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Wozniak, Jason G.Nonlinear six degree of freedom simulation of a twin jet engine transport aircraft
Master of Science (MS), Ohio University, 1997, Electrical Engineering & Computer Science (Engineering and Technology)

Due to stringent requirements placed on current autoland systems for commercial aircraft, simulation has become an essential tool for the development and certification of autoland systems. This thesis presents a simulation designed to support autoland control system design for twin jet engine aircraft. The simulation runs in the SIMULINK graphical simulation environment in MATLAB. The SIMULINK environment enables the designer to implement sensor models and control system designs in block diagram form. This allows for the straightforward modification of feedback paths, gains, and functional blocks. The designer has access to aircraft states, actuator states, and environmental parameters for use in the development and testing of a control system or sensor design.

The simulation presented in this thesis was verified against an existing twin jet engine aircraft simulation maintained by the National Aeronautics and Space Administration (NASA). The test condition selected for the verification was an autoland scenario under high wind conditions that stimulated the aircraft dynamics. The guidance during the test condition was provided by an autoland control system simulation based on the instrument landing system (ILS). The NASA simulation was run under the test condition and the commanded control surface deflections and states were recorded. The simulation presented in this thesis was then run open-loop from the same initial state using the commanded control surface deflections recorded from the NASA simulation.

A comparison of the state histories of the two simulations run under the test scenario demonstrates that the simulation presented in this thesis is consistent with the NASA simulation. However, since these are complex nonlinear simulations, there may be scenarios where the simulations perform differently.

The simulation presented in this thesis is a useful tool for the design of autoland control systems or sensors for twin jet engine transport aircraft. The SIMULINK environment enables a designer to easily implement and modify a control system or sensor model. The designer may then evaluate the design by using the analysis tools available in MATLAB.

Committee:

Douglas Lawrence (Advisor)

Keywords:

Twin Jet Engine Transport Aircraft; Autoland Systems; SIMULINK; MATLAB

Gallaher, Shawn M.A methodology for determining relationships between jet engine disk part geometry and feature dimensions
Master of Science (MS), Ohio University, 2002, Industrial and Manufacturing Systems Engineering (Engineering)
A methodology for determining relationships between jet engine disk part geometry and feature dimensions.

Committee:

Dale Masel (Advisor)

Subjects:

Engineering, Industrial

Keywords:

Jet Engine Disk; Part Geometry; Feature Dimensions

Zhao, WenyuA Probabilistic Approach for Prognostics of Complex Rotary Machinery Systems
PhD, University of Cincinnati, 2015, Engineering and Applied Science: Mechanical Engineering
The growing demand for asset reliability and operation optimization has motivated the development of Prognostics and Health Management (PHM) methodologies and techniques, which facilitates data analytics and enables diagnosis and prognosis of machinery asset. Data-driven PHM approaches mine available data to derive condition indicators (CI) and subsequently health indicators (HI), detect faults as data anomalies, identify faults based on data classification, and predict faults based on trends and trajectories in data. Machine learning and artificial intelligence aid such data science by providing techniques that define clustering models, generate classifiers and forecast future states, as well as define thresholds and boundaries that aid decision-making outcomes. Model-based PHM approaches establish physical models that are derived from first-principal knowledge about the failure mechanism of interest, and simulate fault signatures with high fidelity computation based on the model. There is a growing trend to merge the complementary prognostics methodologies, motivated by the rapid development of big data infrastructure. The challenges associated with learning from large amount of data with high dimension involve comprehending the interdependencies between data variables and the complex physical systems where data is collected from, as well as managing the uncertainty that is underlying with the data due to modeling uncertainty and measurement noise. In this dissertation, a Bayesian theory based modeling and reasoning approach is developed, for learning variable dependency in the form of conditional probability. Two case studies are analyzed and discussed: one addresses the issue of learning the dependency between system operating regime and its performance outcome in a data-driven environment; the other focuses on coupling physical model and sensory measurement with an adaptive filtering approach, which is capable of representing a non-linear system over discrete time slices, sequentially filtering state estimation and predicting remaining useful life of the system. Both case studies are validated with data sets provided by industry partners, and are benchmarked with previously developed and recognized techniques. Finally, conclusions of this research are discussed and prospect research direction is proposed as future work for interested researchers.

