Joint Dynamic Airbreathing Propulsion Simulations Partnerships (JDAPS)

1995 ◽  
Author(s):  
M. W. Davis ◽  
A. K. Owen ◽  
W. F. O’Brien ◽  
W. T. Cousins
Keyword(s):  
Dynamic Behavior ◽  
Engine Performance ◽  
Rotating Stall ◽  
Turbine Engine ◽  
Inlet Distortion ◽  
Dynamic Events ◽  
Engine Dynamic ◽  
Primary Focus ◽  
Engine Start ◽  
Design Guidance

The Joint Dynamic Airbreathing Propulsion Simulations (JDAPS) is a partnership of government, university, and industry organizations for the purpose of developing and applying turbine engine/component numerical simulations to aid in the understanding of turbine engine dynamic behavior. The primary focus of the simulations being developed by the partnership is to aid in the understanding of gas turbine dynamic behavior such as engine surge, compressor rotating stall, the effects of inlet distortion, and dynamic events during engine start. The insight gained from the development and application of these simulations provides design guidance for improved turbine engine performance and operability. By pooling resources, the organizations involved in the JDAPS partnership have access to more support, both financial and technical, than any one organization could afford on its own. Such synergy makes each organization’s return on investment very high.

Validation of a Modified Parallel Compressor Model for Prediction of the Effects of Inlet Swirl on Compressor Performance and Operability

2015 ◽  
Author(s):  
Reginald S. Floyd ◽  
Milton Davis
Keyword(s):  
Pressure Ratio ◽  
Pressure Rise ◽  
Engine Performance ◽  
The United States ◽  
Turbine Engine ◽  
Inlet Distortion ◽  
Inlet Swirl ◽  
Compressor Performance ◽  
Inlet Conditions ◽  
Map Data

Engine inlet distortion complications have plagued the turbine engine development community for decades, and engineers have developed countless methods to identify and combat the harmful effects of inlet distortion. One such type of distortion that has gained much attention in recent years is known as inlet swirl, which results in a significant flow angularity at the face of the engine. This flow angularity can affect the pressure rise and flow capacity of the fan or compressor, and subsequently affect compressor and engine performance. Previous modeling and simulation efforts to predict the effect inlet swirl can have on fan and compressor performance have made great strides, yet still leave a lot to be desired. In particular, a one-dimensional parallel compressor model called DYNTECC (Dynamic Turbine Engine Compressor Code) has been used to analyze the effects of inlet swirl on fan and performance operability of the Honeywell F109 turbofan engine. However, when compared to experimental swirl data gathered at the United States Air Force Academy (USAFA), the model predictions were found to be inaccurate. This paper documents work done to compare the initial predictions generated by DYNTECC to the latest set of experimental swirl data, analyze the potential shortcomings of the initial model, and modify the existing model to more accurately reflect test data. Extensive work was completed to create a methodology that can calibrate the model to existing clean inlet fan map data. In addition, an in depth study of fan/compressor stalling criteria was conducted, and the model was modified to use an alternate stalling criteria that more accurately predicted the point of stall for various swirl inlet conditions. The prediction of the fan stall pressure ratio for all inlet swirl conditions tested is within 2% of the ground test stall point at the same referred fan speed and referred mass flow.

Investigation of the Effects of Inlet Swirl on Compressor Performance and Operability Using a Modified Parallel Compressor Model

2011 ◽  
Author(s):  
Nicholas Fredrick ◽  
Milt Davis
Keyword(s):  
Experimental Data ◽  
Total Pressure ◽  
Engine Performance ◽  
Propulsion System ◽  
Turbine Engine ◽  
Turbofan Engines ◽  
Inlet Distortion ◽  
Inlet Swirl ◽  
Engine Compressor ◽  
Compressor Performance

