Thermographical analysis of turbo-generator rotor

Abstract: Refurbished or newly constructed utility-scale turbo-generator rotors requires stringent acceptance testing before commissioning and subsequent operation thereof. Conventional methods of testing are inadequate in detecting and locating thermally induced problems. This paper presents a thermographic method for carrying out thermal instability testing of generator rotors. An experimental setup is used to map the thermal distribution of the generator rotor. Implementation and testing of the method is carried out in a laboratory setting using a down-scaled turbo-generator rotor

Diagnosis of arcing in retaining rings of turbogenerators

Retaining rings are an important and most highly stressed component of the entire turbogenerator system. Arcing in retaining rings is a very serious problem and could easily escalate to a full-blown failure. In this project we diagnose arcing in the retaining rings. We determine the most likely mechanism by which arcing occurs and the category of events which lead to it. Specifically, we try to test two different mechanisms which could have led to the arc marks. The first one is sparking due to high field efects (or high voltage gradient across the contact junction) and the other is a make-and-break contact arcing owing to the presence of inductance in the system. Experiments performed to measure the contact resistance between the retaining ring and mild iron piece indicate that even very high fault currents cannot produce the voltage required to cause sparking. Transient 3-D finite element simulations show that a make-and-break contact can generate localized voltage spikes, on account of small contact break, which are high enough to lead to arcing. Interestingly this can happen at relatively low currents

Multi-disciplinary investigation of a flap blown turboelectric distributed propulsion blended wing body aircraft.

Growing concerns about the rising costs of fuel as well as environmental issues have led to multiple innovative and futuristic aircraft concepts to tackle these issues. Turboelectric Distributed Propulsion (TeDP) and boundary layer ingestion are two such concepts. When applied to a conceptual aircraft such as the N3-X, it results in a blended wing body (BWB) aircraft with an array of fan propulsors mounted near the rear of the aircraft body and driven by superconducting motors powered by superconducting generators in the wing tip mounted turbogenerators. The elevator flaps of such a BWB aircraft are located at the trailing edge of the aircraft body. Coupled with the exhaust mass flow from the propulsor fan nozzles, it presents a chance to utilize flap blowing and/or thrust vectoring to further improve on the aircraft performance. By utilizing boundary layer ingestion, there can be expected 5-6% total fuel savings while flap blowing can further enhance the fuel savings to a total of 8-9%. However, integration issues such as intake pressure losses, deficiency in fan propulsor efficiency tends to mitigate the benefits derived. Furthermore, it is difficult to separate various design disciplines such as aerodynamics and propulsion in such a high integrated aircraft. Flap blowing further correlates to both disciplines. This dissertation addresses a broad overall design methodology that is both multi-disciplinary and multi-fidelity, addressing the above mentioned issues. Flap blowing can be seen to be a linkage between the often separate aerodynamics and propulsion design disciplines in an aircraft. The strip method code, designed to incorporate flap blowing into the preliminary design and analysis is presented in this study, showing its impact on aerodynamic performance, flight dynamic response and propulsion system design. Furthermore, other disciplines such as boundary layer ingestion, weight, and flight dynamics are considered and incorporated into the methodology. The main figure of merit used is the total fuel consumption of the aircraft and in addition, take-off distances are also studied and analysed. Take-off distances incorporating flap blowing and thrust vectoring demonstrated a reduction in distances between 25-30%. The reduction in take-off distance also led to the study on the potential of re-sizing the BWB outer wings to further reduce total fuel consumption and has shown great promise.PhD in Aerospac

A Comprehensive Optimization Framework for Designing Sustainable Renewable Energy Production Systems

