关键词: 长尾喷管;碳/酚醛;耦合传热;体积烧蚀;表面烧蚀

Abstract: The investigation of heat transfer and ablation characteristics of tail-pipe nozzle of SQ-2 propellant solid rocket motor is conducted via experimental and numerical approach aiming at the problem of thermal protection of tail-pipe nozzle. The cell centered， finite-volume approach is used to solve the Navier-Stokes equation for the fluid domain and heat conduction equation for solid domain， k-ω SST model is selected for turbulence closure in the simulation program. The conjugate heat transfer process is realized by keeping the heat flux of each side consistent and continuous of temperature on the coupling-wall. On the basis of the above simulation methods， a thermodynamic physical property model based on pyrolysis kinetics is established to describe the volume ablation of carbon / phenolic and the simplified heterogeneous reaction model is used to calculate the thermal chemical ablation of the nozzle. The results indicate that the thickness of charring layer and ablation magnitude is consistent with temperature distribution in axial since pressure changes little in the convergent section equivalent section， and reach a minimum value at a distance of about 1.6 mm from the entrance of the equivalent section.The charring rate decreases with time while ablation rate tends to stabilize over time for carbon/phenolic. The ablation rate grows over time for C/C composite used in the throat insert.

Key words: Tail-pipe nozzle;Carbon/phenolic;Conjugate heat transfer;Volumetric ablation;Surface ablation