Serpentine ducts used by both military and commercial aircraft can generate significant flow angularity and total pressure distortion at the engine face. Most low by-pass ratio turbofan engines with mixed exhaust are equipped with inlet guide vanes (IGV) which can reduce the effect of moderate inlet distortion. High by-pass ratio and some low by-pass ratio turbofan engines are not equipped with IGVs, and swirl can in effect change the angle of attack of the fan blades. Swirl and total pressure distortion at the engine inlet will impact engine performance, operability, and durability. The impact on the engine performance and operability must be quantified to ensure safe operation of the aircraft and propulsion system. Testing is performed at a limited number of discrete points inside the propulsion system flight envelope where it is believed the engine is most sensitive to the inlet distortion in order to quantify these effects. Turbine engine compressor models are based on the limited amount of experimental data collected during testing. These models can be used as an analysis tool to improve the effectiveness of engine testing and to improve understanding of engine response to inlet distortion. The Dynamic Turbine Engine Compressor Code (DYNTECC) utilizes parallel compressor theory and quasi-one-dimensional Euler equations to determine compressor performance. In its standard form, DYNTECC uses user supplied characteristic stage maps in order to calculate stage forces and shaft work for use in the momentum and energy equations. These maps were typically developed using experimental data or created using characteristic codes such as the 1-D Mean Line Code (MLC) or the 2-D Streamline Curvature Code. The MLC was created to calculate the performance of individual compressor stages and requires less computational effort than the 2-D and 3-D models. To improve efficiency and accuracy, the MLC has been incorporated into DYNTECC as a subroutine. Rather than independently developing stage maps using the MLC and then importing these maps into DYNTECC, DYNTECC can now use the MLC to develop the required stage characteristic for the desired operating point. This will reduce time and complexity required to analyze the effects of inlet swirl on compressor performance. The combined DYNTECC/MLC was used in the past to model total pressure distortion. This paper presents the result obtained using the combined DYNTECC/MLC to model the effects of various types of inlet swirl on F109 fan performance and operability for the first time.

Design, Development and Application of Vehicle Gas Turbine Engines

1966 ◽  
Vol 181 (1) ◽  
pp. 149-172
Author(s):  
P. A. Phillips ◽  
Peter Spear
Keyword(s):  
Gas Turbine ◽  
Gas Turbines ◽  
Low Cost ◽  
Engine Performance ◽  
Turbine Engines ◽  
Gas Turbine Engines ◽  
Design Development ◽  
Turbine Engine ◽  
Wide Range ◽  
Cycle Temperature

After briefly summarizing worldwide automotive gas turbine activity, the paper analyses the power plant requirements of a wide range of vehicle applications in order to formulate the design criteria for acceptable vehicle gas turbines. Ample data are available on the thermodynamic merits of various gas turbine cycles; however, the low cost of its piston engine competitor tends to eliminate all but the simplest cycles from vehicle gas turbine considerations. In order to improve the part load fuel economy, some complexity is inevitable, but this is limited to the addition of a glass ceramic regenerator in the 150 b.h.p. engine which is described in some detail. The alternative further complications necessary to achieve satisfactory vehicle response at various power/weight ratios are examined. Further improvement in engine performance will come by increasing the maximum cycle temperature. This can be achieved at lower cost by the extension of the use of ceramics. The paper is intended to stimulate the design application of the gas turbine engine.

Effect of Manufacturing Variability on Turbine Engine Performance: A Probabilistic Study

2013 ◽  
Author(s):  
Michael Gorelik ◽  
Jacob Obayomi ◽  
Jack Slovisky ◽  
Dan Frias ◽  
Howie Swanson ◽  
...  
Keyword(s):  
Performance Metrics ◽  
Model Development ◽  
Engine Performance ◽  
Performance Model ◽  
Probabilistic Methods ◽  
System Level ◽  
Turbine Engine ◽  
Probabilistic Study ◽  
Blade Geometry