Committee:

Jay Lee, Ph.D. (Committee Chair); Raj Bhatnagar, Ph.D. (Committee Member); Mark Schulz, Ph.D. (Committee Member); David Thompson, Ph.D. (Committee Member)

Subjects:

Mechanics

Keywords:

Prognostics;PHM;Bayesian Network;Wind Turbine;Jet Engine;Prediction

Benyo, Theresa L.Analytical and Computational Investigations of a Magnetohydrodynamic (MHD) Energy-Bypass System for Supersonic Turbojet Engines to Enable Hypersonic Flight
PHD, Kent State University, 2013, College of Arts and Sciences / Department of Physics
Historically, the National Aeronautics and Space Administration (NASA) has used rocket-powered vehicles as launch vehicles for access to space. A familiar example is the Space Shuttle launch system. These vehicles carry both fuel and oxidizer onboard. If an external oxidizer (such as the Earth's atmosphere) is utilized, the need to carry an onboard oxidizer is eliminated, and future launch vehicles could carry a larger payload into orbit at a fraction of the total fuel expenditure. For this reason, NASA is currently researching the use of air-breathing engines to power the first stage of two-stage-to-orbit hypersonic launch systems. Removing the need to carry an onboard oxidizer leads also to reductions in total vehicle weight at liftoff. This in turn reduces the total mass of propellant required, and thus decreases the cost of carrying a specific payload into orbit or beyond. However, achieving hypersonic flight with air-breathing jet engines has several technical challenges. These challenges, such as the mode transition from supersonic to hypersonic engine operation, are under study in NASA's Fundamental Aeronautics Program. One propulsion concept that is being explored is a magnetohydrodynamic (MHD) energy- bypass generator coupled with an off-the-shelf turbojet/turbofan. It is anticipated that this engine will be capable of operation from takeoff to Mach 7 in a single flowpath without mode transition. The MHD energy bypass consists of an MHD generator placed directly upstream of the engine, and converts a portion of the enthalpy of the inlet flow through the engine into electrical current. This reduction in flow enthalpy corresponds to a reduced Mach number at the turbojet inlet so that the engine stays within its design constraints. Furthermore, the generated electrical current may then be used to power aircraft systems or an MHD accelerator positioned downstream of the turbojet. The MHD accelerator operates in reverse of the MHD generator, re-accelerating the exhaust flow from the engine by converting electrical current back into flow enthalpy to increase thrust. Though there has been considerable research into the use of MHD generators to produce electricity for industrial power plants, interest in the technology for flight-weight aerospace applications has developed only recently. In this research, electromagnetic fields coupled with weakly ionzed gases to slow hypersonic airflow were investigated within the confines of an MHD energy-bypass system with the goal of showing that it is possible for an air-breathing engine to transition from takeoff to Mach 7 without carrying a rocket propulsion system along with it. The MHD energy-bypass system was modeled for use on a supersonic turbojet engine. The model included all components envisioned for an MHD energy-bypass system; two preionizers, an MHD generator, and an MHD accelerator. A thermodynamic cycle analysis of the hypothesized MHD energy-bypass system on an existing supersonic turbojet engine was completed. In addition, a detailed thermodynamic, plasmadynamic, and electromagnetic analysis was combined to offer a single, comprehensive model to describe more fully the proper plasma flows and magnetic fields required for successful operation of the MHD energy bypass system. The unique contribution of this research involved modeling the current density, temperature, velocity, pressure, electric field, Hall parameter, and electrical power throughout an annular MHD generator and an annular MHD accelerator taking into account an external magnetic field within a moving flow field, collisions of electrons with neutral particles in an ionized flow field, and collisions of ions with neutral particles in an ionized flow field (ion slip). In previous research, the ion slip term has not been considered. Detailed thermodynamic cycle analysis of an annular MHD generator and an annular MHD accelerator revealed that including the ion slip term to the generalized Ohm's Law decreased the needed magnetic fields and conductivity levels as compared to previous research. For the MHD generator, the needed magnetic fields decreased from 5 T to 3 T for all flight speeds studied (Mach 7, 5, and 3). The conductivity levels required for the ionized airflow within the MHD generator at 3 T decreased from 11 mhos/m to 9 mhos/m for a flight speed of Mach 7 and remained the same for Mach 5 and 3. For the MHD accelerator, the needed magnetic fields decreased from 5 T to 3 T for flight speeds of Mach 7 and 5, and decreased from 3 T to 1.5 T for a flight speed of Mach 3. The conductivity levels required for the ionized airflow within the MHD accelerator (at 3 T) decreased from 2.6 mhos/m to 1.1 mhos/m for a flight speed of Mach 7 and remained the same for Mach 5 and 3. The MHD energy-bypass system model showed that it is possible to expand the operating range of a supersonic jet engine from a maximum of Mach 3.5 to a maximum of Mach 7. The inclusion of ion slip within the analysis further showed that it is possible to 'drive' this system with maximum magnetic fields of 3 T and with maximum conductivity levels of 11 mhos/m. These operating parameters better the previous findings of 5 T and 10 mhos/m, and reveal that taking into account collisions between ions and neutral particles within a weakly ionized flow provides a more realistic model with added benefits of lower magnetic fields and conductivity levels especially at the higher Mach numbers.

