Current Issue : January - March Volume : 2016 Issue Number : 1 Articles : 4 Articles
The present study focuses on the experimental investigation on the effect of fuel injection strategies on LTC with gasoline on a\nsingle-cylinder CI engine. Firstly, the engine performance and emissions have been explored by sweeping SOI1 and split percentage\nfor the load of 0.9MPa IMEP at an engine speed of 1500 rpm. Then, the double-injection strategy has been tested for load expansion\ncompared with single-injection. The results indicate that, with the fixed CA50, the peak HRR is reduced by advancing SOI1 and\nincreasing split percentage gradually. Higher indicated thermal efficiency, as well as lower MPRR and COV, can be achieved\nsimultaneouslywith later SOI1 and higher split percentage.As split percentage increases,NO...
Abstract: This paper focuses the attention to the possibility of a correct\ncombustion close to the flameless regime, even in the presence of lower\ncalorific value fuels like those that can be found with high\nconcentrations in the bio-mass derived ones. In addition, the authors pay\nattention to the nitric oxide control by means of an optimal choice of the\npilot injector location. The authors follow their previous experiences in\nthe search of feasible modifications to an existing lean-premixed\ncombustor for a definite pollutant abatement from a micro-gas turbine....
This paper presents a mathematical model for predicting the propagation of\ncircumferential waves (acoustic, entropy and vorticity waves) through an annular\nnozzle. Combustion chambers in modern aero-engines are typically annular, and so\na model for circumferential waves is essential for understanding and predicting both\ncombustion noise and thermoacoustic instabilities for such geometries. The linearised\nEuler equations are solved using the Magnus expansion to obtain the reflection and\ntransmission coefficients of the annular nozzle for acoustic, entropy and vorticity\nperturbations. Predictions which account for flow physics, such as a non-zero mean\nflow angle and the generation of vorticity noise, are obtained for the first time.\nResults are compared with two numerical methods, showing that the mathematical\nmodel is able to predict the transmission and reflection of waves for both compact\nand non-compact frequencies. The model is used to prove one particularly interesting\nand relevant feature of annular geometries: the generation of a vorticity wave by the\nacceleration of a circumferential entropy wave. It is shown that this phenomenon\noriginates from the baroclinic torque in the vorticity equation....
The aeroderivate gas turbines are widely used for power generation in the oil and\ngas industry. In offshore marine platforms, the aeroderivative gas turbines provide the energy\nrequired to drive mechanically compressors, pumps and electric generators. Therefore, the\nstudy of the performance of aeroderivate gas turbines based on a parametric analysis is\nrelevant to carry out a diagnostic of the engine, which can lead to operational as well as\npredictive and/or corrective maintenance actions. This work presents a methodology based\non the exergetic analysis to estimate the irrevesibilities and exergetic efficiencies of the main\ncomponents of a two-shaft aeroderivate gas turbine. The studied engine is the Solar Turbine\nMars 100, which is rated to provide 11.86 MW. In this engine, the air is compressed in an\naxial compressor achieving a pressure ratio of 17.7 relative to ambient conditions and a high\npressure turbine inlet temperature of 1220 �°C. Even if the thermal efficiency associated to\nthe pressure ratio of 17.7 is 1% lower than the maximum thermal efficiency, the irreversibilities related to this pressure ratio decrease approximately 1 GW with respect to\nirreversibilities of the optimal pressure ratio for the thermal efficiency. In addition, this paper\ncontributes to develop a mathematical model to estimate the high turbine inlet temperature\nas well as the pressure ratio of the low and high pressure turbines....
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