Thermal Design Engineer II / Senior Thermal Design Engineer

Position Description

The Thermal Design Engineer, CFD will be part of Nitricity's core product engineering team developing megawatt-scale chemical production facilities. Our process converts air into fixed nitrogen in a plasma, producing gas streams at thousands of degrees that must be cooled quickly enough to preserve the nitric oxide we create while recovering as much high-grade heat as possible. Getting this right is central to the efficiency and cost of our product.

In this role, you will be our lead for computational fluid dynamics of high-temperature, chemically reacting air. You will build CFD models that couple fluid flow, heat transfer, and detailed chemical kinetics, and use them to guide the design of our reactors, quench systems, and heat recovery equipment. You will work closely with experts in chemical, mechanical, and electrical engineering and with our test team to validate models against pilot and laboratory data. This position reports to Nitricity's Chief Science Officer.

Responsibilities

• Build, run, and validate CFD models of high-temperature air flows (up to several thousand K) exiting Nitricity's plasma reactors, including turbulent reacting flow, quench, and heat transfer.
• Couple detailed and reduced chemical kinetic mechanisms for N2/O2/NOx chemistry to flow solvers to predict NO formation, NO decomposition during cooling, and overall fixation yield.
• Use simulation results to drive the design of reactors, quench sections, and heat recovery equipment that capture high-grade heat while preserving product.
• Develop and reduce kinetic mechanisms as needed, and perform sensitivity and reaction pathway analysis to identify the steps that control yield and energy efficiency.
• Partner with the experimental team to plan diagnostics and test campaigns (temperature, species, and pressure measurements) that validate and calibrate models.
• Conduct conjugate heat transfer, thermal stress, and materials temperature assessments for components exposed to high-temperature, oxidizing gas.
• Translate CFD and kinetics results into design recommendations, technical specifications, and clear documentation for engineering and leadership.
• Establish simulation best practices at Nitricity, including meshing standards, solver settings, verification and validation workflows, and model version control.
• Work with outside engineering firms and software vendors, and help scale models from laboratory and pilot systems to megawatt-scale commercial plants.

Required Qualifications

• BS in Mechanical, Chemical, or Aerospace Engineering or a related field with 2+ years of relevant experience, or MS, with a focus on fluid mechanics, heat transfer, combustion, or reacting flows.
• Hands-on experience running reacting-flow CFD simulations of high-temperature gas flows using a commercial or open-source package (ANSYS Fluent, STAR-CCM+, CONVERGE, OpenFOAM, or similar).
• Strong grounding in turbulence modeling, turbulence-chemistry interaction, radiation, and heat transfer.
• Working knowledge of chemical kinetics and experience coupling finite-rate chemistry to flow simulations, using tools such as Cantera, CHEMKIN, or equivalent.
• Proficiency with 3D CAD (SolidWorks, Onshape, or similar), including parts, assemblies, and engineering drawings, and preparing geometry and meshes for simulation.
• Working knowledge of GD&T, materials selection, and design for manufacturing for components operating at high temperature.
• Experience validating simulations against experimental data and communicating uncertainty clearly.
• Scripting skills in Python or similar for pre/post-processing, automation, and parametric studies.
• Work well in focused teams with multiple disciplines and thrive in a fast-moving start-up environment.
• Enthusiasm for high-impact, hard tech solutions.

Preferred Qualifications

• Proficiency with ANSYS simulation tools (Fluent, CFX, Chemkin-Pro, and/or Mechanical).
• Experience with AI-enabled modeling and simulation workflows, such as machine learning surrogate models, reduced-order models, AI-assisted design optimization, or automated parametric studies.
• Experience with high-temperature air chemistry, NOx formation and destruction (Zeldovich and related mechanisms), plasma-assisted chemistry, or non-equilibrium flows.
• Experience with rapid quench, gas-phase reactor design, or hypersonic and arc-heated flows.
• Experience with mechanism reduction, chemical reactor network modeling, or 0D/1D reactor models alongside full CFD.
• Background designing heat exchangers or heat recovery equipment for industrial processes.
• Familiarity with HPC environments and cloud-based simulation workflows.

Compensation and Benefits*

• Annual Base Salary $110,000/yr - $150,000/yr
• 3 weeks of paid vacation (accruing)
• Medical and dental insurance
• 401k plan with matching
• Parental leave
• Commuter benefits

*Benefits are subject to change over time and may require employment in CA to be eligible.