Ignition Delay Study of Moist Hydrogen/Oxidizer Mixtures using a Rapid Compression Machine
Authors: A. K. Das, C. J. Sung, Y. Zhang, and G. Mittal
Direct link to the paper: http://dx.doi.org/10.1016/j.ijhydene.2012.01.111
Autoignition of moisthydrogen/oxidizermixtures has been studied experimentally using arapidcompressionmachine (RCM). This work investigated the effect of water addition on ignitiondelays of stoichiometric hydrogen/oxidizermixtures in the end of compression temperature range of TC = 907–1048 K at three different end of compression pressures viz. PC = 10 bar (1 MPa), 30 bar (3 MPa), and 70 bar (7 MPa). RCM experiments were conducted with 0%, 10%, and 40% molar percentages of water in the reactive mixture. At PC = 30 bar and 70 bar, the presence of 10% and 40% water vapor was shown to promote autoignition. However, at PC = 10 bar, water addition (10%) was seen to retard the reactivity, thereby increasing the ignitiondelay. Comparison with different reaction kinetic mechanisms reported in literature shows widely different results of simulated ignitiondelays for the temperature and pressure range studied, although most of the mechanism predictions demonstrate similar trend in ignitiondelay with water addition. A recent chemical kinetic mechanism, which shows good agreement with the present experiments at higher pressure but some discrepancy at lower pressure, was used for brute force sensitivity analysis in order to identify the important reactions for the dry mixtures in the temperature and pressure window investigated. An important reaction identified was further adjusted within the uncertainty limit as an attempt to improve the results from mechanism prediction for the ignitiondelay at low pressure (PC = 10 bar) without water addition. In addition, the modification in the reaction rate leads to good agreement between the experiment data and the mechanism prediction for the moistmixtures at varying compressed pressures.
Citation: A. K. Das, C. J. Sung, Y. Zhang, and G. Mittal, “Ignition Delay Study of Moist Hydrogen/Oxidizer Mixtures using a Rapid Compression Machine,” International Journal of Hydrogen Energy 37 (8), 6901-6911 (2012)