Letteratura scientifica selezionata sul tema "Locomotivas a vapor"

A história da comunicação relaciona-se com o desenvolvimento dos mecanismos de transportes de mercadorias e de produtos. As informações viajavam nas primeiras rotas de comércio por meio de profissionais encarregados por levar mensagens, cartas ou pacotes. O surgimento e o desenvolvimento das locomotivas a vapor facilitou o processo de entregas destes produtos. Desta forma, o presente artigo possui como objetivo abordar como a música Correio da Estação do Brás de autoria de Tom Zé apresenta um breve relato de uma modalidade de comunicação e de informação – o correio - em um período histórico e em uma das regiões mais conhecidas do país, o Bairro do Brás em São Paulo

This article is the first in a series of related publications urgent in the field of railway transport, namely absence of new traction rolling stock and the presence of existing in operation, the condition of which remains uncommented. The article is concerned with the requirements specified in normative documents for the environmental security indices of diesel locomotives operated on the railways of Ukraine, the volume and qualitative characteristics of environmental indices, which must be checked before the operation of the repaired or upgraded locomotive is given; the impact of overhaul reconditioning or modernization measures of locomotives on the environmental indices of exhaust gases was determined. In the context of the article, it is reasonable to consider the safety requirements of the main, even the only source of exhaust gases - internal combustion engines used on locomotives (general view of locomotives is shown in Fig. 1). Safety requirements for engines and methods of their control are usually set in the technical specifications, design and operating documentation for engines of certain types. Engines must also meet the requirements of national technical regulations and national standards for them, taking into account their operational functions for which they are intended. In this case, any danger to personnel, which may occur during the operation of the engine, as a necessary element of the overall system to create a moving force (e.g. locomotive engine), its moving parts, hot surfaces, should be minimal. During the design of engines their purpose, operating conditions, environmental conditions, as well as characteristics of used materials, in particular the brand of diesel fuel should be taken into account. Special attention should be paid to the structure safety of: fuel supply systems; lubrication and cooling systems; engine control systems. The physical factors of dangerous and harmful effect include: moving elements; hot surfaces; exhaust gases; increased noise level; increased vibration level; flame emissions; - excess pressure in the crankcase; electric current. The chemical factors of dangerous and harmful effect include: harmful components of exhaust gases; fuel and fuel vapor; lubrication and its vapour; coolant; non-metallic materials. According to the lists of physical and chemical factors of dangerous and harmful effects of engines, one of the most important is indices of exhaust gases of diesel engines.

Hydrogen has been attracting attention as a fuel in the transportation sector to achieve carbon neutrality. Hydrogen storage in liquid form is preferred in locomotives, ships, drones, and aircraft, because these require high power but have limited space. However, liquid hydrogen must be in a cryogenic state, wherein thermal insulation is a core problem. Inner materials, including glass bubbles, multi-layer insulation (MLI), high vacuum, and vapor-cooled shields, are used for thermal insulation. An analytic study is preferred and proceeds liquid hydrogen tanks due to safety regulations in each country. This study reviewed the relevant literature for thermodynamic modeling. The literature was divided into static, dynamic, and systematic studies. In summary, the authors summarized the following future research needs: The optimal design of the structure, including suspension, baffle, and insulation system, can be studied to minimize the boil-off gas (BOG). A dynamic study of the pressure, mass flow, and vaporizer can be completed. The change of the components arrangement from the conventional diesel–electric locomotive is necessary.

Na segunda metade do século XIX, Portugal investiu em diversas soluções tecnológicas para modernizar diferentes setores da sociedade, sendo o caminho-de-ferro uma das mais imponentes inovações. Além dos benefícios materiais que trouxe em termos de velocidade e capacidade de transporte, a ferrovia desempenhou ainda um importante papel simbólico, como representação indisputada de modernidade, progresso e civilização. Neste artigo, pretendo demonstrar que o sentimento de sublime provocado pela locomotiva a vapor assumiu igualmente contornos religiosos, de religião implícita (tecnologismo), que contribuíram para cimentar a implementação da ferrovia e dos seus principais agentes tecnológicos na sociedade nacional.

