[Amps] Amps Digest, liquid cooling.
David Lisney
g0fvt at hotmail.com
Wed Apr 1 15:54:05 EDT 2015
Hi, I think I would also go for the greatest practical flow, though I think there can be issues with turbulence creating dead spots in the heat exchangers....
Regards David G0FVT
Sent from my iPad
> On 1 Apr 2015, at 20:14, amps-request at contesting.com wrote:
>
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> Today's Topics:
>
> 1. Re: silver mica source (Paul Hewitt)
> 2. Re: more - oil bath GS-35b (Tom Thompson)
> 3. Meter replacement (Kathy Bookmiller via Amps)
> 4. Re: more - oil bath GS-35b (MU 4CX250B)
> 5. more - oil bath GS-35b (Jim Thomson)
> 6. Re: more - oil bath GS-35b (Bill Turner)
> 7. Re: more - oil bath GS-35b (Steve Wright)
>
>
> ----------------------------------------------------------------------
>
> Message: 1
> Date: Wed, 1 Apr 2015 09:21:42 -0700
> From: "Paul Hewitt" <wd7s at earthlink.net>
> To: "'Alex Malyava'" <alex.k2bb at gmail.com>, "'Amps Group'"
> <amps at contesting.com>
> Subject: Re: [Amps] silver mica source
> Message-ID: <000001d06c97$f80d0a10$e8271e30$@earthlink.net>
> Content-Type: text/plain; charset="us-ascii"
>
> Yet another source for silver mica;
> Alltronics.com
> Limited selection but most are .35 cents apiece
> 73, Paul
>
> Paul Hewitt
> WD7S Productions
> QRO Homebrew components
> http://home.earthlink.net/~wd7s/contents.htm
>
> -----Original Message-----
> From: Amps [mailto:amps-bounces at contesting.com] On Behalf Of Alex Malyava
> Sent: Tuesday, March 31, 2015 8:02 AM
> To: Amps Group
> Subject: [Amps] silver mica source
>
> Hi all,
> I need some silver mica caps to be used in 100 W PA LPF and tuner What are
> the options besides mouser.com at $2 a piece?
> I found one place - thetubestore.com in Hamilton, Ontario - with prices like
> few times cheaper that mouser, but I am not sure how reliable those mica
> caps are.
> I think the caps they sell come from India, from simic electronics...
> Are they good? Do they have high Q and low losses as should be for "normal"
> silver mica dipped capacitors?
>
> Thanks,
> Alex K2BB
> _______________________________________________
> Amps mailing list
> Amps at contesting.com
> http://lists.contesting.com/mailman/listinfo/amps
>
>
>
> ------------------------------
>
> Message: 2
> Date: Wed, 01 Apr 2015 11:08:26 -0600
> From: Tom Thompson <w0ivj at tomthompson.com>
> To: Gary Schafer <garyschafer at largeriver.net>, "'Steve Wright'"
> <stevewrightnz at gmail.com>, amps at contesting.com
> Subject: Re: [Amps] more - oil bath GS-35b
> Message-ID: <551C260A.9040105 at tomthompson.com>
> Content-Type: text/plain; charset=windows-1252; format=flowed
>
> The flow through the radiator has to be the same as the flow around the
> tube. The secret is to spend more time in the radiator which has a
> larger surface area than the tube.
>
> Tom W0IVJ
>
>> On 3/31/2015 10:22 PM, Gary Schafer wrote:
>> How is the radiator different from the tube? Heat transfer is about
>> temperature difference, flow rate and turbulent flow. The greater
>> temperature difference the faster the heat transfer.
>>
>> If you slow down the flow thru the radiator you at the same time slow it
>> down at the tube.
>>
>> Faster flow increases turbulence and decreases heat layering giving better
>> contact to the oil/metal surface. Slow flow allows layering of the heat in
>> the oil which acts like an insulator as it flows slower near the metal
>> surface. Faster flow causes more turbulence which breaks up the layering
>> reducing the insulating action. Better heat transfer.
>>
>> See:Laminar flow.
>>
>> 73
>> Gary K4FMX
>>
>>
>>
>>> -----Original Message-----
>>> From: Amps [mailto:amps-bounces at contesting.com] On Behalf Of Steve
>>> Wright
>>> Sent: Sunday, March 29, 2015 11:21 PM
>>> To: amps at contesting.com
>>> Subject: Re: [Amps] more - oil bath GS-35b
>>>
>>>
>>>
>>>> On 30/03/15 17:01, Gary Schafer wrote:
>>>> You do not need to slow the flow down in order to pick up heat. The
>>> faster
>>>> the flow the more heat will be transferred.
