Pressure control in a semi-closed volume upon combustion of solid propellants with an exponent in the combustion law greater than unity

The problem of pressure control in a semi-closed volume by changing the critical cross-sectional area of a gas-release channel is considered upon solid-propellant combustion with the pressure, the combustion rate, and the free volume varied over a wide range (not smaller than one order of magnitude). For a system of automatic pressure control, a control algorithm is chosen and the conditions of partial parametric invariance with respect to the variable dynamic properties of the object to be controlled are formulated. The experimental results obtained upon improvement of the control system for solid rocket propellants whose exponent in the combustion law is greater than unity are given. The reasons for substantially nonstationary modes of operation of this system are considered, and a simplified model that approximates the phenomena of nonstationary combustion of a solid rocket propellant is proposed. The model is identified and the results of mathematical modeling are given. Recommendations on pressure control in the nonstationary modes of operation are given.