Numerical Simulation of Methane-Air DDT in Channels Containing Trace Amounts of Impurity
Abstract
Accidental explosions in industrial and military settings often cause devastating losses to personnel and infrastructure. Many of these events, such as those in coal mines or fuel processing
and transport, are attributed to the accumulation natural gas, which consists of methane with trace amounts impurities which are usually heavier hydrocarbon gases. These heavy hydrocarbons, such as propane (C3H8) and ethane (C2H6), are usually found in trace amounts of up to 20% by volume. These fuels mix with air, create conditions for flame ignition, and subsequently may lead to
a deflagration-to-detonation transition (DDT). This research discusses the conditions under which
flames in idealized channel geometries can accelerate to detonation. DDT was investigated for the
addition of ethane and propane into a methane-air mixture at various geometry scales with constant blockage ratio and channel configuration. Simulations of small channels containing natural
gas were compared with existing experimental data. We found that the location where DDT occurred, LDDT , decreased only slightly as the percentage of impurity changed. The variation was, in
fact, on the order of uncertainly due to turbulence and turbulence interactions (i.e., the stochasticity) in the simulation. The simulations do suggest a decrease in detonation cell size with increased
impurity, which would result in a more robust detonation wave.
Citation
Kunka, Logan Nash (2021). Numerical Simulation of Methane-Air DDT in Channels Containing Trace Amounts of Impurity. Master's thesis, Texas A&M University. Available electronically from https : / /hdl .handle .net /1969 .1 /195708.