Robust Design of Advanced Thermoelectric Conversion Systems: Probabilistic Design Impacts on Specific Power and Power Flux Optimization

2008 ◽  
Vol 1102 ◽  
Author(s):  
Terry J Hendricks ◽  
Naveen K. Karri
Keyword(s):  
System Design ◽  
Thermal Energy ◽  
Integrated System ◽  
System Level ◽  
Specific Power ◽  
Design Parameters ◽  
Probabilistic Design ◽  
Power Flux ◽  
Research Attention ◽  
System Designs

AbstractAdvanced, direct thermal energy conversion technologies are receiving increased research attention in order to recover waste thermal energy in advanced vehicles and industrial processes. Advanced thermoelectric (TE) systems necessarily require integrated system-level analyses to establish accurate optimum system designs. Past system-level design and analysis has relied on well-defined deterministic input parameters even though many critically important environmental and system design parameters in the above mentioned applications are often randomly variable, sometimes according to complex relationships, rather than discrete, well-known deterministic variables. This work describes new research and development creating techniques and capabilities for probabilistic design and analysis of advanced TE power generation systems to quantify the effects of randomly uncertain design inputs in determining more robust optimum TE system designs and expected outputs. Selected case studies involving stochastic TE .material properties demonstrate key stochastic material impacts on power, optimum TE area, specific power, and power flux in the TE design optimization process. Magnitudes and directions of these design modifications are quantified for selected TE system design analysis cases.

Automatic Integration of System-Level Design and System Optimization Based on SysML

2012 ◽  
Vol 249-250 ◽  
pp. 1154-1159
Author(s):  
Yu Sheng Liu ◽  
Wen Qiang Yuan
Keyword(s):  
System Design ◽  
Systems Engineering ◽  
Optimization Model ◽  
System Modeling ◽  
System Optimization ◽  
System Level ◽  
Design Parameters ◽  
System Level Design ◽  
Model Based ◽  
Level Design

Model based systems engineering (MBSE) is becoming a promising approach for the system-level design of complex mechatronics. And several MBSE tools are developed to conduct system modeling. However, the system design cannot be optimized in current MBSE tools. In this study, an approach is presented to conduct the task. A set of optimization stereotype is defined at first which is used to formalize the optimization model based on the system design model. Then the design parameters and their relationships applied optimization stereotypes are extracted and transferred to construct the tool-dependent optimization model. Finally, the optimization model is solved and the results are given back and then modify the corresponding system model automatically. In this paper, MagicDraw is used to model the whole system whereas Matlab optimizer is used for optimization. The combustion engine is chosen as the example to illustrate the proposed approach.

scholarly journals A Study of Student Design Team Behaviors in Complex System Design

2012 ◽  
Vol 134 (12) ◽  
Author(s):  
Jesse Austin-Breneman ◽  
Tomonori Honda ◽  
Maria C. Yang
Keyword(s):  
Complex System ◽  
System Design ◽  
System Integration ◽  
Large Scale ◽  
Engineering Students ◽  
System Level ◽  
Design Parameters ◽  
Local Searches ◽  
Wide Range ◽  
Complex System Design

Large-scale engineering systems require design teams to balance complex sets of considerations using a wide range of design and decision-making skills. Formal, computational approaches for optimizing complex systems offer strategies for arriving at optimal solutions in situations where system integration and design optimization are well-formulated. However, observation of design practice suggests engineers may be poorly prepared for this type of design. Four graduate student teams completed a distributed, complex system design task. Analysis of the teams' design histories suggests three categories of suboptimal approaches: global rather than local searches, optimizing individual design parameters separately, and sequential rather than concurrent optimization strategies. Teams focused strongly on individual subsystems rather than system-level optimization, and did not use the provided system gradient indicator to understand how changes in individual subsystems impacted the overall system. This suggests the need for curriculum to teach engineering students how to appropriately integrate systems as a whole.

Case study of integrated decision-making for deep energy-efficient retrofits

2014 ◽  
Vol 8 (4) ◽  
pp. 434-455 ◽  
Author(s):  
Pelin Gultekin ◽  
Chimay J. Anumba ◽  
Robert M. Leicht
Keyword(s):  
Decision Making ◽  
System Design ◽  
Design Process ◽  
Integrated System ◽  
Comfort Level ◽  
System Level ◽  
Decision Making Process ◽  
Design Decisions ◽  
Content Type

