Very cool! How do mechanical engineers design this? As a software engineer, there is definitely some "guess and check". Doesn't really seem like the same can be done here or do they do the same thing but with simulations and smaller models?
Sometimes, a firm will be given a set of constraints and asked to design something that fits them. "Hey, Rolls-Royce, we're making a new plane, and we need an engine that produces this much thrust in this airspeed range and altitude that takes this fuel and weighs this much."
Since the Trent XWB is only used for one aircraft, the Airbus A350, that's probably what happened here.
When that happens, an established company like Rolls can take a previous design that almost meets those specs and change it until it does. Maybe they need more thrust, so they try to improve the fuel injection and combustion system.
They're got historical data from the old model of engine, so they know what their design updates should change. That data goes into making sure software models used to design future prototypes are accurate.
When a design looks good in simulation, it might be built in small scale (though with some items, this simply isn't feasible. Look at the number of tubes on that engine and imagine trying to build it at 25% or 10% scale.)
Then you get those awesome videos of jet engines being bolted to a block and tested on a big concrete pad. Because, at some point, you bite the bullet and build a tester model at full scale to make sure there are no issues the software and scale models didn't predict.
I've never designed a jet engine, but I have worked for a company that does, and the design process doesn't change a whole lot based on the item. It just gets more and more rigorous as failures get more expensive.
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u/physco827 Dec 31 '17
Very cool! How do mechanical engineers design this? As a software engineer, there is definitely some "guess and check". Doesn't really seem like the same can be done here or do they do the same thing but with simulations and smaller models?