Estudo analítico de dados de pressão de combustão em sistema de ignição por jato turbulento

Abstract

In the present study, pressure data obtained from the Turbulent Jet Ignition (TJI) system was analyzed using MatLab. TJI is characterized by enabling low temperature combustion produced by either lean or dilute air/fuel mixture. The combustion in TJI system is initiated at a small volume chamber denominated prechamber, which is linked to the main combustion chamber via one or multiple small orifices. The novelty of this work is at the investigation of pressure traces in terms of finding critical inflection points such as the Start of Combustion or Start of Heat Release. Several experiments were performed on a Rapid Compression Machine (RCM) with different conditions such as fuel mixture of Methane (CH4) and atmospheric air (Par 1 atm) at stoichiometric (φ = 1) and lean conditions (φ = 0.8 and 0.67). Nozzle diameter was also changed. Three single orifice nozzles were tested with diameters of 2.0, 2.5 and 3.0 mm. Using numerical differentiation implemented in MatLab it was possible to determine the pressure and time of each important combustion event such as Top Dead Center (TDC), Start of Combustion (SOC), Start of Heat Release (SOHR), 0-to-10% and 10-to-90% mass fraction burn duration. Burning time of different air/fuel mixture conditions and nozzle sizes were compared afterward seeking for determining the best experimental set-up.