scholarly journals Design of an Ultra-High Bypass Ratio Fan Stage for a Research Turbojet Engine

2019 ◽  
pp. 2-11
Author(s):  
Károly Beneda ◽  
Bence Sipula
Keyword(s):  
Large Scale ◽  
Engineering Students ◽  
Flow Analysis ◽  
Turbofan Engine ◽  
One Dimensional ◽  
Mechanical Parts ◽  
Theoretical Design ◽  
University Of Technology ◽  
Bypass Ratio ◽  
Scale Types

At the Department of Aeronautics, Naval Architecture and Railway Vehicles of Budapest University of Technology and Economics there is a versatile micro turbojet test bench based on TS-21 turbostarter engine. Besides research and developement purposes it offers a more practical study and experience for the aerospace engineering students. In this study the authors have accomplished a theoretical design of an additional fan stage to the original TS-21 engine. Based on the results of this study a decision can be made, whether the modification of the present device is worth or not. For supplementing this decision, a complex feasability study was carried out from a simple one-dimensional flow analysis through computational fluid dynamics and stress analysis of the mechanical parts. If the designed equipment will be manufactured, the resulting turbofan engine can be used to model large scale types for various research and educational purposes.

Teaching Machine Design Curricula in Developing Countries

2020 ◽  
pp. 247-271
Author(s):  
Fredrick M. Mwema ◽  
Akinsanya Damilare Baruwa ◽  
Esther T. Akinlabi
Keyword(s):  
Developing Countries ◽  
Engineering Students ◽  
Teaching Machine ◽  
Machine Design ◽  
Local Resources ◽  
Theoretical Design ◽  
University Of Technology ◽  
Grouping Students ◽  
Cad Models ◽  
Societal Problems

In this chapter, a feasible approach to implement machine design curricula in developing countries is presented. The argument by the authors is that machine design should train engineering students in such countries to utilize local resources to solve practical societal problems. The approach illustrated here was used during 2015-2016 to teach machine design at Dedan Kimathi University of Technology, DeKUT, in Kenya. The approach involved grouping students of different interests and capabilities and tasking them to identify and study various problems in society. The groups were then required to propose machine design solutions to the identified problems. Finally, the groups were tasked to undertake the theoretical design and build CAD models for their projects. The students were monitored through individual weekly presentations to the instructor. The approach was seen to be successful to facilitate training in machine design.

Influence of Turbine Blade Cooling Efficiency on Turbofan Engine Performance

2013 ◽  
Vol 444-445 ◽  
pp. 1272-1276
Author(s):  
Li Ya Zhu ◽  
Qin Huang
Keyword(s):  
Turbine Blade ◽  
Large Scale ◽  
Pressure Ratio ◽  
Engine Performance ◽  
Cooling Efficiency ◽  
Turbofan Engine ◽  
Turbine Blade Cooling ◽  
Blade Cooling ◽  
Calculation Results ◽  
Bypass Ratio

On the basis of a performance emulation model of turbofan engine, a relation curve was first employed to fix the efficiency of compression components. With the turbine blade cooling efficiency being a restriction, an optimization algorithm was developed on the premise that engine cycle parameters match. The calculation results show that when the turbine blade cooling efficiency was improved at a fixed bypass ratio, the engine overall pressure ratio corresponding to the lowest specific fuel consumption (sfc) grows on a large scale, while the lowest sfc slightly drops and the specific thrust significantly boosts.

Soil/Tire Interaction Analysis Using FEM and FVM

2005 ◽  
Vol 33 (1) ◽  
pp. 38-62 ◽  
Author(s):  
S. Oida ◽  
E. Seta ◽  
H. Heguri ◽  
K. Kato
Keyword(s):  
Large Scale ◽  
Interaction Analysis ◽  
Yield Criterion ◽  
Surrounding Medium ◽  
Flow Analysis ◽  
Measurement Data ◽  
Traction Force ◽  
Elastoplastic Material ◽  
The Road ◽  
Soil Flow

