On pulsating and cellular forms of hydrodynamic instability in liquid-propellant combustion
- Sandia National Labs., Livermore, CA (United States). Combustion Research Facility
An extended Landau/Levich model of liquid-propellant combustion, one that allows for a local dependence of the burning rate on the (gas) pressure at the liquid/gas interface, exhibits not only the classical hydrodynamic cellular instability attributed to Landau, but also a pulsating hydrodynamic instability associated with sufficiently negative pressure sensitivities. Exploiting the realistic limit of small values of the gas-to-liquid density ratio {rho}, analytical formulas for both neutral stability boundaries may be obtained by expanding all quantities in appropriate powers of {rho} in each of three distinguished wavenumber regimes. In particular, composite analytical expressions are derived for the neutral stability boundaries A{sub p}(k), where A{sub p} is the pressure sensitivity of the burning rate and k is the wavenumber of the disturbance. For the cellular boundary, the results demonstrate explicitly the stabilizing effect of gravity on long-wave disturbances, the stabilizing effect of viscosity and surface tension on short-wave perturbations, and the instability associated with intermediate wavenumbers for negative values of A{sub p}, which is characteristic of many hydroxylammonium nitrate-based liquid propellants over certain pressure ranges. In contrast, the pulsating hydrodynamic stability boundary is insensitive to gravitational and surface-tension effects, but is more sensitive to the effects of liquid viscosity since, for typical nonzero values of the latter, the pulsating boundary decreases to larger negative values of A{sub p} as k increases through O(1) values.
- Research Organization:
- Sandia National Lab. (SNL-CA), Livermore, CA (United States)
- Sponsoring Organization:
- USDOE Assistant Secretary for Energy Efficiency and Renewable Energy, Washington, DC (United States); National Aeronautics and Space Administration, Washington, DC (United States)
- DOE Contract Number:
- AC04-94AL85000
- OSTI ID:
- 563184
- Report Number(s):
- SAND-98-8403; ON: DE98050978; CNN: Contract C-32031-E; TRN: AHC29803%%21
- Resource Relation:
- Other Information: PBD: Nov 1997
- Country of Publication:
- United States
- Language:
- English
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