Estimating the Drag Developed by a High Bypass Ratio Turbofan Engine

2018 ◽  
Author(s):  
M. S. Zawislak ◽  
D. J. Cerantola ◽  
A. M. Birk
Keyword(s):  
Engine Performance ◽  
Operating Conditions ◽  
Zone Model ◽  
Pressure System ◽  
Cross Sectional ◽  
Turbofan Engine ◽  
Engine Model ◽  
Integration Techniques ◽  
Drag Analysis ◽  
Bypass Ratio

A high bypass ratio turbofan engine capable of powering the Boeing 757 was considered for thrust and drag analysis. A quasi-2D engine model applying the fundamental thermodynamics conservation equations and practical constraints determined engine performance and provided cross-sectional areas in the low-pressure system. Coupled with suggestions on boat-tail angle and curvature from literature, a representative bypass duct and primary exhaust nozzle was created. 3D steady-RANS simulations using Fluent® 18 were performed on a 1/8th axisymmetric section of the geometry. A modified 3D fan zone model forcing radial equilibrium was used to model the fan and bypass stator. Takeoff speed and cruise operating conditions were modeled and simulated to identify changes in thrust composition and intake sensitivity. Comparison between net thrust predictions by the engine model and measured in CFD were within grid uncertainty and model sensitivity at cruise. Trends observed in a published database were satisfied and calculations coincided with GasTurb™ 8.0. Verification of thrust in this manner gave confidence to the aerodynamic performance prediction of this modest CFD. Obtaining a baseline bypass design would allow rapid testing of aftermarket components and integration techniques in a realistic flow-field without reliance on proprietary engine data.

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.

A Comprehensive Study on Natural Gas HCCI Engine Response to Different Initial Conditions via a Thermo-Kinetic Engine Model

2009 ◽  
Author(s):  
Omid Jahanian ◽  
Seyed Ali Jazayeri
Keyword(s):  
Natural Gas ◽  
Initial Conditions ◽  
Chemical Species ◽  
Engine Performance ◽  
Operating Conditions ◽  
Zone Model ◽  
Operating Characteristics ◽  
Hcci Engine ◽  
Engine Model ◽  
Homogenous Charge Compression Ignition

Homogenous Charge Compression Ignition (HCCI) combustion is a promising concept to reduce engine emissions and fuel consumption. In this paper, a thermo-kinetic model is developed to study the operating characteristics of a natural gas HCCI engine. The zero-dimensional single zone model consist detail chemical kinetics of natural gas oxidation including 325 reactions with 53 chemical species, and is validated with experimental results of reference works for two different engines, Volvo TD 100 and Caterpillar 3500, in 5 operating conditions. Then, the influence of parameters such as manifold temperature/pressure and equivalence ratio on in-cylinder temperature/pressure trends and start of combustion is studied. Measurements for Volvo engine show that SOC occurs 3–5 CAD earlier with every 15K increase in initial temperature. These whole results are explained in detail to describe the engine performance thoroughly.

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

2012 ◽  
Author(s):  
Tashfeen Mahmood ◽  
Anthony Jackson ◽  
Syed H. Rizvi ◽  
Pericles Pilidis ◽  
Mark Savill ◽  
...  
Keyword(s):  
Engine Performance ◽  
Engine Exhaust ◽  
Turbofan Engine ◽  
The Public ◽  
Engine Model ◽  
Turbine Performance ◽  
Lp Turbine ◽  
Engine Components ◽  
Thrust Reverser ◽  
Bypass Ratio

This paper discusses thrust reverser techniques for a mixed exhaust high bypass ratio turbofan engine and its effect on aircraft and engine performance. The turbofan engine chosen for this study was CUTS_TF (Cranfield University Three Spool Turbofan) which is similar to Rolls-Royce TRENT 772 engine and the information available for this engine in the public domain is used for the engine performance analysis along with the Gas Turbine Performance Software, GasTurb 10. The CUTEA (Cranfield University Twin Engine Aircraft) which is similar to the Airbus A330 is used along side with the engine model for the thrust reverser performance calculations. The aim of this research paper is to investigate the effects on mixed exhaust engine performance due to the pivoting door type thrust reverser deployment. The paper looks into the engine off-design performance characteristics and how the engine components get affected when the thrust reverser come into operation. This includes the changes into the operating point of fan, IP compressor, HP compressor, HP turbine, IP turbine, LP turbine and the engine exhaust nozzle. Also, the reverser deployment effect on aircraft, deceleration time and landing distances are discussed.