Abstract Vehicles, such as an agricultural tractor, construction vehicle, mobile machinery, and 4-wheel drive vehicle, are often operated on unpaved ground. In many cases, the ground is deformable; therefore, the deformation should be taken into consideration in order to assess the off-the-road performance of a tire. Recent progress in computational mechanics enabled us to simulate the large scale coupling problem, in which the deformation of tire structure and of surrounding medium can be interactively considered. Using this technology, hydroplaning phenomena and tire traction on snow have been predicted. In this paper, the simulation methodology of tire/soil coupling problems is developed for pneumatic tires of arbitrary tread patterns. The Finite Element Method (FEM) and the Finite Volume Method (FVM) are used for structural and for soil-flow analysis, respectively. The soil is modeled as an elastoplastic material with a specified yield criterion and a nonlinear elasticity. The material constants are referred to measurement data, so that the cone penetration resistance and the shear resistance are represented. Finally, the traction force of the tire in a cultivated field is predicted, and a good correlation with experiments is obtained.

Performance Prediction for Automotive Turbocharger Compressors

1975 ◽  
Vol 189 (1) ◽  
pp. 557-565 ◽  
Author(s):  
A. Whitfield ◽  
F. J. Wallace
Keyword(s):  
Performance Prediction ◽  
Flow Analysis ◽  
Compressor Stage ◽  
Thermodynamic Models ◽  
Flow Rates ◽  
Design Point ◽  
One Dimensional ◽  
Dimensional Flow ◽  
Performance Map ◽  
The Individual

A procedure to predict the complete performance map of turbocharger centrifugal compressors is presented. This is based on a one-dimensional flow analysis using existing published loss correlations that were available and thermodynamic models to describe the incidence loss and slip factor variation at flow rates which differ from the design point. To predict the losses within the complete compressor stage using a one-dimensional flow procedure, it is necessary to introduce a number of empirical parameters. The uncertainty associated with these empirical parameters is assessed by studying the effect of varying them upon the individual losses and upon the overall predicted performance.

A Comparative Study of Genetic Algorithms and Gradient Methods for RM12 Turbofan Engine Diagnostics and Performance Estimation

2004 ◽  
Author(s):  
Tomas Gro¨nstedt ◽  
Markus Wallin
Keyword(s):  
Gas Turbine ◽  
Performance Test ◽  
Gradient Methods ◽  
Performance Testing ◽  
Performance Estimation ◽  
Data Sets ◽  
Data Set ◽  
Turbofan Engine ◽  
Local Optima ◽  
Bypass Ratio

Recent work on gas turbine diagnostics based on optimisation techniques advocates two different approaches: 1) Stochastic optimisation, including Genetic Algorithm techniques, for its robustness when optimising objective functions with many local optima and 2) Gradient based methods mainly for their computational efficiency. For smooth and single optimum functions, gradient methods are known to provide superior numerical performance. This paper addresses the key issue for method selection, i.e. whether multiple local optima may occur when the optimisation approach is applied to real engine testing. Two performance test data sets for the RM12 low bypass ratio turbofan engine, powering the Swedish Fighter Gripen, have been analysed. One set of data was recorded during performance testing of a highly degraded engine. This engine has been subjected to Accelerated Mission Testing (AMT) cycles corresponding to more than 4000 hours of run time. The other data set was recorded for a development engine with less than 200 hours of operation. The search for multiple optima was performed starting from more than 100 extreme points. Not a single case of multi-modality was encountered, i.e. one unique solution for each of the two data sets was consistently obtained. The RM12 engine cycle is typical for a modern fighter engine, implying that the obtained results can be transferred to, at least, most low bypass ratio turbofan engines. The paper goes on to describe the numerical difficulties that had to be resolved to obtain efficient and robust performance by the gradient solvers. Ill conditioning and noise may, as illustrated on a model problem, introduce local optima without a correspondence in the gas turbine physics. Numerical methods exploiting the special problem structure represented by a non-linear least squares formulation is given special attention. Finally, a mixed norm allowing for both robustness and numerical efficiency is suggested.

scholarly journals Specific interplanetary conditions for CIR-, Sheath-, and ICME-induced geomagnetic storms obtained by double superposed epoch analysis

