We study an influence of the gas boundary layer on the combustion of homogeneous solid propellants in stationary and non-stationary conditions. Blow of the combustion surface of solid rocket fuel by hot gas stream results in a significant increase in the rate of combustion. To increase the specific impulse of the rocket, the fuel charge is channeled. The increase of burning rate due to air flow is called by the positive effect of erosion [1]. In recent studies [2, 3], a slight decrease in the rate of combustion at relatively low speed blower was found - the "weak" negative effects of erosion. Such erosive burning must be considered when designing rocket engines with solid fuels (RESF), calculating the fuel load and during operation of the RESF engine. Otherwise, the current mode of the engine and the dynamics of rocket flight will differ significantly with those really observed. Besides, if by virtue of design features a rocket engine, the fuel used and the external environment some risk of acoustic instability appears. The physical factors introduced by the effect of erosion are so severe that this effect takes a key role in the operation of the rocket. Erosive burning is described within the Vilyunov-Klimov model [4], where the main criterion is considered to be the Vilyunov number. The resulting systems of equations for the coefficients of positive and negative erosion are solved numerically using finite difference methods (FDM), including is an implicit method and sweep method in the software package Borland C ++. It is shown that the reason for the increase of the burning rate is the intensification of heat transfer, momentum and mass of the gas combustion zone under the influence of turbulence. The mechanism of the negative erosive burning is as follows: reducing the rate of combustion is due to heat losses from the zone of chemical reactions. This is due to the transition of the heat released by chemical reactions in the kinetic energy of the flow of blowing gas.
References
1) Bulgakov V.K., Lipanov A.M. The theory of erosive burning of solid propellants. Moscow, Science, 2001
2) Sabdenov K.O. On the threshold nature of the erosive burning. J. Combustion and Explosion Physics, 2008, Volume 22, № 6. p. 83-88
3) Sabdenov K.O., Useinov A.B., Zhubanazarov D.M. Hydrodynamic distortion in the front of the combustion of solid propellants. Second international conference «Scientific and Technological Experiments on Automatic Space Vehicles and Small Satellites». Samara, Russia, June 27 – 30, 2011. p. 119 – 122.
4) Vilyunov V.N. To the theory of erosive burning. Reports of USSR Academy of Science, V. 136, Issue 2, 1961, p 381-383
