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Experimental and Numerical Study on Reactivity Controlled Compression Combustion Ignition Natural Gas-diesel

Beladifard, Mohammad Hassan | 2017

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  1. Type of Document: M.Sc. Thesis
  2. Language: Farsi
  3. Document No: 50251 (08)
  4. University: Sharif University of Technology
  5. Department: Mechanical Engineering
  6. Advisor(s): Hosseini, Vahid
  7. Abstract:
  8. According to limitation of fossil fuel consumption and cost, reduction of fuel consumption is very important in internal combustion engine. This requirement becomes twofold in light of the greenhouse effect of CO2 on global warming. Therefore, the use of engines with less fuel consumption is a global success. Diesel engines are among the most productive internal combustion engines. They have a lower fuel economy and carbon monoxide. But unfortunately, these engines respectively in rich and dilute blend have highly soot and nitrogen oxides. One of the methods in the development of the combustion process is the low temperature combustion method, which reduces the production of Knox due to low temperatures. The equivalence ratio is also set to minimize soot production. Its types include homogeneous compression combustion ignition (Hcci), pre-mixed compression combustion ignition (PCCI) and reactivity controlled combustion ignition (RCCI). In the field RCCI, major studies on the type and percentage of fuel pre-mixed with diesel fuel and strategies of direct injection of diesel fuel for better mixing of air and fuel. In this research, has been attempted to numerically and experimentally evaluate Caterpillar's heavy-duty engine and Faryman-style engine respectively. For numerical modeling, the computational fluid dynamics method is used for internal combustion engines.in this study, numerically and experimentally Natural gas fuels are used as a preconditioned and premixed fuel in manifold. Usually the premixed fuel has a low reaction rate and is very resistant to self-ignition (high octane number). Diesel is used as a second fuel, which is sprayed directly into the cylinder with a very high pressure. Diesel should have high reactivity and show low resistance to self-ignition (low octane number). Diesel fuel in order Rapid evaporation and better mixing with air should have good volatility (have a high vapor pressure) and sprayed with high pressure into the cylinder. This research first examines the effect of various parameters in AVL-Fire on a Caterpillar heavy duty engine. Then, the effect of the start time of diesel injection on the Faryman-style engine located in the internal combustion engine laboratory of Sharif University of Technology checked. When the start of diesel spraying approaches TDC, due to the RCCI combustion property, the ignition occurs earlier, resulting in an increase in the maximum temperature and pressure, followed by soot, CO, UHC decrease and NOx increase and then from one time Subsequently, due to the lack of the opportunity for mixing, the combustion enters a Dual-fuel area where the parameter distribution is reversed by the RCCI. Therefore, it is possible to prevent a knock phenomenon by early spraying diesel fuel. Also, with the increased amount of diesel, the combustion will enter the Dual-fuel region erlier, due to the heterogeneous mixing of fuel & air, soot and UHC increase. Also, due to the increase in maximum temperature, the CO and NOx decrease and increase respectively. Increasing the angle of the diesel injector causes the fuel to be concentrated, which increases the heat release rate, the maximum temperature, pressure and NOx, and the reduction of soot and UHC
  9. Keywords:
  10. Low Temperature Combustion ; Natural Gas ; Diesel ; Spark Ignition Engines ; Compression Ignition ; Homogeneous Charge Compression Ignition (HCCI) ; Simi Premixed Compression Combustion Ignition Engines (PCCI) ; Reactivity Controlled Combustion Ignition Engines (RCCI)

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