scholarly journals Systems Engineering in Terms of Exergy

2009 ◽  
Vol 2009 ◽  
pp. 1-7 ◽  
Author(s):  
José A. Camberos ◽  
David J. Moorhouse
Keyword(s):  
Systems Engineering ◽  
Energy Systems ◽  
System Of Systems ◽  
System Level ◽  
Exergy Destruction ◽  
Aerospace Vehicles ◽  
Design And Optimization ◽  
Design Paradigm ◽  
Analysis Design ◽  
The Individual

We address the design of a flight vehicle from the viewpoint of a system of systems and we discuss the integration of the individual technical disciplines. Then a conceptual fundamental methodology and tools required for the analysis, design, and optimization of aerospace vehicles in terms of the efficient use of on-board energy are discussed. This suggests changing the design paradigm to the optimization of a system of energy systems. We propose a foundation for system-level design with optimization based on minimum exergy destruction.

scholarly journals Benefits of Exergy-Based Analysis for Aerospace Engineering Applications—Part I

2009 ◽  
Vol 2009 ◽  
pp. 1-11 ◽  
Author(s):  
John H. Doty ◽  
José A. Camberos ◽  
David J. Moorhouse
Keyword(s):  
Complex System ◽  
Research And Development ◽  
Operating Conditions ◽  
Aerospace Engineering ◽  
The Other ◽  
System Level ◽  
Exploratory Research ◽  
Design Paradigm ◽  
Analysis Design ◽  
Level Performance

This paper compares the analysis of systems from two different perspectives: an energy-based focus and an exergy-based focus. A complex system was simply modeled as interacting thermodynamic systems to illustrate the differences in analysis methodologies and results. The energy-based analysis had combinations of calculated states that are infeasible. On the other hand, the exergy-based analyses only allow feasible states. More importantly, the exergy-based analyses provide clearer insight to the combination of operating conditions for optimum system-level performance. The results strongly suggest changing the analysis/design paradigm used in aerospace engineering from energy-based to exergy-based. This methodology shift is even more critical in exploratory research and development where previous experience may not be available to provide guidance. Although the models used herein may appear simplistic, the message is very powerful and extensible to higher-fidelity models: the 1st Law is only anecessarycondition for design, whereas the 1st and 2nd Laws provide thesufficiencycondition.

scholarly journals System models for resilience in gerontology: application to the COVID-19 pandemic

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Katarzyna Klasa ◽  
Stephanie Galaitsi ◽  
Andrew Wister ◽  
Igor Linkov
Keyword(s):  
The Elderly ◽  
System Level ◽  
Improve Quality ◽  
Care Needs ◽  
Individual Level ◽  
Chronic Stressors ◽  
The World ◽  
Aging Adults ◽  
The Individual

AbstractThe care needs for aging adults are increasing burdens on health systems around the world. Efforts minimizing risk to improve quality of life and aging have proven moderately successful, but acute shocks and chronic stressors to an individual’s systemic physical and cognitive functions may accelerate their inevitable degradations. A framework for resilience to the challenges associated with aging is required to complement on-going risk reduction policies, programs and interventions. Studies measuring resilience among the elderly at the individual level have not produced a standard methodology. Moreover, resilience measurements need to incorporate external structural and system-level factors that determine the resources that adults can access while recovering from aging-related adversities. We use the National Academies of Science conceptualization of resilience for natural disasters to frame resilience for aging adults. This enables development of a generalized theory of resilience for different individual and structural contexts and populations, including a specific application to the COVID-19 pandemic.

scholarly journals Aircraft Requirements for Sustainable Regional Aviation

Aerospace ◽  
2021 ◽  
Vol 8 (3) ◽  
pp. 61
Author(s):  
Dominik Eisenhut ◽  
Nicolas Moebs ◽  
Evert Windels ◽  
Dominique Bergmann ◽  
Ingmar Geiß ◽  
...  
Keyword(s):  
Systems Engineering ◽  
System Level ◽  
Policy Initiative ◽  
The European Union ◽  
Calculation Methods ◽  
Figures Of Merit ◽  
Performance Requirements ◽  
High Level ◽  
Different Levels ◽  
The Eu

