Senior Thermal Engineer

We're partnering with a seed-stage deep-tech startup building AI-native thermal engineering software that’s used to design next-generation heat exchangers for high‑power systems in data centers, defense, and heavy industry. The company sits at the intersection of computational physics, simulation, and AI‑driven design automation, and is now hiring a Senior Thermal Engineer (PhD-level) to act as the critical human‑in‑the‑loop for their design platform and own real‑world thermal hardware development. This is a highly specialised, hands‑on role for a true thermal‑fluids expert — not a generalist mechanical engineer — who can design, validate, and physically reason through complex heat transfer systems from first principles, and bridge the gap between AI‑generated designs and manufacturable hardware. This is a fully remote position with a strong preference for East Coast hours and you must have full right to work in the US with either citizenship or permanent residency at the time of application. Key Responsibilities Design heat exchangers end-to-end, from blank CAD geometry through to simulation‑validated, manufacturable hardware targeting aggressive thermal and pressure‑drop constraints. Act as the human‑in‑the‑loop for an AI‑driven thermal design platform, validating outputs using first‑principles 1D models and high‑fidelity CFD/CHT simulations. Run and interpret advanced thermal‑fluid simulations using tools such as STAR‑CCM+, Ansys Fluent, nTop, PhysicsX, and EES to guide real engineering decisions. Ensure all designs are manufacturable, accounting for additive manufacturing constraints including support strategy, distortion, and post‑processing requirements. Design and execute validation experiments, closing the loop between simulation and physical testing to refine models and design rules. Develop reusable simulation frameworks, parametric tools, and design methodologies to improve team velocity and scale thermal design capability. Key Qualifications PhD in Mechanical Engineering, Thermal Engineering, or a closely related field with a strong focus on thermal‑fluid sciences, plus ~5+ years of post‑PhD industry experience. Deep expertise in heat exchanger design, with at least one example of designing a system from scratch through to validated hardware (ideally at 200kW+ scale). Strong background in data center cooling, HVAC, liquid cooling systems (e.g., CDUs, rack‑level thermal architectures), or similar high‑performance thermal domains. Experience designing for metal additive manufacturing (L‑PBF/SLM), including awareness of distortion, support structures, and powder removal constraints. Advanced proficiency in CFD and conjugate heat transfer simulation (STAR‑CCM+, Ansys Fluent, or equivalent), including full setup and execution of real engineering problems. Ability to build first‑principles 1D thermal models in tools like EES, MATLAB, or Python. Familiarity with topology optimization or generative design tools (e.g., nTop, PhysicsX) applied to thermal systems. Strong ownership mindset with ability to operate independently, define assumptions, and drive problems from ambiguity to solution under tight timelines. By applying to this role you understand that we may collect your personal data and store and process it on our systems. For more information please see our Privacy Notice #J-18808-Ljbffr USA Tech Recruit