Principal Mechanical Engineer - Liquid Cooling

Job Posting Start Date 10-16-2025 Job Posting End Date

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

JETCOOL Technologies, a Flex company, is seeking a Principal Mechanical Engineer to add to our team in Littleton, MA. Join us in shaping the future of data centers while making a significant impact on sustainability. Apply now to be part of our dedicated team of engineers and thinkers!

JetCool has a mission to continuously innovate next-generation cooling solutions to enable the devices that fuel a more sustainable tomorrow. JetCool designs and delivers microconvective cooling technology for high-power electronics, enabling our customers to achieve unprecedented performance and unrivaled sustainability improvements. Our technology creates a ripple effect, enabling the businesses we serve to become more sustainable, profitable, and efficient. Join us to be part of some of today's fastest growing industries, while having a positive impact on society through technology.

What a typical day looks like:

• Lead the initial design, analysis, and optimization of complex fluid systems, including pumps, fluids, tubing, and heat exchangers, for the latest computer processing chipsets.
• Collaborate with customer and partner teams to integrate fluid systems into overall product designs.
• Conduct fluid flow simulations, analyses, and tests to ensure efficient and reliable performance of fluid systems under various operating conditions.
• Perform detailed calculations and analysis of fluid dynamics, pressure drops, thermal performance, and material compatibility.
• Develop and review engineering specifications and documentation for fluid system and heat transfer components and assemblies, ensuring compliance with industry standards and regulatory requirements.
• Assist in maintaining a strong best practice culture, driving additional foundational knowledge and IP through research.
• Identify technical gaps to advocate for research & development and lead research projects, maximizing product impact and benefit.
• Provide technical guidance and mentorship to junior engineers, fostering a culture of continuous learning and development.
• Participate in design reviews, presenting technical findings and recommendations to internal and external stakeholders.
• Contribute to the development of new product concepts and innovations in fluid system design, keeping abreast of industry trends and emerging technologies.
• Support the resolution of technical challenges and issues related to fluid systems throughout the product lifecycle.

The experience we are looking to add to our team:

• Bachelor of Science degree in Mechanical Engineering or related field.
• Minimum of 7 to 10 years of post-collegiate experience, with 4+ years in designing and engineering fluid systems, preferably within the data center thermal management/cooling, automotive, medical, or nuclear industries. Minimum of 3 years working at senior or principal engineer level.
• Profound expertise in fluid dynamics, thermodynamics, and heat transfer, with a strong foundation in engineering principles.
• Ability to independently develop product concepts, performance analysis and design experiments. Track record of new product development, preferably thermal fluid products.
• Strong analytical and problem-solving skills, with the ability to effectively troubleshoot and optimize fluid system performance.
• Excellent communication and documentation skills to convey complex technical concepts to both technical and non-technical audiences.

What you'll receive for the great work you provide:

• Full range of medical, dental, and vision plans
• Life Insurance
• Short-term and Long-term Disability
• Matching 401(k) Contributions
• Vacation and Paid Sick Time
• Tuition Reimbursement

Pay Range (Applicable to Massachusetts)

$123,500.00 USD - $169,800.00 USD Annual

Job Category
Design, Process & Technology Engineering

Relocation: Eligible for domestic relocation only

Is Sponsorship Available?
No

JetCool is an Equal Opportunity Employer and employment selection decisions are based on merit, qualifications, and abilities. We do not discriminate based on: age, race, religion, color, sex, national origin, marital status, sexual orientation, gender identity, veteran status, disability, pregnancy status, or any other status protected by law. We're happy to provide reasonable accommodations to those with a disability for assistance in the application process. Please email and we'll discuss your specific situation and next steps (NOTE: this email does not accept or consider resumes or applications. This is only for disability assistance. To be considered for a position at JetCool, you must complete the application process first).