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A small correction regarding the laws of thermodynamics and convection. - Page 10

post #91 of 108
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Quote:
Originally Posted by doyll View Post

I guess you didn't read the first sentence of my post. rolleyes.gif
And you too. First sentence
What don't you understand"


Claiming the analogy of a tank is is not using honest logic. That is grasping at straw trying to defend a weak position.
Yes, there are many other places in a case that leak air. But we know the path of least resistance is the exhaust vents with fans. The next easiest is vents without fans. tongue.gif

So poke some extra holes in the flippin' tank to resemble the leaks in the case .. use a canvas bag for the tank. That way if the easy flow area is not match the wter will squirt out of the canvas like a sprinkler thumb.gif
If the "tank" does not have at least the equivalent area of the 12" pipe the outflow is restricted. This is not rocket science guys. It not even above ability of a 7 year old to understand.
Why is "The maximum airflow of a case is the lessor of the two; intake or exhaust" ?

I did read the first sentence and then promptly proceeded to disagree because your flawed analogy is only a reflection of a flawed reasoning from a physics point of view.

Air does not need to directly be pushed in order to be propelled in a given direction. Case in point: Laboratory vacuum pumps connected to a Buchner funnel. There's no active component (the vacuum pump isn't actually a pump although a pump is used to create it) but air is displaced nevertheless because of a low pressure zone existing. The same is true for a computer case. There will be a pressure build-up in the case until a point of equilibrium is reached where the internal pressure is sufficiently high to defeat the passive resistance offered by the case. When that point is reached, active intake = passive + active exhaust.

To go back to you're analogy, a 12" pipe can carry just as much water as a 3" pipe. The 3" will simply have more pressure. This is exactly what happens in the human heart where the aorta carries as much blood as all the capillaries (and the capillaries' cross-section is MUCH bigger than the aorta's). And guess what happens in the end? The blood is PASSIVELY (or almost, think of the muscular contractions as the minimal intake being present) brought back to the heart mostly by the new blood arriving in the veins after crossing the capillaries (this would be the high internal pressure created by the strong intake).

The Silverstone 90° cases are the perfect example of this working brilliantly. Multiple massive fans create a strong internal pressure with minimal active exhaust. According to your argumentation, this should provide abysmal cooling, and yet they're probably the best air cooling cases available.
Edited by Snowmen - 11/9/15 at 8:23pm
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post #92 of 108
Quote:
Originally Posted by Snowmen View Post

I did read the first sentence and then promptly proceeded to disagree because your flawed analogy is only a reflection of a flawed reasoning from a physics point of view.

Air does not need to directly be pushed in order to be propelled in a given direction. Case in point: Laboratory vacuum pumps connected to a Buchner funnel. There's no active component (the vacuum pump isn't actually a pump although a pump is used to create it) but air is displaced nevertheless because of a low pressure zone existing. The same is true for a computer case. There will be a pressure build-up in the case until a point of equilibrium is reached where the internal pressure is sufficiently high to defeat the passive resistance offered by the case. When that point is reached, active intake = passive + active exhaust.

To go back to you're analogy, a 12" pipe can carry just as much water as a 3" pipe. The 3" will simply have more pressure. This is exactly what happens in the human heart where the aorta carries as much blood as all the capillaries (and the capillaries' cross-section is MUCH bigger than the aorta's). And guess what happens in the end? The blood is PASSIVELY (or almost, think of the muscular contractions as the minimal intake being present) brought back to the heart mostly by the new blood arriving in the veins after crossing the capillaries (this would be the high internal pressure created by the strong intake).

The Silverstone 90° cases are the perfect example of this working brilliantly. Multiple massive fans create a strong internal pressure with minimal active exhaust. According to your argumentation, this should provide abysmal cooling, and yet they're probably the best air cooling cases available.
For air to move there has to be a pressure differential with lower pressure being the direction it will move to. That's the "physics" of airlfow. rolleyes.gif

That is assuming the case is strong enough to hold the pressure and not rupture .. creating a hole and thus increasing the airflow "escape" / exhaust area. And of course the higher the pressure need to be, the less airflow you intake fans will be able to supply. poke.gif

As above

12" has a maximum flow rate the same as 3"? doh.gif Get a grip on the physical size difference here. A 12" pipe can flow 16 times as much as a 3" pipe .. both at maximum flow. 12" pipe has 113 sq inches of area compared to 3" pipe having 7sq inches. Maybe some of this blood you are talking about need to reach your brain so you can think with a clear head here. biggrin.gif

Silverstone case has a lot better intake area to exhaust area than the case setup in question .. or the 12" to 3" example. Oh! Wait! I forget you believe a 3" hole can pas as much as a 12" hole..

