Thermal Systems Engineer

About the Role

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.

Job Summary

To support our extraordinary teams who build great products and contribute to our growth, we’re looking to add a Jr. Thermal Systems Engineer located in Littleton, MA. Reporting to the Product Manager, the Jr. Thermal Systems Engineer will support thermal-fluid modeling, requirements management, component characterization, testing, and system-performance analysis for liquid-cooling products. This early-career role offers significant hands-on experience with complete cooling loops and system-level engineering.

Key Responsibilities

• Support product requirements, specifications, and verification traceability.
• Develop and update 1D thermal-fluid models.
• Support CFD and conjugate heat-transfer analysis.
• Calculate pressure drop, flow distribution, thermal resistance, heat rejection, and system operating points.
• Support selection and characterization of pumps, radiators, heat exchangers, tubing, and fittings.
• Build and instrument prototypes and thermal-fluid test loops.
• Operate flow meters, pressure transducers, thermocouples, and data-acquisition systems.
• Document assumptions, boundary conditions, uncertainty, results, and recommendations.
• Support investigation of flow imbalance, pressure drop, aeration, cavitation, coolant loss, and thermal-performance issues.
• Participate in design reviews, troubleshooting, and failure investigations.
• Improve reusable models, component libraries, and calculation tools.

Requirements & Tech Stack

• Bachelor’s degree in mechanical, thermal, aerospace, or equivalent practical experience.
• Strong foundation in thermodynamics, fluid mechanics, and heat transfer.
• Exposure to CFD, thermal analysis, or 1D fluid-network modeling.
• Ability to perform fundamental pressure-drop, energy-balance, pump, and heat-exchanger calculations.
• Hands-on aptitude and familiarity with laboratory instrumentation.
• MacroFlow, Cadence Celsius EC, Python, MATLAB, or similar analytical-tool experience is beneficial.

Qualifications

• Internship, co-op, or academic experience involving thermal systems, fluid networks, electronics cooling, HVAC, or liquid cooling preferred.
• Models and calculations are accurate and well documented.
• Test setups generate reliable and repeatable data.
• Analytical predictions improve through test correlation.
• The engineer assumes progressively more complex and independent assignments.

Compensation

• Base pay range: $105,000.00 USD - $144,400.00 USD Annual