DETECTION OF HYDROGEN-AIR FIRES AND EXPLOSIONS IN AEROSPACE VEHICLES VIA OH BAND AND WATER BAND EMISSION

摘要

To provide a basis for reliable hydrogen-air fire and explosion detection in aerospace vehicles, measurements of the absolute value of radiant intensity were made over the OH bands of the ultraviolet and the water bands in the infrared. A surprising result was the increase in OH radiant intensity with decreasing pressure. Diffusion flame variables were hydrogen flow rate, port diameter, and pressure from 760 to less than 20 mm Hg. For explosions, mixture ratio as well as pressure were varied; the rate of increase of emission and pressure after ignition were measured to determine detection lead time. Results where possible are presented as fundamental quantities which can be applied with reasonable rigor to a variety of design situations. Detection based upon monitoring OH radiation is recommended over other properties such as IR radiation, ionization, temperature rise, or pressure rise. Application of the data to specific designs is discussed.