Characterising Mixing and Soot Production Using a Lagrangian Statistical Method

2020 ◽  
Author(s):  
Vasileios Kampanas ◽  
Maxwell Williams ◽  
Andrew Garmory
Keyword(s):  
Statistical Method ◽  
Mixture Fraction ◽  
Aircraft Engine ◽  
Processing Technique ◽  
Reacting Flows ◽  
Residence Times ◽  
Engine Model ◽  
Air Mixing ◽  
Annular Combustor ◽  
Annular Sector

Abstract An understanding of fuel-air mixing, along with the link between turbulent fluid flows and soot production is vital for the design of an efficient, low emissions gas turbine combustor. This paper uses a Lagrangian statistical method to investigate the time histories of mixing hence and soot development for massless parcels tracked within an LES calculation. This provides the advantage of investigating soot development using an inexpensive post-processing technique. The method comprises tracking massless parcels through the flow and recording the local temperature and composition at the parcel location, as well as the age of the parcel. This can be used to give statistical information about various aspects of mixing and soot production, such as distributions of mixture fraction or residence times. The history for each parcel can then be used in a postprocessing step to predict the soot development in time for that parcel path. This has been used to compare Large Eddy Simulations (LES) of reacting flows in both a laboratory aero-engine model combustor and a geometry representative of an annular sector from an aircraft engine combustor. It was found, that when normalized by a reference time scale based on combustor length and bulk velocity, the residence times for the annular sector were considerably shorter and mixture fraction distributions wider. This was due to a much higher chance of parcels being recirculated within the primary zone of the laboratory combustor. Further analysis of the annular combustor sector showed that very different mixing is found between the oxidation ports on the centre of the sector compared to those at the edge. The instantaneous mixing is seen to be less effective for those ports at the edge of the sector and this leads to higher soot levels in these regions.

scholarly journals Aircraft Engine On-Line Diagnostics Through Dual-Channel Sensor Measurements: Development of a Baseline System

2008 ◽  
Author(s):  
Takahisa Kobayashi ◽  
Donald L. Simon
Keyword(s):  
Fault Detection ◽  
Aircraft Engine ◽  
Fault Detection And Isolation ◽  
Channel Measurements ◽  
Sensor Fault ◽  
Engine Model ◽  
Dual Channel ◽  
Sensor Fault Detection ◽  
Baseline System ◽  
On Line

In this paper, a baseline system which utilizes dual-channel sensor measurements for aircraft engine on-line diagnostics is developed. This system is composed of a linear on-board engine model (LOBEM) and fault detection and isolation (FDI) logic. The LOBEM provides the analytical third channel against which the dual-channel measurements are compared. When the discrepancy among the triplex channels exceeds a tolerance level, the FDI logic determines the cause of the discrepancy. Through this approach, the baseline system achieves the following objectives: 1) anomaly detection, 2) component fault detection, and 3) sensor fault detection and isolation. The performance of the baseline system is evaluated in a simulation environment using faults in sensors and components.

A Hybrid Statistical Method for Accurate Prediction of Supplier Delivery Times of Aircraft Engine Parts

2015 ◽  
Author(s):  
Ashis Gopal Banerjee ◽  
Walter Yund ◽  
Dan Yang ◽  
Peter Koudal ◽  
John Carbone ◽  
...  
Keyword(s):  
Statistical Method ◽  
Aircraft Engine ◽  
Accurate Prediction ◽  
Distribution Model ◽  
Prediction Errors ◽  
Hybrid Form ◽  
Delivery Times ◽  
Multivariate Gamma Distribution ◽  
Transportation Times ◽  
Delivery Dates

Aircraft engine assembly operations require thousands of parts provided by several geographically distributed suppliers. A majority of the operation steps are sequential, necessitating the availability of all the parts at appropriate times for these steps to be completed successfully. Thus, being able to accurately predict the availabilities of parts based on supplier deliveries is critical to minimizing the delays in meeting the customer demands. However, such accurate prediction is challenging due to the large lead times of these parts, limited knowledge of supplier capacities and capabilities, macroeconomic trends affecting material procurement and transportation times, and unreliable delivery date estimates provided by the suppliers themselves. We address these challenges by developing a statistical method that learns a hybrid stepwise regression — generalized multivariate gamma distribution model from historical transactional data on closed part purchase orders and is able to infer part delivery dates sufficiently before the supplier-promised delivery dates for open purchase orders. The hybrid form of the model makes it robust to data quality and short-term temporal effects as well as biased toward overestimating rather than underestimating the part delivery dates. Test results on real-world purchase orders demonstrate effective performance with low prediction errors and constantly high ratios of true positive to false positive predictions.

