Internship - R&d Engineer - Numerical

**C**-TEC RECRUTE**

**INTERNSHIP - R&D ENGINEER F/H/X**

**Numerical Thermomechanical Modelling of the Start-up Phase of Vertical semi-continuous Direct Chill Casting of Rolling Slabs: influence of the bottom block design and filling stage and improved description of water cooling.**

**Main objective and key accountabilities**

Starting up the casting of a rolling slab is the riskier step of casting, because during this transient phase strong gradient-driven deformations together with cracking may result in cast abort or scrapping the slabs. e-STURGEoN is an internal tool used to devise, compare and assess vertical direct chill casting start-up recipes along intrinsic, physically-based criteria which be valid across plants and installations, by means of non-dimensional analysis (Fourier Fo and Biot Bi numbers) instead of dimensional process parameters (casting speed V and water flow rate q). This tool calculates a trade-off between the incoming heat and the extracted heat and proposes a potential operating domain under the form of a Bi vs Fo master curve. The validity of this tool relies on a wealth of experimental data together with extensive numerical thermomechanical modelling of the start-up phase. There are two influential parameters which need to be better described or accounted for by numerical modelling, so as to fine-tune the master Bi(Fo) curve for optimum behaviour during start-up: these are on the one hand, the heat transfer laws in the presence of film-boiling and more specifically the influence of water chemistry on the heat transfer coefficient (HTC) as a function of water flow rate and ingot surface temperature: this is being studied experimentally but the translation into HTC laws implemented in the model needs improvement; on the other hand the bottom-block design is known to influence the thermal balance during start-up. It is today accounted for in a very schematic way and our aim is to get a better description of the tendencies thanks to numerical modelling of that influence, while also accounting for the filling stage before the drop starts.

**Context & environment**

Aluminum alloys have always been essential, among other fields, to the aeronautic industry due to their low density and high mechanical properties and nowadays their use is experiencing significant growth in the automotive sector for the purpose of light weighting vehicles.

In this context, we need to cast new alloys and new ingot size in an efficient manner. Having a digital twin model of the casting startup is key for fast prototyping. Since a numerical model is not suited for this purpose (due to computation time) we have developed a simplified 0D (non-dimensional) model (e-STURGEoN). Validation of this simplified model relies on experimental results (from plants or R&D facilities) and numerical results (DOE to explore wider range of product and casting tools). In 2024 we have tune the thermomechanical model to be more predictive in tems o fslab deformation. The objective is to use this new model to improve e-STURGEoN

The intern will be based in the R&D casting team which work on the following topics: recycling, melting, metal quality, casting and solidification. The intern will be supervised by an R&D engineer. There will be interactions with experts in modeling and casting.

**Expected results**:
The complete 3D thermomechanical solidification model will be used together with new heat transfer laws to run numerical Design of Experiments in order to get sensitivity to butt curl and hot cracking and to develop a simplified approach which could be integrated in e-STURGEoN.

**This internship decomposes into several stages**:

- Familiarization with 3D thermomechanical solidification model
- Familiarization with e-STURGEoN
- Integrate new heat transfer laws in our tools for all water chemistries (3D thermomechanical model and e-STURGEoN)
- account for Bottom Blocks design for both filling time and startup (Bi(Fo)) dimensioning
- Run numerical design of experiments
- Improve or validate e-STURGEoN master curve
- Make proposals for experimental trials on C-TEC pilot line (if the numerical DOE approach is not sufficient)

**Profile**:
**Education level: Bac+5 / M.Sc.**

**Mechanical Engineering - Physics or Material Science**

**Competencies & technical & soft skills requirement**:

- Engineering student (last year) or Masters (M2) of Physics or Material Science
- Knowledge in Material science
- modelling skills (heat transfer, thermomechanical)
- computer science skills (Python, Linux,)
- Good communication skills in English and French are essential