2010 ◽  
Vol 28 (12) ◽  
pp. 2177-2186 ◽  
Author(s):  
Yu. I. Yermolaev ◽  
N. S. Nikolaeva ◽  
I. G. Lodkina ◽  
M. Yu. Yermolaev
Keyword(s):  
Large Scale ◽  
Geomagnetic Storms ◽  
Magnetic Cloud ◽  
Magnetic Storms ◽  
Main Phase ◽  
Corotating Interaction Region ◽  
Superposed Epoch Analysis ◽  
Epoch Analysis ◽  
Archive Data ◽  
Scale Types

Abstract. A comparison of specific interplanetary conditions for 798 magnetic storms with Dst <−50 nT during 1976–2000 was made on the basis of the OMNI archive data. We categorized various large-scale types of solar wind as interplanetary drivers of storms: corotating interaction region (CIR), Sheath, interplanetary CME (ICME) including both magnetic cloud (MC) and Ejecta, separately MC and Ejecta, and "Indeterminate" type. The data processing was carried out by the method of double superposed epoch analysis which uses two reference times (onset of storm and minimum of Dst index) and makes a re-scaling of the main phase of the storm in a such way that all storms have equal durations of the main phase in the new time reference frame. This method reproduced some well-known results and allowed us to obtain some new results. Specifically, obtained results demonstrate that (1) in accordance with "output/input" criteria the highest efficiency in generation of magnetic storms is observed for Sheath and the lowest one for MC, and (2) there are significant differences in the properties of MC and Ejecta and in their efficiencies.

Design and Analysis of an Aircraft Thermal Management System Linked to a Low-Bypass Ratio Turbofan Engine

2021 ◽  
Author(s):  
Robert A. Clark ◽  
Mingxuan Shi ◽  
Jonathan Gladin ◽  
Dimitri Mavris
Keyword(s):  
Thermal Management ◽  
Management System ◽  
Environmental Control ◽  
Cooling System ◽  
Heat Transfer Fluid ◽  
Turbofan Engine ◽  
Thermal Management System ◽  
Air Stream ◽  
The Impact ◽  
Bypass Ratio

Abstract The design of an aircraft thermal management system (TMS) that is capable of rejecting heat loads into the bypass stream of a typical low-bypass ratio turbofan engine, or a ram-air stream, is investigated. The TMS consists of an air cycle system (ACS), which is similar to the typical air cycle machines (ACMs) used on current aircraft, both military and commercial. This system turbocharges compressor bleed air and uses heat exchangers in a ram air stream or the engine bypass stream to cool the engine bleed air prior to expanding it to low temperatures suitable for heat rejection. In this study, a simple low-bypass ratio afterburning turbofan engine was modeled in NPSS to provide boundary conditions to the TMS system throughout the flight envelope of a typical military fighter aircraft. The engine was sized to produce sea level static (SLS) thrust roughly equivalent to that of an F-35-class engine. Two different variations of the TMS system, a ram air cooled and a bypass air cooled, were sized to handle a given demanded aircraft heat load, which might include environmental control system (ECS) loads, avionics cooling loads, weapons system loads, or other miscellaneous loads. The architecture and modeling of the TMS is described in detail, and the ability of the sized TMS to reject these demanded aircraft loads throughout several key off-design points was analyzed, along with the impact of ACS engine bleeds on engine thrust and fuel consumption. A comparison is made between the cooling capabilities of the ram-air stream versus the engine bypass stream, along with the benefits and drawbacks of each cooling stream. It is observed that the maximum load dissipation capability of the TMS is tied directly to the amount of engine bleed flow, while the level of bleed flow required is set by the temperature conditions imposed by the aircraft cooling system and the heat transfer fluid used in the ACS thermal transport bus. Furthermore, the higher bypass stream temperatures significantly limit the thermodynamic viability and capability of a TMS designed with bypass air as the ultimate heat sink. The results demonstrate the advantage that adaptive, variable cycle engines (VCEs) may have for future military aircraft designs, as they combine the best features of the two TMS architectures that were studied here.

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