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Determinação do desempenho e caracterização do processo de combustão de um motor propulsor marítimo de ignição por compressão, dois tempos e baixa rotação
| Content Provider | Semantic Scholar |
|---|---|
| Author | Silva, Nerivaldo Rodrigues Da |
| Copyright Year | 2018 |
| Abstract | Research in large marine two-stroke diesel engines is modest compared to other types of smaller engines due to their size, cost, and complexity of the facilities for large engines testing. There is a fair amount of literature provided by leading manufacturers such as MAN Diesel & Turbo (MDT), Wärtsilä, and ABB. However, this literature provides no details on the methodologies and specific conditions of the study are not available in the work due to industrial secrecy. The creation of a virtual prototype and its kinematic simulation using CAD/CAE software is an alternative method to obtain geometrical data, exhaust valve elevation curve, and other parameters for combustion analysis and modeling. The components were 3Dmodeled using reverse engineering methods and tools. CAD/CAE software was used for DMU assembly, component adjustment, and kinematic simulation. The pressure curve as a function of the crankshaft angle was obtained with digital indicator. During part of a ship trip with the engine operating at 98 rpm under stable conditions, the pressure of five cylinders was measured. Its piezoelectric indicator pressure sensor has been temporarily connected to the combustion chamber through the cylinder valves. The average value of 10 cycles measured at each 0.5 degree crankshaft displacement was used. The engine performance analysis was done comparing measured data with data obtained in the factory test and sea test of the ship. While ships are equipped with digital instruments to measure the pressure, the apparent heat release (AHR) rate is not used as a performance indicator, as a tool for failure diagnosis and engine adjustment. In this study, a zero-dimensional model was used to determine the AHR and to complement the performance analysis of the marine engine. Required geometrical data, not available in the literature, were obtained with the creation and kinematic simulation of the Digital Mockup (DMU). Combustion metric parameters were determined with the mass fraction burned fuel curve. The apparent heat release (ARH) rate was determined using the first law of thermodynamics and the ideal gas law through 0D model. The cylinder content is considered to be a homogeneous mixture of gases, without varying the number of moles during the closed phase of the cycle. DMU compression ratio was validated by varying the compression curve modeled by BOOST software until matching the pressure curve measured in the compression phase of the cycle. The study demonstrated that this methodology can be applied and will allow to research large equipment. Heat release (AHR) rate analysis, in addition to being an indicator of energy conversion, could help in the diagnosis of engine failures by identifying the start, the angle of 50% fuel mass burning, combustion end, and possible deviations of fuel quality. A mean AHR value of 66.6 MW was obtained at the mean ATDC angle of 7.3. |
| File Format | PDF HTM / HTML |
| Alternate Webpage(s) | http://repositorio.unicamp.br/jspui/bitstream/REPOSIP/332938/1/Silva_NerivaldoRodriguesDa_D.pdf |
| Language | English |
| Access Restriction | Open |
| Content Type | Text |
| Resource Type | Article |
