Early in my career when I was researching advanced concepts for combustion, I had a great new idea for blending steam, fuel, and air in a way that would improve emissions and operability. I took the concept to a design review with more senior engineers who pointed out that it was great…except there wasn’t a good way to manufacture it.
Many engineers have had similar experiences, and sometimes learn early in their careers to be more careful – and therefore less creative – about new ideas.
Today, advanced manufacturing technology is not only critical for productivity, quality, and new materials, but it is also fundamentally changing the way engineers think about designing and testing parts. New technologies, such as additive manufacturing, where metal parts are built up from powder fused together bit by bit with high-powered, computer-controlled lasers, allow for design concepts otherwise simply impossible to manufacture.
A recent example is the fuel nozzle for the GE LEAP aircraft engine. The fuel nozzle must operate stably across a wide range of conditions from full-power take off to high-altitude reignition, and it must do this with low emissions throughout, requiring intricate internal passages and multiple flow circuits to ensure optimal distribution and precise control of fuel and air. In the past, designs like that were difficult to produce forcing engineers to compromise performance in order to accommodate manufacturing constraints. Now that additive manufacturing processes are available, however, the designers could reconsider a more complex system of cavities and passages that better meets performance requirements, but can still be effectively manufactured. A similar design concept is being employed in GE’s 7HA.02 gas turbines now in development at GE’s new Brilliant Factory in Greenville, SC. It allows for better natural gas and air mixing, and therefore lower emissions, at the very high combustion temperatures of this 61%+ efficiency machine.
An additional benefit is that engineers can design, test and develop concepts faster, particularly in combination with high fidelity simulations. For example, a researcher in turbine aerodynamics or film cooling will typically take a new concept through several iterations of numerical simulation before building test hardware, which can take several weeks using traditional manufacturing processes. We can now build and test multiple versions of hardware in parallel with simulation (which helps validate the simulation and unlocks the complex physical understanding needed to further improve today’s advanced turbomachinery) thanks to new additive and rapid prototyping processes.
Technological development is becoming increasingly convergent and interdependent; advances in one field are frequently enabled by progress in another. The integration of production and engineering through new design methods, digital threads, and manufacturing technology is enabling rapid progress in multiple fields, and, more importantly, is allowing today’s engineers to entirely rethink the possibilities as they design tomorrow’s machines.