Senior Thermal Engineer

About this role

About the Company

We are a renewable energy and ocean technology company committed to rapidly developing and deploying technologies that will ensure a sustainable future for Earth by unlocking the vast energy potential of its oceans. Our focus is on capturing civilizational levels of ultra-low-cost renewable energy for applications including computing and affordable renewable fuels delivered to shore.

The company is a public benefit corporation headquartered in Portland, Oregon, and backed by leading venture capitalists, philanthropic investors, university endowments, and private investment offices. We operate as an idea meritocracy in which the best ideas change the company’s direction on a regular basis.

About the Job

We are looking for a Senior Thermal Engineer who will own the end-to-end thermal simulation workflow for low- and high-power electromechanical systems operating in harsh marine environments, with a strong emphasis on rapid design iteration, first-principles thinking, and high-fidelity CFD where it adds real value.

You will work closely with mechanical engineers, payload architects, electrical engineers, applied physicists, and the prototype team to evaluate concepts, improve designs, define thermal requirements, debug issues, and help move hardware from early architecture through prototype and field validation. The ideal candidate is an expert in thermal CFD and modern simulation workflows, including GPU-accelerated solvers or other methods that enable fast turnaround without sacrificing engineering accuracy.

This is an onsite role based in our Portland office.

Responsibilities

• Own thermal simulation and analysis workflows for onboard payloads, electronics, cooling systems, pressure-contained assemblies, and related mechanical systems.

• Build and execute fast, reliable thermal CFD workflows that support rapid design iteration in close collaboration with mechanical design, electrical engineering, payload architecture, and prototyping teams.

• Translate component-level thermal inputs, power maps, packaging constraints, and environmental conditions into actionable system and subsystem thermal requirements.

• Analyze unit- and payload-level thermal architectures to define required airflow, liquid flow rates, heat sink performance, cold plate requirements, thermal interface assumptions, allowable pressure drops, and related cooling design parameters.

• Work with electrical and mechanical engineers to define cooling interfaces and design targets that can be directly incorporated into board layouts, enclosure designs, heat sinks, manifolds, ducts, cold plates, and other hardware.

• Evaluate and select appropriate modeling approaches, ranging from hand calculations and reduced-order models to detailed CFD, depending on the design question and required fidelity.

• Assess GPU-accelerated and high-performance simulation tools for thermal analysis, including commercial and open-source options such as Fluent, STAR-CCM+, HELYX/OpenFOAM-based workflows, and emerging solver technologies.

• Own the full simulation lifecycle, including geometry preparation, CAD interaction, meshing, solver setup, execution, debugging, convergence assessment, post-processing, visualization, and communication of results.

• Work directly with CAD and design teams, including NX-based workflows, to simplify, prepare, and modify geometry for simulation and rapid design exploration.

• Develop thermal models for high-power compute and electronics payloads, including conduction, convection, liquid cooling, heat exchangers, cold plates, sealed enclosures, and thermal interfaces.

• Analyze cooling architectures for systems operating in rugged, space-constrained, and environmentally exposed conditions.

• Support the design of cooling systems that may use ambient environmental heat sinks, liquid loops, pressure boundaries, and mechanically integrated thermal paths.

• Identify dominant thermal resistances, failure modes, uncertainty sources, and design sensitivities using first-principles reasoning.

• Validate simulation results against prototype tests, lab measurements, field data, and experimental observations.

• Develop post-processing and visualization methods that clearly communicate thermal margins, flow behavior, hot spots, pressure losses, uncertainty, and design tradeoffs.

• Partner with prototype and test teams to define instrumentation plans, test conditions, acceptance criteria, and validation approaches.

• Help build reusable simulation pipelines, templates, automation, and best practices for thermal analysis across payload and onboard system designs.

• Apply engineering judgment to identify misleading, overfit, under-resolved, or physically inconsistent simulation results.

• Contribute to optimization and design exploration workflows, including adjoint methods, parametric studies, surrogate models, and automated geometry or cooling-system optimization where appropriate.

Required Qualifications

• Strong background in thermal engineering, heat transfer, fluid mechanics, and numerical simulation.

• Deep experience with thermal CFD for electronics, compute systems, aerospace, marine, automotive, or other high-power engineered systems.

• Demonstrated ability to use CFD as an engineering tool rather than as a black box.

• Experience translating component-level heat loads, thermal limits, and packaging constraints into system-level cooling requirements and hardware design targets.

• Experience with the full CFD workflow: geometry preparation, meshing, boundary condition definition, solver setup, convergence/debugging, post-processing, and validation.

• Hands-on experience with one or more major CFD tools such as STAR-CCM+, ANSYS Fluent, HELYX/OpenFOAM, or comparable high-performance solvers.

• Experience evaluating model fidelity, mesh sensitivity, turbulence models, conjugate heat transfer, transient effects, boundary condition uncertainty, and numerical error.

• Ability to

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