Committee:

David Allendar, PhD (Committee Co-Chair); Isaiah Blankson, PhD (Committee Co-Chair); John Portman, PhD (Committee Member); Mark Manley, PhD (Committee Member); John West, PhD (Committee Member); Jonathan Maletic, PhD (Committee Member)

Subjects:

Aerospace Engineering; Electromagnetics; Theoretical Physics

Keywords:

magnetohydrodynamics; energy bypass; ion slip; supersonic jet propulsion; hypersonic flight; air-breathing jet engine; weakly ionized gases; plasma flows; thermodynamic cycle analysis

KAMARAJ, JAYACHANDRANMODELING AND SIMULATION OF SINGLE SPOOL JET ENGINE
MS, University of Cincinnati, 2004, Engineering : Aerospace Engineering
A previously validated single spool,non-after burning turbojet engine model GEXX is converted to MATLAB / SIMULINK to illustrate the benefits of a graphical simulation system with a graphical user interface (GUI). The model simulates the dynamics of burner, compressor, turbine, and the gas volume after the turbine(before the nozzle) with compressor bleed, variable compressor stators and variable nozzle area as the inputs.The engine model can be used in four ways:# As a nonreal-time engine model for testing engine control algorithms. # As an embedded model within a control algorithm or observer. # As a system model for evaluating engine sensor and actuator models. # As a subsystem in a powertrain or vehicle dynamics model. Although developed and validated for a specific engine (the high speed spool of the GE16), the modeling procedure is generic enough to be used for a wide range of jet engines. The model which we used as reference for our model is created by matching the basic performance of the engine. The model allows varying the Power Lever Angle(PLA) and altitude during the simulation and the performance is recorded as the time history of the different variables. Similarly, the model was simulated at different flight velocities. The performance of the engine was studied by comparing the output variables at different PLA, altitude and velocity settings. The dynamics of the system can be clearly studied by using this SIMULINK model.

Committee:

Dr. Bruce Walker (Advisor)

Subjects:

Engineering, Aerospace

Keywords:

Single Spool Jet Engine; Turbojet Engine modeling simulation; Simulink modeling simulation; GE16 Engine GEXX

Dowler, John D.Using Neural Networks with Limited Data to Estimate Manufacturing Cost
Master of Science (MS), Ohio University, 2008, Industrial and Systems Engineering (Engineering and Technology)

This paper investigates the ability of a neural network to estimate the cost of jet engine components, specifically shafts and cases. Even with limited data the neural network is able to produce a superior cost estimate in a fraction of the time required by the current cost estimation process.

