability of performing measurements at the temperature conditions typically found at high pressure turbine exit (1100–1400K) and in the long term at combustor exit (2000K or higher).

A High Temperature High Bandwidth Fast Response Total Pressure Probe for Measurements in a Multistage Axial Compressor

2011 ◽  
Author(s):  
Mehmet Mersinligil ◽  
Jean-Franc¸ois Brouckaert ◽  
Nicolas Courtiade ◽  
Xavier Ottavy
Keyword(s):  
High Temperature ◽  
Total Pressure ◽  
Axial Compressor ◽  
Fast Response ◽  
Main Element ◽  
Absolute Pressure ◽  
Pressure Probe ◽  
Resonance Frequencies ◽  
High Bandwidth ◽  
Very High

Over the last decades, fast response aerodynamic probes have been recognized as a robust measurement technique to provide time-resolved flow field data in turbomachinery environments. Still, most of the existing probe designs are restricted to low temperature applications (< 120 °C) either because of sensor temperature range limitations or packaging issues. Measurements in turbomachines also require a small probe size often with a very high bandwidth which are conflictual constraints difficult to satisfy simultaneously. This contribution therefore presents the development of a novel miniature (O̸ 2.5 mm) high temperature single sensor total pressure probe, designed for operation up to 250 °C with a very high bandwidth of 250 kHz. The probe main element is a 1.7 mm diameter commercial piezoresistive transducer placed in a Pitot type arrangement with a flush mounted sensor to provide the highest bandwidth. The details of the probe design are presented as well as the probe calibrations in pressure and in temperature. The effects of using a thermal compensation module or a sense resistor to monitor the temperature drift are described in the context of measurement uncertainty. The probes were characterized in terms of aerodynamic characteristics versus flow angle and Mach number. Shock tube tests have shown a dynamic response of the probe with sensor resonance frequencies well over 300 kHz, with a flat frequency range up to 250 kHz. Two probe prototypes were manufactured and first used in the 3 1/2-stage high speed axial compressor CREATE of the LMFA at E´cole Centrale de Lyon in France. The probes were traversed at each inter blade row plane up to temperatures of 180 °C and absolute pressure of 3 bar. The probe was able to resolve the high blade passing frequencies (∼16 kHz) and several harmonics including rotor-stator interaction frequencies up to 200 kHz. Besides the average total pressure distributions from the radial traverses, phase-locked averages and random unsteadiness are presented. The probe spatial and temporal resolutions are discussed in the context of those results.

A High Temperature High Bandwidth Fast Response Total Pressure Probe for Measurements in a Multistage Axial Compressor

2012 ◽  
Vol 134 (6) ◽  
Author(s):  
Mehmet Mersinligil ◽  
Jean-François Brouckaert ◽  
Nicolas Courtiade ◽  
Xavier Ottavy
Keyword(s):  
High Temperature ◽  
Total Pressure ◽  
Axial Compressor ◽  
Fast Response ◽  
Main Element ◽  
Absolute Pressure ◽  
Pressure Probe ◽  
Resonance Frequencies ◽  
High Bandwidth ◽  
Very High

Over the last decades, fast response aerodynamic probes have been recognized as a robust measurement technique to provide time-resolved flow field data in turbomachinery environments. Still, most of the existing probe designs are restricted to low temperature applications (<120 °C) either because of sensor temperature range limitations or packaging issues. Measurements in turbomachines also require a small probe size often with a very high bandwidth which are conflicting constraints difficult to satisfy simultaneously. This contribution therefore presents the development of a novel miniature (∅ 2.5 mm ) high temperature single sensor total pressure probe, designed for operation up to 250 °C with a very high bandwidth of 250 kHz. The probe main element is a 1.7 mm diameter commercial piezoresistive transducer placed in a Pitot type arrangement with a flush mounted sensor to provide the highest bandwidth. The details of the probe design are presented as well as the probe calibrations in pressure and in temperature. The effects of using a thermal compensation module or a sense resistor to monitor the temperature drift are described in the context of measurement uncertainty. The probes were characterized in terms of aerodynamic characteristics versus flow angle and Mach number. Shock tube tests have shown a dynamic response of the probe with sensor resonance frequencies well over 300 kHz, with a flat frequency range up to 250 kHz. Two probe prototypes were manufactured and first used in the 3½-stage high speed axial compressor CREATE of the LMFA at École Centrale de Lyon in France. The probes were traversed at each interblade row plane up to temperatures of 180 °C and absolute pressure of 3 bars. The probe was able to resolve the high blade passing frequencies (∼16 kHz) and several harmonics including rotor-stator interaction frequencies up to 200 kHz. Besides the average total pressure distributions from the radial traverses, phase-locked averages and random unsteadiness are presented. The probe spatial and temporal resolutions are discussed in the context of those results.