>>> Correct! The faster the oil flow in the tube cooler, the better the
>>> cooling.
>>>
>>> But not so for the radiator. The oil must slow down and be in the
>>> radiator for a finite time for the heat to be transferred from the oil
>>> to the air.
>>>
>>>
>>>
>>>> On another note, you will need as much air movement to cool the
>>> radiator as
>>>> you would need to cool the tube directly. With oil cooling you are
>>> only
>>>> moving the heat from the tube to the radiator. You still have the same
>>>> amount of heat to transfer to the air.
>>> Sure.
>>>
>>>
>>>> Although with the radiator the surface area to cool will be much
>>> larger than
>>>> it is with air cooling the tube so the air velocity can be lower.
>>> Exactly! Very much lower, and very very much quieter. I want to sit
>>> next to my quiet amp - not my vacuum cleaner.
>>>
>>>
>>> Steve
>>>
>>> _______________________________________________
>>> Amps mailing list
>>> Amps at contesting.com
>>> http://lists.contesting.com/mailman/listinfo/amps
>> _______________________________________________
>> Amps mailing list
>> Amps at contesting.com
>> http://lists.contesting.com/mailman/listinfo/amps
>
>
>
> ------------------------------
>
> Message: 3
> Date: Wed, 1 Apr 2015 10:13:23 -0700
> From: Kathy Bookmiller via Amps <amps at contesting.com>
> To: "Amps at contesting.com" <Amps at contesting.com>
> Subject: [Amps] Meter replacement
> Message-ID:
> <1427908403.53572.YahooMailBasic at web120902.mail.ne1.yahoo.com>
> Content-Type: text/plain; charset=us-ascii
>
> Hello,
> I'm fixing up an old Hunter Bandit 2000C. It has one problem left to solve and that is to replace a smashed panel meter. The one that measured plate voltage and current.
> The original meter was made by Ammon instruments of Manchester NH. It has am-2 on the face plate, which I assume was the model number.
> I found two Ammon meters on Ebay that are the same size and style physically and one of them even has the same am-2 on the face plate (the other one's picture doesn't show this)
> I guess my question is, how does one know is this meter will be the same movement. At one time I knew this stuff, but years have dimmed my memory of meter shunts, etc. Out of curiosity, I put my VOM across the terminals of the broken meter and it measures 90 ohms.
> What I hope to do is replace the face plate with my old one and have one that matches the style of the other meter that is used for a watt meter.
> The old one's scales are for 0-3000 volts and up to an amp. current.
> Anyone still remember their analog meter theory and practice?
> Thank you,
> Kathy, W2NK
>
>
>
> ------------------------------
>
> Message: 4
> Date: Wed, 1 Apr 2015 11:22:14 -0600
> From: MU 4CX250B <4cx250b at miamioh.edu>
> To: Bill Turner <dezrat at outlook.com>
> Cc: Amps group <amps at contesting.com>
> Subject: Re: [Amps] more - oil bath GS-35b
> Message-ID: <515673277809306087 at unknownmsgid>
> Content-Type: text/plain; charset=UTF-8
>
> I haven't thought about this deeply, but I'm thinking the rate of heat
> transfer to the oil bath depends only on the temperature difference
> between the oil (adjacent to the tube anode) and the anode
> temperature, as well as the thermal impedance of the tube-oil
> interface. Speeding up the oil flow ensures that cool oil is always
> present at the interface, thus maximizing the temperature difference
> and optimizing heat transfer.
>
> The same reasoning applies to the oil-radiator system, but in reverse.
> Here one wants hot oil and a cool radiator, since that maximizes the
> heat transfer from the oil to the external environment.
>
> There are a few other considerations influencing cooling (such as the
> thermal conductivity of the oil, as well as its specific heat
> coefficient), but those are generally not under the control of the
> builder. Ideally one wants oil with the thermal conductivity of
> diamond, and a swimming pool-sized oil reservoir, but good luck with
> that!
> 73,
> Jim w8zr
>
> Sent from my iPad
>
> On Apr 1, 2015, at 9:20 AM, Bill Turner <dezrat at outlook.com> wrote:
>
> ------------ ORIGINAL MESSAGE ------------(may be snipped)
>
> On Mon, 30 Mar 2015 17:20:50 +1300, Gary and Steve wrote:
>
>
> You do not need to slow the flow down in order to pick up heat. The faster
> the flow the more heat will be transferred.