Due to the complex nature of the parts and the limited amount of data available, data expansion techniques such as doubling data, and data creation were examined. Sensitivity analysis is produced in order to gain an understanding of the underlying functions used by the neural network when generating the cost estimate.

Committee:

Gary R. Weckman, PhD (Advisor); Dale Masel, PhD (Committee Member); Jeffrey Dill, PhD (Committee Member); Helmut Paschold, PhD (Committee Member)

Subjects:

Economics; Engineering; Industrial Engineering

Keywords:

Neural network; cost estimation; limited data; jet engine

Divelbiss, David L.Evaluation of the Impact of Product Detail on the Accuracy of Cost Estimates
Master of Science (MS), Ohio University, 2005, Industrial and Manufacturing Systems Engineering (Engineering)

This paper looks at a current method of generating geometric forging models for jet engine components, specifically jet engine disks and aims to find geometric models that require less information and retain the existing model’s level of accuracy. In order to create models that require less information Attribute Estimating Relationships (AERs) are generated to estimate attribute dimensions, these estimated attribute dimensions are used to generate the forging model of the disk. AERs are generated using two different methods the Standard Deviation (SD) method and the Sum of Squares (SS) method. These two methods are analyzed and the SS method is determined to be superior in this case. Using the SS method to generate AERs it is possible to develop a geometric forging model that requires less information and also retains a high level of accuracy.

Committee:

Dale Masel (Advisor)

Keywords:

Aircraft Engine Cost Estimation; Attribute Estimating Relationships; Jet Engine Disks; Forging Model; Geometric Modeling; Cost Estimation

Ruggeri, Charles R.High Strain Rate Data Acquisition of 2D Braided Composite Substructures
Master of Science in Engineering, University of Akron, 2009, Civil Engineering

The objective of this research was to establish a test methodology to characterize dynamic properties for 2D tri-axial braided composites under impact conditions for applications in advanced jet engine containment structures. New generations of jet engines will be equipped with composite containment cases to significantly reduce weight while maintaining or increasing the impact strength. As a result jet engines will offer greater safety and reduced fuel consumption, while remaining cost effective.

In this study, the T700S/PR520 Graphite/Epoxy system was selected. Impact tests were conducted using gas guns that generate velocities that are equivalent to blade fragments impacting jet engine containment cases during a blade out. A specially formulated gelatin projectile with a cylindrical shape was used to impact square composite plates rigidly supported at all four boundaries in a picture frame fixture. Fabrication of the test articles was consistent with the process used for the jet engine containment structures. High speed cameras were used to measure the projectile velocity, observe projectile and plate deformations, as well to capture images for digital image correlation post processing to measure dynamic in-plane strains and out-of plane displacement fields. Repeated tests were conducted to identify threshold, visible damage, and damage initiation velocities. The methodology and tests results presented in this thesis are unique to braided composites and provide a test methodology needed for composite material model development, and numerical simulation validations. The same test methodology can be used with similar composite systems, as well as systems exposed to aging elements in the future.

Committee:

Wieslaw Binienda, Dr. (Advisor); Robert Goldberg, Dr. (Advisor); Craig Menzemer, Dr. (Advisor)

Subjects:

Aerospace Materials

Keywords:

2D tri-axial braided composites; impact; jet engine containment structures; gelatin projectile; digital image correlation

