Thermo-Structural Response Caused by Structure Gap and Gap Design for Solid Rocket Motor Nozzles

Abstract

Abstract:The thermo-structural response of solid rocket motor nozzles is widely investigated in the design of modern rockets, and many factors related to the material properties have been considered. However, little work has been done to evaluate the effects of structure gaps on the generation of flame leaks. In this paper, a numerical simulation was performed by the finite element method to study the thermo-structural response of a typical nozzle with consideration of the structure gap. Initial boundary conditions for thermo-structural simulation were defined by a quasi-1D model, and then coupled simulations of different gap size matching modes were conducted. It was found that frictional interface treatment could efficiently reduce the stress level. Based on the defined flame leak criteria, gap size optimization was carried out, and the best gap matching mode was determined for designing the nozzle. Testing experiment indicated that the simulation results from the proposed method agreed well with the experimental results. It is believed that the simulation method is effective for investigating thermo-structural responses, as well as designing proper gaps for solid rocket motor nozzles.

Coupled Thermo-Structural Analysis Model of Solid Rocket Motor Nozzle considering the Variation of Friction Coefficient under Operating Conditions

“…(3) The thermo-structural analysis was conducted by adopting pressure load and heat transfer load [21];…”

“…This phenomenon needs to be described by an accurate friction coefficient. It is undeniable that many researchers have attached great importance to the debonding process [17][18][19][20][21][22][23][24][25][26]. However, previous studies mainly adopted the empirical value.…”

Numerical Simulation of Coupling Thermal and Mechanical Influence on Submerged Nozzle in Solid Rocket Motor

“…Hu et al [14] determined the temperature and stress field of the conical trapped joint carbon-carbon nozzle divergent section. Sun et al [15] studied the thermo-structural response of a typical nozzle with consideration of the structure gap based on the finite element method.YU et al [16] considered the influence of the fit clearance of the throat insert on the deformation and stress distribution of the nozzle based on the three-dimensional finite element model. The research shows that the fit clearance of throat insert does not change the overall distribution of stress, but can affect the stress on the matching surface.…”

Probabilistic Reliability Analysis of Carbon/Carbon Composite Nozzle Cones with Uncertain Parameters

“…radiation and conduction are ignored [23][24][25][26]. The mechanical erosion of the material and the ablation of the inner nozzle wall are also neglected [27,28]. (2) Only convective heat transfer between the air and the outer wall of the nozzle is considered, and the radiation heat loss is neglected [29][30][31][32].…”

“…(2) Only convective heat transfer between the air and the outer wall of the nozzle is considered, and the radiation heat loss is neglected [29][30][31][32]. 3The flow field parameters (pressure and temperature) do not change for a SRM in steady-state operations (4) The thermally induced erosion of the insulation material is ignored [27,28].…”