scholarly journals CFD Study of Nozzle Configurations for Ultra High Bypass Engines

1993 ◽  
Author(s):  
H. Zimmermann ◽  
R. Gumucio ◽  
K. Katheder ◽  
A. Jula
Keyword(s):  
Engine Performance ◽  
Operating Conditions ◽  
Aerodynamic Design ◽  
Thrust Coefficient ◽  
Optimum Range ◽  
Installation Effects ◽  
Wide Range ◽  
And Performance ◽  
Aircraft Aerodynamics ◽  
Bypass Ratio

Performance and aerodynamic aspects of ultra-high bypass ratio ducted engines have been investigated with an emphasis on nozzle aerodynamics. The interference with aircraft aerodynamics could not be covered. Numerical methods were used for aerodynamic investigations of geometrically different aft end configurations for bypass ratios between 12 and 18, this is the optimum range for long missions which will be important for future civil engine applications. Results are presented for a wide range of operating conditions and effects on engine performance are discussed. The limitations for higher bypass ratios than 12 to 18 do not come from nozzle aerodynamics but from installation effects. It is shown that using CFD and performance calculations an improved aerodynamic design can be achieved. Based on existing correlations, for thrust and mass-flow, or using aerodynamic tailoring by CFD and including performance investigations, it is possible to increase the thrust coefficient up to 1%.

Towards a Fully Coupled Component Zooming Approach in Engine Performance Simulation

2011 ◽  
Author(s):  
Julien Pilet ◽  
Jean-Loi¨c Lecordix ◽  
Nicolas Garcia-Rosa ◽  
Roger Bare`nes ◽  
Ge´rard Lavergne
Keyword(s):  
Engine Performance ◽  
Simulation Software ◽  
Performance Simulation ◽  
Engine Model ◽  
Component Models ◽  
Mapping Models ◽  
Fully Coupled ◽  
Bypass Ratio ◽  
Very High ◽  
Engine Cycle

This paper presents a fully-coupled zooming approach for the performance simulation of modern very high bypass ratio turbofan engines developed by Snecma. This simulation is achieved by merging detailed 3D simulations and map component models into a unified representation of the whole engine. Today’s state-of-the-art engine cycle analysis are commonly based on component mapping models which enable component interactions to be considered, while CFD simulations are carried out separately and therefore overlook those interactions. With the methodology discussed in this paper, the detailed analysis of an engine component is no longer considered apart, but directly within the whole engine performance model. Moreover, all links between the 3D simulation and overall engine models have been automated making this zooming simulation fully-integrated. The simulation uses the PROOSIS propulsion object-oriented simulation software developed by Empresarios Agrupados for whole engine cycle analysis and the computational fluid dynamics (CFD) code CEDRE developed by ONERA for the high fidelity 3-D component simulations. The whole engine model is created by linking component models through their communication ports in a graphical user-friendly interface. CFD simulated component models have been implemented in PROOSIS libraries already providing mapped components. Simple averaging techniques have been developed to handle 3D-to-0D data exchange. Boundary conditions of the whole engine model remain the same as for the typical 0-D engine cycle analysis while those of the 3-D simulations are automatically given by PROOSIS to CEDRE. This methodology has been applied on an advanced very high bypass ratio engine developed by Price Induction. The proposed zooming approach has been performed on the fan stage when simulating Main Design Point as well as severe case of off-design conditions such as wind-milling. The results have been achieved within the same time frame of a typical CFD fully-converged calculation. A detailed comparison with upcoming test results will provide a first validation of the methodology and will be presented in a future paper.