Mathison, Randall MelsonExperimental and Computational Investigation of Inlet Temperature Profile and Cooling Effects on a One and One-Half Stage High-Pressure Turbine Operating at Design-Corrected Conditions
Doctor of Philosophy, The Ohio State University, 2009, Mechanical Engineering
As the demand for greater efficiency and reduced specific fuel consumption from gas turbine engines continues to increase, design tools must be improved to better handle complicated flow features such as vane inlet temperature distortions, film cooling, and disk purge flow. In order to understand the physics behind these features, a new generation of turbine experiments is needed to investigate these features of interest for a realistic environment.This dissertation presents for the first time measurements and analysis of the flow features of a high-pressure one and one-half stage turbine operating at design corrected conditions with vane and purge cooling as well as vane inlet temperature profile variation. It utilizes variation of cooling flow rates from independent circuits through the same geometry to identify the regions of cooling influence on the downstream blade row. The vane outer cooling circuit, which supplies the film cooling on the outer endwall of the vane and the trailing edge injection from the vane, has the largest influence on temperature and heat-flux levels for the uncooled blade. Purge cooling has a more localized effect, but it does reduce the Stanton Number deduced for the blade platform and on the pressure and suction surfaces of the blade airfoil. Flow from the vane inner cooling circuit is distributed through film cooling holes across the vane airfoil surface and inner endwall, and its injection is entirely designed with vane cooling in mind. As such, it only has a small influence on the temperature and heat-flux observed for the downstream blade row. In effect, the combined influence of these three cooling circuits can be observed for every instrumented surface of the blade. The influence of cooling on the pressure surface of the uncooled blade is much smaller than on the suction surface, but a local area of influence can be observed near the platform. This is also the first experimental program to investigate the influence of vane inlet temperature profile on a cooled turbine operating at design corrected conditions. The vane inlet temperature profile has a substantial effect on the temperature measured at the blade leading edge and the Stanton Numbers deduced for the uncooled blade airfoil. While the temperature profile is slightly reshaped passing through the vane, a radial or hot streak profile introduced at the vane inlet can still be clearly measured at the blade. Hot streak magnitude and alignment also influence the blade temperature and heat-flux measurements. A concurrent effort to predict the blade leading edge and platform temperatures for the uncooled portions of this experiment using the commercial code FINE/Turbo is also presented. This investigation is not intended as a detailed computational study but as a check of current code implementation practices and a sanity check on the data. The best predictions are generated using isothermal wall boundary conditions with the nonlinear harmonic method. This is a novel prediction type that could only be performed using a development version of FINE/Turbo.

Committee:

Dr. Michael Dunn, PhD (Advisor); Dr. Sandip Mazumder, PhD (Committee Member); Dr. William Rich, PhD (Committee Member); Dr. Mohammad Samimy, PhD (Committee Member)

Subjects:

Fluid Dynamics; Mechanical Engineering

Keywords:

turbomachinery; gas turbine; film cooling; temperature distortion; FINE/Turbo; short-duration; vane inlet temperature profile; hot streak; purge cooling; isothermal; blade; vane; jet engine; design-corrected conditions; computational fluid dynamics

DRENSKY, GEORGE K.EXPERIMENTAL INVESTIGATION OF COMPOSITE MATERIAL EROSION CHARACTERISTICS UNDER CONDITIONS ENCOUNTERED IN TURBOFAN ENGINES
PhD, University of Cincinnati, 2007, Engineering : Aerospace Engineering
The design and development of high performance turbomachinery operating in both ambient and high temperature environment in the presence of solid particles requires a thorough knowledge of the fundamental phenomena associated with particulate flow. Because of the serious consequences of turbomachinery erosion on their performance and life expectancy, it is important to have reliable methods for predicting their erosion when solid particles are ingested with the incoming flow. The ingestion of these solid particles over a period of time will reduce the efficiency of the propulsion system, causing increased fuel consumption and reduction in performance and thrust. Many studies, essential to predicting blade surface erosion intensity and pattern, have been conducted at the University of Cincinnati’s Propulsion Laboratory in the past. The studies and experiments at the (UC) laboratory were performed in order to obtain a better understanding and a more realistic prediction of erosion rates of various conventional materials and coatings, while varying impingement angle, particle velocity, particle concentration, particle size, temperature and other important erosion parameters. Solid particle erosion is a complicated process which becomes even more complicated when it comes to composite material structures. In composite materials the mechanisms of erosion are complex, difficult to determine and even more difficult to predict due to the non-homogeneity of the material. Attempts were made to understand some of the basic mechanisms of erosion as early as the beginning of the (20th) century and continue even today. Over the years most of the attention of scientists was concentrated toward understanding the mechanisms occurring in conventional materials. However, due to the growing potential of composite materials and their desirable properties, they became a more focal point of interest.

