Modelling CFD flow and heat transfer

Objectives from modelling CFD flow and heat transfer

The thermal fatigue machine built by Défi Systèmes allows to test metallic parts during cycles of increasing and decreasing temperature with maximum value reaching 600°C.

One test can last for a week and is always monitored by different equipment (cameras, thermocouples, infrared thermometer) positioned at the top of the machine. This equipment cannot stand very high temperatures so the issue was to be able to cool down the walls whilst keeping the heated part at the testing temperature of 600°C with a limited amount of energy.

Technical solution to the problem

A flow of Helium is modelled and simulated to be able to control the temperature in different areas of the machine:

1. Laminar Navier-Stokes equations simulates the flow of Helium.
2. Heat transfer by conduction, convection and radiation simulates the gradients and distribution of temperature, both inside the solid components and in the flow of Helium.

Results from the CFD model and information extracted

The CFD and heat transfer simulation helped the manufacturer to choose a design and the flow rate of Helium with three achievements:

• efficiently cool down the walls and top of the machine to keep the equipment safe and not damage by high temperature exposure;
• without cooling down the center of the machine where is the metallic part that is heated to be tested;
• hence reducing the energy consumption.

Value from CFD and heat transfer model

The CFD simulation also showed that the cooling was more efficient with a lower flow rate than what was initially planned, which means that turbulences could also be decreased in the central zone where energy is sent to heat up the part.

Last, the simulation helped to cut the developement time of the machine by months, and costs were controlled too because insulation material was then not needed on the walls of the machine.