High-temperature high-frequency turbine exit flow field measurements in a military engine with a cooled unsteady total pressure probe

2011 ◽  
Vol 225 (7) ◽  
pp. 954-963 ◽  
Author(s):  
M Mersinligil ◽  
J Desset ◽  
J F Brouckaert
Keyword(s):  
High Temperature ◽  
Total Pressure ◽  
Pressure Sensors ◽  
Field Measurements ◽  
Fast Response ◽  
Turbine Engines ◽  
Pressure Probe ◽  
Gas Turbine Engines ◽  
Time Resolved ◽  
High Bandwidth

The measurement of unsteady pressures within the hot components of gas turbine engines still remains a true challenge for test engineers. Several high-temperature pressure sensors have been developed, but so far, their applications are restricted to unsteady wall static pressure measurements. Because of the severe flow conditions such as turbine inlet temperatures of 1700 °C and pressures of 50 bar or more in the most advanced aero-engine designs, few (if any) experimental techniques exist to measure the time-resolved flow total pressure inside the gas path. This article describes the measurements performed at the turbine exit of a military engine with a cooled fast response total pressure probe. The probe concept is based on the use of a conventional miniature piezo-resistive pressure sensor, located in the probe tip to achieve a bandwidth of at least 40 kHz. Due to the extremely harsh conditions, the probe and sensor are heavily water cooled. The probe was designed to be continuously immersed into the hot gas stream to obtain time series of pressure with a high bandwidth and therefore statistically representative average fluctuations at the blade passing frequency (BPV). The experimental results obtained with a second-generation prototype are presented. The probe was immersed into the engine through the bypass duct between turbine exit and flame-holders of the afterburner of a Volvo RM12 engine, at exhaust temperatures above 900 °C. The probe was able to resolve the BPV (∼17 kHz) and several harmonics up to 100 kHz.

First Unsteady Pressure Measurements With a Fast Response Cooled Total Pressure Probe in High Temperature Gas Turbine Environments

2010 ◽  
Author(s):  
Mehmet Mersinligil ◽  
Jean-Franc¸ois Brouckaert ◽  
Julien Desset
Keyword(s):  
High Pressure ◽  
Pressure Sensor ◽  
Total Pressure ◽  
Fast Response ◽  
Design Stage ◽  
Absolute Pressure ◽  
Pressure Probe ◽  
Probe Design ◽  
Flame Tube ◽  
Blade Passing Frequency

This paper presents the first experimental engine and test rig results obtained from a fast response cooled total pressure probe. The first objective of the probe design was to favor continuous immersion of the probe into the engine to obtain time series of pressure with a high bandwidth and therefore statistically representative average fluctuations at the blade passing frequency. The probe is water cooled by a high pressure cooling system and uses a conventional piezo-resistive pressure sensor which yields therefore both time-averaged and time-resolved pressures. The initial design target was to gain the capability of performing measurements at the temperature conditions typically found at high pressure turbine exit (1100–1400K) with a bandwidth of at least 40kHz and in the long term at combustor exit (2000K or higher). The probe was first traversed at the turbine exit of a Rolls-Royce Viper turbojet engine, at exhaust temperatures around 750 °C and absolute pressure of 2.1bars. The probe was able to resolve the high blade passing frequency (≈23kHz) and several harmonics up to 100kHz. Besides the average total pressure distributions from the radial traverses, phase-locked averages and random unsteadiness are presented. The probe was also used in a virtual three-hole mode yielding unsteady yaw angle, static pressure and Mach number. The same probe was used for measurements in a Rolls-Royce intermediate pressure burner rig. Traverses were performed inside the flame tube of a kerosene burner at temperatures above 1600 °C. The probe successfully measured the total pressure distribution in the flame tube and typical frequencies of combustion instabilities were identified during rumble conditions. The cooling performance of the probe is compared to estimations at the design stage and found to be in good agreement. The frequency response of the probe is compared to cold shock tube results and a significant increase in the natural frequency of the line-cavity system formed by the conduction cooled screen in front of the miniature pressure sensor were observed.