Abstract. Mobile sources are responsible for a substantial controllable portion of the reactive organic carbon (ROC) emitted to the atmosphere, especially in urban environments of the United States. We update existing methods for calculating mobile source organic particle and vapor emissions in the United States with over a decade of laboratory data that parameterize the volatility and organic aerosol (OA) potential of emissions from on-road vehicles, nonroad engines, aircraft, marine vessels, and locomotives. We find that existing emission factor information from Teflon filters combined with quartz filters collapses into simple relationships and can be used to reconstruct the complete volatility distribution of ROC emissions. This new approach consists of source-specific filter artifact corrections and state-of-the-science speciation including explicit intermediate-volatility organic compounds (IVOCs), yielding the first bottom-up volatility-resolved inventory of US mobile source emissions. Using the Community Multiscale Air Quality model, we estimate mobile sources account for 20 %–25 % of the IVOC concentrations and 4.4 %–21.4 % of ambient OA. The updated emissions and air quality model reduce biases in predicting fine-particle organic carbon in winter, spring, and autumn throughout the United States (4.3 %–11.3 % reduction in normalized bias). We identify key uncertain parameters that align with current state-of-the-art research measurement challenges.

Water, sulfur and lead compounds can enter the oil from the combustion chamber ofa running diesel engine. Significant amounts of diesel oil are missing due to water or vapor in thewater system and exhaust gases, which creates emulsion and sediment (sludge) at relatively lowtemperatures and disrupts the lubrication and cooling of friction surfaces and increases wear ofengine parts. Such oil must be drained from the crankcase and regenerated.The most promising method of regeneration of rejected oil, including in the locomotive depot,is hydrodynamic dispersion, which allows to remove water and modify the aging products instead ofa complex process of coagulation or evaporation.The article considers the reason for heating oil during its hydrodynamic dispersion, based onthe probable assumption that heating is due to viscous (internal) friction of oil in the hydrodispersantand hydroelements that ensure its operation.During operation, the oil used in diesel internal combustion engines is a complex mixture ofcarbohydrates and additive components, has certain physicochemical and operational properties.The oil system of the running engine provides greasing and cooling of friction surfaces and is exposed to complex influence of high temperature, oxygen of air, fuel and products of wear of details of theengine and foreign impurity (dust, fuel, water), ie difficult physical and chemical processes occur.aging of oil ".The article considers the reasons for the violation of the oil properties of diesel locomotivesdue to the modes of operation of diesel engines and the ingress of water orits vaporinto the crankcasedue to leaks in the cooling system and exhaust gases. When water enters the oil, an emulsion isformed, which leads to the deterioration of the oil layer between the parts in the friction pairs andincreased wear of the crankshaft bearings with babbit filling fillings and other parts.The presence of water in the oil contributes to its interaction with additives and theirprecipitation, creating an oily sticky mass, which can lead to partial or complete cessation of oilsupply to friction surfaces, reducing the cooling capacity of refrigerated sections of locomotives andheat exchangers. Diesel oil, which has defective performance, is subject to replacement or high-costregeneration, ie the restoration of the original properties in order to reuse it. Regeneration is oneway to save oil.The following sequence of methods must be followed in the complex of technologicalprocesses of regeneration: mechanical – to remove free water and solid contaminants from oil,thermophysical – to evaporate fuel and water residues, as well as physicochemical – coagulation,adsorption. One of the following schemes is used: sludge – treatment with surfactants – fueldistillation – treatment with adsorbent – filtration.The application of these methods requires complex, expensive equipment with high energyconsumption, and this in a locomotive depot (or regional center), as a rule, is not economicallyfeasible.Water and fuel are removed in two stages: evaporation (water and fuel) and adsorption (water).Evaporation of spent oils is performed by heating without pressure or using vacuum without pressureor using vacuum with heating the oil to a temperature of 70-80 °C. This method of restoring theproperties of the oil, although it leads to positive results, but causes significant energy consumption.The most promising method of waste waste treatment is hydrodynamic dispersion, which allowsaging products to be modified instead of a complex coagulation process. In addition, water and fuelare removed from the oil during dispersion as a result of heating.This method can be used in locomotive depots in the regeneration of motor (diesel) oils, whichhave defective parameters for certain indicators.The most expedient is the use of hydrodynamic dispersant (HD) in volumetric hydraulic drivesand internal combustion engines, which with relatively simple design and manufacturability does notcause destruction of oil hydrocarbon molecules, does not require preparation and adjustment beforeoperation, its efficiency in pressure fluctuations decreases. GD is energy efficient, does not causedifficulties when built-in, its durability is higher than ultrasonic and cavitating dispersants.But for the application of GD it is necessary to determine its parameters and regenerationtemperature.The article considers the reason for heating oil during its hydrodynamic dispersion, based onthe probable assumption that heating is due to viscous (internal) friction of oil in the hydrodispersantand hydroelements that ensure its operation.At the same time, we accept the assumption that the oil pressure before the GD and its flow ratein the hydroelements is constant. It was found that the temperature of the oil when dispersed isproportional to its dynamic viscosity, the square of the velocity of the oil and inversely proportionalto the heat transfer coefficient and the radius of the tube, which agrees well with the proposedhypothesis that the cause of oil heating in hydrodynamic dispersion is viscous friction (equation 17),and the oil is heated from 70 ° C to 100 ° C depending on the pressure. The results of experimental studies have shown that the optimal mode of treatment of wateredoil with GD is a pressure of 0.5 MPa at the number of cycles N = 50 and a temperature of 130-135 °C, which is much lower than the flash point of the oil.