Research of the XF3-1 Turbofan Engine

1978 ◽  
Author(s):  
M. Kohzu ◽  
H. Chinone ◽  
M. Miyake ◽  
K. Murashima ◽  
K. Yamanaka ◽  
...  
Keyword(s):  
Research Program ◽  
Engine Performance ◽  
Bench Test ◽  
Turbofan Engine ◽  
The Status ◽  
Test Engine ◽  
Matching Performance ◽  
Basic Studies ◽  
Front Fan ◽  
Bypass Ratio

A research program of low bypass ratio small front fan engines has been in process at Third Research Center of Technical Research and Development Institute of Japan Defence Agency since 1975. The final target of this program is the development of the propulsion engine for the high subsonic small aircraft. As the first phase of this program, the bench test engine XF3-1 was manufactured and the basic studies of the overall engine matching performance and the effect of each component on the engine performance have been carried out. This paper describes the XF3-1 engine, reviews the status of the research and presents the major engineering progress attained through the research.

Modeling of Start-Up From Engine-Off Conditions Using High Fidelity Turbofan Engine Simulations

2015 ◽  
Vol 138 (5) ◽  
Author(s):  
Stefan Bretschneider ◽  
John Reed
Keyword(s):  
Development Process ◽  
Model Development ◽  
Engine Performance ◽  
Static Friction ◽  
Operating Conditions ◽  
High Fidelity ◽  
Turbofan Engine ◽  
Control Laws ◽  
Component Design ◽  
Start Up

Engine models are widely used to simulate the engine behavior at steady state and transient operating conditions over the full flight envelope. Within the engine development process such simulations are used to support component design, evaluate engine performance, operability and test data, as well as to develop and optimize the engine controls. Recent developments have raised interest in the modeling of start-up processes of turbofan engines in order to support the definition of sufficient engine control laws. This implies that simulations are started at a condition where the engine shafts are static and temperatures and pressures are equal to ambient. During start-up the engine can only be operated transiently through the sub-sub-idle region (near zero speed) using a starter torque. The activity presented here was targeted to support the development of industrial-standard high-fidelity turbofan engine models capable of simulating start-up, shutdown or windmilling operation. Within the three previously mentioned cases starting from an engine-off condition, ground start from zero-speed is the most challenging in terms of physical and numerical modeling. For this reason, this paper concentrates on that case only. Zero mass flow and speed at the beginning of the simulation impose a set of special problems that do not exist in standard simulations: the modeling of a static engine-off condition, the modeling of static friction, and the modeling of reverse flows. The requirement to support an existing industrial model development process also made it necessary to apply the same quality of physical modeling to start-up simulations as would be the case for above-idle engine simulations. The physical effects present during engine start are discussed and modeling solutions are presented. Finally, results of a dry crank simulation are presented and discussed, illustrating that the expected effects are present and that the simulation is capable of predicting the correct trends.

Design and Application of a Multidisciplinary Predesign Process for Novel Engine Concepts

2018 ◽  
Vol 141 (1) ◽  
Author(s):  
Stanislaus Reitenbach ◽  
Alexander Krumme ◽  
Thomas Behrendt ◽  
Markus Schnös ◽  
Thomas Schmidt ◽  
...  
Keyword(s):  
Data Model ◽  
Structural Design ◽  
Engine Performance ◽  
Turbofan Engine ◽  
Engine Model ◽  
Modeling Techniques ◽  
Aero Engine ◽  
Open Rotor ◽  
Definition Of ◽  
Engine Components

The purpose of this paper is to present a multidisciplinary predesign process and its application to three aero-engine models. First, a twin spool mixed flow turbofan engine model is created for validation purposes. The second and third engine models investigated comprise future engine concepts: a counter rotating open rotor (CROR) and an ultrahigh bypass turbofan. The turbofan used for validation is based on publicly available reference data from manufacturing and emission certification. At first, the identified interfaces and constraints of the entire predesign process are presented. An important factor of complexity in this highly iterative procedure is the intricate data flow, as well as the extensive amount of data transferred between all involved disciplines and among different fidelity levels applied within the design phases. To cope with the inherent complexity, data modeling techniques have been applied to explicitly determine required data structures of those complex systems. The resulting data model characterizing the components of a gas turbine and their relationships in the design process is presented in detail. Based on the data model, the entire engine predesign process is presented. Starting with the definition of a flight mission scenario and resulting top level engine requirements, thermodynamic engine performance models are developed. By means of these thermodynamic models, a detailed engine component predesign is conducted. The aerodynamic and structural design of the engine components are executed using a stepwise increase in level of detail and are continuously evaluated in context of the overall engine system.

