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 ( P, effectiveness, flow distribution, hot spots), while continuously improving the speed and consistency of how we model and communicate results.

Key Duties & Responsibilities

• 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 ( P 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