fluid flow through two pipes

[Pedro_The_Swift]

This is not a car question,, more a question on how fluids flow through pipes.
I recently had to add T pieces to the inlet and outlet of the heater in my D2, this was to run much hotter water through the LPG regulator.
My question is,
how does the new T'd hose know which way to flow(though I dont think direction matters)
and
what happens to the volume/pressure of water from a 5/8 hose if an identical hose is run off it?
and this might be the same question in reverse;)
how does fluid from a 5/8 hose get back into a 5/8 hose already flowing/full?

Please get as technical as you like, but words of only a couple of syllables,, ok?:D

[bee utey]

Simple really. Viscosity and velocity in a flowing fluid cause pressure differences between different points of the circuit therefore flow happens in that circuit. If water had no viscosity you would have perpetual motion. In the case of your heater circuit the heater core sets up a pressure difference between the two tees and the extra hoses simply allow more flow from the higher pressure to the lower. As soon as your water pump stops turning all flow stops as there is no longer any water velocity. That is why a loss of fan belt causes converters to ice up in short order and sometimes prevent an engine melt down.

[Pedro_The_Swift]

soooo--
if the new hose has less pressure, will more water flow through it than the heater?

[bee utey]

soooo--
if the new hose has less pressure, will more water flow through it than the heater?
I don't think you know what "pressure" means. The new pipes don't "have less pressure", they may or may not have a lower or higher pressure drop at a given flow rate. If you tested the pressure drop* as say 0.2 psi at 2 litres per second through the heater core and its pipes after the tee, and say 0.3 psi at 2 litres a second across the converter and its pipes from the tee, you would say that when connected together (ie the same pressure drop) it's likely that the converter circuit would flow less coolant than the heater. So your pressure drop in a pair of parallel circuits depends on the length of the hoses, the size of the passages in the converter or heater and any other obstruction in the hoses.

Practically, if your converter hose circuit is 6 inches long expect more coolant to flow through the converter, if it's 6 feet long expect the heater to get more. And as I mentioned a few posts ago, I once converted a P38 and had to add a restrictor to the converter circuit as it was mounted on the drivers side right next to the heater hoses. Yours is on the opposite side and the hoses are considerably longer than those to the heater.

I just found the picture I posted up way back in 2009

http://www.aulro.com/afvb/attachments/lpg/18411d1251970820-more-lpg-conversion-pics-p38-diesel-p38-sagem-inj.jpg

The converter on that one is just in front of the brake unit and has short hoses.

* To test pressure drop you could get a calibrated bucket, a garden tap and a pressure gauge at the inlet to the circuit. You'd assume zero pressure at the bucket. Nobody does so in the real world of course, this is just a thought experiment for the kiddies.

[Bradtot]

Hi
Why not put the convertor hoses in series with the heater hoses?
reasons for and against?
My gas convertor is in serires with the heater and I have never had a problem in 20 odd years with 2 Rangies and my daughters disco 1.
Rangie classic with flapper and omvl convertor
Brad:)

[Pedro_The_Swift]

I had that brainstorm too Brad:D
but the man said it put too much coolant throught the reg,, would leave deposits or something?

I would, (now!) weigh that up against having 8 more joins in my cooling system!

[loanrangie]

Hi
Why not put the convertor hoses in series with the heater hoses?
reasons for and against?
My gas convertor is in serires with the heater and I have never had a problem in 20 odd years with 2 Rangies and my daughters disco 1.
Rangie classic with flapper and omvl convertor
Brad:)

This is how i did my 2 rrc's , this makes it less likely to get an airlock and more likely to get a good flow of hot coolant thru the converter.

Sent from my GT-I9300 using AULRO mobile app

[Blknight.aus]

theres no simple answer to your question....

the implied answer is run the 2 heat exhcangers in series. the sequence depends on what you're trying to achieve.

if your heat echangers add heat to the cooling system then you put them in so the exhanger that adds the lesser amount is first in flow. IF you put it in the other way around then you may find the added heat from the first exhanger heats the coolant up to the point where the second exchanger doesnt get any heat transfer.

IF your taking heat out I recommend putting the one in the engine bay in last as you'll pick up some heat on the exhcanger from the heat radiating off of the engine.

if you're doing one addative and one subtractive... take your best guess. I generally route them up whichever way makes the hoses flow better.

[Mick_Marsh]

The correct place to place the supply "T" to the converter is between the water pump and the heater core regulating valve.
If you connect the converter and heater core in series, when you (or the climate control) restricts hot water flow to the heater core, hot water flow to the heater converter is also restricted. This is not neccessarily what you want to achieve.

