Turbomachinery Engineer, R&D

ABOUT FLUIDSTACK We exist to make humanity more free. For most of human history, you farmed or you starved. Technology gave people more time for the things they wanted to do, instead of things they had to do. Powerful AI will be the biggest lever for human choice we've ever built - but only if models are aligned with what humanity actually wants. There are groups building AI who don't share these goals. Whoever deploys frontier compute infrastructure fastest will decide whether AI expands human freedom or shrinks it. We're singularly focused on delivering 10 to 100s of GWs of compute faster than anyone else, rethinking every layer of the stack. We acquire power, design and build data centers, and operate them - with teams spanning hardware and software. Speed and scale are our key differentiators. Come be a part of building civilization-scale infrastructure for AI. We hire people who care deeply about this problem space. If that is you, please apply! HOW WE OPERATE - Be a barrel. Full autonomy. Own things end to end, take on scope without being asked, no permission required to operate outside your core role. - Insane urgency. We drive everything forward as fast as possible. - Reason from first principles. Challenge every assumption. Zero analogy thinking, no egos, the best idea wins. - Love of the game. The frontier of AI is the most interesting problem of our time. We put in long hours at high intensity to push the frontier forward. - Build something that actually matters. If you're going to spend your time, spend it on something that matters to the world. THE THERMOFLUIDS R&D TEAM Examples of key problems the team is working on - Reject 10s of GW of heat, starting now. Fluidstack is targeting 10s of GW of compute over the next two years. Every watt of it becomes heat that has to go somewhere, and no cooling team has ever been asked to open at that scale rather than grow into it. - Design and build the machines, because nobody can supply them. The merchant compressor market cannot deliver at this rate, and the vendor base behind today’s chillers will not scale to gigawatts. We are taking compressor and chiller design in house, working on machine architectures nobody sells today, and going from blank sheet to production faster than this industry thinks is possible. - Own every thermofluids problem behind the fleet, not just the chiller. Working fluid and cycle architecture, heat exchangers at a scale that dominates the cost of the plant, two-phase heat transfer at the chip, and thermal energy storage. All of it is open, and whatever this team lands gets built thousands of times. ROLE SCOPE - Own the aerodynamic design of the centrifugal compressor, from mean-line and 1D through CFD to released impeller, diffuser and return-channel geometry. - Set the machine architecture, including stage count, shaft speed and diameter, while the working fluid decision is still open and moves the answer substantially. - Design the expansion turbine that recovers shaft work from the high-side pressure drop, sharing a shaft with the compressor and the motor instead of throwing that energy away across a valve. - Carry the rotor through rotordynamics, magnetic bearing integration and stress with the structural and mechanical engineers, at the shaft speeds a compact high-speed machine demands. - Take the machine onto the test stand, and close the loop from a measured performance map back into the aerodynamic design.   WHAT WE'RE LOOKING FOR The below is a starting point. We always make space for exceptional people, so if you don't fit this role exactly, tell us where you would https://jobs.ashbyhq.com/fluidstack/05c2e69c-42f9-4fcb-9cf0-a467aaf98f1c. - You’ve designed a radial or axial turbomachine that got built and ran, and you were standing next to it when it did. - You’ve taken a stage from mean-line through CFD and back, and you know the conditions under which your CFD is lying to you. - You’ve worked a rotordynamics problem through to resolution on a real shaft with real bearings, not just in a report. - You’ve made an architecture call early with incomplete data, stage count or speed or bearing type, and lived with it through build and test. - You read a test map and change the design, rather than explaining why the map is wrong. - You’ve worked somewhere the next article was already in the shop before the last one came off test, and you preferred it that way. - Bonus: Turbopumps, gas turbines and cryogenic turbomachinery (launch vehicles, APUs, aero engines). High-speed motor-driven compressors (magnetic bearings, hermetic, oil-free machines). Transcritical and supercritical working fluids (R744, sCO2 cycles). Real-gas property libraries (CoolProp, REFPROP). Vapor-compression machine design (chillers, heat pumps, industrial refrigeration). We are committed to pay equity and transparency. Fluidstack is an Equal Employment Opportunity Employer. All qualified applicants will receive consideration for employment without regard to race, color, religion, sex, national origin, sexual orientation, gender identity, disability and protected veterans’ status, or any other characteristic protected by law. Fluidstack will consider for employment qualified applicants with arrest and conviction records pursuant to applicable law. You will receive a confirmation email once your application has successfully been accepted. If there is an error with your submission and you did not receive a confirmation email, please email careers@fluidstack.io with your resume/CV, the role you've applied for, and the date you submitted your application-- someone from our recruiting team will be in touch.