Water cooling system design

[Squashy]

I have never water cooled a PC before but I have designed large hydraulic systems and tinkered with automobiles all my life and I have some questions.

 

In the drag racing community, racers would remove the thermostat from the engine cooling system allowing them to circulate water through the engine between rounds using a electric water pump. With the right (wrong) combination they start having overheating issues and are left baffled and frustrated. In these cases the water is moving so fast through the radiator it (water) never gets enough time to shed it's heat (energy / BTU's). Like wise the water flowing through the block is trying to cool down a massive amount of heat but it's never around long enough for the transfer of energy to take place. So what ends up happening is all the water get's heated reducing it's cooling capacity. (heat soaked)

How do you solve this you might ask? Restrictor of course.. in place of the thermostat. The restrictor allows the electric water pump to circulate more of the water around the heat source and gives the water in the radiator more time to lose it's energy / heat. Of course the ideal situation would be to re-install the thermostat. ( I feel like this is obvious to a lot of people but I still see people misunderstanding how a heat exchanger operates.)  

 

I say all that to ask,,, Does these water cooled systems have thermostats or restrictors because it doesn't appear that they do? If they don't, I'd love to mess around and design a water cooling system! 

 

I'm sure there is some certified engineers out there reading this that could throw in some formal words and calculations but I have always been the link between reality & theory for Engineers!!!  (Trust me,,, they need me!! I love all the engineers I have ever worked with but every engineer needs a good tech! ) 

 

 

[Cyracus]

18 minutes ago, Squashy said:

Does these water cooled systems have thermostats or restrictors because it doesn't appear that they do? If they don't, I'd love to mess around and design a water cooling system!

Only the restrictions naturally involved (waterblocks, radiators, and the like), have fun testing, share if you find something interesting.

[Squashy]

1 hour ago, Cyracus said:

Only the restrictions naturally involved (waterblocks, radiators, and the like), have fun testing, share if you find something interesting.

It would be fun but I lack the funding! I got some cheap ideas though. 

[Cyracus]

2 minutes ago, Squashy said:

It would be fun but I lack the funding! I got some cheap ideas though. 

Care to share, you've piqued my curiousity

[Squashy]

6 hours ago, Cyracus said:

Care to share, you've piqued my curiousity

I would but I don't know where to start, I will capture some thoughts on paper and share. 

[narrdarr]

22 hours ago, Squashy said:

I have never water cooled a PC before but I have designed large hydraulic systems and tinkered with automobiles all my life and I have some questions.

 

In the drag racing community, racers would remove the thermostat from the engine cooling system allowing them to circulate water through the engine between rounds using a electric water pump. With the right (wrong) combination they start having overheating issues and are left baffled and frustrated. In these cases the water is moving so fast through the radiator it (water) never gets enough time to shed it's heat (energy / BTU's). Like wise the water flowing through the block is trying to cool down a massive amount of heat but it's never around long enough for the transfer of energy to take place. So what ends up happening is all the water get's heated reducing it's cooling capacity. (heat soaked)

How do you solve this you might ask? Restrictor of course.. in place of the thermostat. The restrictor allows the electric water pump to circulate more of the water around the heat source and gives the water in the radiator more time to lose it's energy / heat. Of course the ideal situation would be to re-install the thermostat. ( I feel like this is obvious to a lot of people but I still see people misunderstanding how a heat exchanger operates.)  

 

I say all that to ask,,, Does these water cooled systems have thermostats or restrictors because it doesn't appear that they do? If they don't, I'd love to mess around and design a water cooling system! 

 

I'm sure there is some certified engineers out there reading this that could throw in some formal words and calculations but I have always been the link between reality & theory for Engineers!!!  (Trust me,,, they need me!! I love all the engineers I have ever worked with but every engineer needs a good tech! ) 

 

 

 

[bowrilla]

You will not reach these levels of flowrate in your regular loop to have too much flow in your blocks. I could imagine that the dragster issue is related to laminar flow which is bad because of the non-turbulent flow not mixing your coolant which results in layers of different heat. The mixing will probably only take place in the reservoir and radiators. That means the heat transfer from block to coolant is limited to very little amount of coolant which then will reduce the temperature gradient resulting in less and less efficient heat transfer. For this to happen in a CPU or GPU block it takes very uncommon to unrealistic scenarios. In fact I can't actually think of anything here because of the design of many blocks: vertical intake with a jet plate pressing everything against the bottom of the cold plate and then to the sides through the small channels.

