The paper reports and evaluates the combustion pressures of electrolytically produced stoichiometric hydrogen-oxygen mixtures, spark-ignited inside a variable height (volume 0-250cc) ceramic piston cylinder arrangement. Ignition of mixtures was carried out at room temperature and absolute pressures varying between 5 and 180 kPa.
Maximum combustion pressures were obtained from pressure-time traces and compared to a computer simulation model based on the first law of thermodynamics, ideal gas law and high temperature dissociation of combustion products. Ignition delay time and rate of pressure rise are also investigated.
The results are to be used in a preliminary design of a combustion chamber of a hydrogen-oxygen fuelled engine.
It was found that maximum combustion pressures are dependent on initial mixture pressure, initial water vapour content and surface area/volume ratio of combustion chamber.
The average rate of pressure rise (dP/dT) is independent of chamber height but is a function of initial mixture pressure
Ignition delay time is found to be a function of initial mixture pressure and decreases exponentially from a maximum value of 2.2 ms to 0.3 ms as the precombustion pressure of the mixture is increased.