>
> Correct! The faster the oil flow in the tube cooler, the better the
> cooling.
>
> But not so for the radiator. The oil must slow down and be in the
> radiator for a finite time for the heat to be transferred from the oil
> to the air.
>
> REPLY:
>
> "But not so for the radiator."?
>
> There seems to be something wrong with the logic here. Heat transfer
> doesn't care whether it goes from the tube to the oil or from the oil
> to the radiator, does it? By your logic, if you slow the oil through
> the radiator down to very, very slow the heat transfer will be better.
> But then the tube will overheat and burn up.
>
> Likewise, if you slow down the oil past the tube, the heat transfer
> will be maximum, but again the tube will overheat and burn up.
>
> Can't both be right. I think faster is better for both tube and
> radiator.
>
> Any heat transfer engineers out there?
>
> 73, Bill W6WRT
> _______________________________________________
> Amps mailing list
> Amps at contesting.com
> http://lists.contesting.com/mailman/listinfo/amps
>
> ------------------------------
>
> Message: 5
> Date: Wed, 1 Apr 2015 10:35:19 -0700
> From: "Jim Thomson" <jim.thom at telus.net>
> To: <amps at contesting.com>
> Subject: [Amps] more - oil bath GS-35b
> Message-ID: <A7976B3F1B3D438FABE9BA1BB8DCD416 at JimPC>
> Content-Type: text/plain; charset="UTF-8"
>
> Date: Wed, 1 Apr 2015 16:37:16 +0100
> From: Chris Wilson <chris at chriswilson.tv>
> To: Bill Turner <dezrat at outlook.com>, amps at contesting.com
> Subject: Re: [Amps] more - oil bath GS-35b
> Message-ID: <905754433.20150401163716 at chriswilson.tv>
> Content-Type: text/plain; charset=us-ascii
>
>
> There are optimum flow rates based on heat exchanger coolant medium,
> be it gaseous, or fluid, the type of liquid, and its viscosity. It
> also depends on the surface area of the inside and outside elements of
> the exchanger and the device being cooled. For sure faster flow is
> *NOT* necessarily better. In automotive racing water (or water mix)
> coolant is NOT flowed as fast as possible through the engine, but very
> careful design has water flow going at different rates in different
> parts of the engine. Those who have replaced a cylinder head gasket
> may have noticed the flow restriction hoses of varying sizes in the
> head and gasket. Different areas of the engine run at different
> temperatures, and flow rate is varied to optimize heat extraction.
> Water to air radiators have internal turbulators in high end coolers
> to increase internal surface areas, thermostats have restrictor plates
> to control water flow rates. Current cooling systems use electronic
> water pump drives and electronic thermostats to optimize flow
> according to load, blah blah.
>
> Air flow through heat exchangers is similarly regulated for optimum
> heat exchange speeds.
>
> I am sure in an oil to air heat exchanger with a submerged valve there
> will be an optimal flow rate for the oil and the air, that is far away
> from the fastest flow rate, and there are big differences between
> convection, conduction and radiation. I am most definitely *NOT* a
> heat transfer engineer, but I am a race car engineer and I know a lot
> of science and experimentation goes on in the engine world to maximize
> heat exchanger performance, and engine coolant flow is a lot slower
> than you perhaps imagine.
>
>
> --
> Best regards,
> Chris mailto:chris at chriswilson.tv
>
> ### Us hot rodders run into this exact same issue with superchargers on V8 engines.
> The intercooler is just a small radiator, typ bar + fin type... placed on the hot output
> of the supercharger. Its job is to EXTRACT heat. A small pump passes the distilled
> water /glycol mix to the HE, aka heat exchanger..aka rad # 2. The HEs job is to DUMP heat.
> Mine doesn?t have a fan on the HE,but simply relies on airflow due to vehicle speed.
> Some will use dual fans on the HE, to keep things cooled down a bit at red lights,
> and also between runs at the drag strip etc. For road course folks, the fans don?t provide
> any benefit once above 20-30 mph. They impede airflow.
