Senior Thermal Analyst

U.S. Fusion Energy; Energy (IL); On-site; USD 155,000 - 180,000; Full time

Benefits offered by this job

Medical, dental, and vision coverage

401(k) with company match

Equity participation

Paid time off and holidays

Job summary

Xcimer Energy in Denver, CO, seeks a Senior Thermal Analyst to lead cooling system analyses and CFD work across energy and defense programs. The role focuses on heat transfer, flow physics, and multi-physics integration from concept through testing.

You will build and validate thermo-fluid models, support prototype testing, and drive cross‑disciplinary decisions with design engineers. Requires 8+ years in the field and US work authorization.

Qualifications

• Eight+ years of thermal-fluid/CFD/heat-transfer analysis experience.
• Experience supporting engineered hardware in energy, aerospace, laser, or HVAC domains.
• Expert with STAR-CCM+ and Ansys Fluent for CFD verification/validation.
• Strong fundamentals in heat transfer and thermo-fluids with hand calculations.
• Experience supporting hardware test campaigns and correlating models with data.
• U.S. citizen or eligible to work in the U.S.

Responsibilities

• Lead thermal and CFD analyses for cooling systems and fusion chamber components.
• Build transient and steady-state thermo-fluid models including conduction and radiation.
• Validate CFD/thermal models using analytical methods and experimental data.
• Produce traceable analysis documentation for reviews and design trades.
• Conduct peer reviews and maintain best practices in modeling and assumptions.
• Collaborate with design teams to integrate thermal results into components and systems.
• Support prototype builds and testing by diagnosing issues and guiding actions.
• Contribute to internal thermal workflows and verification/validation processes.

Skills

Thermal-fluid analysis

CFD verification/validation

Turbulent flow modeling

Heat transfer fundamentals

Prototype testing support

Education

B.S. Mechanical Engineering

B.S. Aerospace Engineering

B.S. Nuclear Engineering

Tools

STAR-CCM+

Ansys Fluent

SimCenter

COMSOL

Abaqus

Job description

Denver, CO

Engineering – Analysis & Synthesis Engineering

Full-Time

On-site

Xcimer Energy builds on decades of research in Inertial Fusion Energy (IFE), combined with a groundbreaking new laser architecture, to accelerate the deployment of fusion power plants. Our mission is to deliver clean, limitless fusion energy fast enough to meet global decarbonization goals. Xcimer has assembled a world-class team spanning tough tech, fusion science, and advanced manufacturing, with a proven track record of rapid execution. Backed by leading investors, we are uniquely positioned to bring inertial fusion power from prototype to reality. Join us in powering a better world with fusion.

Senior Thermal Analyst

You will lead the thermal and CFD analysis across Xcimer’s Energy and Defense programs. You will evaluate cooling architectures, analyze steady‑state and transient heat loads, and provide thermal insight that drives system‑level design decisions. You will work closely with design engineers and fellow analysts to ensure thermal behavior is fully integrated into cross‑disciplinary workflows including component design, architecture trades, performance optimization, and experimental validation. You will generate traceable analysis documentation, participate in peer reviews, and provide analysis guidance to design engineers and junior analysts. As hardware progresses from prototype to integrated testing you will support troubleshooting, test correlation, and rapid iteration. We are looking for engineers who enjoy building systems from concept through commissioning and thrive in fast‑paced manufacturing environments.

Responsibilities

• Lead thermal and CFD analyses for cooling systems, gas‑flow pathways, and fusion chamber components.
• Build and maintain transient and steady‑state thermo‑fluid models including conduction, convection, radiation, turbulent flow, and compressible gas dynamics.
• Validate CFD and thermal models using analytical techniques, experimental data, and multi‑physics correlations.
• Produce clear, accurate, and traceable analysis documentation for design reviews, architecture trades, and test readiness.
• Conduct peer reviews of thermal/CFD analyses from other analysts; maintain best practices for modeling, assumptions, margins, and documentation.
• Collaborate with analysts and design engineering teams to ensure thermal results fully integrated into component and system designs.
• Support prototype builds and test operations by diagnosing thermally‑related issues, supporting root‑cause investigations, and recommending corrective actions.
• Contribute to the development of internal thermal/CFD workflows, correlation standards, and analysis verification/validation processes.