Purpose – This paper aims to focus on the decision-making process of integrated system design. Buildings can benefit from different system integration working toward the unified goal of providing the needed conditions and improving the comfort level of occupants. It is important to engage all system needs and priorities in the design by keeping goal into consideration. Even though there is vast potential in the coordination of system design decisions, there is a need to increase the transparency of the decision-making process by developing methods to incorporate multi-dimensional design attributes. Design/methodology/approach – This is achieved by considering all system design priorities with respect to decision attributes, as well as the inter-system inputs based on information and knowledge. Data were collected through interviews, collaboration meetings and design document reviews, which helped to facilitate triangulation. Findings – This paper presents the findings of a case study of deep retrofit design process that seeks to reduce energy consumption through integrated system decisions with several system combinations. In addition, such design decisions highlighted the fact that the values need to be flexible at the system level. Research limitations/implications – This paper presents an in-depth analysis of a single case study. Multiple case studies are being investigated for the future of this research. Practical implications – This paper presents the methods used for integrated design process priorities that will enable design teams to make decisions that lead to improved energy performance in retrofit projects. Originality/value – The case study building in this paper is a showcase building with cutting edge technologies and techniques, as well as a scalable and collaborative design process. It is an example of a best-in-class retrofit process designed through whole building design principles within the target budget. The paper demonstrates system design selection criteria that are embraced by value prioritization.

Design of a Robust Memristive Spiking Neuromorphic System with Unsupervised Learning in Hardware

2021 ◽  
Vol 17 (4) ◽  
pp. 1-26
Author(s):  
Md Musabbir Adnan ◽  
Sagarvarma Sayyaparaju ◽  
Samuel D. Brown ◽  
Mst Shamim Ara Shawkat ◽  
Catherine D. Schuman ◽  
...  
Keyword(s):  
Unsupervised Learning ◽  
Recognition Task ◽  
Single Layer ◽  
Process Variations ◽  
Spike Timing ◽  
System Level ◽  
Design Parameters ◽  
Digital Pulse ◽  
Neuromorphic System ◽  
The Impact

Spiking neural networks (SNN) offer a power efficient, biologically plausible learning paradigm by encoding information into spikes. The discovery of the memristor has accelerated the progress of spiking neuromorphic systems, as the intrinsic plasticity of the device makes it an ideal candidate to mimic a biological synapse. Despite providing a nanoscale form factor, non-volatility, and low-power operation, memristors suffer from device-level non-idealities, which impact system-level performance. To address these issues, this article presents a memristive crossbar-based neuromorphic system using unsupervised learning with twin-memristor synapses, fully digital pulse width modulated spike-timing-dependent plasticity, and homeostasis neurons. The implemented single-layer SNN was applied to a pattern-recognition task of classifying handwritten-digits. The performance of the system was analyzed by varying design parameters such as number of training epochs, neurons, and capacitors. Furthermore, the impact of memristor device non-idealities, such as device-switching mismatch, aging, failure, and process variations, were investigated and the resilience of the proposed system was demonstrated.

Long-Distance, High-Volume Transport of Coal by Slurry Pipeline

1981 ◽  
Vol 103 (4) ◽  
pp. 322-329 ◽  
Author(s):  
T. E. Stripling ◽  
R. G. Holter
Keyword(s):  
System Design ◽  
High Volume ◽  
The United States ◽  
Volume Transport ◽  
Transportation Systems ◽  
Integrated System ◽  
Coal Slurry ◽  
Long Distance ◽  
Pump Stations ◽  
Integrated System Design

Several long-distance, high-volume coal slurry transportation systems are planned or proposed for the United States. These new systems offer a method of transport that is both economical and environmentally attractive. The design of these systems will be a challenge to the pipeline engineer since an integrated, system design of several components is necessary to achieve an optimum overall effect. The pipeline, pump stations, instrumentation and controls, slurry preparation, and utilization facilities must all be considered in the design. The purpose of this paper is to describe the system components of a large coal slurry transportation system in detail and to show the special design considerations required for the overall system design considering the interrelationships of the various components.

scholarly journals TEG Design for Waste Heat Recovery at an Aviation Jet Engine Nozzle

2018 ◽  
Vol 8 (12) ◽  
pp. 2637 ◽  
Author(s):  
Pawel Ziolkowski ◽  
Knud Zabrocki ◽  
Eckhard Müller
Keyword(s):  
Fuel Consumption ◽  
Power Output ◽  
Waste Heat ◽  
Positive Impact ◽  
Element Model ◽  
System Level ◽  
Specific Power ◽  
Transfer Coefficients ◽  
Te Modules ◽  
Te Material

Finite element model (FEM)-based simulations are conducted for the application of a thermoelectric generator (TEG) between the hot core stream and the cool bypass flow at the nozzle of an aviation turbofan engine. This work reports the resulting requirements on the TEG design with respect to applied thermoelectric (TE) element lengths and filling factors (F) of the TE modules in order to achieve a positive effect on the specific fuel consumption. Assuming a virtual optimized TE material and varying the convective heat transfer coefficients (HTC) between the nozzle surfaces and the gas flows, this work reports the achievable power output. System-level requirement on the gravimetric power density (>100 Wkg−1) can only be met for F ≤ 21%. When extrapolating TEG coverage to the full nozzle surface, the power output reaches 1.65 kW per engine. The assessment of further potential for power generation is demonstrated by a parametric study on F, convective HTC, and materials performance. This study confirms a feasible design range for TEG installation on the aircraft nozzle with a positive impact on the fuel consumption. This application translates into a reduction of operational costs, allowing for an economically efficient TEG-installation with respect to the cost-specific power output of modern thermoelectric materials.

