Correction: Numerical Modeling and Analysis of Afterburner Combustion of a Low Bypass Ratio Turbofan Engine

2020 ◽  
Author(s):  
Muhammad Muneeb Safdar ◽  
Jehanzeb Masud ◽  
Bilal Mufti ◽  
Hafiz Usman Naseer ◽  
Aizaz Farooq ◽  
...  
Keyword(s):  
Numerical Modeling ◽  
Turbofan Engine ◽  
Modeling And Analysis ◽  
Bypass Ratio

Numerical Modeling and Analysis of Afterburner Combustion of a Low Bypass Ratio Turbofan Engine

2020 ◽  
Author(s):  
Muhammad Muneeb Safdar ◽  
Jehanzeb Masud ◽  
Bilal Mufti ◽  
Hafiz Usman Naseer ◽  
Aizaz Farooq ◽  
...  
Keyword(s):  
Numerical Modeling ◽  
Turbofan Engine ◽  
Modeling And Analysis ◽  
Bypass Ratio

scholarly journals Special Issue “Applications of Finite Element Modeling for Mechanical and Mechatronic Systems”

2021 ◽  
Vol 11 (11) ◽  
pp. 5170
Author(s):  
Marek Krawczuk ◽  
Magdalena Palacz
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Numerical Modeling ◽  
Engineering Practice ◽  
The Finite Element Method ◽  
Special Issue ◽  
Mechatronic Systems ◽  
Modeling And Analysis ◽  
Modern Engineering ◽  
Concise Description

Modern engineering practice requires advanced numerical modeling because, among other things, it reduces the costs associated with prototyping or predicting the occurrence of potentially dangerous situations during operation in certain defined conditions. Different methods have so far been used to implement the real structure into the numerical version. The most popular have been variations of the finite element method (FEM). The aim of this Special Issue has been to familiarize the reader with the latest applications of the FEM for the modeling and analysis of diverse mechanical problems. Authors are encouraged to provide a concise description of the specific application or a potential application of the Special Issue.

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.

Numerical modeling and analysis of thermal and mechanical behavior for ground wire-clamp system under short-circuit current

2021 ◽  
Vol 201 ◽  
pp. 107497
Author(s):  
Gang Liu ◽  
Wencheng Zheng ◽  
Deming Guo ◽  
Ruidong Peng ◽  
Xuan Lin ◽  
...  
Keyword(s):  
Numerical Modeling ◽  
Mechanical Behavior ◽  
Short Circuit ◽  
Short Circuit Current ◽  
Modeling And Analysis

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.

Numerical modeling and analysis of heat transfer for floatation nozzle with a flexible substrate

2019 ◽  
Vol 137 ◽  
pp. 665-674 ◽  
Author(s):  
Tianlun Huang ◽  
Penghui Tan ◽  
Maoyuan Li ◽  
Yun Zhang ◽  
Huamin Zhou
Keyword(s):  
Heat Transfer ◽  
Numerical Modeling ◽  
Flexible Substrate ◽  
Modeling And Analysis

Numerical modeling and analysis of dual medium thermocline thermal energy storage

2018 ◽  
Vol 16 ◽  
pp. 218-230 ◽  
Author(s):  
Bhaskar Rahul Nandi ◽  
Santanu Bandyopadhyay ◽  
Rangan Banerjee
Keyword(s):  
Numerical Modeling ◽  
Energy Storage ◽  
Thermal Energy ◽  
Thermal Energy Storage ◽  
Modeling And Analysis

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

2021 ◽  
Author(s):  
Robert Clark ◽  
Mingxuan Shi ◽  
Jonathan Gladin ◽  
Dimitri N. Mavris
Keyword(s):  
Thermal Management ◽  
Management System ◽  
Cooling System ◽  
Maximum Load ◽  
Fighter Aircraft ◽  
Turbofan Engine ◽  
Cycle System ◽  
Thermal Management System ◽  
Air Stream ◽  
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, similar to the typical air cycle machines 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. Two variations of the TMS system, a ram air cooled and a bypass air cooled, were sized to handle a given demanded aircraft heat load. The ability of the sized TMS to reject the demanded aircraft load throughout several key off-design points was analyzed. It was observed that the maximum load dissipation capability of the TMS is tied 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. Notably, engine bypass stream temperatures significantly limit the thermodynamic viability of a TMS designed with bypass air as the heat sink. The results demonstrate the advantage that variable cycle engines may have for future aircraft designs.

Sign in / Sign up

Export Citation Format

Share Document