Simulator Jobs in Chicago, IL (NOW HIRING)

We are seeking a Principal Engineer - CFD Simulation Engineering to join our team. The ideal candidate will be a highly experienced technical leader with deep expertise in physics-based modeling and simulation, particularly in CFD, thermal-fluid sciences, fire and explosion modeling, refrigerant leakage, battery thermal runaway, combustion, multiphase flows, turbulence modeling, and electronic cooling.

A core requirement of this role is strong expertise in simulation Verification & Validation (V&V), including application of industry-recognized frameworks best practices for ensuring model credibility and reliability.

The candidate should have a strong background in applying advanced simulation methods to complex engineering problems involving product safety, certification, design validation, hazard analysis, and failure investigation. The candidate will be responsible for driving technical excellence, consistency, and engineering quality in simulation methodologies across global teams

A global leader in applied safety science, UL Solutions (NYSE: ULS) transforms safety, security and sustainability challenges into opportunities for customers in more than 110 countries. UL Solutions delivers testing, inspection and certification services, together with software products and advisory offerings, that support our customers' product innovation and business growth. The UL Mark serves as a recognized symbol of trust in our customers' products and reflects an unwavering commitment to advancing our safety mission. We help our customers innovate, launch new products and services, navigate global markets and complex supply chains, and grow sustainably and responsibly into the future. Our science is your advantage.

• Ph.D. / Master's in Mechanical, Aerospace, Chemical, Fire Engineering, Thermal Sciences, or related field (Ph.D. preferred) with 10-12+ years of experience in CFD, simulation, safety engineering, or applied R&D
• The candidate is not only a subject-matter expert in simulation physics but also a recognized authority in simulation credibility and V&V.
• The candidate should be capable of ensuring that simulation outputs are technically defensible, repeatable, validated, and suitable for high-stakes engineering and certification decisions. 
• The candidate must demonstrate the ability to bridge advanced physics modeling with structured validation frameworks, enabling confident decision-making in safety-critical applications.
• Proficiency in CFD tools: ANSYS Fluent, STAR-CCM+, OpenFOAM, CONVERGE, FDS
• Strong fundamentals in: Turbulence (RANS, LES), Heat transfer, Combustion & fire modeling, and Multiphase flows
• Hands-on experience in: Refrigerant leakage & gas dispersion, Fire / explosion modeling, Thermal & safety simulations
• Experience in test correlation, validation, and technical reporting
• Ability to lead complex engineering problems and work with cross-functional teams
• Strong communication and documentation skills
• Experience in safety, certification, or regulated environments
  Exposure to UQ, risk-based modeling, or HPC
  Basic scripting (Python/MATLAB)
• Core Skills: CFD | Combustion | Multiphase Flow | Refrigerant Leakage | Fire & Explosion | V&V | Thermal Analysis | Risk Assessment

What you'll experience working for ULS 

UL Solutions has been pioneering change since 1894 and we're still leading the way. From day one, we've blazed a trail protecting the planet and everyone on it. Our teams have influenced billions of products, plus services, software offerings and more. We break things, burn things and blow things up. All in the name of safety science. 

That's where you come in - because none of it could happen without you. It takes passion to protect people, problem-solving to safeguard personal data and conviction to make the world a more sustainable place. It takes bold ideas and brilliant minds to build a better world for future generations across the globe.  

This is more than a job. It's a calling. A passion to use our expertise and play our part in creating a more secure, sustainable world today - and tomorrow. As a member of our safety science community, you'll use your ideas, your energy and your ambition to innovate, challenge and ultimately, help create a safer world. 

Everyone here is unique. But we're also a global community, working together to help create a safer world. Join UL Solutions and you can connect with the brightest minds in the business, all bringing their distinct perspectives and diverse backgrounds together to deliver real change. 

Empowering our customers to keep the world safe means thinking ahead. It means investing in training and empowering our people to learn and innovate. At UL Solutions, we help build a better future - one where everyone benefits. 

Join UL Solutions to be at the center of safety. To learn more about us and the work we do, visitUL.com

Total Rewards: We understand compensation is an important factor as you consider the next step in your career. The estimated salary range for this position is $142,000 to $190,000 USD and is based on multiple factors, including job-related knowledge/skills, experience, geographical location, as well as other factors. This position is eligible for annual bonus compensation with a target payout of 20% of the base salary. This position also provides health benefits such as medical, dental and vision; wellness benefits such as mental and financial health; and retirement savings (401K) commensurate with the standard rewards offered in each individual location or country. We also provide full-time employees with paid time off including vacation (15 days), holiday and personal days (totaling 12 days) and sick time off (72 hours).

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• Serve as the principal technical authority for advanced simulation projects involving CFD, fire/explosion, refrigerant leakage, battery thermal runaway, combustion, multiphase flows, turbulence modeling, and electronic cooling.
• Lead and enforce simulation Verification & Validation (V&V) methodologies, ensuring alignment with ASME V&V 10 / V&V 20 standards, NASA CFD and modeling credibility guidelines, Oberkampf & Roy (Verification and Validation in Scientific Computing) principles, etc.
• Define and implement best practices for:
  • Code verification and solution verification
  • Model validation against experimental data
  • Uncertainty quantification (UQ)
  • Sensitivity analysis
  • Grid convergence and mesh independence studies
  • Error estimation and documentation of model limitations
• Establish model credibility frameworks for simulation-based decision-making, especially for safety-critical applications.
• Lead simulation-based investigations in:
  • Refrigerant leakage and dispersion (flammability and ignition risk)
  • Battery thermal runaway propagation and vent gas hazards
  • Fire, smoke, and explosion dynamics
  • Combustion and reacting flows
  • Multiphase and phase-change systems
  • Electronics cooling and thermal reliability
• Ensure test-to-simulation correlation and apply structured V&V approaches to build confidence in simulation predictions.
• Develop and review technical reports and documentation with clear articulation of:
  • Modeling assumptions
  • Validation evidence
  • Uncertainty bounds
  • Applicability and limitations of the model
• Act as the technical approver/reviewer for high-impact simulation studies, ensuring V&V rigor before results are used for certification or decision-making.
• Guide teams in selecting appropriate modeling approaches (analytical, CFD,  reduced order, and digital twins) based on required fidelity and validation maturity.
• Work closely with testing, certification, and regulatory teams to ensure simulation outputs are aligned with engineering standards and safety requirements.
• Mentor engineers on V&V best practices, simulation credibility, and physics-based modeling techniques.
• Contribute to the development of internal V&V guidelines, checklists, and simulation governance frameworks.
• Represent the organization in external technical forums, standard committees, and discussions related to simulation credibility and digital engineering.