The biggest question we ask ourselves as Engineers is, "Are these results reliable?"
Whether we are plugging numbers into SOLIDWORKS or painstakingly writing pages of hand calculations, we need to know we can trust our results.
SOLIDWORKS Flow Simulation is a reliable CFD analysis tool that enables you to quickly and effectively simulate fluid flow, heat transfer and fluid forces.
So let's directly compare the output of SOLIDWORKS Flow Simulation to thermal resistance data from an experimental test rig for a conjugate heat transfer scenario.
The setup involves a computer chip (power transistor) and heat sink as described in “Unshrouded Plate Fin Heat Sinks for Electronics Cooling: Validation of a Comprehensive Thermal Model and Cost Optimization in Semi-Active Configuration” by Ventola et al.
We're working with the experimental test rig described by Ventola et al. as shown below. A computer chip (transistor) is mounted on a heat sink which has a thermocouple fitted to record the temperature. This is then fitted into a ducting system with fan to provide cooling.
Comparing SOLIDWORKS Flow Simulation against physical test data using this example is an excellent way to validate and have confidence in the software because it proves that it can replicate what happens in a real world scenario.
Ultimately, it means you can predict if a new design will be fit for purpose before deciding to prot
MODELLING THE COMPONENTS IN SOLIDWORKS
To replicate the test rig, a CAD model was created in SOLIDWORKS.
A chip component provides the heat power while an aluminium heat sink sits on top. The material properties are set up inside SOLIDWORKS.
Check out this tutorial to learn how to create custom materials in SOLIDWORKS.
SETTING UP THE SOLIDWORKS FLOW SIMULATION STUDY
An air cavity was created surrounding the fins of the heat sink at ambient pressure and temperature.
This meant the flow simulation could be considered as an internal study. The boundary conditions are illustrated below.
Heat conduction and gravity were also activated.
RUNNING THE STUDIES
Several studies were run at various volume flow rates corresponding to different fan speeds on the experimental test rig.
Each one corresponded to a particular air temperature and heat power on the chip and can be seen in the table below.
To ensure we get an accurate result with the geometry, a mesh sensitivity study was run with just under 2.5 million cells.
The outputs of this showed little difference when compared against a faster model containing less than 90 thousand cells (within 4%). Results for the fast simulation are reported for all except the test case (marked with an *).
THE RESULTS
We've tabulated the results below. They compare the analytical hand calculations, experimental test rig data and the CFD Flow Simulation results.
The thermal resistance is calculated using the below formula.
It's always helpful to visualize results to get a wider perspective of what is happening throughout the cross section.
SOLIDWORKS Flow Simulation cut plots, ISO plots, and 3D visualisation abilities give a great overview and provide you with plenty of presentation material.
Thermal Resistance vs Volume Flow Rate 2D cut plot showing velocity. 3D surface plot showing temperature.
ISO surface plots showing temperature. 2D Cut plot showing temperature with velocity vectors. 2D Cut plot showing temperature (transverse). SOLIDWORKS can handle a wide variety of simulation types. Check out this blog to find out what common mistake can be mitigated in fatigue analysis.
CONCLUSION
Flow Simulation matched the experimental test rig data to within 4% of the calculated thermal resistance values.
This is an excellent result and highlights the reliability and accuracy of SOLIDWORKS Flow Simulation.
Having a validated model means the effect of any new design changes can be quickly investigated in SOLIDWORKS with confidence to avoid any costly failures.
It can also help to optimise the design by answering questions such as:
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Can a cheaper fan be used?
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Would a higher power chip overheat?
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Does the heat sink need to be so big?
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Would other components be cooled enough if added?
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Can the position of the fan be changed to make the design more compact?
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Would restricted access cause ventilation dead spots?
Take the Next Steps...
Adding the power of SOLIDWORKS Flow Simulation to your design portfolio means having the ability to answer all these questions and more.
It allows you to design in an affordably rapid manor and try out many “what if” scenarios that would simply take too long, or be too costly by and other method.
To find out more, visit our Flow Simulation pages, or fill in a contact form if you'd like us to get in touch to see how SOLIDWORKS Flow Simulation can help improve the products you design and create.
We also have our own in-house simulation consultancy team with a proven track record in providing high-quality simulation consultancy services, for companies with projects that require quick turnaround or more advanced software capability.
Here’s a quick rundown of how we can help you get the best from SOLIDWORKS Simulation and virtual testing with our Simulation services.
If you have found this useful, have any questions, or if you are interested in modelling composites in this kind of
detail please get in touch.
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