High Pressure Optical Measurements of Temperature At Turbine Rotor Inlet Conditions

2021 ◽  
Author(s):  
Scott Egbert ◽  
Darrel Zeltner ◽  
Mohsen Rezasoltani ◽  
Dale Tree
Keyword(s):  
Temperature Measurement ◽  
Optical Measurement ◽  
Spectral Band ◽  
Optical Signal ◽  
Operating Conditions ◽  
Optical Measurements ◽  
Inlet Temperature ◽  
Gas Temperature ◽  
Band Ratio ◽  
Inlet Conditions

Abstract In gas turbine engines, measurement of the rotor inlet temperature remains particularly challenging because of harsh operating conditions and limited access. The Integrated Spectral Band Ratio (ISBR) method is a non-intrusive optical emission gas temperature measurement technique suitable for this application. Optical fibers made of sapphire were used to transmit the radiative signal from the post combustion zone to a Fourier Transform Infrared (FTIR) spectrometer. The ratio of spectral bands of H2O, nominally 100 cm-1 wide between 4600 and 6200 cm-1 were used to infer temperature. ISBR and thermocouple measurements were obtained during two temperature sweeps; one at high load and one at low load (pressures of 1.2 and 0.7 MPa, respectively). The average of three thermocouples 76 mm downstream of the ISBR measurements were on the order of 200 K lower than the ISBR temperatures, consistent with a radiative correction and the heat loss between the two measurements. The change in ISBR temperature (95 K) during the sweep was similar to the change in average thermocouple temperature (89 K). Repeatability of the optical measurement at a given operating condition was on the order of ± 15 K and the absolute uncertainty of a single ISBR temperature measurement was estimated to be ± 61 K. A linear correlation with an R-squared value of 0.97 was also found between raw optical signal and thermocouple measurements suggesting that once a calibrated measurement is obtained.

High Pressure Optical Measurements of Temperature at Turbine Rotor Inlet Conditions

2020 ◽  
Author(s):  
Scott C. Egbert ◽  
Darrel Zeltner ◽  
Mohsen Rezasoltani ◽  
Dale R. Tree
Keyword(s):  
Temperature Measurement ◽  
Optical Measurement ◽  
Spectral Band ◽  
Optical Signal ◽  
Operating Conditions ◽  
Optical Measurements ◽  
Inlet Temperature ◽  
Gas Temperature ◽  
Band Ratio ◽  
Inlet Conditions

Abstract The measurement of combustion product gas temperature is valuable for the development and control of many combustion systems. In gas turbine engines, measurement of the rotor inlet temperature remains particularly challenging because of harsh operating conditions and limited access. The Integrated Spectral Band Ratio (ISBR) method is a non-intrusive optical emission gas temperature measurement technique suitable for this application. Optical fibers made of sapphire were used to transmit the radiative signal from the post combustion zone to a Fourier Transform Infrared (FTIR) spectrometer without the need for probe cooling. The ratio of spectral bands of H2O, nominally 100 cm−1 wide between 4600 and 6200 cm−1 were used to infer temperature. ISBR and thermocouple measurements were obtained during two temperature sweeps; one at high load and one at low load (pressures of 1.2 and 0.7MPa, respectively). The average of three thermocouples 76 mm downstream of the ISBR measurements were consistently on the order of 200 K lower, consistent with a radiative correction and the heat loss between the two measurements. The change in ISBR temperature (95 K) during the sweep was similar to the change in average thermocouple temperature (89 K). Repeatability of the optical measurement at a given operating condition was on the order of ± 15 K and the absolute uncertainty of a single ISBR temperature measurement was estimated to be ± 61 K. A linear correlation with an R-squared value of 0.97 was also found between raw optical signal and thermocouple measurements suggesting that once a calibrated measurement is obtained, changes in gas temperature can be determined using a correlation of the raw signal to produce the temperature.

scholarly journals Temperature Measurement Using Infrared Spectral Band Emissions From H2O

2016 ◽  
Vol 138 (4) ◽  
Author(s):  
Daniel J. Ellis ◽  
Vladimir P. Solovjov ◽  
Dale R. Tree
Keyword(s):  
Water Vapor ◽  
Optical Measurement ◽  
Spectral Band ◽  
Combustion Products ◽  
Infrared Emission ◽  
Optical Measurements ◽  
Reactor Wall ◽  
Gas Temperature ◽  
Infrared Spectral ◽  
Gas Measurement