Qualifications

• Education: B.S. in Mechanical Engineering, Aerospace Engineering, Nuclear Engineering, or related field.
• Experience: 8+ years of thermal‑fluid, CFD, or heat‑transfer analysis experience supporting engineered hardware (Energy, Aerospace, Laser Systems, HVAC).
• Expert proficiency with commercial CFD tools (e.g., STAR‑CCM+, Ansys Fluent) and experience with CFD verification/validation.
• Demonstrated experience with turbulent flow modeling, compressible and incompressible fluids, convection and radiation heat transfer, and cooling system design.
• Strong fundamentals in classical heat transfer and thermo‑fluids, including hand calculations and closed‑form thermal analysis methods.
• Demonstrated experience supporting hardware test campaigns, thermal instrumentation, flow diagnostics, and correlating models with experimental data.
• Must be a U.S. citizen or national, U.S. permanent resident (Green Card holder), or lawfully admitted into the U.S. as a refugee or granted asylum.

Desired

• M.S. or advanced degree in Mechanical Engineering, Aerospace Engineering, Nuclear Engineering, or related field.
• Hardware selection and/or design experience: fans, pumps, heat exchangers, piping, and other supporting equipment.
• Experience developing multi‑physics simulation environments involving thermal, flow, mechanical stress using simulation tools (SimCenter, COMSOL, Abaqus, etc.).
• Experience with high‑temperature systems, transient pulsed heat deposition, gas lasers, or fusion‑related thermal environments.
• Familiarity with engineering materials, manufacturing processes, cooling strategies, and how they affect thermal performance and reliability.
• Familiarity with scripting languages (Python, MATLAB, VBA) for automating workflows and post‑processing results. CAD/PLM experience (NX, Teamcenter).

$155,000 - $180,000 a year

Candidates may be considered for other positions at Xcimer Energy, and our actual base salary will be determined on an individual basis and may vary based on job‑related knowledge and skills, education, and experience. The range is published in accordance with Colorado Equal Pay for Equal Work Act and California Equal Pay Act.

Equal Employment Opportunity

Xcimer Energy is proud to be an Equal Opportunity/Affirmative Action Employer and is committed to attracting, retaining, and developing a highly qualified, diverse, and dedicated work force. Xcimer Energy hires and promotes people on the basis of their qualifications, performance, and abilities. We support the establishment and maintenance of a workplace that fosters trust, equality, and teamwork, in which all employees recognize and appreciate the diversity of individual team members. We provide all qualified applicants for employment and employees with equal opportunities for hire, promotion, and other terms and conditions of employment, regardless of their race, color, religion, gender, sexual orientation, gender identity, national origin/ethnicity, age, physical or mental disability, genetic factors, military/veteran status, or any other status or characteristic protected by federal, state, and/or local law. Xcimer Energy will consider for employment qualified applicants with criminal histories in a manner consistent with applicable federal, state, and local laws. For more information on “EEO Is the Law,” please see here and here.

Benefits

• Medical, dental, and vision coverage
• Basic and supplemental life insurance
• Short‑and‑long‑term disability
• Paid parental leave for employees at the time of birth or adoption
• 401(k) with a company match of up to 6%
• Eligible employees also receive equity, allowing them to share in the company’s long‑term success.
• Flexible Paid Time Off (ATO) approach. Rather than a fixed number of vacation days, employees are trusted to take the time they need to rest and recharge while meeting the expectations of their role and team.
• Paid sick time
• 13 company‑paid holidays
• Annual paid company shutdown
• Benefits are available to regular employees, including part‑time and fixed‑term roles, as well as interns, with eligibility varying by benefit.

We may use artificial intelligence (AI) tools to support parts of the hiring process, such as reviewing applications, analyzing resumes, or assessing responses and identifying potential inconsistencies or verification signals in application materials based on available information. These tools assist our recruitment team but do not replace human judgment. Final hiring decisions are ultimately made by humans. If you would like more information about how your data is processed, please contact us.