>
> ## faster pump speeds will make the intercooler work better..and extract more heat,
> BUT the entire assy is one big loop. Pump the hot water/glycol coolant through the
> intercooler-HE loop too fast, and all you end up doing is spinning hot water around,
> with no increase in eff at all. Unless the HE (external radiator in the case of the GS35B)
> can dump the heat as fast as its being generated, you are wasting your time with faster pump speeds.
>
> ## 1 watt = 3.15 BTU. 1 kw = 3150 BTU In the case of the proposed GS35B
> setup, 1-2 kw CCS of heat to extract..then dump is not a big issue. And with
> ssb /cw modes, the heat generated is going to be a lot less. Beware of advertised GPM
> flow rates on pumps. They are typ for no load. IE: fire hose connected from 55 gallon
> drum of water, to input of pump.... then another big diam hose from output to the ground.
>
> ## Once actually hooked up to the tight bends and puny size fittings, small tubing, and
> the restrictions inside the GS35B tube and the external radiator, the actual measured flow rates
> drop like a rock. Install a much bigger pump, and flow rates typ increase very little
> if any.
>
> ## check out the BTU specs for small radiators...like automatic transmission coolers.
> They are typ 8000-20,000 BTU rated..provided airflow of XXX CFM is put through em.
> I had to install a 2nd auto tranny cooler in series with my oem cooler, since the tranny temps
> climbed way too fast in just a few secs when super charger on..and gas pedal mashed. Like
> 170-200 F in just 7 secs.
>
> ## Old style radiators were tube + fin type. Better types are bar + plate. You can also get em
> in single, dual or triple core..and also single and dual pass. My bar + plate Tranny cooler uses a unique
> T stat......operates on viscosity. The hotter the synthetic tranny fluid gets, the higher it rides up either side
> of the rad. At that point it makes more and more parallel passes from one side to the other.
>
> ## The GS35B, with its low dissipation, will not be an issue. Perhaps 2-5000 btu at most.
> Ultimately... ALL the heat has to be eventually transferred to the air ! BTW, you will have to provide
> some cooling to the base seals of the tube, where the fil connections are made. With Eimac water cooled
> tubes, or vapor phase cooled tubes, a small air pump, is used to cool the fil pins.
> Same deal with a normal air cooled tube which uses anode to base flow.... instead of the usual base to anode flow,
> typ 3-5 cfm on a 3CX-3000A7. But uses anode to base flow ...nobody..its fubar and requires way more cfm.
> The additional air flow to the base will not be required if the entire tube is immersed in oil, like you proposed.
>
> ## A 2-4 GPM pump will more than meet your requirements. Then perhaps a pair of 120 mm square
> fans, like the 65 cfm rotron whisper types.. placed in front of the external rad. They are very quiet, and can be
> further lowered in speed with a simple metal finned resistor, variac, variable dc supply etc. Shroud the front of the
> rad, where the fans are... other wise you are wasting your time... air will leak like a sieve out the sides.
> Un shrouded rads don?t work too well. IMO, you are better off pushing air through the rad, vs sucking
> it through the back end of the rad. Then you don?t have hot air passing in and out past the fan bearings.
>
> later.... Jim VE7RF
>
>
>
>
>
>
> ------------------------------
>
> Message: 6
> Date: Wed, 1 Apr 2015 12:07:42 -0700
> From: Bill Turner <dezrat at outlook.com>
> To: Amps group <amps at contesting.com>
> Subject: Re: [Amps] more - oil bath GS-35b
> Message-ID: <BLU436-SMTP188E77DF89A601D05497B54C0F30 at phx.gbl>
> Content-Type: text/plain; charset="us-ascii"
>
> ------------ ORIGINAL MESSAGE ------------(may be snipped)
>
> On Wed, 1 Apr 2015 11:22:14 -0600, W8ZR wrote:
>
> I haven't thought about this deeply, but I'm thinking the rate of heat
> transfer to the oil bath depends only on the temperature difference
> between the oil (adjacent to the tube anode) and the anode
> temperature, as well as the thermal impedance of the tube-oil
> interface. Speeding up the oil flow ensures that cool oil is always
> present at the interface, thus maximizing the temperature difference
> and optimizing heat transfer.
> REPLY:
>
> You said it better than I did. Sounds right to me.