Currently, there is no satisfactory method for measuring the temperature of the gas phase of combustion products within a solid fuel flame. The industry standard, a suction pyrometer or aspirated thermocouple, is intrusive, spatially and temporally averaging, and difficult to use. In this work, a new method utilizing the spectral emission from water vapor is investigated through modeling and experimental measurements. The method employs the collection of infrared emission from water vapor over discrete wavelength bands and then uses the ratio of those emissions to infer temperature. This method was demonstrated in the products of a 150 kWth natural gas flame along a 0.75 m line of sight, averaged over 1 min. Results from this optical method were compared to those obtained using a suction pyrometer. Data were obtained at three fuel air equivalence ratios that produced products at three temperatures. The optical measurement produced gas temperatures approximately 3–4% higher than the suction pyrometer. The uncertainty of the optical measurements is dependent on the gas temperature being ±9% at 850 K and 4% or less above 1200 K. Broadband background emission assumed to be emitted from the reactor wall was also seen by the optical measurement and had to be removed before an accurate temperature could be measured. This complicated the gas measurement but also provides the means whereby both gas and solid emission can be measured simultaneously.

Mechanical Design and Testing of a 2.5 MW sCO2 Compressor Loop

2021 ◽  
Author(s):  
Stefan D. Cich ◽  
J. Jeffrey Moore ◽  
Chris Kulhanek ◽  
Meera Day Towler ◽  
Jason Mortzheim
Keyword(s):  
High Efficiency ◽  
Mechanical Design ◽  
Guide Vane ◽  
Operating Conditions ◽  
Inlet Guide Vane ◽  
Inlet Temperature ◽  
Design Changes ◽  
Wide Range ◽  
Inlet Conditions ◽  
Design And Testing

Abstract An enabling technology for a successful deployment of the sCO2 close-loop recompression Brayton cycle is the development of a compressor that can maintain high efficiency for a wide range of inlet conditions due to large variation in properties of CO2 operating near its dome. One solution is to develop an internal actuated variable Inlet Guide Vane (IGV) system that can maintain high efficiency in the main and re-compressor with varying inlet temperature. A compressor for this system has recently been manufactured and tested at various operating conditions to determine its compression efficiency. This compressor was developed with funding from the US DOE Apollo program and industry partners. This paper will focus on the design and testing of the main compressor operating near the CO2 dome. It will look at design challenges that went into some of the decisions for rotor and case construction and how that can affect the mechanical and aerodynamic performance of the compressor. This paper will also go into results from testing at the various operating conditions and how the change in density of CO2 affected rotordynamics and overall performance of the machine. Results will be compared to expected performance and how design changes were implanted to properly counter challenges during testing.

A Comparative Analysis of Turbine Rotor Inlet Temperature Models

2011 ◽  
Author(s):  
Cristhian Maravilla Herrera ◽  
Sergiy Yepifanov ◽  
Igor Loboda
Keyword(s):  
Gas Turbines ◽  
Thermal State ◽  
Turbine Rotor ◽  
Remaining Useful Life ◽  
Operating Conditions ◽  
Inlet Temperature ◽  
Gas Temperature ◽  
Thermal Boundary Conditions ◽  
Power Setting ◽  
Stress Estimation

Life usage algorithms constitute one of the principal components of gas turbine engines monitoring systems. These algorithms aim to determine the remaining useful life of gas turbines based on temperature and stress estimation in critical hot part elements. Knowing temperatures around these elements is therefore very important. This paper deals with blades and disks of a high pressure turbine (HPT). In order to monitor their thermal state, it is necessary to set thermal boundary conditions. The main parameter to determine is the total gas temperature in relative motion at the inlet of HPT blades Tw*. We propose to calculate this unmeasured temperature as a function of measured gas path variables using gas path thermodynamics. Five models with different thermodynamic relations to calculate the temperature Tw* are proposed and compared. All temperature models include some unmeasured parameters that are presented as polynomial functions of a measured power setting variable. A nonlinear thermodynamic model is used to calculate the unknown coefficients included in the polynomials and to validate the models considering the influence of engine deterioration and operating conditions. In the validation stage, the polynomial’s inadequacy and the errors caused by the measurement inaccuracy are analyzed. Finally, the gas temperature models are compared using the criterion of total accuracy and the best model is selected.

