Project Objectives

The objective of the SEC project is to develop and demonstrate novel multidisciplinary technologies that enhance operability and maximize performance of engine components throughout the propulsion system operating range. The SEC project will combine novel flow control concepts, smart sensors and controls to allow fluid-dynamic and structural "morphing" or changing a components behavioral characteristic. Computational tools and associated modeling techniques are developed to reduce time, cost, and risk barriers It will apply this approach to seals and bearings, rotordynamics, airfoil and flow separation, combustors and aeroelasticity in turbomachinery.

The SEC project is primarily directed towards the NASA Code R Goal One: Revolutionize Aviation, Objective 1- Safety and Objective 2- Emissions; and Goal Three: Pioneer Technology Innovation, Objective 9 - Engineering Innovation.

The goal of this project is to develop and demonstrate technologies that will enable the development of engines for future subsonic aircraft to maximize performance with minimal environmental impact.

The principal aim of the SEC project is to seek out and develop the enabling technologies that will minimize all environmentally harmful engine emissions. The SEC Project provides technologies for NASA and other Federal Government Agency focused programs (such as the NASA UEET Program) and Industry development programs. The need to consider the impact of NOx and CO2 on the environment requires this program element to also consider methods for reducing the fuel burn of advanced aeropropulsion systems. To meet the future requirements of industry, NASA and Other Federal Government Agencies, this program specifically looks beyond the current focussed aeronautics programs to develop and demonstrate the benefits of smart operability of turbomachinery and engine systems; and to explore and demonstrate low fuel-burn, low-emissions concepts.

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Technical Summary

The SEC Project consists of several elements of research and development.

(a) Compressor Technologies

The first compressor effort is to develop and apply flow control techniques that control aerodynamic blockage, entropy production, circulation, and stability to enhance the performance and operability of compression systems for advanced aeropropulsion applications. The approach will be to apply the increasing base of flow control knowledge, techniques, and technology developed for various applications to the internal flow fields of single and multi-stage compressors. The potential payoffs for this effort include: higher component efficiency due to reduced loss production, reduced blade count due to higher blade-loading levels, increased operability, enhanced compression system stability, and reduced acquisition and operating costs.

The second compressor effort is to improve the operability of highly loaded turbomachinery when flutter is encountered by varying the aeroelastic behavior of the compressor blading. The approach will be to use physical and numerical experiments to better understand the aeroelastic behavior of turbomachinery, determine the sensitivity of flutter to the structural and flow parameters, and study flutter suppression alternatives.

The third compressor effort is to enhance the performance and operability of gas turbine engines by utilizing wave rotor technology in a topping cycle that increases engine overall pressure ratio and peak cycle temperatures. The objective of this effort is the demonstration of a viable wave rotor unit.

(b) Turbine Technologies

The first turbine effort will be to develop and demonstrate novel multidisciplinary technologies that enhance operability and maximize performance of engine components throughout the propulsion system operating envelope, accurate design and analysis tools are required. Under these tasks, research involves the development, assessment, and application of Computational Fluid Dynamics (CFD) tools and models for turbine aerothermodynamics design and analysis, and the acquisition and analysis of experimental measurements of flow and heat transfer in turbines. Significance of better-managed coolant flows is that the overall thermodynamic efficiency of the engine is improved, with resultant lower fuel burn. This same technology also favorably impacts design and development cycle time, and contributes to reduced cost.

The second turbine effort will be to study the feasibility of active and passive separation flow control for LPT airfoils and transition duct. This effort will involve experimental and numerical methods to study the feasibility of separation delay using selected flow control schemes in the LPT flow environment.

The third turbine effort is to obtain detailed flow measurements on a state-of-the-art turbine model, necessary for assessing advanced design features, as well as, improving fundamental understanding of the dominant flow phenomena in multistage axial turbines. These results will provide better modeling capabilities to the designer.

The fourth turbine effort will be a multistage Computation Flow simulation of a multi-stage low-pressure (LP) turbine to demonstrate and assess modeling adequacy to predict LP turbine performance lapse in low Reynolds Number.

(c) Combustor

The first combustor effort will be the development of ultra-low emission Lean Direct Injection (LDI) injectors using silicon-carbide laminates. The silicon carbide laminates will enable significantly better fuel injectors that have a higher temperature capability and capable of precision micro-machining. The silicon carbine base structure for the LDI injectors will also provide for the incorporation of Micro Electro-Mechanical Mechanisms (MEMS) for active control.

A second combustor effort is the continued development and validation of the National Combustor Code (NCC), especially in the areas of physicochemical and numerical modeling of advanced combustors.

The third combustor effort will be development of quantitative laser diagnostic techniques for the measurement of multi-species concentration and temperature in high pressure flames. This data is critical in understanding and modeling the combustion processes and implementation of them into codes such as the National Combustion Code.

(d) Structural Dynamics

The first structural dynamics effort is to reduce turbomachinery blade vibrations caused by fluid-structure interactions. The objective is to provide structural dynamic experimental data and analytical methods that can be used to reduce turbomachinery blade vibration problems caused by fluid-structure interactions. This research will produce a high fidelity three-dimensional computer simulation for flutter and forced response prediction but with short enough run time to be used early in the design cycle. Experimentation will be performed to develop methods to reduce vibration of rotating blades caused by fluid-structure interactions. The experiments will focus on a novel self-tuning impact damper that function inside a blade.

