Principal Scientist, Process Modeling, Digital Insights

Merck & Co.; Rahway (NJ); Hybrid; USD 173,000 - 273,000; Full time

Benefits offered by this job

Medical Insurance

Dental Insurance

Vision Insurance

401(k)

Paid Holidays

Flexible Work Arrangements

Job summary

Merck & Co., Inc. in Rahway, NJ seeks a Principal Scientist to lead CFD and engineering simulations for bioreactor scale-up.

You will own end-to-end modeling, validate against experiments, and collaborate with process development to define scale-up criteria across biologics and small-molecule operations. The role emphasizes leadership in transport phenomena, physics-based modeling, and engineering equivalence, with a hybrid work arrangement and a strong focus on enabling robust manufacturing

Qualifications

• Ph.D. in Chemical Engineering, Mechanical Engineering, Bioengineering, Physics, Biology, Chemistry, Data Science or closely-related field with 6+ years experience.
• MS in Chemical Engineering, Mechanical Engineering, Bioengineering, Physics, Biology, Chemistry, Data Science or closely-related field with 8+ years experience.
• BS in Chemical Engineering, Mechanical Engineering, Bioengineering, Physics, Biology, Chemistry, Data Science or closely-related field with 10+ years experience.

Responsibilities

• Lead CFD and engineering simulation of bioreactor mixing and gassing to characterize P/V, shear, mixing time, pH and component gradients, kLa, and gas gradients toward defining engineering equivalence between development and manufacturing scales.
• Design scale-down models that reproduce the critical hydrodynamic and mass-transfer environment of the manufacturing-scale bioreactor, in partnership with process development scientists.
• Extend physics-based modeling to other sensitive bioprocess unit operations, including harvest (centrifugation, depth filtration) and TFF (UF/DF, viral filtration), to quantify shear and hydrodynamic risk to product quality.
• Own end-to-end modeling project execution: problem framing, geometry and mesh strategy, solver setup, validation against experimental data, and clear communication of predictions and their limitations to cross-functional stakeholders.
• Support vessel and site characterization studies and standard workplans to support enterprise scale-up/scale-down strategy.
• Mentor junior scientists on the Process Modeling & Analytics team; grow their technical judgment in transport phenomena, CFD methodology, and simulation-based decision making.
• Shape the team's modeling roadmap and establish practical standards for simulation workflows (case setup, HPC/cloud use, validation, reuse) that scale across the portfolio.
• Support engineering simulations extending from biologics to small-molecule organic drug substance unit operations (e.g., crystallization, reactor mixing) as pipeline needs require.

Skills

CFD expertise

Transport phenomena

Python

MATLAB

Education

Ph.D. in Chemical Engineering or related field

M.S. in Chemical Engineering or related field

B.S. in Chemical Engineering or related field

Tools

M-Star CFD

ANSYS Fluent

STAR-CCM+

COMSOL

OpenFOAM

Job description

Summary

We are seeking a Principal Scientist to join our Digital Insights team within the Development Sciences and Clinical Supply Digital Technologies organization (DDT). Digital is the multiplier that will allow DSCS to deliver better experiments faster, efficient filing and launch, more robust supply chains and higher-confidence decisions across the portfolio. The DSCS Digital Technologies organization is responsible for the invention and application of new digital tools/workflows to support scientists across drug substance development, drug product development and analytical development. We aspire to embed digital technologies into the fabric of DSCS culture to drive transformational impact across the CMC space. In this Principal Scientist role, the successful candidate will apply first-principles engineering, computational fluid dynamics (CFD), and physics-based simulation to bring predictive rigor to scale-up across a multi-modality pipeline from small to large molecules, with a current focus on biologics. This role will serve as our senior technical authority on CFD and engineering simulation for drug substance development, with an emphasis on bioreactor scale-up/scale-down and other sensitive bioprocess unit operations. They will lead physics-based assessments of mixing (P/V, shear, pH gradients) and gassing (kLa, O2 distribution) to define engineering equivalence between scales and to inform scale-down model design.

Responsibilities

• Lead CFD and engineering simulation of bioreactor mixing and gassing to characterize P/V, shear, mixing time, pH and component gradients, kLa, and gas gradients toward defining engineering equivalence between development and manufacturing scales.
• Design scale-down models that reproduce the critical hydrodynamic and mass-transfer environment of the manufacturing-scale bioreactor, in partnership with process development scientists.
• Extend physics-based modeling to other sensitive bioprocess unit operations, including harvest (centrifugation, depth filtration) and TFF (UF/DF, viral filtration), to quantify shear and hydrodynamic risk to product quality.
• Own end-to-end modeling project execution: problem framing, geometry and mesh strategy, solver setup, validation against experimental data, and clear communication of predictions and their limitations to cross-functional stakeholders.
• Support vessel and site characterization studies and standard workplans to support enterprise scale-up/scale-down strategy.
• Mentor junior scientists on the Process Modeling & Analytics team; grow their technical judgment in transport phenomena, CFD methodology, and simulation-based decision making.
• Shape the team's modeling roadmap and establish practical standards for simulation workflows (case setup, HPC/cloud use, validation, reuse) that scale across the portfolio.
• Support engineering simulations extending from biologics to small-molecule organic drug substance unit operations (e.g., crystallization, reactor mixing) as pipeline needs require.

