Thermofluid Systems Test Engineer

Flex•Littleton, MA

1d•Onsite

About The Position

At JetCool, 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 JetCool 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 Thermofluid Systems Test Engineer located in Littleton, MA. Reporting to the Mechanical Development Associate Principal Engineer the Thermofluid Systems Test Engineer we are seeking a Thermofluid Systems Test Engineer with strong hands on expertise in thermofluid systems to join our engineering team. This is an execution focused role with clear ownership from early development through qualification and product release.

Requirements

7+ years of hands‑on experience testing and qualifying thermo-fluid systems in data center cooling, automotive, medical, or industrial environments, including direct experience with CDUs or comparable systems.
Strong practical understanding of fluid dynamics, thermodynamics, and heat transfer, applied to test execution and data interpretation.
Demonstrated experience leading performance and qualification testing, including flow, pressure, thermal efficiency, durability, and fault‑mode testing.
Proven ability to design, build, instrument, and commission custom thermo-fluid test stands with pumps, valves, heat exchangers, sensors, and safety interlocks.
Experience developing and executing structured test plans, qualification matrices, and acceptance criteria, with ownership of test execution and results.
Strong data acquisition and analysis skills, including sensor selection, calibration, data logging, and post‑processing.
Proficiency with PLC‑based controls and test automation, including modifying control logic for automated sequences and safe system operation.
Demonstrated ability to troubleshoot complex system‑level issues through hands‑on testing and structured root‑cause analysis.
Ability to clearly document and communicate test plans, results, failures, and margin assessments to engineering teams and senior stakeholders.

Responsibilities

Own hands‑on testing of Coolant Distribution Units (CDUs) and related subsystems, including pumps, heat exchangers, tubing, valves, and fluids.
Design, build, instrument, and operate automated thermo-fluid test stands to characterize flow, pressure drop, thermal performance, and system behavior.
Develop and maintain PLC‑based controls, data acquisition, and automation for repeatable, long‑duration, and qualification testing.
Execute test plans, analyze results, and deliver clear, test‑driven feedback to design and systems engineering teams.
Support design reviews and product decisions by translating test data into actionable insights and risk assessments.
Improve lab capability by identifying gaps in tooling, instrumentation, controls, and test coverage for CDU development and validation.
Support troubleshooting and root‑cause investigations across development, qualification, production, and field issues related to thermo-fluid performance.