Oxidation Behavior of LTA/YSZ Intermixed Layer Coating

2018 ◽  
pp. 107-130
Author(s):  
Pritee Purohit ◽  
Shashikant T. Vagge
Keyword(s):  
Gas Turbines ◽  
Operating Conditions ◽  
Inlet Temperature ◽  
Power Generators ◽  
Industrial Gas Turbines ◽  
The Mean ◽  
Aero Engines ◽  
Industrial Gas Turbine ◽  
Day By Day ◽  
Very High

This chapter describes how for power generators like gas turbines and aero engines, the economic and environmental challenges are increasing day by day for producing electricity more efficiently. The efficiency of power generators can be increased by changing its operating conditions like inlet temperature and procedure. Currently, the inlet temperature to the industrial gas turbine is reaching up to 1400°C. Also, in aero engines, the ring temperature reaches around 1550°C. Therefore, the coatings used in aero engine applications undergo short duration thermal cycles at very high temperature. The mean metal temperatures reach around 950°C and can increase up to 1100°C. But in industrial gas turbines, it varies from 800 to 950°C. Operating temperature of industrial gas turbines slowly reaches to maximum and ideally remains constant for thousands of hours, unlike aero engines.

scholarly journals Characterization of Periodic Incoming Wakes in a Low-Pressure Turbine Cascade Test Section by Means of a Fast-Response Single Sensor Virtual Three-Hole Probe

2019 ◽  
Vol 4 (3) ◽  
pp. 26
Author(s):  
Julien Clinckemaillie ◽  
Tony Arts
Keyword(s):  
Total Pressure ◽  
High Speed ◽  
Control Volume ◽  
Low Pressure ◽  
Fast Response ◽  
Pressure Probe ◽  
Flow Angle ◽  
Low Pressure Turbine ◽  
Wide Range ◽  
Good Agreement

This paper aims at evaluating the characteristics of the wakes periodically shed by the rotating bars of a spoked-wheel type wake generator installed upstream of a high-speed low Reynolds linear low-pressure turbine blade cascade. Due to the very high bar passing frequency obtained with the rotating wake generator (fbar = 2.4−5.6 kHz), a fast-response pressure probe equipped with a single 350 mbar absolute Kulite sensor has been used. In order to measure the inlet flow angle fluctuations, an angular aerodynamic calibration of the probe allowed the use of the virtual three-hole mode; additionally, yielding yaw corrected periodic total pressure, static pressure and Mach number fluctuations. The results are presented for four bar passing frequencies (fbar = 2.4/3.2/4.6/5.6 kHz), each tested at three isentropic inlet Mach numbers M1,is = 0.26/0.34/0.41 and for Reynolds numbers varying between Re1,is = 40,000 and 58,000, thus covering a wide range of engine representative flow coefficients (ϕ = 0.44−1.60). The measured wake characteristics show fairly good agreement with the theory of fixed cylinders in a cross-flow and the evaluated total pressure losses and flow angle variations generated by the rotating bars show fairly good agreement with theoretical results obtained from a control volume analysis.

Bond coating issues in thermal barrier coatings for industrial gas turbines

2005 ◽  
Vol 219 (2) ◽  
pp. 101-107 ◽  
Author(s):  
I. G. Wright ◽  
B. A. Pint
Keyword(s):  
High Temperature ◽  
Oxide Layer ◽  
Thermal Barrier Coatings ◽  
Gas Turbines ◽  
Metallic Surface ◽  
Thermal Barrier ◽  
Protective Oxide ◽  
Barrier Coatings ◽  
Bond Coating ◽  
Industrial Gas Turbines

