Injector Demo

The injector is arguably the most critical component of a liquid rocket engine. It must meter propellant flow, atomize liquids into fine droplets, and ensure uniform mixing across the combustion chamber cross-section.

For this project, we explored a pintle injector design. Pintle injectors use a central post (the pintle) surrounded by an annular gap through which propellants are injected. The central stream impinges on the outer annular flow, creating a radial spray pattern that distributes propellants across the chamber.

Low-Pressure Water Test

To validate the basic flow behavior before committing to high-pressure hardware, we built a simple demonstration model. Since the test was conducted at low pressure (ordinary tap water pressure), we used tangential injection into the annular gap to ensure the flow worked properly and created the desired swirl pattern.

The video shows the mixing behavior of the test setup.

Please notice that:

• This is a low-pressure visualization test only, not representative of actual injector performance.
• Due to low pressure, there is almost no atomization. The flow remains in large liquid sheets and streams rather than fine droplets.
• However, the umbrella-shaped dispersion and impingement pattern match expectations for a pintle injector geometry.

This test confirms the basic fluid dynamics of the design. Actual performance at operating pressure would produce better atomization and more uniform mixing.