Education Minimum Requirement

• Ph.D. in Chemical Engineering, Mechanical Engineering, Bioengineering, Physics, Biology, Chemistry, Data Science or a closely-related field with at least 6 years of industrial/pharmaceutical or relevant experience.
• M.S. in Chemical Engineering, Mechanical Engineering, Bioengineering, Physics, Biology, Chemistry, Data Science or a closely-related field with at least 8 years of industrial/pharmaceutical or relevant experience.
• B.S. in Chemical Engineering, Mechanical Engineering, Bioengineering, Physics, Biology, Chemistry, Data Science or a closely-related field with at least 10 years of industrial/pharmaceutical or relevant experience.

Required Experience and Skills

• Chemical engineering training (or closely related) with deep grounding in transport phenomena, fluid mechanics, mixing theory, and gas-liquid mass transfer.
• Extensive hands-on CFD expertise using tools such as M-Star CFD, ANSYS Fluent, STAR-CCM+, COMSOL, or OpenFOAM-including geometry, meshing, solver setup, and post-processing for stirred-tank and gas-liquid systems.
• Demonstrated experience characterizing bioreactors at development and manufacturing scale: quantifying power input, tip speed, shear, mixing times, kLa, and gas hold-up, and connecting those outputs to scale-up decisions.
• Track record of designing scale-down models and defining engineering-equivalence criteria that hold up when a process moves between scales.
• Ability to validate simulations against experimental data and to articulate model credibility, sensitivities, and uncertainty to advise action and decision.
• Scientific leadership and mentorship experience; comfortable growing modeling capability in others rather than only doing the work personally.
• Strong scripting skills in Python (or MATLAB) for pre-/post-processing and workflow automation around commercial CFD tools.

Preferred Experience and Skills

• Direct experience in an industrial biologics setting (cell culture bioreactor scale-up, harvest, or TFF) as a process development scientist or process engineer
• Familiarity with the shear-sensitivity of biologics (cells, proteins) and how interfacial and hydrodynamic phenomena connect to product quality.
• Experience with single-use bioreactors and single-use downstream trains at industrial scale.
• Fluency with population balance modeling and/or multiphase methods (Eulerian-Eulerian, Eulerian-Lagrangian, VOF) as applied to bubbles, droplets, or particulates.
• Familiarity with small-molecule organic drug substance unit operations (e.g., crystallization, reactive systems, liquid-liquid mixing).
• Experience coupling CFD outputs to data-driven or reduced-order surrogates.
• Prior use of modeling and simulation in technology transfer, process characterization, or troubleshooting at scale.

Required Skills

Adaptability, Adaptability, Cell Culture Process Development, Cell Line Development, Chemical Engineering, Computational Fluid Dynamics (CFD), Computer Simulations, Data Analysis, Engineering Leadership, Engineering Physics, High Performance Computing (HPC), Innovative Thinking, Leadership Mentoring, Materials Science, Model Development, Model Driven Design, Multiscale Modeling, Pharmaceutical Process Development, Process Engineering, Process Modeling, Process Simulation, Professional Collaboration, Professional Networking, Quality by Design, Simulation Modeling {+ 3 more}

US and Puerto Rico Residents Only

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As an Equal Employment Opportunity Employer, we provide equal opportunities to all employees and applicants for employment and prohibit discrimination on the basis of race, color, age, religion, sex, sexual orientation, gender identity, national origin, protected veteran status, disability status, or other applicable legally protected characteristics.--As a federal contractor, we comply with all affirmative action requirements for protected veterans and individuals with disabilities.- For more information about personal rights under the U.S. Equal Opportunity Employment laws, visit:

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We are proud to be a company that embraces the value of bringing together, talented, and committed people with diverse experiences, perspectives, skills and backgrounds. The fastest way to breakthrough innovation is when people with diverse ideas, broad experiences, backgrounds, and skills come together in an inclusive environment. We encourage our colleagues to respectfully challenge one another's thinking and approach problems collectively.

The salary range for this role is $173,200.00 - $272,600.00.

This is the lowest to highest salary we in good faith believe we would pay for this role at the time of this posting.

The successful candidate will be eligible for annual bonus and long-term incentive, if applicable.

We offer a comprehensive package of benefits. Available benefits include medical, dental, vision healthcare and other insurance benefits (for employee and family), retirement benefits, including 401(k), paid holidays, vacation, and compassionate and sick days. More information about benefits is available at https://jobs.merck.com/us/en/compensation-and-benefits.

San Francisco Residents Only

We will consider qualified applicants with arrest and conviction records for employment in compliance with the San Francisco Fair Chance Ordinance.

Los Angeles Residents Only

We will consider for employment all qualified applicants, including those with criminal histories, in a manner consistent with the requirements of applicable state and local laws, including the City of Los Angeles' Fair Chance Initiative for Hiring Ordinance.

Search Firm Representatives Please Read Carefully

Merck & Co., Inc., Rahway, NJ, USA, also known as Merck Sharp & Dohme LLC, Rahway, NJ, USA, does not accept unsolicited assistance from search firms for employment opportunities. All CVs / resumes submitted by search firms to any employee at our company without a valid written search agreement in place for this position will be deemed the sole property of our company. No fee will be paid in the event a candidate is hired by our company as a result of an agency referral where no pre-existing agreement is in place. Where agency agreements are in place, introductions are position specific. Please, no phone calls or emails.

Employee Status: Regular

Relocation: Domestic

VISA Sponsorship: No

Travel Requirements: 10%

Flexible Work Arrangements: Hybrid

Shift: Not Indicated

Valid Driving License: No

Hazardous Material(s): n/a

Job Posting End Date: 09/30/2026

*A job posting is effective until 11:59:59PM on the day BEFORE -the listed job posting end date. Please ensure you apply to a job posting no later than the day BEFORE the job posting end date.

Requisition ID: R416234