24-11-2010, 10:35 AM
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Pulsed Detonation Thermal Spray
Abstract
Pulsed detonation thermal spray coating is used to enhance the material properties at the surface of an object. The present research implements computational fluid dynamic modeling to identify the efficiency of energy and mass delivered to potential target locations. Six cases of a hydrogen-air mixture are used to investigate the gas flow from the instant of ignition to the instant of flow reversal at the tube exit. Flow monitors are included in the model to represent potential target locations. These monitors are placed at different axial locations in order to record mass flow rate and the flow rate of enthalpy over time. The results indicate that there exists a quasi-steady jet that is efficient and predictable in delivery of energy and mass from the tube exit to potential target locations positioned on the centerline. The duration of the quasi-steady jet is dependent on the fraction of combustible gas (i.e., % fill). Much of the initial energy and mass delivered from the jet avoids the flow monitors. This is found to be related to the evolution of the jet behind the blast wave where energy is lost in expansion and vorticity production. It is also found that nearly 11-18% of the available energy and 20-23% of the available mass remains in the tube after flow reversal.