Center Body Burner for Sequential Combustion: Superior Performance at Lower Emissions

2021 ◽  
Author(s):  
A. Ciani ◽  
J. P. Wood ◽  
M. Maurer ◽  
B. Bunkute ◽  
D. Pennell ◽  
...  
Keyword(s):  
Gas Turbines ◽  
Laser Doppler Anemometry ◽  
Fluid Dynamic ◽  
Mixture Fraction ◽  
Nox Reduction ◽  
Water Channel ◽  
Superior Performance ◽  
Fuel Flexibility ◽  
Air Mixing ◽  
Center Body

Abstract Modern gas turbines call for an ultra-high firing temperature and fuel flexibility while keeping emissions at very low levels. Sequential combustion has demonstrated its advantages toward such ambitious targets. A sequential combustion system, as deployed in the GT26 and GT36 engines, consists of two burners in series, the first one optimized to provide the optimum boundary condition for the second one, the sequential burner. This is the key component for the achievement of the required combustor performance dictated by F and H class engines, including versatile and robust operation with hydrogen-based fuels. This paper describes the key development considerations used to establish a new sequential burner surpassing state-of-the-art hardware in terms of emission reduction, fuel flexibility and load flexibility. A novel multi-point injector geometry was deployed based on combustion and fluid dynamic considerations to maximize fuel / air mixing quality at minimum pressure loss. Water channel experiments complemented by CFD describe the evolution of the fuel / air mixture fraction through the mixing section and combustion chamber to enable operation with major NOx reduction. Furthermore, Laser Doppler Anemometry and Laser Induced Fluorescence were used to best characterize the interaction between hot-air and fuel and the fuel / air mixing in the most critical regions of the system. To complete the overview of the key development steps, mechanical integrity and manufacturing considerations based on additive manufacturing are also presented. The outcome of 1D, CFD and fluid dynamic experimental findings were then validated through full-scale, full-pressure combustion tests. These demonstrate the novel Center Body Burner is enabling operation at lower emissions, both at part load and full load conditions. Furthermore, the validation of the burner was also extended to hydrogen-based fuels with a variety of hydrogen / natural gas blends.

scholarly journals Aircraft Engine On-Line Diagnostics Through Dual-Channel Sensor Measurements: Development of an Enhanced System

2008 ◽  
Author(s):  
Takahisa Kobayashi ◽  
Donald L. Simon
Keyword(s):  
Fault Detection ◽  
Diagnostic System ◽  
Aircraft Engine ◽  
Fault Detection And Isolation ◽  
Channel Measurements ◽  
Engine Model ◽  
Dual Channel ◽  
Sensor Fault Detection ◽  
Baseline System ◽  
On Line

In this paper, an enhanced on-line diagnostic system which utilizes dual-channel sensor measurements is developed for the aircraft engine application. The enhanced system is composed of a nonlinear on-board engine model (NOBEM), the hybrid Kalman filter (HKF) algorithm, and fault detection and isolation (FDI) logic. The NOBEM provides the analytical third channel against which the dual-channel measurements are compared. The NOBEM is further utilized as part of the HKF algorithm which estimates measured engine parameters. Engine parameters obtained from the dual-channel measurements, the NOBEM, and the HKF are compared against each other. When the discrepancy among the signals exceeds a tolerance level, the FDI logic determines the cause of discrepancy. Through this approach, the enhanced system achieves the following objectives: 1) anomaly detection, 2) component fault detection, and 3) sensor fault detection and isolation. The performance of the enhanced system is evaluated in a simulation environment using faults in sensors and components, and it is compared to an existing baseline system.

