15 April, 2020
Accurate thermal modelling is vital for electronic devices that operate in a wide range of environments.
Not all electronics equipment is designed to spend its life in the hands of a careful consumer or the cooled, controlled, environment of a data center. Some devices must be designed to operate in the harshest of environments; from beneath the scorching desert sun, to onboard an aircraft undergoing changing pressure and temperature cycles. Some devices may even have to survive in the cold vacuum of outer space.
For these devices, extremes of weather are commonplace. As such accurate thermal simulation is vital to ensure electronics remain online and operate as intended.
By virtually simulating physics, such as altitude, heat radiation, temperature or even gravity, designers can run rigorous tests on their designs, pushing them to their limits without the need to build expensive prototypes, or even leave the comfort of their testing labs.
When building such simulations, it’s vital that engineers account for the wide range of stressors that their devices may face when they enter a real-world environment. With this in mind, here are 5 points that thermal engineers need to consider when modelling equipment for a rugged or hostile environment:
1. Paints and Surface Finishes
Different paints and finishes can significantly impact the heat or solar radiation properties of individual surfaces. CFD modelling can be useful in understanding the effects that different paints and finishes can have upon the component temperatures of an end device. With 6SigmaET, you can accurately import detailed models for this very purpose, adjusting the heat and radiation properties per surface to reflect different paints and finishes.
2. Solar radiation
Electronics thermal analysis has never been so relevant to devices that spend a significant amount of time baking in the harsh sun. A user can specify a time and location and 6SigmaET’s built-in solar intensity calculator simulates values for peak hours of exposure, giving engineers a pragmatic idea of calculated solar intensity.
3. Vacuum conditions
Accurate, reliable thermal simulations for aerospace electronics are also fundamentally important. In space, it’s not so easy to keep things cool, and heat is typically removed from a device and transferred to a radiator using heat pipes. To account for these conditions, you can model vacuum environments in 6SigmaET through a ‘temperature only’ solution and by setting the thermal conductivity of air to zero (There is no point solving flow equations for air that doesn’t exist). Then simply check heat radiation is activated and you’re ready to solve.
4. Sealed Boxes and Potting
This refers to the sealed enclosures of aerospace applications. Accurate thermal analysis is needed to track heat from components conducted from the enclosure through the potting material. Potting can be modelled in 6SigmaET using the ‘gap pad’ object which is added to fill the space between PCB and enclosure. The ‘gap pad’ is intelligent in that it ‘knows’ to be overwritten by the components. A material is assigned corresponding to the potting material used.
5. Transient environments
Some equipment may be subject to environments that change significantly in a short space of time. Aerospace electronics could, in one moment, be situated on the ground where there is an ambient temperature of 20 C and a few minutes later be at an altitude where the ambient temperature is below -50 C. This can be modelled in 6SigmaET by specifying temperature vs time curves in an environment.
Using thermal simulation, engineers can test their designs in a multitude of different environments and investigate any thermal issues before they occur. Simulation-centric design reduces the number of protypes that must be built as well as the amount of testing required. In sectors with a high need for performance and reliability, thermal simulation is integral to completing projects efficiently, accurately and safely.
To find out the best CFD solutions to match your unique needs, contact us here.
Blog written by: Matt Evans, Product Engineer