scholarly journals Numerical Analysis of Fuel Effects on Advanced Compression Ignition Using a Virtual Cooperative Fuel Research Engine Model

2020 ◽  
Author(s):  
Krishna C. Kalvakala ◽  
Pinaki Pal ◽  
Yunchao Wu ◽  
Goutham Kukkadapu ◽  
Christopher Kolodziej ◽  
...  
Keyword(s):  
Engine Speed ◽  
Driving Forces ◽  
Engine Performance ◽  
Kinetic Mechanism ◽  
Operating Conditions ◽  
Compression Ignition ◽  
Charge Condition ◽  
Engine Model ◽  
Primary Reference ◽  
Fuel Effects

Abstract Growing environmental concerns and demand for better fuel economy are driving forces that motivate the research for more advanced engines. Multi-mode combustion strategies have gained attention for their potential to provide high thermal efficiency and low emissions for light-duty applications. These strategies target optimizing the engine performance by correlating different combustion modes to load operating conditions. The extension from boosted SI mode at high loads to advanced compression ignition (ACI) mode at low loads can be achieved by increasing compression ratio and utilizing intake air heating. Further, in order to enable an accurate control of intake charge condition for ACI mode and rapid mode-switches, it is essential to gain fundamental insights into the autoignition process. Within the scope of ACI, homogeneous charge compression ignition (HCCI) mode is of significant interest. It is known for its potential benefits, operation at low fuel consumption, low NOx and PM emissions. In the present work, a virtual Cooperative Fuel Research (CFR) engine model is used to analyze fuel effects on ACI combustion. In particular, the effect of fuel Octane Sensitivity (S) (at constant RON) on autoignition propensity is assessed under beyond-RON (BRON) and beyond-MON (BMON) ACI conditions. The 3D CFR engine computational fluid dynamics (CFD) model employs finite-rate chemistry approach with multi-zone binning strategy to capture autoignition. Two binary blends with Research Octane Number (RON) of 90 are chosen for this study: Primary reference fuel (PRF) with S = 0, and toluene-heptane (TH) blend with S = 10.8, representing paraffinic and aromatic gasoline surrogates. Reduced mechanisms for these blends are generated from a detailed gasoline surrogate kinetic mechanism. Simulation results with the reduced mechanisms are validated against experimental data from an in-house CFR engine, with respect to in-cylinder pressure, heat release rate and combustion phasing. Thereafter, the sensitivity of combustion behavior to ACI operating condition (BRON vs BMON), air-fuel ratio (λ = 2 and 3), and engine speed (600 and 900rpm) is analyzed for both fuels. It is shown that the sensitivity of a fuel’s autoignition characteristics to λ and engine speed significantly differs at BRON and BMON conditions. Moreover, this sensitivity is found to vary among fuels, despite the same RON. This study also indicates that the octane index (OI) fails to capture the trend in the variation of autoignition propensity with S under BMON conditions.

A Study of Thermal Fatigue Life Prediction of Air-Cooled Turbine Blades

1978 ◽  
Author(s):  
T. Maya ◽  
I. Katsumata ◽  
M. Itoh
Keyword(s):  
Fatigue Life ◽  
Thermal Fatigue ◽  
Life Prediction ◽  
Turbine Blades ◽  
Operating Conditions ◽  
Test Rig ◽  
Emission Method ◽  
Turbofan Engine ◽  
Thermal Fatigue Life ◽  
Bypass Ratio

One of the techniques for estimation of thermal fatigue life of air-cooled turbine blades is assured through coincidence between the results of experimental and analytical works. The actual turbine blades were tested on the test rig utilizing alternating hot and cold jet method under simulated operating conditions of the high-bypass ratio turbofan engine. Acoustic emission method is applied to detect the crack initiation of tested blades. The experimental data were analyzed statistically and the result was well close to the analytical value which was calculated using structural analysis program NASTRAN and universal slope relation.

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