Pulsating hydrodynamic instability and thermal coupling in an extended Landau/Levich model of liquid-propellant combustion. 2. Viscous analysis

Margolis, Stephen B.

Sandia National Laboratories

关键词: Pulsations;    Liquid Fuels;    37 Inorganic, Organic, Physical And Analytical Chemistry;    Viscosity;    Hydrodynamics;   

DOI  :  10.2172/751015
RP-ID  :  SAND2000-8201
RP-ID  :  AC04-94AL85000
RP-ID  :  751015

美国|英语

来源: UNT Digital Library

【 摘 要 】

A pulsating form of hydrodynamic instability has recently been shown to arise during liquid-propellant deflagration in those parameter regimes where the pressure-dependent burning rate is characterized by a negative pressure sensitivity. This type of instability can coexist with the classical cellular, or Landau, form of hydrodynamic instability, with the occurrence of either dependent on whether the pressure sensitivity is sufficiently large or small in magnitude. For the inviscid problem, it has been shown that when the burning rate is realistically allowed to depend on temperature as well as pressure, that sufficiently large values of the temperature sensitivity relative to the pressure sensitivity causes the pulsating form of hydrodynamic instability to become dominant. In that regime, steady, planar burning becomes intrinsically unstable to pulsating disturbances whose wavenumbers are sufficiently small. In the present work, this analysis is extended to the fully viscous case, where it is shown that although viscosity is stabilizing for intermediate and larger wavenumber perturbations, the intrinsic pulsating instability for small wavenumbers remains. Under these conditions, liquid-propellant combustion is predicted to be characterized by large unsteady cells along the liquid/gas interface.