Probing the Pre-Ignition Behavior of Negative Temperature Coefficient Fuels at Low to High Temperatures: A Case Study of Dimethyl Ether

Pre-ignition, involving complex interactions of physical and chemical processes, occurs not only in actual combustion engines but also fundamental research equipment such as rapid compression machines shock tubes. Thus, identifying the conditions prone to pre-ignition is critical for interpretation ignition data fuel design. Shock tube experiments with dimethyl ether (DME) were carried out this study investigate behavior during auto-ignition. The experimental included a wide range temperatures (620–1370 K), pressures (1–9 atm), equivalence ratios (0.5–5.0). results indicate that DME occur transition region from high temperature an intermediate (~1000 decrease pressure equivalency ratio will aggravate behavior. Theoretical analysis was then performed using four physical-based criteria: perturbation sensitivity delay times, thermal diffusivity, dimensionless parameter analogous Damköhler number, Sankaran number. According observations theoretical analysis, it found (Stp = 75 ?s/K) number (Sap 1) are best available criteria predicting negative coefficient (NTC) fuels. non-NTC fuels can be accurately predicted by diffusivity they deviate greatly when NTC This strategy expected provide feasible method under which may revealing mechanisms other