A study of flame acceleration and the possibility of detonation with silane mixtures

Mixtures of silane and nitrous oxide are one of a number of gaseous reactants used in the final stages of semiconductor device fabrication processes and whose explosion properties in confined volumes such as exhaust gas piping systems are not known. In the present paper we report the results of theoretical and experimental studies of the propensity for flame acceleration and potential deflagration to detonation transition (DDT) hazard for silane-nitrous oxide mixtures in a 50 mm diameter pipe; together with an investigation of the effectiveness of nitrogen dilution as an explosion mitigation method. Preliminary results for ethylene-oxygen nitrogen are also presented from commissioning tests in the same apparatus to illustrate the explosion development process in a much studied explosive mixture. The experimental DDT limits are compared with criteria proposed by earlier investigators, based on detonation cell width. As no cell width data was available for the silane mixtures the cell widths used were those predicted using high temperature chemical reaction data.