Numerical Study of Mist Film Cooling in Combustor at Operating Conditions

2009 ◽  
Author(s):  
Srinivasa Rao Para ◽  
Xianchang Li ◽  
Ganesh Subbuswamy
Keyword(s):  
Gas Turbine ◽  
Film Cooling ◽  
Numerical Study ◽  
Operating Conditions ◽  
Inlet Temperature ◽  
Gas Temperature ◽  
Cooling Effectiveness ◽  
Wall Functions ◽  
Film Cooling Effectiveness ◽  
Combustor Liner

To improve the gas turbine thermal performance, apart from using a high compression ratio, the turbine inlet temperature must be increased. Therefore, the gas temperature inside the combustion chamber needs to be maintained at a very high level. Hence, cooling of the combustor liner becomes critical. Among all the cooling techniques, film cooling has been successfully applied to cool the combustor liner. In film cooling, coolant air is introduced through discrete holes and forms a thin film between the hot gases and the inner surface of the liner, so that the inner wall can be protected from overheating. The film will be destroyed in the downstream flow because of mixing of hot and cold gases. The present work focuses on numerical study of film cooling under operating conditions, i.e., high temperature and pressure. The effect of coolant injection angles and blowing ratios on film cooling effectiveness is studied. A promising technology, cooling with mist injection, is studied under operating conditions. The effect of droplet size and mist concentration is also analyzed. The results of this study indicate that the film cooling effectiveness can increase ∼11% at gas turbine operating conditions with mist injection of 2% coolant air when droplets of 10μm and a blowing ratio of 1.0 are applied. The cooling performance can be further improved by higher mist concentration. The commercial CFD software, Fluent 6.3.26, is used in this study and the standard k-ε model with enhanced wall functions is adopted as the turbulence model.

scholarly journals Gas Turbine Combustion Efficiency

1985 ◽  
Author(s):  
Barry Schlein
Keyword(s):  
Unique Feature ◽  
Iterative Solution ◽  
Combustion Efficiency ◽  
Operating Conditions ◽  
Inlet Temperature ◽  
Gas Temperature ◽  
Fuel Flow ◽  
Flow Pressure ◽  
High Mach ◽  
Engine Type

A method of correlating combustor efficiency as a function of geometry and operating conditions is presented. A simple equation correlates all the data for a given engine type with a single parameter. The correlating parameter is a function of fuel flow, pressure, temperature and volume in a form similar to others in the literature. The unique feature of the correlating parameter is its use of internal gas temperature rather than the commonly used combustor inlet temperature. The result is an equation requiring an iterative solution since combustion efficiency is a part of the correlating parameter. With use of a computer this is easily handled. The correlation fits engine data over all flight conditions from high altitude, high Mach number to sea level idle. The correlation is compared to engine test data for several engines.

A Simple Method for the Prediction of Wall Temperatures in Gas Turbines

1978 ◽  
Author(s):  
D. Kretschmer ◽  
J. Odgers
Keyword(s):  
Film Cooling ◽  
Gas Turbines ◽  
Operating Conditions ◽  
Inlet Temperature ◽  
Gas Temperature ◽  
Empirical Formulas ◽  
Simple Method ◽  
Hot Gas ◽  
Manufacturing Tolerances ◽  
Factor Governing

The cited method predicts wall temperatures generally within an accuracy of ± 6 percent, The biggest single factor governing the wall temperature is shown to be the hot gas temperature. Other factors discussed are the effects of changes in inlet temperature, fuel types, the geometry of the film cooling devices and manufacturing tolerances. Empirical formulas are given for the prediction of effective temperatures within the various combustor zones. Some comparisons are made between predictions and measurements of wall temperatures over a range of operating conditions.

scholarly journals Characterization of Nonequilibrium Condensation of Supercritical Carbon Dioxide in a de Laval Nozzle

2017 ◽  
Vol 140 (4) ◽  
Author(s):  
Claudio Lettieri ◽  
Derek Paxson ◽  
Zoltan Spakovszky ◽  
Peter Bryanston-Cross
Keyword(s):  
Carbon Dioxide ◽  
Supercritical Carbon Dioxide ◽  
Laval Nozzle ◽  
Optical Measurements ◽  
Inlet Temperature ◽  
De Laval Nozzle ◽  
Inlet Conditions ◽  
Nonequilibrium Condensation ◽  
Supercritical Carbon

Carbon capture and storage could significantly reduce carbon dioxide (CO2) emissions. One of the major limitations of this technology is the energy penalty for the compression of CO2 to supercritical conditions. To reduce the power requirements, supercritical carbon dioxide compressors must operate near saturation where phase change effects are important. Nonequilibrium condensation can occur at the leading edge of the compressor, causing performance and stability issues. The characterization of the fluid at these conditions is vital to enable advanced compressor designs at enhanced efficiency levels but the analysis is challenging due to the lack of data on metastable fluid properties. In this paper, we assess the behavior and nucleation characteristics of high-pressure subcooled CO2 during the expansion in a de Laval nozzle. The assessment is conducted with numerical calculations and corroborated by experimental measurements. The Wilson line is determined via optical measurements in the range of 41–82 bar. The state of the metastable fluid is characterized through pressure and density measurements, with the latter obtained in a first-of-its-kind laser interferometry setup. The inlet conditions of the nozzle are moved close to the critical point to allow for reduced margins to condensation. The analysis suggests that direct extrapolation using the Span and Wagner equation of state (S–W EOS) model yields results within 2% of the experimental data. The results are applied to define inlet conditions for a supercritical carbon dioxide compressor. Full-scale compressor experiments demonstrate that the reduced inlet temperature can decrease the shaft power input by 16%.