>
> 73, Bill W6WRT
>
>
> ------------------------------
>
> Message: 7
> Date: Thu, 02 Apr 2015 08:13:41 +1300
> From: Steve Wright <stevewrightnz at gmail.com>
> To: amps at contesting.com
> Subject: Re: [Amps] more - oil bath GS-35b
> Message-ID: <551C4365.4000605 at gmail.com>
> Content-Type: text/plain; charset=windows-1252; format=flowed
>
> Thanks greatly Chris for your additions there. It would have been a lot
> of work for me to make clear examples like that, but you see them
> regularly so can comment concisely. Most of my lessons learned about
> cooling have been from the automotive world, in particular, pushing the
> coolant through the radiator so fast, that the radiator cannot extract
> the heat from it. I've added a few comments to your words - if one of
> them is glaringly wrong, do feel free to put your big boot on top of the
> offending section! Best regards mate! ;)
>
> On 02/04/15 05:00, chris at chriswilson.tv wrote:
> There are optimum flow rates based on heat exchanger coolant medium [...]
> [...] depends on the surface area of the inside and outside elements
> of the exchanger and the device being cooled.
> Different areas of the engine run at different temperatures, and flow
> rate is varied to optimize heat extraction.
> Flow rates can easily be managed in parallel circuits by using
> restrictors and valving. Flows depend on the type of exchanger, cooling
> or heating. In serial circuits, flow (coolant time) is managed by tube
> size or length.
>
>
> For sure faster flow is *NOT* necessarily better. In automotive racing
> water (or water mix) coolant is NOT flowed as fast as possible through
> the engine, but very careful design has water flow going at different
> rates in different parts of the engine.Race cars must not undercool some part, but may not throw loads of
> energy at the problem when that loss of power may cost them the race.
> Correspondlingly, in the shack we won't run fans and pumps at full speed
> because they are noisy, and may be counterproductive.
>
>
> thermostats have restrictor plates to control water flow rates.
> Current cooling systems use electronic water pump drives and
> electronic thermostats to optimize flow according to load, blah blah.
> Air flow through heat exchangers is similarly regulated for optimum
> heat exchange speeds.The thermostat must not open and blow hot coolant through the radiator
> at high velocity, or there will not be enough time for the heat to be
> removed.
>
>
> I am sure in an oil to air heat exchanger with a submerged valve there
> will be an optimal flow rate for the oil and the air, that is far away
> from the fastest flow rate [...]Slower is better. Monitor the output temperature of the radiator and
> throttle coolant flow, but then there must be adequate coolant flow for
> the tubeset. Size of radiator is adjusted to get "coolant time in the
> radiator".
>
> ****************
>
> Yes, a oil-cooled tubeset is a parallel path. It may be that one tube
> runs hotter and measures must be taken. I hope not. Maybe a piece of
> pipework may be pinched slightly to compensate.
>
> I think I have most of the "cooling stuff" in the ballpark. I won't be
> spending much more time on it unless I find a show-stopper or someone
> else does, so if anyone has a well thought out show-stopper I'd be keen
> hear it!
>
> Note for readers just joining
> ************************************
>
>
>
> ------------------------------
>
> Message: 3
> Date: Wed, 1 Apr 2015 10:13:23 -0700
> From: Kathy Bookmiller via Amps <amps at contesting.com>
> To: "Amps at contesting.com" <Amps at contesting.com>
> Subject: [Amps] Meter replacement
> Message-ID:
> <1427908403.53572.YahooMailBasic at web120902.mail.ne1.yahoo.com>
> Content-Type: text/plain; charset=us-ascii
>
> Hello,
> I'm fixing up an old Hunter Bandit 2000C. It has one problem left to solve and that is to replace a smashed panel meter. The one that measured plate voltage and current.
> The original meter was made by Ammon instruments of Manchester NH. It has am-2 on the face plate, which I assume was the model number.
> I found two Ammon meters on Ebay that are the same size and style physically and one of them even has the same am-2 on the face plate (the other one's picture doesn't show this)
> I guess my question is, how does one know is this meter will be the same movement. At one time I knew this stuff, but years have dimmed my memory of meter shunts, etc. Out of curiosity, I put my VOM across the terminals of the broken meter and it measures 90 ohms.
> What I hope to do is replace the face plate with my old one and have one that matches the style of the other meter that is used for a watt meter.
> The old one's scales are for 0-3000 volts and up to an amp. current.
> Anyone still remember their analog meter theory and practice?