[LandyAndy]

The correct place to place the supply "T" to the converter is between the water pump and the heater core regulating valve.
If you connect the converter and heater core in series, when you (or the climate control) restricts hot water flow to the heater core, hot water flow to the heater converter is also restricted. This is not neccessarily what you want to achieve.

I was under the impression modern climate control units run hot water to the heater core 100% all the time.Blend motors control a flap that allows an amount of heated air to be drawn into the climate controled air if its required.
Could be wrong,not often:p
:p:p:p:p
Andrew

[Mick_Marsh]

I was under the impression modern climate control units run hot water to the heater core 100% all the time.Blend motors control a flap that allows an amount of heated air to be drawn into the climate controled air if its required.
Could be wrong,not often:p
:p:p:p:p
Andrew
That might be the case with Landrovers. With my Commodore, there is a valve. There is a valve on the Landrover I have a gas system on (but that isn't climate control).

[bee utey]

That might be the case with Landrovers. With my Commodore, there is a valve. There is a valve on the Landrover I have a gas system on (but that isn't climate control).
The gas converter can still be in series with the heater so long as you use the Commodore style 4 way heater valve. Flow through the circuit is maintained at all times, heater on or off. If you tee the converter before the 4 way valve then the converter gets too little flow when the valve is in the bypass position. Some LRV8's ran a similar valve to isolate the heater, I think it was the 1994 soft dash RRC. I've retrofitted them to some vehicles with worn heater blend flaps.

[Mick_Marsh]

The gas converter can still be in series with the heater so long as you use the Commodore style 4 way heater valve. Flow through the circuit is maintained at all times, heater on or off. If you tee the converter before the 4 way valve then the converter gets too little flow when the valve is in the bypass position. Some LRV8's ran a similar valve to isolate the heater, I think it was the 1994 soft dash RRC. I've retrofitted them to some vehicles with worn heater blend flaps.
4 way?
It has an inlet and an outlet. The heater core temperature varies.

[bee utey]

4 way?
It has an inlet and an outlet. The heater core temperature varies.

This is a standard V6 heater valve

https://www.aulro.com/afvb/images/imported/2015/03/1031.jpg

Heater TAP TO Suit Holden Commodore VN VP VR VS VT VX VY V6 | eBay (http://www.ebay.com.au/itm/Heater-Tap-to-suit-Holden-Commodore-VN-VP-VR-VS-VT-VX-VY-V6-/131282207337?pt=LH_DefaultDomain_15&hash=item1e91078269)

This is a standard V8 heater valve

https://www.aulro.com/afvb/images/imported/2015/03/1032.jpg

Holden VN VP VQ VR VS VT V8 Heater TAP Gates Quality | eBay (http://www.ebay.com.au/itm/Holden-VN-VP-VQ-VR-VS-VT-V8-Heater-Tap-GATES-QUALITY-/271141784733?pt=LH_DefaultDomain_15&hash=item3f214f4c9d)

Both are on-off valves, neither regulates the flow incrementally. The V6 version allows flow to bypass the heater on full cold setting, the V8 one simply stops it. With the V8 valve you tee in the converter before the valve, with a V6 type you run the converter in series.

[Mick_Marsh]

This is a standard V6 heater valve

https://www.aulro.com/afvb/images/imported/2015/03/1031.jpg

Heater TAP TO Suit Holden Commodore VN VP VR VS VT VX VY V6 | eBay (http://www.ebay.com.au/itm/Heater-Tap-to-suit-Holden-Commodore-VN-VP-VR-VS-VT-VX-VY-V6-/131282207337?pt=LH_DefaultDomain_15&hash=item1e91078269)

This is a standard V8 heater valve

https://www.aulro.com/afvb/images/imported/2015/03/1032.jpg

Holden VN VP VQ VR VS VT V8 Heater TAP Gates Quality | eBay (http://www.ebay.com.au/itm/Holden-VN-VP-VQ-VR-VS-VT-V8-Heater-Tap-GATES-QUALITY-/271141784733?pt=LH_DefaultDomain_15&hash=item3f214f4c9d)

Both are on-off valves, neither regulates the flow incrementally. The V6 version allows flow to bypass the heater on full cold setting, the V8 one simply stops it. With the V8 valve you tee in the converter before the valve, with a V6 type you run the converter in series.
Ah, yes. That's it. The V8 model. Inlet and outlet.
Thankyou for confirming my post.