Launching anything into space requires plenty of fuel. The Space Shuttle, for example, needed over 3.5 million pounds of fuel. This is 15 times greater than the mass of a blue whale.
A space launch can consume a lot of fuel. Hence, a new type of fuel-efficient rocket engine for launch vehicles is undergoing development. This particular rocket engine will be extremely lightweight since it will consume far less fuel than conventional rocket engines.
Another advantage is that it will have a simpler construction. However, at this stage, the rocket engine design still needs research for stability and control.
University of Washington Research
University of Washington researchers have published a mathematical model that illustrates the manner in which these engines work. Using this information, engineers can design tests for the first time that can enhance the performance and improve the stability of these engines. This research can be found in the journal Physical Review, January 10, 2020.
The rotating engine concept is still in its earliest stages. James Koch, a doctoral student at the University of Washington specializing in astronautics and aeronautics, states that although there is a lot of data concerning these engines, explaining the results is not simple. Researchers are working to uncover the working principle behind the numbers. However, research is making progress as pattern formations can help to explain some of these results. This method proved to be much more useful than taking an engineering perspective such as finding the data points for maximum engine performance.
Conventional rocket engines generate thrust by burning propellant and then expelling it through a specially designed nozzle.
The Detonation Process
Rotating detonation engines have a different process for generating thrust. A typical engine has concentric cylinders inside. The propellant passes through gaps in the cylinders. When ignition takes place, there is a shockwave due to rapid heat release. A pulse of gas moving faster than the speed of sound propagates with high temperature and pressure. The ignition process is actually a detonation.
In conventional engines, a lot of moving parts are required for controlling and directing the gas flow in a manner that will generate optimal thrust. Rotating detonation engines can achieve this without the use of moving engine parts as the shock wave compresses gas flowing through the combustion chamber.
However, the problem lies in control since detonations can be quite unpredictable.
Experimentation
Researchers sought to unravel the underlying working principle by setting up an experimental model in which they could control parameters like the gap between the cylinders. High-speed cameras were in place to record data from combustion. Each experiment was completed in just half a second. However, since the cameras can record 240,000 frames per second, researchers had tens of thousands of images for each experiment. Researchers scrutinized these images to study the detonation process. The data and the consequent mathematical model will help to develop fuel-efficient rocket engines that will make space flights more economical.