While turbine engine Original Equipment Manufacturers (OEMs) accumulated significant experience in the application of probabilistic methods (PM) and uncertainty quantification (UQ) methods to specific technical disciplines and engine components, experience with system-level PM applications has been limited. To demonstrate the feasibility and benefits of an integrated PM-based system, a numerical case study has been developed around the Honeywell turbine engine application. The case study uses experimental observations of engine performance such as horsepower and fuel flow from a population of engines. Due to manufacturing variability, there are unit-to-unit and supplier-to-supplier variations in compressor blade geometry. Blade inspection data are available for the characterization of these geometric variations, and CFD analysis can be linked to the engine performance model, so that the effect of blade geometry variation on system-level performance characteristics can be quantified. Other elements of the case study included the use of engine performance and blade geometry data to perform Bayesian updating of the model inputs, such as efficiency adders and turbine tip clearances. A probabilistic engine performance model was developed, system-level sensitivity analysis performed, and the predicted distribution of engine performance metrics was calibrated against the observed distributions. This paper describes the model development approach and key simulation results. The benefits of using PM and UQ methods in the system-level framework are discussed. This case study was developed under Defense Advanced Research Projects Agency (DARPA) funding which is gratefully acknowledged.

Method for Operational Diagnostics of the Prepumping State of Gas Turbine Engines Based on Invariants of Acoustic Processes

NDT World ◽  
2021 ◽  
pp. 58-61
Author(s):  
Aleksey Popov ◽  
Aleksandr Romanov
Keyword(s):  
Gas Turbine ◽  
Acoustic Signal ◽  
Acoustic Method ◽  
Random Processes ◽  
Rotating Stall ◽  
Turbine Engines ◽  
Gas Turbine Engines ◽  
Turbine Engine ◽  
Software Complex ◽  
Operational Diagnostics

A large number of aviation events are associated with the surge of gas turbine engines. The article analyzes the existing systems for diagnostics of the surge of gas turbine engines. An analysis of the acoustic signal of a properly operating gas turbine engine was carried out, at which a close theoretical distribution of random values was determined, which corresponds to the studied distribution of the amplitudes of the acoustic signal. An invariant has been developed that makes it possible to evaluate the development of rotating stall when analyzing the acoustic signal of gas turbine engines. A method is proposed for diagnosing the pre-surge state of gas turbine engines, which is based on processing an acoustic signal using invariant dependencies for random processes. A hardware-software complex has been developed using the developed acoustic method for diagnosing the pre-surge state of gas turbine engines.

Simple Instrumentation Rake Designs for Gas Turbine Engine Testing

1996 ◽  
Author(s):  
Peter D. Smout ◽  
Steven C. Cook
Keyword(s):  
Gas Turbine ◽  
Mechanical Damage ◽  
Engine Performance ◽  
Leading Edge ◽  
Gas Turbine Engine ◽  
Calibration Data ◽  
Turbine Engine ◽  
Industry Standard ◽  
Repair Costs ◽  
Engine Testing

The determination of gas turbine engine performance relies heavily on intrusive rakes of pilot tubes and thermocouples for gas path pressure and temperature measurement. For over forty years, Kiel-shrouds mounted on the rake body leading edge have been used as the industry standard to de-sensitise the instrument to variations in flow incidence and velocity. This results in a complex rake design which is expensive to manufacture, susceptible to mechanical damage, and difficult to repair. This paper describes an exercise aimed at radically reducing rake manufacture and repair costs. A novel ’common cavity rake’ (CCR) design is presented where the pressure and/or temperature sensors are housed in a single slot let into the rake leading edge. Aerodynamic calibration data is included to show that the performance of the CCR design under uniform flow conditions and in an imposed total pressure gradient is equivalent to that of a conventional Kiel-shrouded rake.

In-flight adaptive modeling using polynomial LPV approach for turbofan engine dynamic behavior

2017 ◽  
Vol 64 ◽  
pp. 223-236 ◽  
Author(s):  
Feng Lu ◽  
Junning Qian ◽  
Jinquan Huang ◽  
Xiaojie Qiu
Keyword(s):  
Dynamic Behavior ◽  
Adaptive Modeling ◽  
Turbofan Engine ◽  
Engine Dynamic
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