Senior CFD Engineer

Last Energy is building productized nuclear plants with manufacturing-style repeatability. We’re hiring a CFD Engineer focused on heat exchangers to drive thermal-fluid analysis from first-pass sizing through detailed geometry decisions. You’ll own the CFD workflow end-to-end and turn simulations into clear trade studies and recommendations that directly inform hardware design (ΔP, effectiveness, flow distribution, hot spots), while continuously improving the speed and consistency of how we model and communicate results.

• Build and run CFD models for heat exchanger components and flow paths (headers/manifolds, distributors, tube/fin passages, shell-side features, compact HX geometries, etc.)
• Drive pressure drop and heat transfer performance predictions and trade studies (ΔP vs UA/effectiveness, temperature approach, flow distribution, hot spots)
• Develop a repeatable CFD workflow: geometry → mesh → solve → post-process → standardized report package
• Execute parametric sweeps and sensitivity analyses to support rapid iteration and design decisions
• Improve throughput by reducing model failure modes and cycle time through automation, templates, and best practices
• Translate CFD outputs into actionable design changes in collaboration with mechanical design and systems engineering
• Create or refine engineering correlations / reduced-order models (Nu, f, HTC) to feed sizing and system tools where appropriate
• Support vendor and partner alignment by clearly defining assumptions, boundary conditions, acceptance criteria, and evidence packages
• B.S. in Mechanical, Aerospace, or a related engineering field (M.S./PhD a plus)
• Strong fundamentals in heat transfer and fluid mechanics; comfort reasoning from first principles and sanity-checking results
• 4+ years of hands-on CFD experience in thermal-fluids applications (more experience welcomed; we can level this role)
• Experience with heat exchangers or closely related mass/heat transfer hardware (compact HX, manifolds, internal flows, finned passages, etc.)
• Proficiency in at least one major CFD solver: ANSYS Fluent/CFX, STAR-CCM+, OpenFOAM, or COMSOL
• Practical meshing and modeling judgment: boundary layers, y+, turbulence model selection, convergence criteria, grid independence
• Ability to communicate results clearly to non-CFD stakeholders and defend assumptions under schedule pressure
• Multi-phase or boiling/condensing modeling experience is a plus
• Experience with flow distribution challenges and mitigation (distributors, baffles, headers) is a plus
• Experience with flow-induced vibration considerations or coupling CFD insights to structural risk is a plus
• Python-based automation of meshing/runs/post-processing; comfort on HPC environments (Slurm/PBS) is a plus
• Experience producing decision-grade analysis packages in high-reliability industries is a plus