EXPANSION COEFFICIENTS AND NORMAL BURNING VELOCITIES OF PROPANE-AIR MIXTURES BY THE CLOSED VESSEL TECHNIQUE

The normal burning velocities of propane-air mixtures were calculated from the expansion coefficients and the cubic law constants of flame propagation in the early stage of closed vessel explosions, using the adiabatic compression model. The experiments were made in a spherical vessel with central ignition in various initial conditions: pressure within 0.3÷1.3 bar, temperature within 298÷423 K, propane concentration within 2.80÷6.22 vol.%. The expansion coefficients were computed for the adiabatic isobaric combustion, assuming equilibrium is reached in the flame front. The normal burning velocities are compared with literature data and with normal burning velocities calculated from the same cubic law constants, using the isothermal compression model.