MEASUREMENT AND MODELING OF SOOT FORMATION AND DEPOSITION IN FUEL RICH HIGH PRESSURE KEROSENE COMBUSTION

Combustion of kerosene propellants often deposits soot on chamber walls. These deposits act as a thermal barrier and can significantly affect the analysis of cooling systems. This is especially vital for reusable engines since the accumulated soot deposit can make the wall heat flux vary between every firing. This dissertation discusses a computational and experimental effort to understand the main drivers of these soot deposits. The computational approach employs the Method of Moments with Interpolative Closure (MOMIC) model to predict soot particle dynamics; Brownian and thermophoretic diffusion for particle transport to the chamber surface; and the Hydrogen-Abstraction-Acetylene-Addition (HACA) mechanism for soot surface growth. These models were incorporated in a 1D plug flow reactor. Two-dimensional axisymmetric reacting CFD simulations were also run to understand the flow field influence on the near wall gas phase chemistry. Simultaneously, a fuel rich kerosene and gaseous oxygen experiment was developed and fired to obtain soot deposit thickness measurements for model comparison. The results show the reduced order plug flow model can satisfactorily predict the soot thickness and that thermophoresis is the dominant deposition mechanism. However, though the model can predict deposit mass trends, it underpredicts the absolute values for some conditions and may need an additional mechanism.