Common household chemicals like hydrogen peroxide (H2O2) are used for everything from rocket fuel to bleaching therapies. Its capacity for catalytic breakdown, a process that has long captivated scientists and engineers, is among its most intriguing qualities. Hydrogen peroxide naturally breaks down into water and oxygen at a moderate pace. However, the addition of specific catalysts can substantially speed up this reaction. In fact, the Norwegian University of Science and Technology (NTNU) conducted a thorough study on the catalytic decomposition of hydrogen peroxide, which is our guidance in the simulation. As the title suggests, this is a Numerical paper validation study. The thesis title is “ A CFD-model of the Fluid Flow in a Hydrogen Peroxide Monopropellant Rocket Engine in ANSYS Fluent”.

Figure 1: Plot of the Absolute pressure and Mach number versus the position of the Nozzle. Given in Figure 7.5. of thesis

Simulation Process

The model consists of different regions defined for axisymmetric geometry. 18200 Structured grid hasten the simulation accuracy and robustness. Due to the convergence issues found with the Eulerian model, a final attempt to model this fluid flow was performed with the mixture multiphase model enabled. However, each of the phases consists of several species. This means Species Transport model is also activated. With the mixture model selected for the multiphase model, the built-in model for the Arrhenius equation is no longer available. A User-defined Function (UDF) was therefore written to calculate the reaction rate of the decomposition process.

Figure 2: Problem description of thermal and catalytic decomposition of hydrogen peroxide

Post-processing

The simulation results for the catalytic decomposition of hydrogen peroxide seem to be well-validated based on the photos that have been presented. Figure 3, which compares the Mach number values between a reference paper and a CFD simulation, provides the most important proof for this claim. The graph shows excellent agreement at different positions between the Paper Mach number (orange line) and the CFD Mach number (blue line). This strong correlation suggests that the simulation correctly represents the flow behavior, especially the supersonic expansion that happens when the hydrogen peroxide breaks down and leaves the nozzle. The flow field is visualized in the remaining contours, which display the typical patterns of temperature, velocity, and perhaps pressure or density distributions of a supersonic exhaust plume. The validity of the overall simulation results for the catalytic decomposition process is strongly supported by the consistency between the simulated Mach number profile and the reference data.

Figure 3: Mach number comparison