Sorry, but we are going to have to agree to disagree .. or at least quite this debate. There is no way we can discuss this with the illogical rational you use.
post #93 of 108
Quote:
Originally Posted by doyll View Post

For air to move there has to be a pressure differential with lower pressure being the direction it will move to. That's the "physics" of airlfow. rolleyes.gif

That is assuming the case is strong enough to hold the pressure and not rupture .. creating a hole and thus increasing the airflow "escape" / exhaust area. And of course the higher the pressure need to be, the less airflow you intake fans will be able to supply. poke.gif

Listen to what you're saying here, doyll. This is a completely unrealistic example. Obviously, there is no computer case which could rupture from the fans on it and we all agree that air (like water and electricity) follows the path of least resistance. However, like water and electricity, the path of least resistance isn't the only path the air will follow, but simply the path which will contain the largest volume of the moving air.

And yes, an increase in pressure (resistance) creates an inversely proportional airflow, but for the love of Buddha, we're not talking about this. We're talking about this.

Quote:
Originally Posted by doyll View Post

12" has a maximum flow rate the same as 3"? doh.gif Get a grip on the physical size difference here. A 12" pipe can flow 16 times as much as a 3" pipe .. both at maximum flow. 12" pipe has 113 sq inches of area compared to 3" pipe having 7sq inches.

I think what you're missing here is that he's saying that the 3" pipe is moving the same volume at a higher pressure, not that the maximum flow rate of the two pipes is equal. In this analogy, the maximum flow rate isn't reached by either pipe. That would result in something ridiculous like, oh I dunno, a computer case rupturing due to air pressure from fans. Anyway, it's just an analogy. It helps some people understand and it's lost on others. C'est la vie.

Quote:
Originally Posted by doyll View Post

Maybe some of this blood you are talking about need to reach your brain so you can think with a clear head here. biggrin.gif

No need to be rude here, buddy.

Quote:
Originally Posted by doyll View Post

Silverstone case has a lot better intake area to exhaust area than the case setup in question .. or the 12" to 3" example. Oh! Wait! I forget you believe a 3" hole can pas as much as a 12" hole..

The Silverstone case, in its stock configuration, has 3x 180mm intake fans and 1x 120mm exhaust fan. Correct me if I'm wrong, but that is almost exactly the setup in question.. 4.5:1 intake to exhaust. If you remember, I said I'm employing two 280mm rads and only one 140mm exhaust. So our friends at Silverstone have a similar idea, but an even more disproportionate intake to exhaust ratio. So if you concede that the Silverstone is a good design, then my original suggestion of running all radiator fans on intake with only one exhaust isn't really that much worse.

Quote:
Originally Posted by doyll View Post

Sorry, but we are going to have to agree to disagree .. or at least quite this debate. There is no way we can discuss this with the illogical rational you use.

This may be the truest statement in your whole post.

I would hope, however, that we could all have a nice discussion without anyone getting bent out of shape. If not, then thanks for your input so far and peace out. smile.gif
post #94 of 108
Thread Starter 
Quote:
Originally Posted by doyll View Post

For air to move there has to be a pressure differential with lower pressure being the direction it will move to. That's the "physics" of airlfow. rolleyes.gif

That is assuming the case is strong enough to hold the pressure and not rupture .. creating a hole and thus increasing the airflow "escape" / exhaust area. And of course the higher the pressure need to be, the less airflow you intake fans will be able to supply. poke.gif

As above

So you're basically saying I'm right?
Quote:
Originally Posted by doyll View Post

12" has a maximum flow rate the same as 3"? doh.gif Get a grip on the physical size difference here. A 12" pipe can flow 16 times as much as a 3" pipe .. both at maximum flow. 12" pipe has 113 sq inches of area compared to 3" pipe having 7sq inches. Maybe some of this blood you are talking about need to reach your brain so you can think with a clear head here. biggrin.gif

Silverstone case has a lot better intake area to exhaust area than the case setup in question .. or the 12" to 3" example. Oh! Wait! I forget you believe a 3" hole can pas as much as a 12" hole..

