COMBUSTION SIMULATION OF A PARAFFIN BASED SOLID FUEL WITH GASEOUS OXYGEN INSIDE A HYBRID ROCKET MOTOR

Resumo

During the past two decades, the state of art of hybrid rocket propulsion area has been in
research of blends containing paraffin-based fuels because paraffin itself shows higher regression rate

compared to traditional fuels commonly used, such as hydroxyl-terminated polybutadiene or polyethy-
lene, but it does not have good mechanical properties, which increases the risk of grain cracking and

rupturing. With the objective to benefit the database development of paraffin-based hybrid rocket propul-
sion, this work is devoted to present a numerical study of the combustion process of paraffin and gaseous

oxygen during the propulsion of a 100 newtons hybrid rocket motor. The paraffin solid wax was chosen
for the simulation since it exhibits more data about the regression rate with gaseous oxygen in literature.
The simulations utilize a mesh with around 100000 quadrilaterals elements, with an average orthogonal
quality of 96.5% and an average skewness of 11% . An axis-symmetric volume domain is considered.

Paraffin is studied as hexadecane (C16H34) using a reduced reaction mechanism of diesel from “Creck-
modeling”. Paraffin is evaluated as a gas at 0, 5 and 10 seconds during a test of the hybrid rocket motor

and the results of the simulations are compared. The results analyzed are temperature, pressure and ve-
locity profiles inside the hybrid rocket motor. The nozzle and the plume of the exhaust product gases are

as well evaluated. This work will contribute to a project of a hybrid rocket motor, where it will operate
with paraffin solid wax and other paraffin-based blends on a laboratory test bench.