Combustion characteristics of methanol with turbulent jet ignition in a constant volume combustion chamber

Methanol is a renewable and sustainable energy source with potential to overcome energy scarcity, global warming, and environmental pollution caused by the overdependence on fossil energy. However, its application in engines faces challenges, particularly the cold start issues. Turbulent jet ignition presents a promising solution due to its advantage of multipoint ignition, and thereby a comprehensive study of turbulent jet ignition can contribute to guide the design and optimization of methanol engines. This work establishes an experimental system, employing the high speed schlieren imaging technique to observe the propagation of methanol jet flames, and investigates the influence on the combustion characteristics of various operating parameters, such as the initial temperature and pressure and the intervals between the two ignitions. The results indicate that the propagation of the jet flame accelerates with the equivalence ratio increasing from 0.8-1.2. When the equivalence ratio is 1.0 and 1.2, the higher initial pressure results in slower development of the jet flame. Additionally, a short ignition interval leads to sluggish jet flame development and prolonged combustion duration, while an excessively prolonged ignition interval makes it impossible to generate effective jet flame. This research provides valuable insights for optimizing the jet ignition operation and enhancing the efficiency of methanol engines.