Responsável por grande parte do transporte do minério de ferro do Brasil, a ferrovia tem grande importância no crescimento do país. Os trens têm sua tração concentradas nas locomotivas diesel / elétricas onde qualquer tipo de falha pode acarretar em atraso na entrega das principais matérias prima do país. O prejuízo causado pelas falhas nas locomotivas impulsionou a área de engenharia de manutenção da MRS Logística S/A, a trabalhar na redução destas falhas. Em um estudo foi verificado que o Motor de Tração DC possui grande índice de falhas nas locomotivas. O principal modo de falha é o isolamento elétrico para massa da armadura e da carcaça. Este trabalho apresenta um teste para melhoria na qualificação do isolamento para massa em Motor de Tração DC, utilizado em locomotiva diesel / elétrica. O novo parâmetro para a qualificação do isolamento elétrico tem como objeto de estudo o teste de ângulo de fase ou de fator de potência. Neste parâmetro, a condição do isolamento pode ser estimada tratando-o como o dielétrico em um capacitor. A mudança na capacitância ou no fator de potência é uma medida da condição do isolamento do motor de tração. O resultado deste estudo foi retirado em mais de 800 testes feitos em carcaças e armaduras em variadas condições de isolamento e, aplicando o conceito estatístico de média, para definição do valor ideal. Com esse novo parâmetro espera-se ter uma redução considerável das falhas ligadas ao isolamento elétrico e uma melhora na eficiência do transporte ferroviário Brasileiro.

Abstract The use of pumped two-phase cooling to improve the thermal management of insulated gate bipolar transistor (IGBT) in rail transportation is a novel cooling technology. An experimental investigation on pumped two-phase cold plate of IGBT used in HXD1C locomotives was conducted at a mass flow rate of 0.1 kg/s–0.29 kg/s and a heat flux of 6.2 W/cm2, with R245fa as the working fluid. The experimental results showed that the base temperature nonuniformity can be controlled within 2.2 °C at flow rates of 0.14 kg/s and 0.19 kg/s, which is of great benefit to the reliability of IGBT. Based on well known correlations for saturated flow boiling in tubes, an analytical model was developed and compared with the experimental data. The model could predict the base temperature data within an error band of ±3 °C, as well as capture the trend of base temperature as a function of vapour quality and mass flow rate. The performance of the pumped two-phase cold plate of IGBT could be further improved with the aid of the developed model.

