Saturday, 9 November 2019

Supercomputers and Jet Engines

We all know that supercomputers are used to design jet engines. Designing and understanding the performance characteristics of a jet engine would likely take millions of core-hours on large HPC systems.

But, a random fact thrown out over lunch at May's industry HPC leaders group meeting sparked an interesting conversation.

If a jet engine takes many megawatt-hours of supercomputing to design - how many MW does a jet engine create, and thus how many petaflops could a jet engine support if it were the power source?

The HPC leaders of GE, Boeing, ExxonMobil and others drew together their shared knowledge of aerospace and HPC - and some use of google search - to built a fun picture.

The most powerful commercial jet engine on the market is the General Electric GE90, as often used on the Boeing 777 aircraft. This comes in many variants, so I’ve fudged the detail of the numbers here.

Each GE90 delivers about 120kW of electrical power to the aircraft. 120kW doesn’t get you a lot of supercomputer. Assuming a CPU based system ("boring but most useful", to steal a line from Dan Stanzione) it would probably be just under one petaflops of computing capacity, depending on the details of hardware choices.

But that only accounts for the designed electricity feed directly supplied from the GE90. The GE90 produces O(100,000) lb of thrust. The lunch geeks’ calculations concluded that means a GE90 is capable of producing around 80MW of power if a very efficient generator was attached. Even allowing for a good bit of conversion inefficiency, that means a 50MW electrical power output should be no trouble for the GE90. As a check, the LM9000 power generation turbine (based on GE90) produces 65MW.

So, a GE90 could easily power the HPC system that designed itself (I think it's a fair guess that GE isn't currently running over 50MW of HPC kit). More interestingly, a GE90 would also have enough oomph to comfortably power the exascale supercomputers that will design its successors.

Of course, running a jet engine at full tilt 24x7 near the data centre would be a noisy, expensive, and very environmentally unfriendly way to generate electricity.

Plus, as was pointed out at our lunch discussion, who wants their supercomputers to smell of JetA fuel?

1 comment:

Anonymous said...

Next question: How many gallons of JetA would it take to fuel the engine to run HPC for a year?