> Thank you,
> Kathy, W2NK
>
>
>
> ------------------------------
>
> Message: 4
> Date: Wed, 1 Apr 2015 11:22:14 -0600
> From: MU 4CX250B <4cx250b at miamioh.edu>
> To: Bill Turner <dezrat at outlook.com>
> Cc: Amps group <amps at contesting.com>
> Subject: Re: [Amps] more - oil bath GS-35b
> Message-ID: <515673277809306087 at unknownmsgid>
> Content-Type: text/plain; charset=UTF-8
>
> I haven't thought about this deeply, but I'm thinking the rate of heat
> transfer to the oil bath depends only on the temperature difference
> between the oil (adjacent to the tube anode) and the anode
> temperature, as well as the thermal impedance of the tube-oil
> interface. Speeding up the oil flow ensures that cool oil is always
> present at the interface, thus maximizing the temperature difference
> and optimizing heat transfer.
>
> The same reasoning applies to the oil-radiator system, but in reverse.
> Here one wants hot oil and a cool radiator, since that maximizes the
> heat transfer from the oil to the external environment.
>
> There are a few other considerations influencing cooling (such as the
> thermal conductivity of the oil, as well as its specific heat
> coefficient), but those are generally not under the control of the
> builder. Ideally one wants oil with the thermal conductivity of
> diamond, and a swimming pool-sized oil reservoir, but good luck with
> that!
> 73,
> Jim w8zr
>
> Sent from my iPad
>
>> On Apr 1, 2015, at 9:20 AM, Bill Turner <dezrat at outlook.com> wrote:
>>
>> ------------ ORIGINAL MESSAGE ------------(may be snipped)
>>
>> On Mon, 30 Mar 2015 17:20:50 +1300, Gary and Steve wrote:
>>
>>
>>>> You do not need to slow the flow down in order to pick up heat. The faster
>>>> the flow the more heat will be transferred.
>>>
>>> Correct! The faster the oil flow in the tube cooler, the better the
>>> cooling.
>>>
>>> But not so for the radiator. The oil must slow down and be in the
>>> radiator for a finite time for the heat to be transferred from the oil
>>> to the air.
>>
>> REPLY:
>>
>> "But not so for the radiator."?
>>
>> There seems to be something wrong with the logic here. Heat transfer
>> doesn't care whether it goes from the tube to the oil or from the oil
>> to the radiator, does it? By your logic, if you slow the oil through
>> the radiator down to very, very slow the heat transfer will be better.
>> But then the tube will overheat and burn up.
>>
>> Likewise, if you slow down the oil past the tube, the heat transfer
>> will be maximum, but again the tube will overheat and burn up.
>>
>> Can't both be right. I think faster is better for both tube and
>> radiator.
>>
>> Any heat transfer engineers out there?
>>
>> 73, Bill W6WRT
>> _______________________________________________
>> Amps mailing list
>> Amps at contesting.com
>> http://lists.contesting.com/mailman/listinfo/amps
>
>
> ------------------------------
>
> Message: 5
> Date: Wed, 1 Apr 2015 10:35:19 -0700
> From: "Jim Thomson" <jim.thom at telus.net>
> To: <amps at contesting.com>
> Subject: [Amps] more - oil bath GS-35b
> Message-ID: <A7976B3F1B3D438FABE9BA1BB8DCD416 at JimPC>
> Content-Type: text/plain; charset="UTF-8"
>
> Date: Wed, 1 Apr 2015 16:37:16 +0100
> From: Chris Wilson <chris at chriswilson.tv>
> To: Bill Turner <dezrat at outlook.com>, amps at contesting.com
> Subject: Re: [Amps] more - oil bath GS-35b
> Message-ID: <905754433.20150401163716 at chriswilson.tv>
> Content-Type: text/plain; charset=us-ascii
>
>
> There are optimum flow rates based on heat exchanger coolant medium,
> be it gaseous, or fluid, the type of liquid, and its viscosity. It
> also depends on the surface area of the inside and outside elements of
> the exchanger and the device being cooled. For sure faster flow is
> *NOT* necessarily better. In automotive racing water (or water mix)
> coolant is NOT flowed as fast as possible through the engine, but very
> careful design has water flow going at different rates in different
> parts of the engine. Those who have replaced a cylinder head gasket
> may have noticed the flow restriction hoses of varying sizes in the
> head and gasket. Different areas of the engine run at different
> temperatures, and flow rate is varied to optimize heat extraction.
> Water to air radiators have internal turbulators in high end coolers
> to increase internal surface areas, thermostats have restrictor plates
> to control water flow rates. Current cooling systems use electronic
> water pump drives and electronic thermostats to optimize flow
> according to load, blah blah.
