Experimental setup

Yesterday I finished the first part of the setup i.e. the feed system: from the air supply to the water tank to the injector. Here are some pictures:

The air supply in the Aerodynamics lab is 10 bar. The gas passes a manual valve, a check valve, a relief valve set just above 10 bar and a regulator with a range of 1-10 bar. This is what you can see on the main wood panel. On its other side, the water tank is pressurized by the regulated air and the liquid goes towards the injector. It first passes through a pressure transducer and a solenoid valve connected to the electronic box. This consists of a small voltage divider and a data acquisition board (NI 6211). The pressure is displayed and the valve is controlled by the control panel made in LabView.

After the safety check is passed, next week, Prof. Ferry Schrijer will help me with the main part of this project i.e. measuring the size of the droplets. Since the jet velocity is 30 m/s and the size of the droplets is expected to be around 50 μm, the taken pictures must be completely frozen in order to collect relevant data. This cannot be done by the shutter of the high speed camera as it is too slow, but instead, a light source will be used for a shorter period (in the order of ns). More about the equipment will follow in a later post.

Sizing the droplets of a rocket injector

Last year, around October, I have been admitted to the Honours Programme by TU Delft’s faculty of Aerospace Engineering. This programme consists of extracurricular courses (such as Personal Leadership, Cybersecurity, Design Thinking, etc.) and a research project worth of 13 ECTS. The latter has been a challenge for me to choose because I was told that I can take any domain in our faculty to dig into. After several months of visiting different professors, I made my choice of working in Space Engineering with Prof. Barry Zandbergen, who is now my supervisor for the current research.

So what am I doing specifically? I can’t just say I am a space engineer who plays with rockets in his spare time (ok, maybe sometimes). The goal of this research is to characterize the droplets of a plain orifice rocket injector. Here is my literature study.

So why is this so important? There is an optimum when it comes to the size/volume of a droplet at a certain distance from the injector. If the droplet is too small, it will evaporate quickly, before penetrating into the combustion chamber. If the droplet is too big, the engine overall will not reach its maximum efficiency.

In order to achieve the objective, experiments are to be held as the behavior of the atomization process is non-linear and models are very hard to predict. Therefore in my experiments, water will be emerged through a simple injector and pictures will be taken at different upstream pressures. I will keep you posted with the experimental setup and the final results.