THE VENTING OF EXPLOSIONS IN DUCT SYSTEMS PART II: THE VENTING OF EXPLOSIONS IN A PENTANE-AIR MIXTURE IN A DUCT 6 FT. LONG x 6 IN. DIAMETER
Rasbash, D.J. and Rogowski, Z.W., 1957. THE VENTING OF EXPLOSIONS IN DUCT SYSTEMS PART II: THE VENTING OF EXPLOSIONS IN A PENTANE-AIR MIXTURE IN A DUCT 6 FT. LONG x 6 IN. DIAMETER. Fire Research Notes298
The effect has been studied of relief vents on the maximum
pressure reached in explosions in a mixture containing 3.37%
pentane in air in a steel tube 6 ft. long x 6 in. diameter.
Ignition was near one end of the tube and the vents could be
placed at either end of the tube. The maximum pressure reached
when open vents were used decreased inversely as the 0.75 to
1.5 power of the vent area. This pressure was 3 - 5 times
greater when the vent was remote from the ignition source than
when it was near this source. Howover with large open vents
near the ignition source, vibrations with a large amplitude
became established; the maximum pressure in these vibrations
increased as the vent area increased. Calculations have been
made of the venting requirements of the explosions on the
assumption that the rate of combustion when a vent is present in
the tube is the same as when no vent is present. When the vent
was covered by a disc of thin material the maximum pressure
reached depended on the static bursting pressure of the disc if
this pressure was larger than the pressure reached with the open
vent. Cross shaped cutters gave a large reduction of the maximum
pressure reached with brown paper and aluminium discs but a negligible
reduction with polythene discs.