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International Journal of Energetic Materials and Chemical Propulsion
ESCI SJR: 0.142 SNIP: 0.16 CiteScore™: 0.29

ISSN Print: 2150-766X
ISSN Online: 2150-7678

International Journal of Energetic Materials and Chemical Propulsion

DOI: 10.1615/IntJEnergeticMaterialsChemProp.v5.i1-6.920
pages 903-917

CHARGE DESIGN AND NON-ACOUSTIC INSTABILITY OF SOLID ROCKET MOTOR

Igor G. Assovskiy
Semenov Institute of Chemical Physics, The Russian Academy of Sciences, Kosygin Str. 4, Moscow 117977, Russia
Sergey Rashkovskiy
Institute for Problems in Mechanics of the RAS

ABSTRACT

The goal of this paper is to make a correlation between non-acoustic low frequency instability of combustion in a solid rocket motor (SRM) and geometrical characteristics of the charge and motor cavity. The problem is considered in detail for SRM having end-burning or tubular charge. The analysis is carried out using an original model of unsteady combustion in SRM. This model allows the flame temperature and the temperature distribution in gas flow to fluctuate with pressure in combustion chamber (the Mache effect). A laminar one-dimensional gas flow (without dissipation and mixing) is assumed and described using the Lagrangian approach. The propellant unsteady combustion is formulated in framework of Zel'dovich phenomenological approach. Emphasis is on dependence of the critical conditions of stable combustion on the Mache effect and on sizes of pre-nozzle volume and propellant channel. The analysis shows that the instability region is wider for SRM with a charge channel than for motor with end-buming charge, at the same free volume of motor cavity. A pre-nozzle volume stabilizes the combustion process. The boundary of instability depends mainly on the pre-nozzle part of the cavity but is not sensitive to the channel volume of propellant charge.