The influence of injector design on the decay of pre-ignition turbulence in a spherical explosion chamber

This paper reports on an experimental study to characterize the turbulent Row field inside a 20 1 Siwek chamber during the pre ignition period. An acrylonitrile-butadiene-styrene model of the chamber was constructed with optical quality windows enabling laser Doppler anemometry (LDA) to be used for turbulence measurements. Alumina (Al2O3) particles were used as the seed dust for measuring the gas-phase turbulence. Three specific dust dispersion systems have been investigated: (1) the deflector plate (also referred to as the rebound nozzle); (2) the perforated annular nozzle; and (3) the circular "Dahoe" nozzle. It is assumed that changing the method of dust dispersion alters the turbulence characteristics. The flow field is non-stationary, i.e., the mean (or predominant fluid flow) and superimposed velocity fluctuations upon the mean decrease with time. Furthermore, there are variations from injection to injection. A procedure has been developed to analyze this non-stationary signal to extract the mean and fluctuating components of velocity, thereby paving the way for decay "laws" to be determined for a particular nozzle configuration. (C) 2001 Elsevier Science Ltd. All rights reserved.