Testing Transitions Inside Air-Breathing Scramjet Engines
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Testing Transitions Inside Air-Breathing Scramjet Engines

November 20, 2019

Hi everyone! My name is Sibylle Walter and I am from the great state of Maryland. I am currently a PhD student working at the University of Colorado in Boulder. Through the NASA Aeronautical Scholarship Program I was able to spend my summer here at the NASA Glenn Research Center in Cleveland Ohio, working with my mentors Dave Davis and Dave Saunders. Together, we have been working on the Large Scale Inlet Mode Transition Experiment, or also known as LIMX What you’re looking at here is a mode transition, which LIMX was developed to study. A mode transition refers to the opening and closing of the doors called cowls, switching between different engines. In this case, it is for a turbine based combined cycle engine called a TBCC engine for short with a turbojet first stage and a ramjet second stage that can operate in tandem or independently. You probably know the first TBCC-like engine without knowing it. It was the J58 which powered the SR71 Blackbird. The SR71 had the same engine configuration as most fighter planes a turbojet with an afterburner. However, what made the SR71 special was that the engine thrust could be increased at high speeds by bypassing the turbine and pulling all that extra air into the afterburner, simulating a ramjet. This made the SR71 the fastest manned aircraft to ever fly, a record it has held for almost four decades. Another application of a TBCC engine would have been the National Aerospace Plane, or NASP for short. the goal of NASP was to create a reusable launch vehicle that would use the oxygen in the air to bring a space faring vehicle close to the edge of our atmosphere instead of climbing all the way up carrying its own oxidizer tank, like rockets do. LIMX was designed to explore inlet designs for a vehicle similar to NASP. The TBCC engine technology has the potential to make space travel much cheaper, but of course presents its own challenges. Earlier you saw me in front of NASA Glenn’s 1 foot by 1 foot supersonic wind tunnel. This is their 10 foot by 10 foot supersonic wind tunnel, where the LIMX model was actually tested. Behind me you can see a model. It’s not the LIMX model, but it is representative of the kinds of models we test in this wind tunnel. My job was to take all that test data and see well, what is the flow actually doing as it is moving through the inlet? This helps researchers determine if they have to make any design changes to the model in the future to make it work even better. Well I hope my video helped give you some insights into what NASA does in the realms of high speed inlets and show you how much fun it can be to be a NASA intern! Thank you so much for joining me.

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  1. Is it possible to tune Ramjets like one tunes a horn ?  What if one set up a purposeful tuned sound vibration in the pipe. Could this do anything to increase thrust whatsoever or change they dynamics of the engine for the better ? just a thought.. I would like your thought on this if possible. Am I just being silly?  🙂

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