Thermal analysis and air flow modelling of electrical machines

Thermal analysis is an important topic that can affect the electrical machine performance, reliability, lifetime and efficiency. In order to predict the electrical machine thermal performance accurately, thermal analysis of electrical machines must include fluid flow modelling. One of the technologies which may be used to estimate the flow distribution and pressure losses in throughflow ventilated machines is flow network analysis, but suitable correlations that can be used to estimate the pressure losses in rotor ducts due to fluid shock is not available. The aim of this work is to investigate how the rotation affects the pressure losses in rotor ducts by performing a dimensional analysis. Apart from the additional friction loss due to the effects of rotation, other rotational pressure losses that appear in a rotor-stator system are: duct entrance loss due to fluid shock and combining flow loss at the exit of the rotor-stator gap. These losses are analysed using computational fluid dynamics (CFD) methods. The CFD simulations use the Reynolds-averaged Navier Stokes (RANS) approach. An experimental test rig is built to validate the CFD findings. The investigation showed that the CFD results are consistent with the experimental results and the rotational pressure losses correlate well with the rotation ratio (a dimensionless parameter). It shows that the rotational pressure loss generally increases with the increase in the rotation ratio. At certain operating conditions, the rotational pressure loss can contribute over 50 % of the total system loss. The investigation leads to an original set of correlations for the pressure losses in air ducts in the rotor due to fluid shock which are more suitable to be applied to fluid flow modelling of throughflow ventilated machines. Such correlations provide a significant contribution to the field of thermal modelling of electrical machines. They are incorporated into the air flow modelling tool that has been programmed in Portunus by the present author. The modelling tool can be integrated with the existing thermal modelling method, lumped-parameter thermal network (LPTN) to form a complete analytical thermal-fluid modelling method

High speed high power electrical machines

DEng ThesisHigh Speed High Power (HSHP) electrical machines push the limits of electromagnetics, material capabilities and construction techniques. In doing so they are able to match the power performance of high speed turbomachinery such as gas turbines, compressors and expanders. This makes them attractive options for direct coupling to such machinery as either a power source or as a generator; eliminating the need for gearboxes and achieving a smaller system size and greater reliability. The design of HSHP machines is a challenging, iterative process. Mechanical, electromagnetic and thermal constraints are all placed on the machine shape, topology, operating point and materials. The designer must balance all of these constraints to find a workable solution that is mechanically stable, can work within the available electrical supply and will not overheat. This thesis researches the fundamental origins and interaction of the mechanical, electromagnetic and thermal constraints on electrical machines. Particular attention was paid to improving the accuracy of traditional mechanical rotor design processes, and improving loss estimation in inverter fed machines. The issues of selecting an appropriate electric loading for low voltage machines and choosing effective, economic cooling strategies were explored in detail. An analytical iterative design process that combines mechanical, electromagnetic and thermal design is proposed; this process balances the need for speed versus accuracy for the initial design of a machine, with Finite Element Analysis used only for final validation of performance and losses. The design process was tested on the design and manufacture of a 1.1MW 30,000rpm PM dynamometer used in an industrial test stand. The machine operating point was chosen to meet a gap in the industrial machines market and exceed the capabilities of other commercially available machines of the same speed. The resulting machine was successfully tested and comfortably meets the performance criteria used in the design process

Advanced Burner Test Reactor Preconceptual Design Report.

