Systems Senior Staff Engineer

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USA, MA, Littletontime type:
Full time posted on:
Posted Todaytime left to apply:
End Date:
April 17, 2026 (30+ days left to apply) job requisition :
WD215466

Job Posting Start Date 02-19-2026 Job Posting End Date 04-17-2026

At Jet Cool, a Flex company, we’re at the forefront of liquid cooling innovation, delivering advanced solutions that empower our partners in AI and high-performance computing. United by a shared purpose, our teams are pushing the limits of what’s possible and tackling complex challenges.

A career at Jet Cool offers the opportunity to make a real impact by helping build smarter, more sustainable data centers. Together, we’re not just advancing technology — we’re redefining cooling standards to create a more sustainable tomorrow.##

Job Summary To support our extraordinary teams who build great products and contribute to our growth, we’re looking to add a
** Senior Thermal Systems Engineer
** located in
** Littleton, MA.
** Reporting to the
** Product Manager
** the
** Senior Thermal Systems Engineer
** will own the end-to-end architecture, analysis, validation, and deployment of direct-to-chip (D2C) cooling systems used to cool high-TDP CPUs/GPUs/accelerators. They will be the technical leader partnering with Product Management, Mechanical/Electrical Engineering, Manufacturing, Quality, Reliability, and key customers to deliver robust, scalable products that meet performance, reliability, and cost targets.
** What a typical day looks like:
** Own thermal architecture & modeling
* Define system-level thermal requirements (TDP range, ΔT, coolant temperature, flow rate, pressure drop, acoustic & power budgets).
* Apply first principles in fluid dynamics and heat transfer to analyze design concept thermal performance
* Build and validate 1D/3D models (e.g., FloEFD, Icepak, Macro Flow, ANSYS Fluent, COMSOL) for cold plates, manifolds, quick-disconnects (QDs), pumps, and CDUs.
* Perform sensitivity trade-offs (flow distribution, fin geometry, microchannel optimization, TIM selection, manifold topology).Design liquid cooling subsystems
* Specify and refine cold plates, CDUs, manifolds, hoses/QDs, reservoirs, filters, sensors, and controls.
* Collaborate with ME/EE on mechanical stack-up, materials, corrosion mitigation (galvanic compatibility), and leak risk reduction.
* Define DFX (DFM/DFA/DFT) and lead EVT/DVT/PVT from prototypes to mass production.

Validate and qualify
* Develop test plans for thermal performance, pressure integrity, leak detection, long-term reliability (HALT/HASS), and contamination control (particulates, biogrowth).
* Execute lab and rack-scale testing (pump curves, flow balance, ΔP mapping, heat load emulation, transient behavior).
* Drive failure analysis and corrective actions (FMEAs, 8D/PPS).Partner across the business
* Work with Product Management on PRDs, roadmaps, and business cases.
* Support manufacturing process development (leak/pressure test stations, purge and fill, cleanliness criteria) and supplier selection/qualification.
* Engage with customers: define requirements, run pilots, analyze fleet telemetry, and support deployment at scale.
** The experience we’re looking to add to our team:
*** BS/MS in Mechanical Engineering or Aerospace Engineering or related field (PhD a plus).
* 5+ years experience in thermal design/validation for high-power electronics…