Sorry, but we are going to have to agree to disagree .. or at least quite this debate. There is no way we can discuss this with the illogical rational you use.

If I were wrong, you'd be dead. A normal aorta has a cross-sectional area of roughly 0,8 cm^2. Your total capillary cross-section is roughly 600 cm^2. Yet, they both have the same flow despite one being more than 600 times larger.
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post #95 of 108
D[/QUOTE]
Quote:
Originally Posted by Snowmen View Post

So you're basically saying I'm right?
If I were wrong, you'd be dead. A normal aorta has a cross-sectional area of roughly 0,8 cm^2. Your total capillary cross-section is roughly 600 cm^2. Yet, they both have the same flow despite one being more than 600 times larger.
Obviously not. You are trolling

You got that backwards. If you were right we would all be dead. Air does nasty things when it gets into our bloodstreams. .biggrin.gif
Quote:
Originally Posted by mmurray View Post

I would hope, however, that we could all have a nice discussion without anyone getting bent out of shape. If not, then thanks for your input so far and peace out. smile.gif
We you can compare air and water, but not electricity .. or blood.


When thought processes (definitely no rational) are that a 3" pipe can flow as much as a 12" one and the circulatory system of blood is like airflow, there is nothing rational to discuss.


Like psyclum said:
Quote:
moral of the story... don't necro a 3 year old thread unless you really feel the need to open that can of worms biggrin.gif

Or answer anyone one who necros them. biggrin.gif
Edited by doyll - 11/10/15 at 8:56am
post #96 of 108
For me personally, the couple of posts that Snowmen made were worth the price of necromancy alone. I also appreciate doyll and other opposing viewpoints even though I don't believe they are correct. This would be a boring ass world if everyone agreed and advancement of any kind would be pretty scarce if we didn't challenge each other.

Like I said, arguing with an analogy can do more harm than good with some folks so putting the water, electricity, and circulatory system aside, could you just confirm or deny that the Silverstone 90° design is effective?
post #97 of 108
Well ..... Considering the logic you guys are bent on believing, the SilverStone 90 degree will flow all the blood you have with no problems.

It will make on hell of a mess though. biggrin.gif
post #98 of 108
I'll take your sarcasm as tacit concession that 4.5:1 intake:exhaust is effective. tongue.gif
post #99 of 108
Quote:
Originally Posted by mmurray View Post

I'll take your sarcasm as tacit concession that 4.5:1 intake:exhaust is effective. tongue.gif

IF AND ONLY IF the airflow design of the case is right for it. you guys are completely missing the point arguing back and forth without proper context... Doyll is correct in everything he's said so far... you guys are simply refusing to see the point.... it's funny this is coming from me who uses no exhaust fans in my case at all (yes even my PSU is passive so no exhaust fan there) and i have 3 giant intake fans (AP181). in my particular case, the airflow design is made for such configuration and it works well w/o an exhaust fan but that's not always the case for all chassis. not even all of the Silverstone rotated mobo cases have that kind of airflow design. (RV03 and FT03 will actually work better with an exhaust fan since there is leakage early in its airflow design) i have also seen ehume's builds with no exhaust fans at all in the case, but that does NOT mean what Doyll says is wrong, it's just ehume has modded his case to the point where there is no reason to put exhaust fans in there at all... it's like if you are using a Inwin "Frame"(S, H, D) series cases or any open bench chassis... you can have 100:1 intake to exhaust ratio and it will still work well...

the arguments are going nowhere... you guys obviously have an idea of how things work in your heads and there is little point in offering any kind of advice. ripping apart Doyll's comments w/o looking at it from the context of the information he's trying to offer is your loss. you guys seem to have the basic concept of cooling down so all we are talking about is optimization anyway... It's a matter of a few decibels of cost at the end of the day so just do whatever you guys feels is right. You are simply paying maybe 3 decibels more for the same cooling Doyll is trying to help you with.

If you really look at cooling, it all comes down to how many decibels you are willing to pay for your cooling.

you wont have a problem with any kind of heat if you use this as your exhaust fan

jet-test.jpg

the only problem is it will cost you about 130 decibels.... (and alot of jet fuel biggrin.gif )
post #100 of 108
Quote:
Originally Posted by mmurray View Post

I'll take your sarcasm as tacit concession that 4.5:1 intake:exhaust is effective. tongue.gif
Only when the 4.5 : 1 is blood .. and probably troll breath too.. poke.gif
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