Experimental and Numerical Study on the Effect of Hydrogen Addition on Laminar Burning Velocity of Ethanol-Air Mixtures

To understand the effect of hydrogen addition on the laminar burning velocity (LBV) of ethanol-air mixtures, experiments were conducted in a constant volume combustion chamber with the high-speed schlieren photography technique. The experiments were carried out under the equivalence ratios (ERs) of 0.7-1.4, an initial temperature of 400 K, an initial pressure of 0.1 MPa, and hydrogen fractions of 30% and 90% by volume, respectively. The effects of ER, initial temperature, initial pressure, and hydrogen fractions on the LBV were investigated. Moreover, adiabatic flame temperature (AFT), heat release rate (HRR), flow rate sensitivity analysis, and ROP (rate of production) analysis were also performed. Results showed that LBV increased with increasing hydrogen addition and temperature but decreased with increasing pressure. The hydrogen addition significantly increased the HRR of ethanol-hydrogen-air flames. The sensitivity analysis showed that R5 (O-2 + H = O + OH) significantly influenced the LBV.