 

The video that @narrdarrposted shows pretty well that very slow flow to increase cooling capacity is a myth based on some misconceptions. A high flow rate might reduce the time every coolant molecule stays in contact with the coldplate per "cycle" (as in moving a fixed amount of coolant through the loop) but at the same time there are more "cycles" per given timeframe. Yes, the amount of heat energy transferred each "cycle" impacting the heat gradient but since it happens more often per given intervall the total amount of energy that is being transfered is not significantly different unless you move to the extreme ends. 

 

People also miss the point that even though too little of a temperature gradient will almost bring the transfer of heat to a stop, the coolant will just heat up a bit resulting in a temperature gradient and then again more efficient heat transfer. If you end up with overheating blocks (be it engine or cooling blocks) your loop is not well designed. You will need more radiator space or more airflow (common car radiators just like pc water cooling radiators need airflow to work).

[Squashy]

2 hours ago, bowrilla said:

You will not reach these levels of flowrate in your regular loop to have too much flow in your blocks. I could imagine that the dragster issue is related to laminar flow which is bad because of the non-turbulent flow not mixing your coolant which results in layers of different heat. The mixing will probably only take place in the reservoir and radiators. That means the heat transfer from block to coolant is limited to very little amount of coolant which then will reduce the temperature gradient resulting in less and less efficient heat transfer. For this to happen in a CPU or GPU block it takes very uncommon to unrealistic scenarios. In fact I can't actually think of anything here because of the design of many blocks: vertical intake with a jet plate pressing everything against the bottom of the cold plate and then to the sides through the small channels.

 

The video that @narrdarrposted shows pretty well that very slow flow to increase cooling capacity is a myth based on some misconceptions. A high flow rate might reduce the time every coolant molecule stays in contact with the coldplate per "cycle" (as in moving a fixed amount of coolant through the loop) but at the same time there are more "cycles" per given timeframe. Yes, the amount of heat energy transferred each "cycle" impacting the heat gradient but since it happens more often per given intervall the total amount of energy that is being transfered is not significantly different unless you move to the extreme ends. 

 

People also miss the point that even though too little of a temperature gradient will almost bring the transfer of heat to a stop, the coolant will just heat up a bit resulting in a temperature gradient and then again more efficient heat transfer. If you end up with overheating blocks (be it engine or cooling blocks) your loop is not well designed. You will need more radiator space or more airflow (common car radiators just like pc water cooling radiators need airflow to work).

I understand exactly what you are saying.

 

[Squashy]

13 hours ago, narrdarr said:

 

I agree for the give design of this hardware. The only way I could see maximizing that system would be to ditch the water and go to a synthetic and remove all air from the system.

I really like those flow sensor's, I bet they are expensive! 

[Squashy]

Here is what I'm thinking:

1. Reduce tube size

2. Tube & Fin cooler instead of Plate.

3. Create a expansion chamber at the CPU

4. Gear style pump post expansion chamber

 

The whole loop would need to be pressurized. I'm got some nitrous and carburetor jet I'm think that would work good at the inlet of the expansion chamber. The only part I'm unsure of is the gearotor style pump.

[Cyracus]

On 11/23/2020 at 9:18 AM, Squashy said:

I really like those flow sensor's, I bet they are expensive!

https://modmymods.com/fittings/flow-rate-pressure-sensors.html?dir=desc&limit=all&order=price  Not too bad

[bowrilla]

1 hour ago, Cyracus said:

https://modmymods.com/fittings/flow-rate-pressure-sensors.html?dir=desc&limit=all&order=price  Not too bad

They are VERY sensitive though in terms of turbulences. You really need to make sure to have enough straight tube running to and from it or the measurement will be off. And don't even think about adding any funky fluid additives because those will most likely clog the small holes in front of the membranes.