scholarly journals Misalignment in Gas Foil Journal Bearings: An Experimental Study

2008 ◽  
Author(s):  
Samuel A. Howard
Keyword(s):  
Journal Bearings ◽  
System Level ◽  
Design Parameters ◽  
Foil Bearing ◽  
Alignment System ◽  
Successful Design ◽  
Shaft Alignment ◽  
Bearing Force ◽  
Management Schemes ◽  
Level Performance

As gas foil journal bearings become more prevalent in production machines, such as small gas turbine propulsion systems and microturbines, system level performance issues must be identified and quantified in order to provide for successful design practices. Several examples of system level design parameters that are not fully understood in foil bearing systems are thermal management schemes, alignment requirements, balance requirements, thrust load balancing, and others. In order to address some of these deficiencies and begin to develop guidelines, this paper presents a preliminary experimental investigation of the misalignment tolerance of gas foil journal bearing systems. Using a notional gas foil bearing supported rotor and a laser-based shaft alignment system, increasing levels of misalignment are imparted to the bearing supports while monitoring temperature at the bearing edges. The amount of misalignment that induces bearing failure is identified and compared to other conventional bearing types such as cylindrical roller bearings and angular contact ball bearings. Additionally, the dynamic response of the rotor indicates that the gas foil bearing force coefficients may be affected by misalignment.

Direct Coupling of a Two-Dimensional Fan Model in a Turbofan Engine Performance Simulation

2016 ◽  
Author(s):  
Ioannis Templalexis ◽  
Alexios Alexiou ◽  
Vassilios Pachidis ◽  
Ioannis Roumeliotis ◽  
Nikolaos Aretakis
Keyword(s):  
Three Dimensional ◽  
Engine Performance ◽  
System Level ◽  
Design Parameters ◽  
High Fidelity ◽  
Two Dimensional ◽  
Performance Simulation ◽  
Cfd Models ◽  
Component Design ◽  
Complex Phenomena

Coupling of high fidelity component calculations with overall engine performance simulations (zooming) can provide more accurate physics and geometry based estimates of component performance. Such a simulation strategy offers the ability to study complex phenomena and their effects on engine performance and enables component design changes to be studied at engine system level. Additionally, component interaction effects can be better captured. Overall, this approach can reduce the need for testing and the engine development time and cost. Different coupling methods and tools have been proposed and developed over the years ranging from integrating the results of the high fidelity code through conventional performance component maps to fully-integrated three-dimensional CFD models. The present paper deals with the direct integration of an in-house two-dimensional (through flow) streamline curvature code (SOCRATES) in a commercial engine performance simulation environment (PROOSIS) with the aim to establish the necessary coupling methodology that will allow future advanced studies to be performed (e.g. engine condition diagnosis, design optimization, mission analysis, distorted flow). A notional two-shaft turbofan model typical for light business jets and trainer aircraft is initially created using components with conventional map-defined performance. Next, a derivative model is produced where the fan component is replaced with one that integrates the high fidelity code. For both cases, an operating line is simulated at sea-level static take-off conditions and their performances are compared. Finally, the versatility of the approach is further demonstrated through a parametric study of various fan design parameters for a better thermodynamic matching with the driving turbine at design point operation.

scholarly journals Modeling Airtanker Flight Distance between Concurrent Fires: The Development and Use of Statistical Distribution Parameters

2008 ◽  
Vol 54 (1) ◽  
pp. 47-57
Author(s):  
Francis E. Greulich
Keyword(s):  
System Design ◽  
Analytical Methods ◽  
Statistical Distribution ◽  
Flight Distance ◽  
Design Parameters ◽  
Initial Attack ◽  
System Planning ◽  
Protection Zone ◽  
Transfer Activity ◽  
Distribution Parameters

Abstract Airtankers, while actively engaging in initial attack, are sometimes reassigned and flown directly to another randomly occurring initial attack fire. Airtanker system planning that means to incorporate this fire-to-fire transfer activity needs information about the flight distance between these randomly located fires. Moments of the distance distribution, derived in this article, can be used to characterize and evaluate fire-to-fire airtanker dispatch within and between protection areas. A hypothetical example illustrates how a proposed change in an airtanker protection zone can affect not only airbase-to-fire flight distance but also fire-to-fire flight distance. In this example, the expected airbase-to-fire distance and the expected total transfer-flight distance are both significantly reduced, but at the same time, somewhat unexpectedly, the average fire-to-fire flight distance actually increases. The discovery and quantification of such unanticipated results can potentially influence airtanker system design. These key system design parameters can now be obtained through the exceedingly fast and accurate analytical methods presented here.

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