Combustion pressure and oxidizer mass flux are key factors influencing the performance of hybrid rocket motors. In the present work, the decoupled effects of oxidizer mass flux and combustion pressure on turbulent combustion characteristics were investigated. First, a finite-length combustion theory of fuel grains was developed to identify the main sensitive parameters, including flame structure and the recirculation zone, which affect the combustion of solid fuel. Then, a two-dimensional transient numerical model, based on the coupling characteristics of the heat transfer process in solid fuel grains and dynamic combustion flow, was developed and validated through fire experiments under a wide range of inflow conditions. A quantitative analysis was conducted to assess the impact of flame structure and the recirculation zone on the dynamic combustion characteristics of finite-length solid fuel. The results showed that the fuel characteristic temperatures of the front and central parts are negatively correlated with flame height, while the characteristic temperature of the rear part is positively correlated with the recirculation zone temperature. Both the mass flow rate and combustion pressure are negatively correlated with flame height and positively correlated with the temperature of the recirculation zone. Compared to combustion pressure, the influence of mass flow rate is more significant. The transient processes of the solid fuel regression rate under different inflow conditions exhibit a consistent tendency: an increase in mass flow flux and combustion pressure results in faster attainment of peak regression rate and stabilization.

中文翻译：

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氧化器质量通量和燃烧压力对有限长度固体燃料湍流燃烧特性的解耦效应


燃烧压力和氧化剂质量通量是影响混合动力火箭发动机性能的关键因素。在本工作中，研究了氧化剂质量通量和燃烧压力对湍流燃烧特性的解耦效应。首先，建立了燃料颗粒的有限长度燃烧理论，确定了影响固体燃料燃烧的主要敏感参数，包括火焰结构和再循环区。然后，基于固体燃料颗粒传热过程与动态燃烧流的耦合特性，建立了二维瞬态数值模型，并在较宽的流入条件下通过火实验进行了验证。进行了定量分析，以评估火焰结构和再循环区对有限长度固体燃料动态燃烧特性的影响。结果表明：前部和中央部的燃料特性温度与火焰高度呈负相关，而后部的特性温度与再循环区温度呈正相关。质量流量和燃烧压力都与火焰高度呈负相关，与再循环区的温度呈正相关。与燃烧压力相比，质量流量的影响更为显著。不同流入条件下固体燃料回归速率的瞬态过程表现出一致的趋势：质量流量和燃烧压力的增加导致峰值回归速率更快达到和稳定。