Dissertação (mestrado) - Universidade Federal de Santa Catarina. Centro Tecnologico
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A atividade de maquinistas e auxiliares de maquinista, na operação de locomotivas a vapor, é aqui abordada sob o ponto de vista da Ergonomia, ou seja, da sua adequação às características do operador humano. O estudo visa o estabelecimento de um diagnóstico das condições de trabalho permitindo a compreensão desta realidade e fornecendo seus aspectos determinantes. O diagnóstico constitui-se no elemento básico da ação ergonômica, que visa a melhoria das condições de trabalho. As locomotivas a vapor são utilizadas no transporte de carvão no sul do Estado de Santa Catarina pela Divisão Operacional de Tubarão, pertencente à RFFSA. Formam a demanda desta Análise a reconhecida insalubridade da atividade, os altos índices de acidentes de trabalho na Divisão e a própria necessidade de renovação do parque de locomotivas. São dados a conhecer inicialmente o histórico da ferrovia, suas relações com a região e as perspectivas da extração do carvão. Num segundo momento são expostas e discutidas três correntes metodológicas ligadas à proteção do trabalhador: a segurança do trabalho, a psicopatologia do trabalho e a ergonomia. É desenvolvida a seguir a análise de condições de trabalho, que tem como preocupação subjacentes o conhecimento de metodologias específicas à avaliação dos vários parâmetros pertinentes. São examinadas, assim, a organização formal do trabalho e as condições físicas e ambientais em que este se desenvolve, complementadas pela visão do trabalhador. Finaliza a dissertação o diagnóstico da situação e um inventário sumário de recomendações para a melhoria das condições de trabalho.

Diesel fuel carriage in locomotives, while safe in normal operational conditions, presents a potential hazard in the event of serious accident or derailment. Development of an effective mitigation method against this hazard requires an understanding of operational conditions that lead to fuel spill and fire. This paper describes a study of fire hazard stemming from rail accidents and potential approaches to mitigation. Data for the study was obtained from a large sample of National Transportation Safety Board (NTSB) investigation reports for accidents involving both freight and passenger locomotive accidents over a 10-year period. Approximately 25% of the events reviewed resulted in fuel release. In addition, of the events that resulted in fuel loss, a large majority (almost 70%) resulted in fire. Most cases with major fires led to loss of life and/or property, including destruction of multiple locomotives. Typical road locomotives carry 3,000–4,500 gallons of diesel fuel during normal operation. As the locomotive consumes fuel, large volumes are available for vapor generation within the tank. In a post-collision scenario, the vapor that vents to the atmosphere at temperatures close to flash point of the fuel presents a significant fire hazard. Further, flammable mists can be generated by the sprays that develop due to fuel leaks from the post-impact movement of a train. Previous laboratory tests on a scaled tank demonstrated that fire in a fuel-rich vapor can flash back inside the tank causing an explosion or a large fire. This paper also assesses potential technologies to prevent or mitigate fire hazards in locomotive fuel tanks. These include fuel tank leak prevention or reduction of outflow from breached fuel tanks, monitoring vapor concentration within fuel tanks, and limiting vapor concentrations inside tank to maintain levels below the Lower Explosive Limit (LEL). Potential benefits of the latter method include minimization of pollution from escaping vapor as well as partial recovery of reusable fuel from vapor.

Diesel fuel used in locomotives generally does not pose a fire hazard. However, diesel vapor generated within tank vapor space attains flammability condition as the fuel temperature gets closer to the fuel-flash point, which may cause a fire hazard in the event of a tank breach due to collision or derailment of the locomotive. As a part of an ongoing Federal Railroad Administration (FRA) sponsored research effort, a proof-of-concept laboratory scale demonstration has shown that it is possible to circulate the mixture of diesel vapor and air through a small vapor condenser unit to reclaim the fuel vapor. The recovered fuel is shown to possess almost similar specific heat value and hydrocarbon constituents as that of neat diesel fuel and hence reusable. Furthermore, the vapor reclamation process enables mitigation of fire hazard and reduction of diesel vapor escape to the environment. In order to assess the real potential of diesel vapor reclamation on a running locomotive, real-time fuel temperature data was collected during a medium-haul run of a BNSF Railway freight locomotive. This paper presents the real-time fuel temperature data collected on a BNSF Railway instrumented locomotive tank as well as results of computational fluid dynamics (CFD) analyses performed for the full-scale locomotive tank. In continuation of the research and development effort, the design of a scaled up diesel vapor reclamation system is presented. The scope of its integration with a railroad freight locomotive is summarized and subsequent steps for its performance evaluation on a running locomotive are discussed.

