La tecnolog\u00eda de motores para vectores del tipo \u201cRotating Detonation Engine\u201d tiene m\u00e1s de 60 a\u00f1os, pero sus resultados no han sido satisfactorios. Investigadores de la University of Central Florida\u201d han revitalizado la idea de una nueva generaci\u00f3n de motores, que empleando un sistema de explosiones controladas, permite motores m\u00e1s simples y livianos, as\u00ed como un uso m\u00e1s eficiente del combustible para propulsar cohetes al espacio.<\/p>\n
For most aerospace<\/span> engineers, an explosion in a rocket engine is a disaster. But for Kareem Ahmed, it\u2019s the entire point. As the director of the Propulsion and Energy Research Laboratory at the University of Central Florida, Ahmed has spent the past few years developing a next-generation rocket engine that uses controlled explosions to boost stuff into space. It\u2019s called a rotating detonation engine<\/a>, and it promises to make rockets lighter, faster, and simpler. But before it ever heads to space, engineers and physicists need a better understanding of how the hell it works.<\/p>\n \u201cThe challenge has been trying to understand what\u2019s really happening inside and to be able to predict the performance,\u201d Ahmed says. \u201cWe want to get them to the point where they are as predictable as a traditional engine.\u201d<\/p>\n Rotating detonation engines, or RDEs, sound like something out of science fiction, but the concept is about as old as the space age itself. In the late 1950s and early ’60s, aerospace engineers working on rocket engines envisioned RDEs as a way to turn a problem into a solution. \u201cSometimes the rocket motors would get a real bad instability and you\u2019d get an explosion,\u201d pioneer Arthur Nicholls recalled in a University of Michigan interview<\/a> shortly before his death. \u201cThen it led to the idea\u2014well, what if we use that?\u201d<\/p>\n RDEs are fundamentally the same as all other rocket engines: A fuel and oxidizer are ignited, and as they rapidly expand they are pushed out of a nozzle at high speeds, which blasts the rocket in the opposite direction. But the devil, as always, is in the details. In conventional liquid rocket engines like the kind used by SpaceX, the fuel and oxidizer are pressurized and fed into the ignition chamber using bulky turbopumps and other complicated machinery. A rotating detonation engine doesn\u2019t need these pressurization systems, because the shock wave from the detonation provides the pressure.<\/p>\n In the RDE developed by Ahmed and his colleagues, hydrogen and oxygen are fed into a combustion chamber. A small tube is used to send a shock wave into the chamber, which triggers the detonation. As the pressure wave moves through the chamber, it encounters more hydrogen and oxygen being fed into the front of the engine by dozens of tiny injectors. When the detonation wave hits the fresh fuel and oxidizer, it rapidly raises the temperature and pressure of the gases. This causes them to combust and send a flame shooting out of the rocket engine.<\/p>\n We\u2019re accustomed to thinking of an explosion as a one-off event\u2014something blows up and that\u2019s that. But a functional RDE requires sustaining the initial detonation, which is where the \u201crotating\u201d part comes in. The propellant is fed to the engine through a specially designed injection plate with dozens of small holes that act like a racetrack for the detonation wave, allowing it to rotate around the cylinder. The rotating wave feeds off new propellant and will generate new detonation waves in an endless loop until there\u2019s no more fuel flowing into the chamber.<\/p>\n Earlier this month, Ahmed and a team of researchers from the University of Central Florida and the US Air Force published<\/a> the test results from the first rotating detonation engine to use hydrogen and oxygen for propellant. This chemical cocktail is regularly used to propel the upper stage of a rocket on the final leg of its journey to orbit. But Ahmed says that many engineers believed this chemical mixture was too volatile to be used in a rotating detonation engine. \u201cHydrogen is a crazy fuel,\u201d he says. \u201cMost believed it wasn\u2019t possible to detonate hydrogen and oxygen, because it would tend to deflagrate like a typical rocket engine, rather than a detonation motor.\u201d<\/p>\n The number of waves produced by the engine is determined by how much propellant is being pumped into the system. The engine built by Ahmed and his colleagues had five waves, but other RDEs have had up to eight. It\u2019s still unclear how the number of waves affects the performance of the engine, which will require a better understanding of the waves themselves. To study the waves produced by their engine, Ahmed and his colleagues added a chemical tracer into the propellant and filmed the engine using a high-speed camera rolling at over 200,000 frames per second. The result<\/a> looks like a throbber, the spinning wheel on your PC that tells you when a computer application is hanging.<\/p>\n