Committee:

Dr. Widen Tabakoff (Advisor)

Subjects:

Engineering, Aerospace

Keywords:

Composite materials; Erosion Tunnel; Erosion; Models and Correlations; Jet Engine Performance

Tuncay, OrbayWireless Strain Gauge System in a Multipath Environment
Master of Science, The Ohio State University, 2008, Electrical and Computer Engineering

A wireless strain sensing system utilizing passive, wireless, physically small and light weight sensors is desirable for measuring strain in harsh environments such as jet engine compressor and turbine blades. A cluttered and time varying environment results in high loss, blockage, multipath and modulation of the electromagnetic wave. Also, temperature changes affect the sensitivity of the strain measurement. Isolating the information signal from the reverberations in the environment requires time delays in the order of 100s of ns for jet engine environment. Therefore, a wireless strain gauge system that utilizes surface acoustic wave (SAW) strain sensors was studied and tested.

SAW strain sensors are designed to operate at 2.45GHz. Electron beam lithography is used to achieve minimum required feature size at this frequency. The fabrication process is outlined and scanning electron microscope images of some results are given.

A transceiver circuit is designed and constructed. The circuit is tested in free space, in the presence of signal blockage and a time varying channel. Measurements are shown to be in good agreement with predicted data. Sources of errors in the setup are identified to be leakage from transceiver circuit switches and bounce waveforms from the transceiver antenna.

A General Electric J85 jet engine compressor section is analyzed for signal propagation characteristics. Minimum frequency that can propagate through the compressor section is determined to be 5.2GHz. Measurements are done to show that circumferential polarization propagates stronger than radial inside the compressor section. An analytical approximation for the compressor section is generated by modeling compressor section blades as rectangular waveguides. Good agreement on cutoff frequency is achieved for circumferential polarization with the analytical predictions and measurement.

SAW temperature and strain sensors are measured in comparison to traditional gauges. This concept can be generalized to measuring many different physical quantities wirelessly without disturbing the operation of the equipment.

Committee:

Roberto Rojas-Teran (Advisor); Eric Walton K. (Committee Member); Jonathan Young D. (Committee Member)

Subjects:

Electrical Engineering; Engineering; Experiments

Keywords:

wireless strain sensor; surface acoustic wave (SAW); jet engine; multipath; RFID; strain gauge; wireless strain measurement; SAW fabrication; Lithium Niobate

