Design help needed..

[Myth]

So, now we finally made our first serious wb. Just one problem.. it performs really poor (like a maze 3)..

I have a few ideas to what the problems might be.. but would like to hear your opinions about it..

The water from the inlet is probably not reaching the bottom.. i'm thinking of trying to use a 12mm copper pipe, allowing water only to get out 2-3mm above the bottom..

We made the bottom 3 mm thick, except in the middle where we went down to 1 mm. I guess that is a bit to thin for this design especially if the water isn't getting down there.. :shrug:

The area with "fins" is about 20 mm, perhaps it needs to be expanded to lets say 30 mm?

Any ideas or suggestions are welcome, before we head back to the workshop again..

Sorry about my poor spelling and grammar.. it's late and i had to drink a lot of beer to wash down some dissapointment

[Kobuchi]

Firstly, how did you test it? How many times?

[Myth]

Mouted it 5 times and tested, using fresh thermalgrease everytime. There was no difference in temps between the 5 runs.

[joemac]

Try using a thin metal piece to direct the flow of water guiding it to the outlet. Some more information may help such as pump, radiator etc that you are using :shrug: . Try posting a picture of your rig up and working that will also help spot potential problems.

[Myth]

I was running the test using a Eheim 1048, a heatercore from a VW and 12mm tubing. Sorry cant take any pictures of the setup right now :-(

I was also considering the use of something to guide the flow, or something to guide the flow to the bottom of the center..

[Kobuchi]

Originally Posted by Myth

The water from the inlet is probably not reaching the bottom.

That's what it's all about. You know. How far from ...uh... floor to ceiling? Make a new base from thinner stock?

It is an elegant design overall.

Maybe retrofit a jettier inlet? That way you needn't modify the block.

Directing the flow: also known as restricting the flow. That's good to a point when it happens where it should. All the redirection/restriction should be accomplished by heat bearing surfaces, ideally. Otherwise it's just wasted energy. Adding a little wall to direct water toward the outlet won't do a thing; water already flows directly to the outlet, steering clear of the bottom. I can think of some changes that would demand other manufacturing techniques, so I won't mention them. I hope after the beer wears off you'll find a solution using the existing tooling.

Any chance the base is deflecting? If the fins come up full height they may be supported best by a metal (e.g. brass) top.

[Myth]

I think i'll start of trying to make some sort of inlet made out of a 12mm copper pipe, which would fit into the hole drilled for inlet.. perhaps something that's more narrow then 12mm down at the bottom to get more of a jet effect.

The flow director i was thinking of would be one preventing the water from taking the easy path from the pins to the outlet, forcing it to go right og left. In my original idea it should have been milled out, but it a sometime during work we decided that it prob. would not have the desired effekt.

We have access to a rather well equipped workshop, so the changes you were thinking of would be welcome, even if they require different manufacturing techniques.

[Kobuchi]

Originally Posted by Myth

The flow director i was thinking of would be one preventing the water from taking the easy path from the pins to the outlet, forcing it to go right og left.

But you want it to go down, not right or left! So a flow director must be three dimensional. That's where the additional tooling comes in. I imagined channels wider at the bottoms (flow then favours the slightly less restrictive route along the bottom), or, fins with passages cut through at their bases. That'll keep a thin base stable. Or concentric rings, maybe, like a Stonehenge with all the tops connected? Do you have access to a lathe?

Anyway, I love the overall concept of your block, and don't like making suggestions that would complicate it (what I'm doing). Just starting with a thinner base-plate could best solve the problem.

[Myth]

I appreciate all input, since the goal here is to make a good looking block which also performs well.

Our channels are actually cut deeper then the overall base, and perhaps bending them inward in the top would make more water favour the then easier passage at the bottom. As for a flow restriction that will make sure water gets to the bottom, and perhaps also makes it favour a certain way through yhe block i have several ideas which we will try out soon..

We have access to a lathe and a lot of other equipment.. so we have a variety of tools and possibilities which can be tried out..

[JFettig]

That looks like a nice block from what I can see through the fuzzy plastic, I think what you need is a jet, try epoxying a 8-32 plastic washer in the inlet barb, first drill it out to 1/4" or a little less. the plastic washer should be 3/8" OD wich should fit right into normal 1/4" npt hosebarbs.


Jon

[Myth]

#10

The Plastic is actually not that fuzzy, but it's has a kind of blue color. I was thinking about trying something similar to what you suggest, and think i'll give it a go tomorrow.. I also think i'll try replacing the inlet barb with a ½" copper pipe which then should go all the way down to 2mm from the bottom.. Hopefully that would also force water down to the bottom since it would fit around the 4 center fins..

[Kobuchi]

Great plan, Myth. Can you make the inlet pipe height adjustable? A top plate of resilient (not brittle) plastic, threaded slightly undersize, will do. A taper pipe thread tap will get you there and allow some play. Then adjust while running water through it to find the narrowest gap acceptible for whatever pump/system you're running the block with. This type of inlet may be removed (for cleaning inside block) many times without weakening the seal.

[bigben2k]

I think that the issue is with the baseplate thickness. Got any numbers on that, or is it top secret?

[Myth]

In this version the baseplate is 1,5mm thick at the center.. I'm making a new one with a 3mm baseplate soon, because i guess that will help performance too..

[bigben2k]

yep, I would suspect that 1.5 is a bit on the thin side for this design.

Please report results!

[Myth]

Will do.. We are drawing the sucker in CAD and are going to use CNC this time since it just takes soo much time making one using a lathe and a mill.