Internship | CFD for Thermowells

Become an intern at TNO!

About this position

Thermowells are widely used for temperature measurements in process installations. Flow around a thermowell generates dynamic forces that can induce vibrations and potentially lead to fatigue failure.

While analytical methods are commonly used for thermowell design, advanced Computational Fluid Dynamics (CFD) and Finite Element Analysis (FEA) techniques offer the potential for more accurate predictions of vibration amplitudes and fatigue stresses. The objective of this internship is to assess the predictive capability of CFD–FEA simulations for thermowell vibration analysis by benchmarking numerical results against experimental test data.

The student will use existing thermowell test data and compare measured vibrations with CFD-FEA response predictions. The outcome will be an evaluation of the accuracy, limitations, and applicability of numerical methods for thermowell integrity assessments.

What will be your role?

• Review literature on flow-induced vibrations of thermowells and relevant design standards (e.g., ASME PTC 19.3 TW).
• Study available experimental thermowell test data.
• Develop CFD models for selected thermowell geometries and operating conditions.
• Predict flow-induced excitation forces and the corresponding vibration response.
• Compare numerical predictions with experimental measurements.
• Determine the accuracy and practical limitations of CFD–FEA approaches for thermowell assessments.

What we expect from you

• MSc student in Mechanical Engineering, Aerospace Engineering or a related discipline.
• Strong interest in fluid mechanics, structural dynamics, and numerical modelling.
• Experience with CFD software (e.g., ANSYS Fluent) is preferred.
• Basic knowledge of finite element analysis and structural dynamics.
• Familiarity with Python and/or MATLAB for data processing and comparison of simulation and test results.
• You can work independently on different aspects of scientific research, including literature review and academic writing.
• You are collaborative and proactive.
• You are available to work on location in Rijswijk.

What you'll get in return

An internship at TNO means working in an environment where substance and impact are central. You will become part of a knowledge organisation where research and practice come together, and where experts collaborate on solutions to current societal and technological challenges.

Your internship is a period in which you can discover what suits you, where your strengths lie and what you would like to learn next. You are part of a professional working environment, gain insight into how things work in practice, and have the opportunity to build experience that goes beyond this internship alone. For many students, an internship is therefore also a first step in discovering whether TNO could be a potential next step after graduation.

In addition, we offer you:

• A professional and innovative internship environment in which you actively contribute to societal and technological challenges, working alongside leading experts in your field.
• Personal and dedicated supervision, with focus on your learning objectives, development and study assignment.
• Room to develop: you gain relevant work experience, develop both your subject-specific and professional skills, and build a valuable network.
• Use of a laptop and the facilities you need to perform your work effectively.
• A monthly internship allowance of € 615 for a full-time internship, for MSc, BSc and vocational education (MBO) students.
• Up to eight hours of leave per internship month for a full-time internship, allowing you to balance your internship with your studies and personal life.
• A contribution towards travel expenses if you are not entitled to a student travel card.
• A free membership to Jong TNO: the network for young colleagues, where you can meet other TNO colleagues and participate in sports activities, professional and personal development activities, and social events such as the annual ski trip.