>
> Air flow through heat exchangers is similarly regulated for optimum
> heat exchange speeds.
>
> I am sure in an oil to air heat exchanger with a submerged valve there
> will be an optimal flow rate for the oil and the air, that is far away
> from the fastest flow rate, and there are big differences between
> convection, conduction and radiation. I am most definitely *NOT* a
> heat transfer engineer, but I am a race car engineer and I know a lot
> of science and experimentation goes on in the engine world to maximize
> heat exchanger performance, and engine coolant flow is a lot slower
> than you perhaps imagine.
>
>
> --
> Best regards,
> Chris mailto:chris at chriswilson.tv
>
> ### Us hot rodders run into this exact same issue with superchargers on V8 engines.
> The intercooler is just a small radiator, typ bar + fin type... placed on the hot output
> of the supercharger. Its job is to EXTRACT heat. A small pump passes the distilled
> water /glycol mix to the HE, aka heat exchanger..aka rad # 2. The HEs job is to DUMP heat.
> Mine doesn?t have a fan on the HE,but simply relies on airflow due to vehicle speed.
> Some will use dual fans on the HE, to keep things cooled down a bit at red lights,
> and also between runs at the drag strip etc. For road course folks, the fans don?t provide
> any benefit once above 20-30 mph. They impede airflow.
>
> ## faster pump speeds will make the intercooler work better..and extract more heat,
> BUT the entire assy is one big loop. Pump the hot water/glycol coolant through the
> intercooler-HE loop too fast, and all you end up doing is spinning hot water around,
> with no increase in eff at all. Unless the HE (external radiator in the case of the GS35B)
> can dump the heat as fast as its being generated, you are wasting your time with faster pump speeds.
>
> ## 1 watt = 3.15 BTU. 1 kw = 3150 BTU In the case of the proposed GS35B
> setup, 1-2 kw CCS of heat to extract..then dump is not a big issue. And with
> ssb /cw modes, the heat generated is going to be a lot less. Beware of advertised GPM
> flow rates on pumps. They are typ for no load. IE: fire hose connected from 55 gallon
> drum of water, to input of pump.... then another big diam hose from output to the ground.
>
> ## Once actually hooked up to the tight bends and puny size fittings, small tubing, and
> the restrictions inside the GS35B tube and the external radiator, the actual measured flow rates
> drop like a rock. Install a much bigger pump, and flow rates typ increase very little
> if any.
>
> ## check out the BTU specs for small radiators...like automatic transmission coolers.
> They are typ 8000-20,000 BTU rated..provided airflow of XXX CFM is put through em.
> I had to install a 2nd auto tranny cooler in series with my oem cooler, since the tranny temps
> climbed way too fast in just a few secs when super charger on..and gas pedal mashed. Like
> 170-200 F in just 7 secs.
>
> ## Old style radiators were tube + fin type. Better types are bar + plate. You can also get em
> in single, dual or triple core..and also single and dual pass. My bar + plate Tranny cooler uses a unique
> T stat......operates on viscosity. The hotter the synthetic tranny fluid gets, the higher it rides up either side
> of the rad. At that point it makes more and more parallel passes from one side to the other.
>
> ## The GS35B, with its low dissipation, will not be an issue. Perhaps 2-5000 btu at most.
> Ultimately... ALL the heat has to be eventually transferred to the air ! BTW, you will have to provide
> some cooling to the base seals of the tube, where the fil connections are made. With Eimac water cooled
> tubes, or vapor phase cooled tubes, a small air pump, is used to cool the fil pins.
> Same deal with a normal air cooled tube which uses anode to base flow.... instead of the usual base to anode flow,
> typ 3-5 cfm on a 3CX-3000A7. But uses anode to base flow ...nobody..its fubar and requires way more cfm.
> The additional air flow to the base will not be required if the entire tube is immersed in oil, like you proposed.
>
> ## A 2-4 GPM pump will more than meet your requirements. Then perhaps a pair of 120 mm square
> fans, like the 65 cfm rotron whisper types.. placed in front of the external rad. They are very quiet, and can be
> further lowered in speed with a simple metal finned resistor, variac, variable dc supply etc. Shroud the front of the
> rad, where the fans are... other wise you are wasting your time... air will leak like a sieve out the sides.
> Un shrouded rads don?t work too well. IMO, you are better off pushing air through the rad, vs sucking
> it through the back end of the rad. Then you don?t have hot air passing in and out past the fan bearings.
