Senior Thermofluids Engineer - Heat Exchanger Design & CFD

Senior Thermofluids Engineer - Design and simulate the heat-transfer core of a new class of power hardwareEl Segundo, CA | On-siteOpportunity SummaryWe are looking for a hands-on thermofluids engineer who is equally comfortable building geometry in CAD and running internal-flow CFD on it. You will be the technical owner of the heat exchangers inside a megawatt-scale power unit, from first sizing calculations through detailed design, supplier builds, and test. This role suits someone who has done this work at an early-stage hardware company or a technical engineering consultancy, where you owned the problem end to end and could not hand the CAD or the simulation off to someone else.The team is small and moving fast. Hardware is already on the floor and testing is underway, so your designs will be cut, welded, and run on a short cycle, and the results will feed straight back into your next iteration.About UsWe are a venture-backed energy technology company building compact, factory-built power generation equipment for fast-growing electricity demand, including data centers. Our system pairs advanced turbomachinery with high-performance heat transfer hardware to deliver more power in a smaller footprint than conventional plants. We recently moved into a larger facility in El Segundo and are scaling the engineering team around our first full-scale units.Job DutiesOwn the thermal and hydraulic design of the recuperator, primary heater, and air-cooled heat rejection hardwareSize heat exchangers using effectiveness-NTU methods, pressure-drop budgets, and channel and core geometry tradesCreate and revise detailed CAD of cores, headers, manifolds, and flow passages yourselfRun 3D CFD on internal flows, including conjugate heat transfer, flow maldistribution, and header and manifold lossesUse CFD results to drive geometry changes directly, closing the loop between analysis and designBuild and maintain 1D network models to predict performance at design point, part load, and off-design conditionsBalance thermal performance against pressure drop, structural limits, packaging, cost, and manufacturabilityPartner with cycle, structures, turbomachinery, and manufacturing engineers on interfaces and requirementsLead technical work with heat exchanger vendors and fabricators from design review through inspection and acceptanceSupport build, instrumentation, and testing, then correlate models against test dataQualificationsBachelor's degree or higher in mechanical or aerospace engineering, or a closely related field5+ years of hands-on engineering on thermal-fluid hardwareExperience at an early-stage hardware startup or an engineering consultancy, owning technical problems end to end with limited supportDeep, hands-on 3D CFD experience on internal flows such as channels, manifolds, headers, and piping, including conjugate heat transfer (external aerodynamics experience alone is not a fit)Strong CAD skills, with a track record of building and modifying your own detailed mechanical modelsDirect experience designing and sizing heat exchangers, including effectiveness, pressure drop, and flow distributionProficiency with 1D or network thermal-hydraulic modelingHave taken at least one thermal-fluid design from concept through fabrication and testClear communicator who can walk through technical work in depth and defend design decisionsPreferred ExperienceSupercritical CO₂ or other high-pressure, high-temperature, or near-critical working fluidsCompact, high-effectiveness heat exchangers such as printed-circuit, microchannel, or plate-fin designsnTop or other implicit and field-driven design or topology optimization toolsAdditively manufactured heat exchangers or complex internal flow geometryAir-cooled or dry-cooling heat rejection systemsCombustion-side heat transfer, including fired heater designPressure-boundary mechanical design and familiarity with ASME BPVCCommercial CFD tools such as STAR-CCM+, Ansys Fluent, or CFXCorrelating thermal and hydraulic models against test dataWhy Join UsOwn a subsystem that directly sets the efficiency, size, and cost of the entire power unitDo the CAD, the CFD, and the hardware rather than sitting in a pure analysis seatSee your designs built and tested in weeks, not yearsWork alongside the founders and a small team of experienced turbomachinery and power hardware engineersEarly, meaningful equity ownership in a company in a high-growth phaseMedical, dental, and vision coverageFully stocked kitchen with coffee, snacks, and mealsCompensation Details$170,000 - $230,000 + equity