Laminar burning velocity measurement of hydrous methanol at elevated temperatures and pressures

Methanol is an important renewable energy source that absorbs water easily. The water can be present inadvertently or as a result of the manufacturing process. Although adding water into methanol will further improve the anti-knock rating for spark ignition engines, the burning velocity, flame stability and the flammability range will be reduced. The laminar burning velocity of methanol containing up to 40% water in volume (W0, W20 and W40) has been measured for a wide range of temperature (350-450 K), pressures (1-4 bar) and equivalence ratio (0.7-1.4) using a constant volume vessel and a schlieren imaging system. The experimental data using the pressure rise data (but excluding cellularity) have been fitted to a correlation with twelve coefficients. The laminar burning velocities for W0, W20 and W40 are 54 cm/s, 31 cm/s and 24 cm/s respectively for stoichiometric mixture at 2 bar and 400 K. Results showed a decrease in burning velocity with pressure and an increase with temperature. Water as a diluent led to reduction of the burning velocity. The correlated burning velocity data for methanol are in good agreement with published data. The cellularity occurred earlier as the initial mixture became rich, while a higher water fraction delayed the onset of cellularity.