>
> later.... Jim VE7RF
>
>
>
>
>
>
> ------------------------------
>
> Message: 6
> Date: Wed, 1 Apr 2015 12:07:42 -0700
> From: Bill Turner <dezrat at outlook.com>
> To: Amps group <amps at contesting.com>
> Subject: Re: [Amps] more - oil bath GS-35b
> Message-ID: <BLU436-SMTP188E77DF89A601D05497B54C0F30 at phx.gbl>
> Content-Type: text/plain; charset="us-ascii"
>
> ------------ ORIGINAL MESSAGE ------------(may be snipped)
>
>> On Wed, 1 Apr 2015 11:22:14 -0600, W8ZR wrote:
>>
>> I haven't thought about this deeply, but I'm thinking the rate of heat
>> transfer to the oil bath depends only on the temperature difference
>> between the oil (adjacent to the tube anode) and the anode
>> temperature, as well as the thermal impedance of the tube-oil
>> interface. Speeding up the oil flow ensures that cool oil is always
>> present at the interface, thus maximizing the temperature difference
>> and optimizing heat transfer.
>
> REPLY:
>
> You said it better than I did. Sounds right to me.
>
> 73, Bill W6WRT
>
>
> ------------------------------
>
> Message: 7
> Date: Thu, 02 Apr 2015 08:13:41 +1300
> From: Steve Wright <stevewrightnz at gmail.com>
> To: amps at contesting.com
> Subject: Re: [Amps] more - oil bath GS-35b
> Message-ID: <551C4365.4000605 at gmail.com>
> Content-Type: text/plain; charset=windows-1252; format=flowed
>
> Thanks greatly Chris for your additions there. It would have been a lot
> of work for me to make clear examples like that, but you see them
> regularly so can comment concisely. Most of my lessons learned about
> cooling have been from the automotive world, in particular, pushing the
> coolant through the radiator so fast, that the radiator cannot extract
> the heat from it. I've added a few comments to your words - if one of
> them is glaringly wrong, do feel free to put your big boot on top of the
> offending section! Best regards mate! ;)
>
>> On 02/04/15 05:00, chris at chriswilson.tv wrote:
>> There are optimum flow rates based on heat exchanger coolant medium [...]
>
>> [...] depends on the surface area of the inside and outside elements
>> of the exchanger and the device being cooled.
>
>> Different areas of the engine run at different temperatures, and flow
>> rate is varied to optimize heat extraction.
>
> Flow rates can easily be managed in parallel circuits by using
> restrictors and valving. Flows depend on the type of exchanger, cooling
> or heating. In serial circuits, flow (coolant time) is managed by tube
> size or length.
>
>
>> For sure faster flow is *NOT* necessarily better. In automotive racing
>> water (or water mix) coolant is NOT flowed as fast as possible through
>> the engine, but very careful design has water flow going at different
>> rates in different parts of the engine.
> Race cars must not undercool some part, but may not throw loads of
> energy at the problem when that loss of power may cost them the race.
> Correspondlingly, in the shack we won't run fans and pumps at full speed
> because they are noisy, and may be counterproductive.
>
>
>> thermostats have restrictor plates to control water flow rates.
>> Current cooling systems use electronic water pump drives and
>> electronic thermostats to optimize flow according to load, blah blah.
>> Air flow through heat exchangers is similarly regulated for optimum
>> heat exchange speeds.
> The thermostat must not open and blow hot coolant through the radiator
> at high velocity, or there will not be enough time for the heat to be
> removed.
>
>
>> I am sure in an oil to air heat exchanger with a submerged valve there
>> will be an optimal flow rate for the oil and the air, that is far away
>> from the fastest flow rate [...]
> Slower is better. Monitor the output temperature of the radiator and
> throttle coolant flow, but then there must be adequate coolant flow for
> the tubeset. Size of radiator is adjusted to get "coolant time in the
> radiator".
>
> ****************
>
> Yes, a oil-cooled tubeset is a parallel path. It may be that one tube
> runs hotter and measures must be taken. I hope not. Maybe a piece of
> pipework may be pinched slightly to compensate.
>
> I think I have most of the "cooling stuff" in the ballpark. I won't be
> spending much more time on it unless I find a show-stopper or someone
> else does, so if anyone has a well thought out show-stopper I'd be keen
> hear it!
>
> Note for readers just joining
> ************************************
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