Bringing Thermal Simulations into Early Development Through SOLIDWORKS
Until the inevitable heat death of the universe, thermal energy will invariably transfer along temperature gradients and bleed off as electrical or mechanical work. As a result, engineers from various industries will need to perform thermal simulations early in the development cycle to ensure that their products will not overheat.
Engineers need to remember to perform thermal analysis on industrial equipment like the shredder pictured above. Otherwise, the equipment can overheat during use, damaging the equipment. (Image courtesy of Dassault Systèmes.)
Take an industrial shredder. At first glance, a thermal analysis might not seem necessary when designing the equipment, but any mechanical engineer worth their salt will know that when metal shreds, heat will be generated, resulting in thermal stresses on the equipment. If this heat isn’t accounted for in the design phases, then production processes can suffer from a lot of downtime while waiting for material cool-downs.
As for consumer products, they are becoming more complex, smarter and smaller. “This is a very common challenge in electronic devices,” said Lotfi Derbal, senior product portfolio manager at SOLIDWORKS. “Electronic devices have less and less space to provide airflow as they get smaller and smaller, so it is an ongoing issue that needs to be examined to keep the equipment in good health. Finding effective solutions to heat transfer problems has become an increasingly important part of new product development.”
By simulating the heat transfer of a product, engineers will be better informed through the development of the product. Prototypes are costly to work with and it is quite difficult to map out heat flux when dealing with prototypes. As a result, simulation is a much faster and affordable option when looking to optimize a product’s thermal flow.
“While designing your product, you can compare temperature distribution, heat flux and air circulation,” noted Derbal. “With this type of insight and knowledge, you will be able to analyze innovative new concepts more cost-effectively. It doesn’t matter if you’re designing high-tech electronic gadgets, consumer products, medical devices, HVAC systems or industrial heaters/coolers.”
Simulation in CAD Brings Thermal Analysis Early into the Development Cycle
A great way to bring thermal assessments into the early design cycle is to use simulation-in-CAD tools. This particular breed of computer-aided engineering (CAE) software integrates the simulation tools into the CAD environment.
Simulation in CAD democratizes the workflow by packaging it into a familiar user interface (UI). This will reduce the amount of training engineers will need as they will be using a tool that is already familiar to them. SOLIDWORKS offers a series of simulation-in-CAD tools that incorporate thermal analysis.
“With SOLIDWORKS Simulation and/or Flow Simulation, you can simulate structural thermal and fluid flow as well as coupling it with heat transfer, such as convection, conduction or radiation,” said Derbal. “Designers can apply heat sources, thermal properties on components, and define fan position. [Users also] get the resultant temperature distribution for both the fluid and the product itself.”
SOLIDWORKS Simulation and Flow Simulation have the capability to assess numerous heat transfer problems. And as it is incorporated into the CAD environment, an engineering team can save time—and often money—using the simulation-in-CAD option.
How Thermal Simulations Differ from Structural Simulations
Engineers familiar with simulation in CAD have likely spent much of their time with the structural finite element analysis (FEA) capabilities. Though much of the workflow will transfer over, thermal assessments are not as easy as modeling a structural simulation.
Natural and forced convection problems, like the ones pictured above, have heat transfer coefficients that are hard to pinpoint without computational fluid dynamic studies. (Image courtesy of Dassault Systèmes.)
Derbal explained that, “thermal analysis is not as intuitive as structural analysis because of the complexity of combining heat transfer laws like conduction, radiation and convection.”
Much of this difficulty comes from determining the convective heat transfer coefficients needed to create an accurate assessment. Engineers can make an educated guess or model the fluid flow within Flow Simulation to determine a more accurate coefficient value.
“Conduction is easy; it’s based on material properties,” explained Derbal. “But for forced or natural convection, you have to deal with known or estimated heat transfer coefficients for wall conditions as well as for emissivity and thermal resistance.”
“Using SOLIDWORKS Flow Simulation,” he added, “you may take into account the real environment. Engineers can couple the fluid flow, both internal and/or external, and heat transfer analysis. Then most of the coefficients will be calculated by the software.”
Engineers who are having difficulty setting up their thermal simulations can gain access to online learning material, such as tutorials and manuals, on MySolidWorks.
Versatility of SOLIDWORKS’ Thermal Simulation Offerings
The thermal simulation tools available in the SOLIDWORKS Simulation portfolio offer design engineers a lot of the versatility that they will need for their early development cycle assessments. However, like many other simulation-in-CAD options, an analyst might find the UI too restrictive for their advanced CAE needs.
Simulation is targeting engineering designers who are trying to give themselves direction when producing their designs early in the development cycle. It isn’t meant to be used for the advanced product verification stages.
In this respect, the simulation-in-CAD tool should be considered for its numerous thermal assessments and multiphysics simulation options such as:
- Coupling thermal and static loadings to assess thermal stresses
- Thermal contractions and expansions
- Fully coupled computational fluid dynamics (CFD) and thermal conjugate heat transfer when using Flow Simulation
“Most of thermal analysis can be simulated as steady state at least for predesign,” recommended Derbal. “However, transient thermal analysis can be necessary for strongly nonlinear and time-dependent problems, which need computer resources and large solver times.”
Performing a transient simulation will, of course, require more computational power than the steady-state analysis. This might be a lot of work for a computer optimized to work with CAD but not CAE.
To combat this, Simulation allows for a few tricks to keep the computation analysis down when working with transient simulations. Derbal suggested the following processes:
- Increase the time step if there is little risk of missing transient detail
- Use a function to govern the time step based on manual and automatic intervals
- Assess the flow field using time-averaged results
As for engineers working with heating, ventilation and air conditioning (HVAC) or electronics cooling, Derbal suggested that there are SOLIDWORKS modules with thermal analysis tools specifically tailored to these disciplines. For instance, HVAC engineers can access tools like human comfort factors, while electronics design engineers can perform Joule heating calculations that assess the heat released from a direct electrical current.
To find out more about the capabilities of SOLIDWORKS Simulation, read: SOLIDWORKS 2016 Adds Tools to Help Simulations and Validation.
About the Author
Shawn Wasserman (@ShawnWasserman) is the Internet of Things (IoT) and Simulation Editor at ENGINEERING.com. He is passionate about ensuring engineers make the right decisions when using computer-aided engineering (CAE) software and IoT development tools. Shawn has a Masters in Bio-Engineering from the University of Guelph and a BASc in Chemical Engineering from the University of Waterloo.