Measurement of Concentration Limits

During large -scale experiments performed at normal conditions [1], 4% H2 low concentration limit (LCL) hydrogen-air mixtures have been tested at the lower ignition limit (small portions of H2 burn due to diffusion and most of the H2 does 

Gelfand et at., Thermo-Gas Dynamics of Hydrogen Combustion and Explosion, Shock Wave and High Pressure Phenomena, 

Unlike ignition limits of many other mixtures that could be found in the literature [2-4] there was lack of experimental data on the H2 + O2 + steam ignition limits. Only a single, not readily available experimental work [5] could be found for a H2 + air + steam mixture, where the limit concentration curve obtained was not quite correct. 

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Because internal combustion engines can work using hydrogen + hydrocarbon mixtures (including natural gas), some measurements of concentration limits of flame propagation in multi-component combustible gas mixtures have been performed. Information on the methodology used to obtain the data can be found in [17, 22-24]. Some useful information from the aforementioned publications is given below. 

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