固体火箭发动机碳/碳复合材料喷管的传热及烧蚀特性研究

To accurately analyze the ablation process of the nozzle and predict the accurate ablation rate, a dynamically coupled model that integrates chemical ablation, mechanical erosion, and wall recession, based on FLUENT software and user defined functions, is developed in this paper. Numerical simulations were conducted to model the flow, heat transfer, and ablation within the nozzle, exploring the flow characteristics, heat transfer, ablation process, and the factors affecting ablation. The results indicated that the ablation was most severe in the upstream region of the nozzle throat, with the peak ablation rate reaching 0. 44 mm · s^-1 at the 5th second. Chemical ablation was the primary factor causing nozzle ablation, and it was positively correlated with the inlet pressure and inlet temperature of the nozzle. The influence of radiative heat transfer on erosion was particularly noticeable during the initial ignition phase. Mechanical erosion primarily occurred in the converging section of the nozzle and was approximately proportional to the particle size and the mass flow rate. The peak value of mechanical erosion rate was 0. 04 mm · s^-1 when the particle diameter was 100 μm. Additionally, the peak mechanical erosion rate increased by 0. 01 to 0. 02 mm · s^-1 for every 25 μm increase in particle diameter, and approximately 0. 015 mm · s^-1 for every increase of 0. 2 kg · s^-1 in mass flow rate. The research provides a reference basis for the thermal protection design of solid rocket engine nozzles.