As the world has recognized the importance of diversifying its energy resource portfolio away from fossil resources and more towards renewable resources such as biomass, there arises a need for developing strategies which can design renewable sustainable value chains that can be scaled up efficiently and provide tangible net environmental benefits from energy utilization. The objective of this research is to develop and implement a novel decision-making framework for the optimal design of renewable energy systems. The proposed optimization framework is based on a distributed, systematic approach which is composed of different layers including systems-based strategic optimization, detailed mechanistic modeling and operational level optimization. In the strategic optimization the model is represented by equations which describe physical flows of materials across the system nodes and financial flows that result from the system design and material movements. Market uncertainty is also incorporated into the model through stochastic programming. The output of the model includes optimal design of production capacity of the plant for the planning horizon by maximizing the net present value (NPV). The second stage consists of three main steps including simulation of the process in the simulation software, identification of critical sources of uncertainties through global sensitivity analysis, and employing stochastic optimization methodologies to optimize the operating condition of the plant under uncertainty. To exemplify the efficacy of the proposed framework a hypothetical lignocellulosic biorefinery based on sugar conversion platform that converts biomass to value-added biofuels and biobased chemicals is utilized as a case study. Furthermore, alternative technology options and possible process integrations in each section of the plant are analysed by exploiting the advantages of process simulation and the novel hybrid optimization framework. In conjunction with the simulation and optimization studies, the proposed framework develops quantitative metrics to associate economic values with technical barriers. The outcome of this work is a new distributed decision support framework which is intended to help economic development agencies, as well as policy makers in the renewable energy enterprises

Energy: A continuing bibliography with indexes (Issue 29)

This bibliography lists 1360 reports, articles, and other documents introduced into the NASA scientific and technical information system from January 1, 1981 through March 31, 1981

Energy: A special bibliography with indexes, April 1974

This literature survey of special energy and energy related documents lists 1708 reports, articles, and other documents introduced into the NASA scientific and technical information system between January 1, 1968, and December 31, 1973. Citations from International Aerospace Abstracts (IAA) and Scientific and Technical Aerospace Reports (STAR) are grouped according to the following subject categories: energy systems; solar energy; primary energy sources; secondary energy sources; energy conversion; energy transport, transmission, and distribution; and energy storage. The index section includes the subject, personal author, corporate source, contract, report, and accession indexes

ECOS 2012

The 8-volume set contains the Proceedings of the 25th ECOS 2012 International Conference, Perugia, Italy, June 26th to June 29th, 2012. ECOS is an acronym for Efficiency, Cost, Optimization and Simulation (of energy conversion systems and processes), summarizing the topics covered in ECOS: Thermodynamics, Heat and Mass Transfer, Exergy and Second Law Analysis, Process Integration and Heat Exchanger Networks, Fluid Dynamics and Power Plant Components, Fuel Cells, Simulation of Energy Conversion Systems, Renewable Energies, Thermo-Economic Analysis and Optimisation, Combustion, Chemical Reactors, Carbon Capture and Sequestration, Building/Urban/Complex Energy Systems, Water Desalination and Use of Water Resources, Energy Systems- Environmental and Sustainability Issues, System Operation/ Control/Diagnosis and Prognosis, Industrial Ecology

Industry and Tertiary Sectors towards Clean Energy Transition

The clean energy transition is the transition from the use of nonrenewable energy sources to renewable sources and is part of the wider transition to sustainable economies through the use of renewable energy, the adoption of energy-saving measures, and sustainable development techniques. The clean energy transition is a long and complex process that will lead to an epochal change, and it will allow safeguarding the health of the environment in the long term. For its success, it necessitates contribution from everyone, from the individual citizen to large multinationals, passing through SMEs; national and international policies play a key role in paving the way to this process. This Special Issue is focused on technical, financial, and policy-related aspects linked to the transition of industrial and service sectors towards energy saving and decarbonization. These different aspects are interrelated and, as such, they have been analyzed with an interdisciplinary approach, for example, by combining economic and technical information. The collected papers focus on energy efficiency and clean-energy key technologies, renewable sources, energy management and monitoring systems, energy policies and regulations, and economic and financial aspects

Energy: A continuing bibliography with indexes

This bibliography lists 1546 reports, articles, and other documents introduced into the NASA scientific and technical information system from April 1, 1981 through June 30, 1981