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EMC2 · 02-22-2002, 11:39 PM

X1 block -
You can use flow diversion walls (basically a fin) to help split the flow between the channels. At the inlet pipe put one in the center. Then halfway to the main block put another one splitting each of the two areas into 4. Also, if you can adjust the size of the channels, you can affect the flow, smaller channels in the middle, slightly wider on the outsides. Just keep in mind that the center is where most of the heat is, so you don't want to divert too much to the outside.

From the pic, the channels look really small. You might want to increase the height of the channels. Same goes for the base plate thickness.

To solve the smooth curve fabrication issue, you could use 45 degree angled turns and make the ends like mini-surge tanks (similiar to a radiator or heater core).

Of course, pure copper will be better than brass from a thermal standpoint.

X2 block -
Shallow threads aren't enough to get a swirling flow at the flow rates you want. Nor would the density difference be enough to create the mixing action from centrifugal force.

From the positive side though, the threaded walls would create a quite turbulent flow at the wall surface. The big issue would be keeping the threads very shallow with as coarse of a pitch as possible. If there is much depth to the threads, you can end up hurting your heat transfer do to almost no flow on the inside surface of the threads. You could solve that by adjusting the tap size versus drill/pipe size to get shallow threads. Or you could go back after tapping in deep threads and redrill the hole with the next size drill bit, which would both reduce the thread depth and create a flat surface at the peaks of the threads.

X1-X2 combined -

You could actually do the same thing with your X1 design by using tubular channels "embedded in a box" like Brad mentioned. Approximately 70% (depends on tube wall thickness) of the flow would be through the inside of the tubes with the remainder of the flow between the outside of the tubes and the inside of the box walls the tubes are embedded in. The one problem there is the size of the 'contact patch' with the bottom plate. A way around the problem would be to crossdrill the top of the base plate to create round grooves that the pipes rested in. A groove that was as deep as 1/4 the diameter of the pipe would give you slightly more surface contact than the pipe diameter.

An alternative way to get the same results would be to take a solid block and cross drill the round channels directly into it. The two issues to solve there are fabricating the "end caps" to create the chambers at the inlet/outlet sides (same as with the X1 block) and doing it this way would force you to use a larger size channel (the smaller the drill bit the shorter the channel can be).

02-22-2002, 11:39 PM	#8
EMC2 Cooling Savant Join Date: Feb 2002 Location: Dark Side of the Moon Posts: 365	My 25 cents X1 block - You can use flow diversion walls (basically a fin) to help split the flow between the channels. At the inlet pipe put one in the center. Then halfway to the main block put another one splitting each of the two areas into 4. Also, if you can adjust the size of the channels, you can affect the flow, smaller channels in the middle, slightly wider on the outsides. Just keep in mind that the center is where most of the heat is, so you don't want to divert too much to the outside. From the pic, the channels look really small. You might want to increase the height of the channels. Same goes for the base plate thickness. To solve the smooth curve fabrication issue, you could use 45 degree angled turns and make the ends like mini-surge tanks (similiar to a radiator or heater core). Of course, pure copper will be better than brass from a thermal standpoint. X2 block - Shallow threads aren't enough to get a swirling flow at the flow rates you want. Nor would the density difference be enough to create the mixing action from centrifugal force. From the positive side though, the threaded walls would create a quite turbulent flow at the wall surface. The big issue would be keeping the threads very shallow with as coarse of a pitch as possible. If there is much depth to the threads, you can end up hurting your heat transfer do to almost no flow on the inside surface of the threads. You could solve that by adjusting the tap size versus drill/pipe size to get shallow threads. Or you could go back after tapping in deep threads and redrill the hole with the next size drill bit, which would both reduce the thread depth and create a flat surface at the peaks of the threads. X1-X2 combined - You could actually do the same thing with your X1 design by using tubular channels "embedded in a box" like Brad mentioned. Approximately 70% (depends on tube wall thickness) of the flow would be through the inside of the tubes with the remainder of the flow between the outside of the tubes and the inside of the box walls the tubes are embedded in. The one problem there is the size of the 'contact patch' with the bottom plate. A way around the problem would be to crossdrill the top of the base plate to create round grooves that the pipes rested in. A groove that was as deep as 1/4 the diameter of the pipe would give you slightly more surface contact than the pipe diameter. An alternative way to get the same results would be to take a solid block and cross drill the round channels directly into it. The two issues to solve there are fabricating the "end caps" to create the chambers at the inlet/outlet sides (same as with the X1 block) and doing it this way would force you to use a larger size channel (the smaller the drill bit the shorter the channel can be).