The goals of the Global Nuclear Energy Partnership (GNEP) are to expand the use of nuclear energy to meet increasing global energy demand, to address nuclear waste management concerns and to promote non-proliferation. Implementation of the GNEP requires development and demonstration of three major technologies: (1) Light water reactor (LWR) spent fuel separations technologies that will recover transuranics to be recycled for fuel but not separate plutonium from other transuranics, thereby providing proliferation-resistance; (2) Advanced Burner Reactors (ABRs) based on a fast spectrum that transmute the recycled transuranics to produce energy while also reducing the long term radiotoxicity and decay heat loading in the repository; and (3) Fast reactor fuel recycling technologies to recover and refabricate the transuranics for repeated recycling in the fast reactor system. The primary mission of the ABR Program is to demonstrate the transmutation of transuranics recovered from the LWR spent fuel, and hence the benefits of the fuel cycle closure to nuclear waste management. The transmutation, or burning of the transuranics is accomplished by fissioning and this is most effectively done in a fast spectrum. In the thermal spectrum of commercial LWRs, some transuranics capture neutrons and become even heavier transuranics rather than being fissioned. Even with repeated recycling, only about 30% can be transmuted, which is an intrinsic limitation of all thermal spectrum reactors. Only in a fast spectrum can all transuranics be effectively fissioned to eliminate their long-term radiotoxicity and decay heat. The Advanced Burner Test Reactor (ABTR) is the first step in demonstrating the transmutation technologies. It directly supports development of a prototype full-scale Advanced Burner Reactor, which would be followed by commercial deployment of ABRs. The primary objectives of the ABTR are: (1) To demonstrate reactor-based transmutation of transuranics as part of an advanced fuel cycle; (2) To qualify the transuranics-containing fuels and advanced structural materials needed for a full-scale ABR; and (3) To support the research, development and demonstration required for certification of an ABR standard design by the U.S. Nuclear Regulatory Commission. The ABTR should also address the following additional objectives: (1) To incorporate and demonstrate innovative design concepts and features that may lead to significant improvements in cost, safety, efficiency, reliability, or other favorable characteristics that could promote public acceptance and future private sector investment in ABRs; (2) To demonstrate improved technologies for safeguards and security; and (3) To support development of the U.S. infrastructure for design, fabrication and construction, testing and deployment of systems, structures and components for the ABRs. Based on these objectives, a pre-conceptual design of a 250 MWt ABTR has been developed; it is documented in this report. In addition to meeting the primary and additional objectives listed above, the lessons learned from fast reactor programs in the U.S. and worldwide and the operating experience of more than a dozen fast reactors around the world, in particular the Experimental Breeder Reactor-II have been incorporated into the design of the ABTR to the extent possible

Handbook of data on selected engine components for solar thermal applications

A data base on developed and commercially available power conversion system components for Rankine and Brayton cycle engines, which have potential application to solar thermal power-generating systems is presented. The status of the Stirling engine is discussed

Bibliography of Lewis Research Center technical publications announced in 1980

This compilation of abstracts describes and indexes over 780 research reports, journal articles, conference presentations, patents and patent applications, and theses resulting from the scientific and engineering work performed and managed by the Lewis Research Center in 1980. All the publications were announced in Scientific and Technical Aerospace Reports and/or International Aerospace Abstracts

Numerical Heat Transfer and Fluid Flow 2021

This reprint focuses on experiments, modellings, and simulations of heat transfer and fluid flow. Flowing media comprise single- or two-phase fluids that can be both compressible and incompressible. The reprint presents unique experiments and solutions to problems of scientific and industrial relevance in the transportation of natural resources, technical devices, industrial processes, etc. In the presented works, the formulated physical and mathematical models together with their boundary and initial conditions and numerical computation methods for constitutive equations lead to solutions for selected examples in engineering

Thermal integration of electrical power and life support systems for manned space stations

Thermal integration of life support and electrical power systems of six-man space station to obtain maximum utilization of waste energy from power generating syste

Diccionario interactivo ilustrado técnico bilingüe : herramientas, materiales y elementos para la construcción y afines

Diccionario producto de la colaboración de instructores de los programas de construcción, automatismos, refrigeración, motores y carpintería del Centro de Operación y Mantenimiento Minero del SENA, en el que se recopila alfabéticamente en idioma inglés y de forma visual los materiales y equipos utilizados comúnmente en construcción así como su definición y su traducción al español.Dictionary product of the collaboration of instructors of the programs of construction, automatisms, refrigeration, motors and carpentry of the Center of Operation and Mining Maintenance of the SENA, in which the materials and equipment commonly used in English are collected alphabetically in English language construction as well as its definition and its translation into Spanish.Aa-Bb--Cc-Dd--Ee-Ff--Gg-Hh--Ii-Jj--Kk-Ll--Mm-Nn--Oo-Pp--Qq-Rr--10.Ss-Tt-- Uu-Vv--Ww--Contrucction Program--Automation Program--Refrigeration Program--Automotive ProgramnaTítulo en portada “Diccionario interactivo técnico ilustrado bilingüe; materiales, herramientas y elementos para la construcción y afines”204 página