Boron Particle Ignition in Secondary Chamber of Ducted Rocket

J X Hu,Z X Xia,W H Zhang,D Q Wang,Z B Fang,L Y Huang

doi:10.1155/2012/160620

Abstract

In the secondary chamber of ducted rocket, there exists a relative speed between boron particles and air stream. Hence, the ignition laws under static conditions cannot be simply applied to represent the actual ignition process of boron particles, and it is required to study the effect of forced convective on the ignition of boron particles. Preheating of boron particles in gas generator makes it possible to utilize the velocity difference between gas and particles in secondary chamber for removal of the liquid oxide layer with the aid of Stoke's forces. An ignition model of boron particles is formulated for the oxide layer removal by considering that it results from a boundary layer stripping mechanism. The shearing action exerted by the high-speed flow causes a boundary layer to be formed in the surface of the liquid oxide layer, and the stripping away of this layer accounts for the accelerated ignition of boron particles. Compared with the King model, as the ignition model of boron particles is formulated for the oxide layer removal by considering that it results from a boundary layer stripping mechanism, the oxide layer thickness thins at all times during the particle ignition and lower the ignition time.

Highlights

Systematic advances in missile propulsion systems technology have provided large increases in missile performance capabilities
An ignition model of boron particles is formulated for the oxide layer removal by considering that it results from a boundary layer stripping mechanism
The model of boron ignition developed in this study involves nine independent parameters, value of which must be input to the resulting numerical computer program for prediction of particle ignition time and minimum gas temperature required for particle ignition [18]

Summary

Introduction

Systematic advances in missile propulsion systems technology have provided large increases in missile performance capabilities. Boron has been considered for many years as a prime candidate used for increasing the ducted rocket capabilities based on its high potential energy release on both a volumetric and gravimetric basis coupled with a high energy of combustion, high combustion temperature, and low-molecular-weight products [2]. These properties make boron an attractive material for use in ducted rocket propellants [3]. An ignition model of boron particles is formulated for the oxide layer removal by considering that it results from a boundary layer stripping mechanism

Boundary Layer Stripping Analysis

Results and Discussion

Conclusions