The second structural dynamics effort is to develop magnetic bearings for aerospace applications. The magnetic bearings effort is to demonstrate in a convincing manner that oil-free magnetic suspension technology is a viable alternative to conventional rolling element bearings in current production gas turbine engines. In this effort we will develop and demonstrate magnetic suspension components that can continuously operate within the gas turbine engine environment. Issues to be addressed include capacity, compactness, durability, efficiency, bandwidth, and noise.

(e) Mechanical Components

The first effort on acoustic seals is to exploit acoustic principles to develop seals that operate with zero- or no-leakage and with meaningful clearances to avoid shaft-to-seal contact - typical of current turbine seals.

The second effort is on non-contacting turbine seals, and to exploit hydrodynamic principles to develop seals that exhibit low leakage and operate without seal-to-shaft contact for long-life and excellent high-speed performance.

(f) Controls

The controls effort is to enable stable, ultra-low-emissions combustors through the use of active combustion control and related technologies. The effort will address the demonstration of active combustion instability suppression for a realistic, high-frequency combustion instability, as well as developing advanced effective control methods for active combustion instability suppression and integrated control methods which simultaneously optimize combustor emissions, operability, and stability

(g) Sensors

The effort on high temperature sensors consists of two tasks, one being the development and demonstration of a probe, which uses a black body multi-wavelength pyrometer system for measurement of high gas and surface temperatures. The second is the development and demonstration of passive acoustic tomography as a non-intrusive temperature sensor for control and condition monitoring in propulsion systems.

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Milestones

Milestone	Output	Outcome
SEC-1.1 Investigate active control of high-frequency instabilities in combustion flows (9/01).	Demonstrate the active suppression of thermo-acoustic driven pressure high-frequency instabilities in a combustor using modulated fuel injection with state-feedback based control laws.	The ability to suppress high-frequency thermo-acoustic driven pressure oscillations using modulated fuel injection will enable stable combustor operation at lean fuel/air mixture conditions, resulting in lower emissions.
SEC-1.2 Demonstrate concepts for reduction in gaseous, particulate, and aerosol emissions (09/02).	Demonstrate revolutionary fuel injector concepts that utilize advanced technology, including metals, ceramics, and MEMS technology in flame-tube tests, to achieve the 80% NOx reduction goal, and reduce particulate and aerosol emissions. (Note: This goal exceeds the UEET Programs goal of 70% NOx reduction)	The development of a revolutionary, controlled, durable, and “smart” low emissions fuel injection system will enable aircraft engine to operate more efficiently, be environmentally friendly, reduce operating costs, and increase operating safety margins.
SEC CMP.1  Demonstrate Compressor Operating Range Extension in multi-stage compressor (09/01)	Demonstrate multi-stage compressor operating range extension using tip injection.	Extending the operating range of multi-stage compressor using tip injection will allow for greater compressor operability.
SEC CMP.2  Demonstrate Scheduled Flow Control Strategy to Eliminate Compression System Variable Geometry (09/02)	Large-low speed flow field data and compressor performance data.	Demonstrate potential to eliminate compression system variable geometry by regulating IGV/stator circulation aerodynamic blockage levels using a scheduled flow control strategy.
SEC TRB.1  Develop Enhanced Coarse Grid Model for Turbine Blade Film Cooling (09/01)	Enhanced turbine blade film cooling model for analysis tools such as APNASDA and Glenn-HT Codes	Enhanced turbine blade film cooling model that accounts for the highly three-dimensional flow effects, that at the same time maintains computational efficiency.
SEC TRB.2  Demonstrate Plasma Glow Discharge Device for LPT Flow Control  (09/01)	Demonstrated operation of a plasma glow discharge device in relevant LPT flow environment	Demonstrate the operation of a plasma glow discharge device in relevant LPT flow environment
SEC CMB.1  Release NCC Version 2.0  (09/03)	Provide NCC Version 2.0 Code	Develop and validate NCC incorporating high-pressure spray combustion, detailed yet computationally efficient chemistry and an alternative flow solver “FLUX”.
SEC MD.1  Demonstrate High Temperature, High Load Capacity magnetic Bearing (07/02)	Demonstrated Magnetic Bearing suitable for Aerospace Applications	Demonstrated high temperature, high load capacity magnetic bearing will establish the feasibility for use of the magnetic bearing in aerospace applications.
SEC MD.2  Deliver Multi-stage Linearized Aeroelastic Analysis Code (09/04)	Multi-stage Linearized Aeroelastic Analysis Code and Users Manual	Provide a three-dimensional advanced aeroelastic analysis code for multi-stage system flutter and forced response analysis.
SEC MC.1  Fabricate Prototype Acoustic Seal (09/03)	Fabricated Prototype Acoustic Seal	Design and fabricate hardware for a prototype acoustic seal.
SEC MC.2  Complete Advanced Non-Contacting Seal Testing  (06/03)	Completed non-contacting seal performance testing (Leakage vs. T, P, Speed)	Complete Generation 2 non-contacting seal performance testing (Leakage vs. T, P, Speed)
SEC SEN.1  Demonstrate Passive Acoustic Tomography (09/01)	Demonstrated passive acoustic tomography in a burner rig	Demonstrates the feasibility of passive acoustic tomography to map temperatures inside a volume, for control and condition monitoring of propulsion systems.

 

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