Thrust Reverser for a Separate Exhaust High Bypass Ratio Turbofan Engine and its Effect on Aircraft and Engine Performance

2011 ◽  
Author(s):  
Tashfeen Mahmood ◽  
Anthony Jackson ◽  
Vishal Sethi ◽  
Pericles Pilidis
Keyword(s):  
Engine Performance ◽  
Aircraft Engine ◽  
Performance Characteristics ◽  
System Level ◽  
Performance Models ◽  
Turbofan Engine ◽  
Engine Model ◽  
Rate Deceleration ◽  
Thrust Reverser ◽  
Bypass Ratio

This paper discusses thrust reversing techniques for a separate exhaust high bypass ratio turbofan engine and its effect on aircraft and engine performance. Cranfield University is developing suitable thrust reverser performance models. These thrust reverser performance models will subsequently be integrated within the TERA (Techno-economic Environmental Risk Analysis) architecture thereby allowing for more detailed and accurate representations of aircraft and engine performance during the landing phase of a typical civil aircraft mission. The turbofan engine chosen for this study was CUTS_TF (Cranfield University Twin Spool Turbofan) which is similar to the CFM56-5B4 engine and the information available in the public domain is used for the engine performance analysis along with the Gas Turbine Performance Software, ‘GasTurb 10’ [1]. The CUTEA (Cranfield University Twin Engine Aircraft) which is similar to the Airbus A320 is used alongside with the engine model for the thrust reverser performance calculations. The aim of this research paper is to investigate the effects on aircraft and engine performance characteristics due to the pivoting door type thrust reverser deployment. The paper will look into the overall engine performance characteristics and how the engine components get affected when the thrust reversers come into operation. This includes the changes into the operating point of fan, booster, HP compressor, HP turbine, LP turbine, bypass nozzle and core nozzle. Also, thrust reverser performance analyses were performed (at aircraft/engine system level) by varying the reverser exit area by ± 5% and its effect on aircraft deceleration rate, deceleration time and landing distances were observed.

scholarly journals Optimizing Aircraft Performance With Adaptive, Integrated Flight/Propulsion Control

1990 ◽  
Author(s):  
R. H. Smith ◽  
J. D. Chisholm ◽  
J. F. Stewart
Keyword(s):  
Fuel Consumption ◽  
Control Algorithm ◽  
Aircraft Engine ◽  
Inlet Temperature ◽  
Operating Characteristics ◽  
Engine Operation ◽  
Engine Model ◽  
Life Mode ◽  
Aircraft Performance ◽  
Propulsion Control

An adaptive, integrated flight/propulsion control algorithm called Performance Seeking Control (PSC) has been developed to optimize total aircraft performance during steady state engine operation. The multi-mode algorithm will minimize fuel consumption at cruise conditions; maximize excess thrust (thrust minus drag) during aircraft accelerations, climbs, and dashes; and extend engine life by reducing Fan Turbine Inlet Temperature (FTIT) when the extended life mode is engaged. On-board models of the inlet, engine, and nozzle are optimized to compute a set of control trims, which are then applied as increments to the nominal engine and inlet control schedules. The on-board engine model is continually updated to match the operating characteristics of the actual engine cycle through the use of a Kalman filter, which accounts for anomalous engine operation. The PSC algorithm will be flight demonstrated on an F-15 test aircraft under the direction of the NASA Ames/Dryden Flight Research Facility. This paper discusses the PSC design strategy, describes the control algorithm, and presents results from high fidelity, nonlinear aircraft/engine simulations. Simulation results indicate that thrust increases as high as 15% and specific fuel consumption reductions up to 3% are realizable by the PSC system.

Development of an Aeroderivative Gas Turbine Dry Low Emissions Combustion System

1994 ◽  
Vol 116 (3) ◽  
pp. 542-546 ◽  
Author(s):  
G. Leonard ◽  
J. Stegmaier
Keyword(s):  
Gas Turbine ◽  
Aircraft Engine ◽  
System Component ◽  
Test Results ◽  
Combustion System ◽  
Fuel Delivery ◽  
Component Test ◽  
Engine Combustion ◽  
Annular Combustor ◽  
New System

This paper gives the development status of GE’s new aeroderivative premixed combustion system. This system consists of a new fuel staged annular combustor, compressor rear frame, first-stage turbine nozzle, electronic staging controller, and fuel delivery system. Component test results along with a description of the combustion system are presented. This new system will reduce NOx emissions by 90 percent relative to the original aircraft engine combustion system while maintaining low emissions of CO and UHCs. Tests of a LM6000 gas turbine equipped with the new system are planned for early 1994.

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