Oscillating flames in open tubes

When a flame passes along a tube that is open at both ends a self induced fluctuating pressure/flow field is created which the flame has to traverse. Here fuel rich (1.1 < ϕ < 1.4) propane-air flames have been filmed travelling along a 20 mm internal diameter quartz tube. Fluctuations in the flame’s progression were observed to increase as the flame propagated, achieving a maximum oscillation amplitude of ±10 mm at 220 Hz that decayed as the flame progressed further towards the end of the tube. The impact of the periodic pressure gradients on the flame shape could be discerned with tongues of unburned reactants pushed into the products as well as the corresponding rapid acceleration of the flame into the unburned mixture. The impact of the fluctuations on flame chemistry was monitored by capturing the CH∗ and C2 chemiluminescence using a high speed colour camera. The CH∗/C2∗ ratio was observed to decrease as the flame was pulled back towards the burned mixture; and increased when the flame was pushed forwards. This was consistent throughout the flame progress even when small oscillations in the flame position were measured. This could be a significant feature of flames in this environment

An Application of Hydrogen Thermophysical Properties Database “All in One Live CD”

A database for the thermophysical properties of hydrogen that supports a wide range of parameters including high pressures and high temperatures is being developed. The database performance requirements were studied and, in this paper, an application that combines a server-client database and a live CD is proposed. For this, an "All in One Live CD" application has been developed. Web interfaces provide excellent user interfaces for databases. However, there are some disadvantages for web interfaces related to server maintenance and access restrictions. This new application, the "All in One Live CD," is free of these disadvantages, and provides a database with a property estimation service independent of the computer environment. From a single boot via the "All in One Live CD," the database becomes accessible on multiple computers so that this feature makes the new application a unique solution as a distribution media.The original publication is available at www.springerlink.co