Gas Temperature Measurement in the Hot Section of Turbine Engines

1995 ◽  
Author(s):  
George W. Tregay ◽  
Paul R. Calabrese ◽  
Mark J. Finney ◽  
Kevin B. Stukey
Keyword(s):  
Temperature Measurement ◽  
Optical Probe ◽  
Electric Utility ◽  
Optical Signal ◽  
Turbine Engines ◽  
Probe Design ◽  
Nasa Lewis Research ◽  
Gas Temperature ◽  
General Electric ◽  
Sensing Element

An optical sensor system extends gas temperature measurement capability in turbine engines beyond the present generation of sensor hardware for production engines. The sensing element incorporates a thermally emissive insert to generate an optical signal proportional to the gas temperature at the tip of the probe. The use of a sapphire lightguide allows operation above the melting point of nickel based alloys. Sensor development for aircraft turbines has included flight hardware for use on the Fiber Optic Control System Integration (FOCSI) Program sponsored by NASA Lewis Research Center. The optical probe harness measured exhaust gas temperatures in a General Electric F404 engine. Signals from four probes were optically combined at a single detector assembly to determine the average gas temperature. A comparison of optical and thermocouple temperature measurements was conducted during a preflight engine test. The durability of the probe design has been evaluated in an electric-utility operated gas turbine under the sponsorship of the Electric Power Research Institute. The temperature probe was installed between the first stage rotor and second stage nozzle on a General Electric MS 7001B turbine at Houston Lighting and Power Company. Two probes have been used in the field test and they have a combined total of 4660 hours of operation near 1600°F and 330 starts.

Wetness Measurement and Droplet Transport Analysis in Actual Steam Test on a Scaled Low Pressure Turbine

2020 ◽  
Author(s):  
Yasuhiro Sasao ◽  
Kiyoshi Segawa ◽  
Takeshi Kudo ◽  
Ryo Takata ◽  
Masaki Osako ◽  
...  
Keyword(s):  
Steam Turbine ◽  
Measurement Errors ◽  
Phase Distribution ◽  
Optical Measurement ◽  
Three Dimensional ◽  
Peak Position ◽  
Operating Conditions ◽  
Quantitative Prediction ◽  
Inlet Temperature ◽  
Circumferential Distribution

Abstract Understanding the phenomenon and quantitative prediction of wet loss, quantitative prediction of erosion are still challenges in ST development. The aim of the actual steam test reported in this paper was to verify the performance of a newly developed ST. Still a comprehensive understanding of the wetness phenomenon is also a significant issue. Therefore, in connection with the actual steam test, efforts were made to develop a method for analyzing the three-dimensional causes of wetness loss and erosion. As the first report on the wet phenomenon analysis performed in this actual steam test, this paper reports wet measurement results and analysis results. In the actual steam testing of a 0.33 scaled steam turbine, wetness measurements were carried out at the third stage (L-1) and the final stage (L-0), and its characteristic wetness distribution was analyzed using our original CFD-code MHPS-NT. This 0.33 scaled steam turbine consists of the final three stages (LP-end) and the inlet steam conditioning stage (total of four stages), and wetness distributions in the blade height-wise were measured using two different wetness probes under several operating conditions. Wetness distribution did not change linearly with changes in ST inlet temperature, but dynamic changes in peak position and shape were observed. From the ST inlet to the exhaust chamber, the generation of fine droplets, the capturing of droplets by the wall surfaces, and the behavior of water films and coarse droplets were comprehensively analyzed using a three-dimensional (3-D) unsteady Eulerian-Lagrangian coupling solver that takes into account non-equilibrium condensation. This CFD code (MHPS-NT) is an improved version of Original-NT developed by Tohoku University. By considering the relative position and structure of the wet probe and blade cascade in CFD, it was found that the wetness is formed remarkable circumferential distribution by the moisture separation of the upstream blade rows and end-walls. The circumferential distribution of wetness can be a factor that makes it difficult to grasp the liquid phase distribution inside the steam turbine as an error factor independent of the accuracy of the optical measurement device. Due to the effects of water droplet capturing, the LP-end outlet wetness at the design point may be underestimated by 21% relative. It is also reported that because the wetness has a distribution in the meridian direction, wetness measurements by the wet probe may contain measurement errors independent of the measurement accuracy.

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