Content
Introduction
ColdStream supports 3 types of cases:
- Custom designs
- Standard designs
- Simulations
The first two options are optimizations, where ColdStream will return an optimized design. The third option is to be used of you already have a design and you would like to know its performance.
The standard design selector is an efficient and effective way to generate standard heatsink designs that are widely available on the market. A few examples are fin heatsinks for LEDs, extruded heatsinks for PCBs, heatsinks for processors etc.
✎ Note |
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| Standard design cases optimize for the best off-the-shelf heatsink for your case. |
A heatsink transfers heat from a component to a fluid medium where the heat is dissipated away. The general idea is the more surface area there is, the better the heatsink will perform.
Pins
As the name already indicates, a pin heatsink has pins extruding from its base plate. These pins can in theory be cylindrical, elliptical, square, ... . Currently, ColdStream only supports cylindrical pins.
A pin heatsink is one of the most common heatsinks types on the market. Pin heatsinks have a large surface area given the heatsink volume, which makes them perform well for any possible orientation. For pins heatsinks, the growth of the thermal boundary layer along the direction of the air flow is limited by the discontinuous surface formed by the pins. In addition, the discontinuous geometry of the pins also increase the pressure drop across the heatsink which causes a lower flow rate for a given in- and outlet pressure condition.
Fins
For a fin heatsink, the design is not discontinuous anymore in 1 of the 2 horizontal directions. This will cause the thermal boundary layer to build along the entire surface of the fin.
✎ Note |
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| Research has shown that fin heatsinks peform better for most of the natural convection cases. Pins are advantages when the incoming fluid flow can come from multiple directions as the performance is more or less independent of the orientation. Fins perform poorly when the fluid flow is perpendicular to it. In forced convection cases, research has shown pin heatsinks to outperform fin heatsinks even when considering the increased pressure drop across the pins. |
Case setup
The case setup for standard designs is similar to the case setup for custom designs. The difference is in the definition of the design region and the manufacturing settings.
The following two subchapters delve deeper into these differences.
Design subregion
For standard designs, the design geometry should be a cuboid. Make sure the design geometry is a solid and it does not contain any small features, holes or sliver surfaces.
⚠ Important |
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| ColdStream can work with any orientation or position of the design region. The parent region of the design should be of type fluid and at-least one of the flat faces of the design region should touch another region of type solid. |
Manufacturing settings
Depending how you would like to manufacture your standard heatsink, different types of heatsinks can be selected. The following table gives a clear overview of all heatsink types and their manufacturing techniques:
| Heatsink type | Manfacturing technique | Fillet radius at the base | Fillet radius at the tip | Chamfer angle |
|---|---|---|---|---|
| Pins | Extrusion | 0 mm | 0.5 mm | 0° |
| Die casting | 0.5 mm | 0.5 mm | 1° | |
| Forging | 0 mm | 0.5 mm | 1° | |
| Fins | Extrusion | 0 mm | 0.5 mm | 0° |
| Die casting | 0.5 mm | 0.5 mm | 1° | |
| CNC milling | 0 mm | 0 mm | 0° |
⚠ Important |
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| The design subregion must be able to accomodate at least 5 fins/pins in each direction. The minimal width of the pins/fins equals 1 mm. |
The user has the option to select one or more of these manufacturing options according to the user's manufacturing capabilities. The results will contain the best heatsink for each manufacturing type from which the user has the option to select the one that suits them the best. It is also possible to select multiple materials for the heatsink.
Extruded heatsinks are easily manufacturable and can be produced at a low cost. However, the dimensions of extruded heatsinks are limited.
With forging, heatsinks can also be produced at a low cost, given that a high number of similar heatsinks are produced.
CNC milling can achieve complex geometries, meaning that this technique allows for a high design flexibility. This high flexibility comes at the cost of a production costs.
How it works
Once the case setup is complete, you are ready to validate the case setup and submit the case. After the submission, the optimizer iterates through several pre-defined parameters of a heatsink and optimizes them. The parameters include, but are not limited to the element (pin or fin) dimensions, the base plate dimensions and the number of elements. The results of a standard design will also show the parameter set that defines a particular heatsink.
Results
The results show a detailed evolution of the optimization. For each design iteration, the geometry, performance and multiple contours of fields are available on the platform. The design evolution is plotted with the design iteration on the x-axis and the performance of that design on the y-axis. You can access the parameters of the heatsink for a particular design iteration and choose to view results for that iteration.
