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Re: [Amps] Amps Digest, liquid cooling.

To: "amps@contesting.com" <amps@contesting.com>
Subject: Re: [Amps] Amps Digest, liquid cooling.
From: David Lisney <g0fvt@hotmail.com>
Date: Wed, 1 Apr 2015 20:54:05 +0100
List-post: <amps@contesting.com">mailto:amps@contesting.com>
 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@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@earthlink.net>
> To: "'Alex Malyava'" <alex.k2bb@gmail.com>,    "'Amps Group'"
>    <amps@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@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@contesting.com
> http://lists.contesting.com/mailman/listinfo/amps
> 
> 
> 
> ------------------------------
> 
> Message: 2
> Date: Wed, 01 Apr 2015 11:08:26 -0600
> From: Tom Thompson <w0ivj@tomthompson.com>
> To: Gary Schafer <garyschafer@largeriver.net>,    "'Steve Wright'"
>    <stevewrightnz@gmail.com>, amps@contesting.com
> Subject: Re: [Amps] more - oil bath GS-35b
> Message-ID: <551C260A.9040105@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@contesting.com] On Behalf Of Steve
>>> Wright
>>> Sent: Sunday, March 29, 2015 11:21 PM
>>> To: amps@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@contesting.com
>>> http://lists.contesting.com/mailman/listinfo/amps
>> _______________________________________________
>> Amps mailing list
>> Amps@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@contesting.com>
> To: "Amps@contesting.com" <Amps@contesting.com>
> Subject: [Amps] Meter replacement
> Message-ID:
>    <1427908403.53572.YahooMailBasic@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@miamioh.edu>
> To: Bill Turner <dezrat@outlook.com>
> Cc: Amps group <amps@contesting.com>
> Subject: Re: [Amps] more - oil bath GS-35b
> Message-ID: <515673277809306087@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@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@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@telus.net>
> To: <amps@contesting.com>
> Subject: [Amps] more - oil bath GS-35b
> Message-ID: <A7976B3F1B3D438FABE9BA1BB8DCD416@JimPC>
> Content-Type: text/plain;    charset="UTF-8"
> 
> Date: Wed, 1 Apr 2015 16:37:16 +0100
> From: Chris Wilson <chris@chriswilson.tv>
> To: Bill Turner <dezrat@outlook.com>, amps@contesting.com
> Subject: Re: [Amps] more - oil bath GS-35b
> Message-ID: <905754433.20150401163716@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@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@outlook.com>
> To: Amps group <amps@contesting.com>
> Subject: Re: [Amps] more - oil bath GS-35b
> Message-ID: <BLU436-SMTP188E77DF89A601D05497B54C0F30@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@gmail.com>
> To: amps@contesting.com
> Subject: Re: [Amps] more - oil bath GS-35b
> Message-ID: <551C4365.4000605@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@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@contesting.com>
> To: "Amps@contesting.com" <Amps@contesting.com>
> Subject: [Amps] Meter replacement
> Message-ID:
>    <1427908403.53572.YahooMailBasic@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@miamioh.edu>
> To: Bill Turner <dezrat@outlook.com>
> Cc: Amps group <amps@contesting.com>
> Subject: Re: [Amps] more - oil bath GS-35b
> Message-ID: <515673277809306087@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@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@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@telus.net>
> To: <amps@contesting.com>
> Subject: [Amps] more - oil bath GS-35b
> Message-ID: <A7976B3F1B3D438FABE9BA1BB8DCD416@JimPC>
> Content-Type: text/plain;    charset="UTF-8"
> 
> Date: Wed, 1 Apr 2015 16:37:16 +0100
> From: Chris Wilson <chris@chriswilson.tv>
> To: Bill Turner <dezrat@outlook.com>, amps@contesting.com
> Subject: Re: [Amps] more - oil bath GS-35b
> Message-ID: <905754433.20150401163716@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@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@outlook.com>
> To: Amps group <amps@contesting.com>
> Subject: Re: [Amps] more - oil bath GS-35b
> Message-ID: <BLU436-SMTP188E77DF89A601D05497B54C0F30@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@gmail.com>
> To: amps@contesting.com
> Subject: Re: [Amps] more - oil bath GS-35b
> Message-ID: <551C4365.4000605@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@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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