Sr. Thermodynamics Performance Engineer

• Own the integrated cycle performance model — steady-state and dynamic — for our direct-fired sCO₂ Brayton power loop, maintaining and advancing it through the hardware lifecycle


• Run performance prediction and sensitivity studies ahead of test campaigns; reconcile model output against test data to drive model refinement and surface component-level insights


• Own the architecture call on how our dynamic modeling stack should evolve over time — what platform, what fidelity, on what evidence


• Build property tables, turbomachinery map handling, heat exchanger transient models, and combustor representations appropriate to the cycle and fidelity required


• Collaborate with combustion, turbomachinery, and heat exchanger engineers to integrate component data into system-level models; collaborate with controls and software teams on closed-loop simulation and HIL planning


• Develop simulation infrastructure — scripted scenario runs, parameter sweeps, validation cases — that makes the model usable by engineers beyond yourself

Requirements

• Bachelor's degree in Chemical, Mechanical, Aerospace, Nuclear, or related Engineering field


• 6+ years of experience in cycle performance analysis, thermodynamic systems modeling, or dynamic process simulation


• Strong fundamentals in thermodynamics, fluid mechanics, and heat transfer, applied to integrated multi-component systems


• Demonstrated experience building dynamic simulation models of fluid/thermal systems in an industry-grade 1D system simulation platform — and a clear point of view on tool tradeoffs for closed-loop power cycle applications


• Working knowledge of integrated power loop equipment — heat exchanger sizing, compressor/pump curves, valve Cv, piping hydraulics — and how each shows up in dynamic response


• Programming proficiency: Python for data reduction and automation; one of MATLAB/Simulink, Modelica, or equivalent for modeling


• Strong ownership mentality and comfort driving rigorous analysis in a fast-paced startup environment

Preferred Qualifications

• Deep experience with industry dynamic simulation platforms (such as GT-SUITE, Modelica/Dymola, NPSS, Flownex, Simcenter Amesim, or equivalent) applied to turbomachinery, power cycles, or closed-loop thermal-fluid systems


• Background in nuclear thermal-hydraulics with fast-dynamic single-phase modeling experience (RELAP, TRACE, MARS, ATHLET, GAMMA, or equivalent), particularly applied to gas-cooled or sCO₂ reactor concepts


• Working knowledge of real-fluid EOS handling (REFPROP, CoolProp, Span-Wagner) and turbomachinery map interpolation near critical conditions


• History of making and defending tool/methodology decisions in a constrained engineering environment


• Experience with supercritical CO₂, closed Brayton cycles, high-pressure systems (100+ bar), or other high-density working fluids


• Experience coupling plant models to control systems for HIL testing, controller validation, FMU export, or operator training simulators


• Hands-on plant startup, commissioning, or field troubleshooting on first-of-a-kind or developmental systems


• Background in rocketry, gas turbine, advanced reactors, or high-performance turbomachinery environments

Compensation & Benefits

• Pre-IPO stock options


• Medical, dental, and vision insurance (Arbor covers 90% for employees)


• Basic life insurance fully covered


• Health savings account (HSA) with matching


• Flexible savings account (FSA)


• Unlimited PTO  


• 12+ company holidays, including Earth Day!  


• 401(k)


• Commuter benefits


• Annual learning and development stipend


• And more!

Base Pay: $165,000 - $180,000 USD/year. The salary is subject to the applicant's skills, qualifications, experience, and geographic location.