The laminar flame speeds of H₂/air with steam dilution (up to 33 vol%) were measured over a wide range of equivalence ratio (0.9–3.0) at atmospheric and elevated pressures (up to 5 atm) by an improved Bunsen burner method. Burke, Sun, HP (High Pressure H₂/O₂ mechanism), and Davis mechanisms were employed to calculate the laminar flame speeds and analyze different effects of steam addition. Four studied mechanisms all underestimated the laminar flame speeds of H₂/air/H₂O mixtures at medium equivalence ratios while the Burke mechanism provided the best estimates. When the steam concentration was lower than 12%, increasing pressure first increased and then decreased the laminar flame speed, the inflection point appeared at 2.5 atm. When the steam concentration was greater than 12%, increasing the pressure monotonously decrease the laminar flame speed. The chemical effect was amplified by elevated pressure and it played an important role for the inhibiting effect of the pressure on laminar flame speed. The fluctuations of the chemical effect at 1 atm were mainly caused by three-body reactions, while the turn at 5 atm was mainly caused by the direct reaction effect. Elevated pressure and steam addition amplified the influences of uncertainties in the rate constants for elementary reactions, which might leaded to the disagreement between experimental and simulation results.

通过改进的本生燃烧器方法，在大气压和最高压力（最高5 atm）的相当当量比（0.9–3.0）的大范围当量比（0.9–3.0）下，测量了H ₂ /空气在蒸汽稀释下（高达33 vol％）的层流火焰速度。采用Burke，Sun，HP（高压H ₂ / O ₂机理）和Davis机理来计算层流火焰速度并分析蒸汽添加的不同影响。四种研究机制均低估了H ₂ / air / H ₂的层流火焰速度在中等当量比的O混合物中，伯克机制提供了最佳估计。当蒸汽浓度低于12％时，先增加压力然后降低层流火焰速度，拐点出现在2.5个大气压下。当蒸汽浓度大于12％时，增加压力会单调降低层流火焰速度。高压增强了化学作用，并且在压力对层流火焰速度的抑制作用中起着重要作用。1 atm处化学效应的波动主要由三体反应引起，而5 atm处的转弯主要由直接反应效应引起。升高的压力和蒸汽添加量放大了基本反应速率常数不确定性的影响，