Thermal barrier coatings are intended to work in conjunction with internal cooling schemes to reduce the metal temperature of critical hot gas path components in gas turbine engines. The thermal resistance is typically provided by a 100-250 μm thick layer of ceramic (most usually zirconia stabilized with an addition of 7–8 wt% of yttria), and this is deposited on to an approximately 50 μ thick, metallic bond coating that is intended to anchor the ceramic to the metallic surface, to provide some degree of mechanical compliance, and to act as a reservoir of protective scale-forming elements (Al) to protect the underlying superalloy from high-temperature corrosion. A feature of importance to the durability of thermal barrier coatings is the early establishment of a continuous, protective oxide layer (preferably α-alumina) at the bond coating—ceramic interface. Because zirconia is permeable to oxygen, this oxide layer continues to grow during service. Some superalloys are inherently resistant to high-temperature oxidation, so a separate bond coating may not be needed in those cases. Thermal barrier coatings have been in service in aeroengines for a number of years, and the use of this technology for increasing the durability and/or efficiency of industrial gas turbines is currently of significant interest. The data presented were taken from an investigation of routes to optimize bond coating performance, and the focus of the paper is on the influences of reactive elements and Pt on the oxidation behaviour of NiAl-based alloys determined in studies using cast versions of bond coating compositions.

Development and Testing of Harsh Environment, Wireless Sensor Systems for Industrial Gas Turbines

2009 ◽  
Author(s):  
David Mitchell ◽  
Anand Kulkarni ◽  
Alex Lostetter ◽  
Marcelo Schupbach ◽  
John Fraley ◽  
...  
Keyword(s):  
High Temperature ◽  
Gas Turbine ◽  
Gas Turbines ◽  
Turbine Blades ◽  
Operating Conditions ◽  
Condition Based Maintenance ◽  
Harsh Environment ◽  
Sensor Systems ◽  
Wireless Telemetry ◽  
Industrial Gas Turbines

The potential for savings provided to worldwide operators of industrial gas turbines, by transitioning from the current standard of interval-based maintenance to condition-based maintenance may be in the hundreds of millions of dollars. In addition, the operational flexibility that may be obtained by knowing the historical and current condition of life-limiting components will enable more efficient use of industrial gas turbine resources, with less risk of unplanned outages as a result of off-parameter operations. To date, it has been impossible to apply true condition-based maintenance to industrial gas turbines because the extremely harsh operating conditions in the heart of a gas turbine preclude using the necessary advanced sensor systems to monitor the machine’s condition continuously. Siemens, Rove Technical Services, and Arkansas Power Electronics International are working together to develop a potentially industry-changing technology to build smart, self-aware engine components that incorporate embedded, harsh-environment-capable sensors and high temperature capable wireless telemetry systems for continuously monitoring component condition in the hot gas path turbine sections. The approach involves embedding sensors on complex shapes, such as turbine blades, embedding wireless telemetry systems in regions with temperatures that preclude the use of conventional silicon-based electronics, and successfully transmitting the sensor information from an environment very hostile to wireless signals. The results presented will include those from advanced, harsh environment sensor and wireless telemetry component development activities. In addition, results from laboratory and high temperature rig and spin testing will be discussed.

Test Evolution and Oil-Free Engine Experience of a High Temperature Foil Air Bearing Coating

2006 ◽  
Author(s):  
Daniel Lubell ◽  
Christopher DellaCorte ◽  
Malcolm Stanford
Keyword(s):  
High Temperature ◽  
Gas Turbines ◽  
Solid Lubricants ◽  
Deposition Process ◽  
Air Bearing ◽  
Free Gas ◽  
Foil Bearings ◽  
Start Up ◽  
High Temperature Operation

During the start-up and shut-down of a turbomachine supported on compliant foil bearings, before the bearings have full development of the hydrodynamic gas film, sliding occurs between the rotor and the bearing foils. Traditional solid lubricants (e.g., graphite, Teflon®) readily solve this problem at low temperature. High temperature operation, however, has been a key obstacle. Without a suitable high temperature coating, foil air bearing use is limited to about 300°C (570°F). In oil-free gas turbines, a hot section bearing presents a very aggressive environment for these coatings. A NASA developed coating, PS304, represents one tribological approach to this challenge. In this paper, the use of PS304 as a rotor coating operating against a hot foil gas bearing is reviewed and discussed. During the course of several long term, high cycle, engine tests, which included two coating related failures, the PS304 technology evolved and improved. For instance, a post deposition thermal treatment to improve dimensional stability, and improvements to the deposition process to enhance strength resulted from the engine evaluations. Largely because of this work, the bearing/coating combination has been successfully demonstrated at over 500°C (930°F) in an oil-free gas turbine for over 2500 hours and 2900 start-stop cycles without damage or loss of performance when properly applied. Ongoing testing at Glenn Research Center as part of a long term program is over 3500 hours and 150 cycles.

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