Clark, AdamPredicting the Crosswind Performance of High Bypass Ratio Turbofan Engine Inlets
Doctor of Philosophy, The Ohio State University, 2016, Aero/Astro Engineering
Takeoffs in crosswind conditions are a common occurrence in flight operations around the world, and flow separation from the inlet of a jet engine at this condition can lead to fan stall, surge, or aeromechanical excitation. The ability to predict flow separation and reattachment is critical to the design of a performance-optimized inlet and to reduce the risk of crosswind performance shortfalls during engine certification. This dissertation shows the derivation of an aerodynamic loading coefficient referred to as the Reattachment Parameter (RP). Analysis of wind tunnel test data for five different inlet designs at five different crosswind speeds show that inlet reattachment occurs when a single, critical value of RP is reached. A process for predicting flow reattachment is developed that relies solely on static pressure distributions from inviscid CFD and the RP coefficient. Validation of predictions from this process were accomplished with wind tunnel testing of two new ultra-high bypass ratio (UHBR) inlets and full-scale testing of a new conventional-length inlet on a modern turbofan engine. The average error in the reattachment predictions of the two UHBR inlets was 1.4% of peak flow and 4.3% of peak flow for the full-scale engine test. Reattachment predictions with the RP process were consistently found to be more accurate than those from RANS CFD. A second key advantage of the RP process is that, by leveraging inviscid CFD, a reattachment prediction can be made with about 1/100,000th the computational cost of a RANS prediction, which provides a tremendous advantage during inlet design work. Results from the RP process suggested that spinner size and shape may affect the crosswind performance of an inlet, so the effect of replacing a standard wind tunnel spinner with one that is larger and more representative of flight hardware was examined. Analysis with the RP process predicted reattachment with the larger spinner would occur 10.6% of peak flow earlier than the smaller spinner. Wind tunnel testing of both spinners showed a 9.5% of peak flow earlier reattachment for the larger spinner. Finally, the ability of the RP coefficient to quantify the circumferential distribution of aerodynamic loading is used to develop a novel design strategy referred to as `load balancing'. Knowledge of the circumferential locations which experience the highest aerodynamic loading allows a designer to alter the inlet geometry in order to achieve a more uniform load distribution. This process provides inlet designers with a unique ability to improve the crosswind performance of an inlet without negatively affecting other important performance characteristics.

Committee:

Jen-Ping Chen (Advisor); Jeffrey Bons (Committee Member); Michael Dunn (Committee Member); Richard Freuler (Committee Member)

Subjects:

Aerospace Engineering

Keywords:

CFD; jet engine; inlet; crosswind; separation; reattachment; distortion; IDC; RANS; Euler; inviscid; loading parameter; pressure gradient; aerodynamics; nacelle; angle of attack; separation bubble; aerodynamic loading; pressure coefficient; hysteresis

Yarlagadda, SantoshPerformance Analysis of J85 Turbojet Engine Matching Thrust with Reduced Inlet Pressure to the Compressor
Master of Science in Mechanical Engineering, University of Toledo, 2010, College of Engineering

Jet engines are required to operate at a higher rpm for the same thrust values in cases such as aircraft landing and military loitering. High rpm reflects higher efficiency with increased pressure ratio. This work is focused on performance analysis of a J85 turbojet engine with an inlet flow control mechanism to increase rpm for same thrust values. Developed a real-time turbojet engine integrating aerothermodynamics of engine components, principles of jet propulsion and inter component volume dynamics represented in 1-D non-linear unsteady equations. Software programs SmoothC and SmoothT were used to derive the data from characteristic rig test performance maps for the compressor and turbine respectively. Simulink, a commercially available model-based graphical block diagramming tool from MathWorks has been used for dynamic modeling of the engine. Dynamic Look-up tables in Simulink were used to interpolate the real-time performance of the engine from rig-test data. Simulink model for the J85 turbojet engine was verified for performance accuracy with available test data of the engine.

A flow control mechanism that produces a pressure drop across inlet is assumed and the analysis is carried with reduced compressor inlet pressure for matching thrust. Compressor inlet pressure is reduced to a percentage of atmospheric pressure and to produce the desired thrust with reduced inlet pressure, the engine operates at a higher shaft rpm. With increase in shaft rpm, pressure and temperature ratio values across the compressor-turbine assembly increases. Performance parameters of the engine are analyzed with the increase in compressor pressure ratio and shaft rpm.

Specific fuel consumption, specific thrust, component pressure ratios, thermal and propulsive efficiencies are the performance parameters of the engine that are analyzed on the model with reduced inlet pressure for the real-time test cases of desired thrust range. Limitations of the analysis are discussed along with possible industrial applications of this flow control mechanism.

Committee:

Konstanty Masiulaniec, PhD (Advisor); Terry Ng, PhD (Committee Member); Sorin Cioc, PhD (Committee Member)

Subjects:

Mechanical Engineering

Keywords:

aircraft engines; real-time modeling; jet engine performance