This work presents a novel approach for the modelling of the regression rate in hybrid rocket engines loaded with paraffin-fuel. Two different motor thrust classes have been considered in this work to extend the validity of the numerical model on two motor geometries (200 N and 1 kN). The work consists of two parts. Firstly, a unique and general empirical law of the regression rate was found for both the motor configurations, which are governed by different consumption mechanisms due to the injection system. Ballistic reconstruction techniques have been introduced to reproduce the temporal trend of the regression rate during the burning time and to increase the number of experimental tests used for the development of accurate and reliable regression laws. Experimental observations in the larger motor suggest that the entrainment is dominated by mass diffusive transport phenomena, which is modelled here by a Fick-like relation. This model, coupled with a sophisticated gas-surface interaction treatment, allowed the evaluation of the regression rate in each point of the grain surface by computational fluid dynamic simulations. Then, the overall model has been validated on experimental and reconstructed data. Finally, the effect of the motor configuration on the fuel consumption is shown, thus revealing the crucial influence of the separation zone delivered by the axial injection.

这项工作提出了一种模拟装载石蜡燃料的混合火箭发动机的回归率的新方法。在这项工作中考虑了两种不同的电机推力等级，以扩展数值模型在两种电机几何形状（200 N 和 1 kN）上的有效性。作品由两部分组成。首先，为两种电机配置找到了一个独特且普遍的回归率经验定律，由于喷射系统，它们受不同的消耗机制控制。已经引入弹道重建技术来重现燃烧期间回归率的时间趋势，并增加用于开发准确可靠的回归定律的实验测试的数量。现象，这里用 Fick 类关系建模。该模型与复杂的气体-表面相互作用处理相结合，允许通过计算流体动力学模拟评估晶粒表面每个点的回归率。然后，在实验和重建数据上验证了整个模型。最后，显示了电机配置对燃料消耗的影响，从而揭示了轴向喷射提供的分离区的关键影响。