Rayleigh-Taylor instability: Modelling and effect on coherent deflagrations

The modelling of Rayleigh-Taylor instability during premixed combustion scenarios is presented. Experimental data obtained from experiments undertaken by FM Global using their large-scale vented deflagration chamber was used to develop the modelling approach. Rayleigh-Taylor instability is introduced as an additional time-dependent, combustion enhancing, mechanism. It is demonstrated that prior to the addition of this mechanism the LES deflagration model under-predicted the experimental pressure transients. It is confirmed that the instability plays a significant role throughout the coherent deflagration process. The addition of the mechanism led to the model more closely replicating the pressure peak associated with the external deflagration.