Flammable materials such as gasoline, ethanol, and diesel fuel are commonly transported in bulk via rail. In many cases, pockets of vapor can be generated inside the tank that can present a hazard if spilled during a collision or other catastrophic accident. Vapor conditions above the Lower Explosive Limit (LEL) if exposed to an external ignition source can result in an explosion or fire. Alternately, residual vapors within a tank present an explosion hazard if not properly vented or inerted prior to maintenance activities. This paper summarizes a generalized study of hazards associated with flammable liquids using computation fluid dynamics (CFD) to predict vapor conditions within a tank or following a spill. The analysis was verified in laboratory testing using scaled tank geometries. A demonstration case was developed using diesel fuel in a locomotive fuel tank. Typical road locomotives carry 3000–5000 gal of diesel fuel during normal operation. As the locomotive consumes fuel, large volumes are available for vapor generation within the tank. In a post-collision scenario, under ambient temperatures over the flash point of the fuel, the vapor that vents to the atmosphere presents a significant fire hazard. Further, flammable mists can be generated by the sprays that develop due to fuel leaks from a moving train. Studies of accident cases over a 10 year period indicated that a fire occurred in 80% of the accidents in which fuel was spilled. A CFD analysis was applied to the geometry associated with a locomotive fuel tank. The analysis models the two phase flow using the “volume of fluid” formalism in Fluent, and using a user defined diesel fuel evaporation algorithm. The tank and environmental parameters included fuel volume, fuel temperature, and air flow within the tank, and critical values of vapor content, temperature and velocity were plotted. The analysis predicted ignition of the external vapor cloud at temperatures relevant to a spill in a summer environment in the southwest, and propagation of the flame into the fuel tank. Laboratory testing confirmed the analysis: Once ignited, a flame propagated into the tank, causing an explosion and fire. The analysis methods developed can be applied to a variety of geometries and fluids, providing a basis for full scale testing. The overall intent of the analysis is to aid in the development of fire mitigation approaches for fuel and flammable material transport that would be practical for railroad use.

Systems that store heat in a liquid that can generate vapor for various applications by flash evaporation, sometimes known as steam accumulators, are a relatively simple way for integrated heat storage and vapor/steam generation. Applications include buffering of the transient heat supply and demand in conventionally-fuelled boilers, locomotives and steam power generation systems and more recently in solar thermal power. The information available about this type of heat storage was mostly about steady state operation with little attention to the flash evaporation aspects. In this paper we describe the state of the art and a well-instrumented facility for the experimental study of a variant of such systems, the Heat Storage Flash Boiler that includes a 19.28 m3 storage/flash tank, which was developed by us for experimental examination of its storage and discharge performance for temperatures between 65 °C and 120 °C and pressures from 0.5 to 2 bars (50–200 kPa).. The applicability of such a facility as a generator of steam for feeding a turbine or other purposes has been demonstrated. Flashing has been induced at water temperatures between 80 °C and 100 °C. At 97 °C, the average flow rates obtained ranged between 14 kg/hr for a driving pressure drop of Δpf = 3.2 cm Hg (4.266 kPa), and 390 kg/hr for Δpf = 5.1 cm Hg (6.799 kPa). Specific attention was paid to key issues including the flash evaporation phenomenon, conditions for choked flow of the steam and for mist entrainment, and need and ways for the storage water deaeration. Detailed results for the experimental runs, and the mass flow generation rate of water evaporated was well-correlated to the driving pressure drop for flashing, Δpf. The experiments have provided useful information about the associated heat storage issues and flash steam generation phenomena. Basic considerations and methods for the design of integrated thermal storage/steam generation systems, the Heat Storage Flash Boilers are presented.