Modeling of Plasma Induced Ignition and Combustion
Abstract
Electrothermal-chemical (ETC) ignition systems have been demonstrated in gun systems to provide desirable characteristics including reproducible shorter ignition delays. We present a combined theoretical and experimental study of the capillary discharge with an aim to develop a capillary plasma source with efficient energy conversion. In addition, a detailed understanding of the dynamics of the plasma-propellant interaction is considered one of the key elements to the future success of practical ETC gun implementation. We address this issue by developing a model of the propellant ablation under plasma effect based on the kinetic theory of ablation. The major emphasis in the present capillary discharge model is the ablation phenomenon. A kinetic approach is used to determine the parameters at the interface between the kinetic Knudsen layer and the hydrodynamic layer. In parallel, a parametric experimental study of the capillary ablation process is conducted at Army Research Laboratory. Both experimental measurements and simulations indicate that the ablated mass increases with the peak discharge current and that a smaller diameter capillary yields a larger ablated mass. It is found that model predictions agree well with experimental measurements. The ablation model is coupled with a model of the plasma generation in the capillary discharge that allows calculation of the effective heat flux from the plasma. Calculations are performed for specific experimental conditions in which ablated mass of a double-base and a nitramine composite propellant are studied. One representative solution reproduces the experimentally determined ablated mass for the double-base propellant of 5.3 mg via an effective heat flux on the order of 4x10(exp 8) J/m squared s. The effective heat flux that corresponds to the experimentally measured ablated mass is determined for different propellants.
Document Details
- Document Type
- Technical Report
- Publication Date
- Jun 01, 2006
- Accession Number
- ADP023641
Entities
People
- Andy Porwitzky
- Iain D. Boyd
- Michael Keidar
Organizations
- University of Michigan