Creating a Custom Waterblock-Updated version
Creating a Custom Waterblock-Updated version
I was wondering if any one would have any details/tips on building a custom waterblock or fluid/thermodynamics(, as in a new design for a waterblock. I have a $350 budget for this project. I have looked at the only block I know has been built by a individual modder/designer,Cathar(as a project/low volume block): The Cascade XS/XXX (and the Swiftech Storm is based off of that). I'm doing this for my project for the Siemens Competition (see:
http://www.collegeboard.com/siemens/?CampaignID=4566
). I have access to CAD and fluid/thermal simulation programs. I also have connections to get tops,etc Rapid Prototyped for low cost. And CNC milling for Copper, again for reduced price.
Note: my knowledge of Calculus is limited as I am only in 11th grade. So please list good references when it comes to formulas,etc. Most of the work will be done in CAD so I doubt there would be much hand calculations that I would need. I have looked at xtremesystems,etc but there weren't much info. I will post this at XS later. This will be my main pet project for the summer.
Thanks.
^Thanks. I have seen that before. The problem is there are no info on design,theory etc to base my designs off of. Still searching...
The core idea is achieving high turbulence within the cooling zone (large surface area) while minimizing flow limitations.
The impingement design used by Cathar's Swiftech Storm is outdated, causing significant flow restrictions.
Current popular and efficient designs include squeezing water through micro-channels as in EK Supreme and spraying onto micro-pins without an additional nozzle, then releasing from the four corners as seen in Dtek FuZion (v1/v2).
You're in a great position, you don't need advanced math to tackle heat transfer challenges—just a bit of algebra. When designing a system like this, it's essential to understand the thermal interface resistance, the conductivity, the thickness of your substrate, and the heat transfer coefficient (h) for your fluid. In simple terms, you determine "h" for a flow (gas or liquid) using the Reynolds number (Re).
The "heat transfer" section on Wikipedia offers useful insights into thermal circuits that will help you gauge performance. Still, my intuition suggests that regardless of your shape choices, these factors won't be decisive...
As mentioned earlier, your heat transfer depends heavily on the Reynolds number of the fluid movement. A key aspect in calculating this number is a characteristic length scale—such as a pipe diameter or similar. Inside a water block, the passages are usually too small to benefit from them. Another crucial element is flow velocity, or for a fixed cross-section, the flow rate. To achieve efficient flow, you typically need very high velocities, which often require significant pressure drops. Most water pumps available aren't powerful enough for this purpose.
You can't simply connect a large pipe to a copper plate—there isn't enough surface area for effective heat transfer.
If you're thinking about cutting out a block with tiny channels, be aware of cavitation risks. Liquids avoid sharp turns because they create low-pressure zones inside corners. If the pressure drops below the liquid's vapor pressure, it can turn into vapor even at lower temperatures. This is undesirable for two reasons: first, the low-pressure areas in heat transfer regions; second, it obstructs the flow.
So, how do you maximize surface area without introducing sharp angles? A spiral path could work—move along the center and wind outward. Choose a robust pump and study its performance data (manufacturer specs usually include this). Your fluid mechanics software can help calculate shear stress across your block's walls. By integrating these values (multiplying stress by area at each point and summing), you can determine pressure drops for any design.
It seems you have access to solid simulation tools. Use them to fine-tune the spiral channel dimensions—size, wall thickness, height, etc. Maintaining a high Reynolds number with turbulent flow throughout will likely benefit from wider channels. Consider using a ball-end mill for precise cutting, ensuring a rounded bottom for better heat diffusion.
With careful design, you can achieve lower thermal resistance by placing less copper at the bottom and possibly performing stress analysis to prevent deformation under pressure.
For machining, plan to smooth the surface and aim for a near-mirror finish for optimal results.
In terms of resources, even though you have textbooks on thermal analysis, online references can be helpful. If you're near a university library, check their engineering section—heat transfer courses are usually available during sophomore or junior years. The required textbooks will likely be there.
Good luck!
Thank you both! I read this book last year for my project on how fluid affects heatpipe efficiency. I used Re and merit numbet for it. Most of the information I gathered came from that book. I didn’t realize Re could be applied to this kind of work. Thanks, Wick!
I hope you’re all well. I would have chosen one option over another. Unfortunately, these are only available at college, and I’m still in high school.
😉
Wick, could you suggest any other reference books? I already have access to this:
http://books.google.com/books?id=VEZ1ljs...-a#PPP1,M1
I haven’t read it yet (just received it today) since I’m preparing for final exams.
I can check the George Mason library:
http://magik.gmu.edu/cgi-bin/Pwebrecon.c...PAGE=First
Basically, in the range of a few hundred microns?
I noticed you're still in high school, but that doesn't stop you from checking out GMU's engineering library. The heat/mass transfer course isn't heavily math-intensive (usually) and does require some familiarity with fluid mechanics to a degree.
The book you mentioned is about thermodynamics, which is a different topic from heat transfer—often the two are combined since matter diffusion follows similar principles to thermal energy movement.
I'm not sure what roughness specification means for improving the thermal interface surface, but Intel's datasheet should clarify that. Flatness seems more critical than roughness. A bowlingball might look smooth, but it wouldn't provide good thermal contact!
I'll check what options I have for accessing GMU's courses.
Looking into Intel CPU/LGA775/i7 details might help.
Appreciate any tutorials or resources you can share.
Shadow, are you referring to smoothing the internal (water journals) or the external (mount surface)? I’m not entirely sure, but it might help if you add pins, impingements, or increase the surface area in the journals—something common in most commercial blocks. You seem to be aiming for the mount surface to be polished to around 1200 grit or similar. (I assume anything above that isn’t important for cooling or heat conduction.) The more heat you can extract from the CPU, the better, as long as it’s also removed from the block.