Recently, the new Green Deal policy initiative was presented by the European Union. The EU aims to achieve a sustainable future and be the first climate-neutral continent by 2050. It targets all of the continent’s industries, meaning aviation must contribute to these changes as well. By employing a systems engineering approach, this high-level task can be split into different levels to get from the vision to the relevant system or product itself. Part of this iterative process involves the aircraft requirements, which make the goals more achievable on the system level and allow validation of whether the designed systems fulfill these requirements. Within this work, the top-level aircraft requirements (TLARs) for a hybrid-electric regional aircraft for up to 50 passengers are presented. Apart from performance requirements, other requirements, like environmental ones, are also included. To check whether these requirements are fulfilled, different reference missions were defined which challenge various extremes within the requirements. Furthermore, figures of merit are established, providing a way of validating and comparing different aircraft designs. The modular structure of these aircraft designs ensures the possibility of evaluating different architectures and adapting these figures if necessary. Moreover, different criteria can be accounted for, or their calculation methods or weighting can be changed.

scholarly journals USING MODEL-BASED SYSTEMS ENGINEERING FOR NEED-BASED AND CONSISTENT SUPPORT OF THE DESIGN PROCESS

2021 ◽  
Vol 1 ◽  
pp. 3369-3378
Author(s):  
Stephan Husung ◽  
Christian Weber ◽  
Atif Mahboob ◽  
Sven Kleiner
Keyword(s):  
Systems Engineering ◽  
Development Process ◽  
Added Value ◽  
System Level ◽  
System Failure ◽  
Model Based ◽  
Continuous Use ◽  
Model Based Systems Engineering ◽  
Consistent Support ◽  
Modelling Approaches

AbstractModel-Based Systems Engineering (MBSE) is an efficient approach to support product development in order to meet today's challenges. The MBSE approach includes methods and, above all, modelling approaches of the technical system with the aim of continuous use in development. The objective of this paper is to use the potential of the MBSE models and to show the added value of such models on the system level when used as a single source. With this objective, this paper presents a three-step approach to systematically identify and apply meaningful modelling approaches within MBSE, based on the needs during the development process. Furthermore, an FMEA example is included in this paper to elaborate the use of MBSE in the system failure analysis.

scholarly journals Rotor Interaction Noise in Counter-Rotating Propfan Propulsion Systems

2011 ◽  
Vol 134 (1) ◽  
Author(s):  
Andreas Peters ◽  
Zoltán S. Spakovszky
Keyword(s):  
Polar Angle ◽  
Secondary Flows ◽  
Tip Vortex ◽  
System Level ◽  
Analysis Tool ◽  
Acoustic Analogy ◽  
Wake Interaction ◽  
Open Rotor ◽  
And Performance ◽  
The Individual

Due to their inherent noise challenge and potential for significant reductions in fuel burn, counter-rotating propfans (CRPs) are currently being investigated as potential alternatives to high-bypass turbofan engines. This paper introduces an integrated noise and performance assessment methodology for advanced propfan powered aircraft configurations. The approach is based on first principles and combines a coupled aircraft and propulsion system mission and performance analysis tool with 3D unsteady, full-wheel CRP computational fluid dynamics computations and aeroacoustic simulations. Special emphasis is put on computing CRP noise due to interaction tones. The method is capable of dealing with parametric studies and exploring noise reduction technologies. An aircraft performance, weight and balance, and mission analysis was first conducted on a candidate CRP powered aircraft configuration. Guided by data available in the literature, a detailed aerodynamic design of a pusher CRP was carried out. Full-wheel unsteady 3D Reynolds-averaged Navier-Stokes (RANS) simulations were then used to determine the time varying blade surface pressures and unsteady flow features necessary to define the acoustic source terms. A frequency domain approach based on Goldstein’s formulation of the acoustic analogy for moving media and Hanson’s single rotor noise method was extended to counter-rotating configurations. The far field noise predictions were compared to measured data of a similar CRP configuration and demonstrated good agreement between the computed and measured interaction tones. The underlying noise mechanisms have previously been described in literature but, to the authors’ knowledge, this is the first time that the individual contributions of front-rotor wake interaction, aft-rotor upstream influence, hub-endwall secondary flows, and front-rotor tip-vortices to interaction tone noise are dissected and quantified. Based on this investigation, the CRP was redesigned for reduced noise incorporating a clipped rear-rotor and increased rotor-rotor spacing to reduce upstream influence, tip-vortex, and wake interaction effects. Maintaining the thrust and propulsive efficiency at takeoff conditions, the noise was calculated for both designs. At the interaction tone frequencies, the redesigned CRP demonstrated an average reduction of 7.25 dB in mean sound pressure level computed over the forward and aft polar angle arcs. On the engine/aircraft system level, the redesigned CRP demonstrated a reduction of 9.2 dB in effective perceived noise (EPNdB) and 8.6 EPNdB at the Federal Aviation Regulations (FAR) 36 flyover and sideline observer locations, respectively. The results suggest that advanced open rotor designs can possibly meet Stage 4 noise requirements.

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