[AT] Airflow calculations of perforated metal for radiator screens
Cecil Bearden
crbearden at copper.net
Fri Jun 18 06:32:22 PDT 2021
Ken: Have you tried these guys?? I use them a
lot...https://www.apairinc.com/
Cecil
On 6/18/2021 8:09 AM, Ken Knierim wrote:
> I got a $20 handheld anemometer from Amazon I use for measuring
> airflow now. Takes the guesswork out of it. I got it when my son built
> a wind tunnel project for school and now I use it when working on
> cooling calculations for my RF generators. Well, that and my pawn-shop
> FLIR camera. Now you can get a FLIR add on for a cell phone too. I got
> the FLIR when I was working on a 200kW RF system and for some reason I
> didn't want to put my hand in it to see where the hotspots were. Handy
> tools. :)
>
> Now I'm trying to figure out how to upgrade my old R-12 based R4
> compressor to a more modern and efficient Sanden compressor on my 86
> Blazer. Of course it worked when it was cooler but now that we're in
> the mid teens it's not keeping up. Around 118 and I had 90 degree air
> coming out. bleh. Already upgraded the fan clutch to the big-block
> version and that helped but that was before the heat got here.
>
> Ken in AZ
>
>
> On Fri, Jun 18, 2021 at 5:46 AM Cecil Bearden <crbearden at copper.net
> <mailto:crbearden at copper.net>> wrote:
>
> Steve:
>
> I remember all that and had to work with it in hydrology and flow
> calculations for the last 40 years. However for the last 10 I
> have had a computer program available that does all that stuff and
> all I have to do is plug in some numbers. Back when I was
> approving plans for new construction, I could look at an
> applications, the spillway size and the location and ddo it in my
> head....
> Cecil
>
> On 6/18/2021 4:55 AM, Stephen Offiler wrote:
>> I haven't done flow calculations in a long, long time, and Fluids
>> was not among my favorite subjects back in school... so with that
>> said, my gut feeling is that Mark's 56% blockage is probably
>> somewhere in the right ballpark but dependent on factors like
>> whether the airflow is laminar or turbulent, maybe Reynold's
>> numbers.... now I'm just spewing stuff I learned 40 years ago.
>> Mostly to say, there might not *be* a good way to calculate this
>> outside of a lab with a flow bench; really, the thing to do is
>> try it, and take measurements. No idea if you can see high-side
>> pressure while on the road but I doubt it. Any readouts for
>> coolant or trans temperatures?
>>
>> SO
>>
>>
>> On Fri, Jun 18, 2021 at 1:03 AM magreer67 <magreer67 at gmail.com
>> <mailto:magreer67 at gmail.com>> wrote:
>>
>> Wouldn't that be 56% blockage and 44% open to flow through?
>> Mark Greer
>>
>>
>>
>> Sent from my Verizon, Samsung Galaxy smartphone
>>
>>
>> -------- Original message --------
>> From: Cecil Bearden <crbearden at copper.net
>> <mailto:crbearden at copper.net>>
>> Date: 6/17/21 11:34 PM (GMT-05:00)
>> To: at at lists.antique-tractor.com
>> <mailto:at at lists.antique-tractor.com>
>> Subject: Re: [AT] Airflow calculations of perforated metal
>> for radiator screens
>>
>> The .188 diameter staggered pattern gives .444 sqin hole area
>> over a 1 sq in area. So I guess it would result in a 44%
>> blockage. However it would be tabout 5 inches from the
>> grille and then the A/C condensor sets about 6 inches back
>> from that. I think there would be sufficient room to pull air
>> from above and below. It just may cause some additional drag
>> at high speeds. I think I will try it and make it easy to
>> remove in case it blocks too much airflow. I have to do
>> something. Time and ability to work on this stuff gets more
>> valuable daily...
>> Cecil
>>
>> On 6/17/2021 7:48 PM, Brad Loomis wrote:
>>> The 455 diesel lawn tractor I use at work has a pull out
>>> screen ahead of the radiator. I'm not there so I can't
>>> measure it. But I will try tomorrow and report back. It does
>>> keep the foxtails, thistle, mustard, and whatever else I
>>> kick up out of the radiator.
>>> Brad
>>>
>>> On Thu, Jun 17, 2021 at 5:23 PM Cecil Bearden
>>> <crbearden at copper.net <mailto:crbearden at copper.net>> wrote:
>>>
>>> I had to wash the A/C condensor and radiator out on my
>>> 2011 Chevy truck
>>> yesterday before I could make a trip to pick up some
>>> auction items. I
>>> put the gauges on my a/c system and it showed 35 low and
>>> 350 high.
>>> before I did anything I went to the water hose and got
>>> it down to 150
>>> pretty quickly on the high side. The amount of bugs was
>>> crazy. I will
>>> have to remove the radiator and condensor to get them
>>> clean as there is
>>> no room to get anything in the front or behind the fan.
>>> I have one of
>>> those heavy cowcatcher style grill guards in the front.
>>> This truck has
>>> about 170K miles and has made 3 trips to Alaska, so it
>>> may have more
>>> bugs than usual, but the bugs and thi8stle seeds are
>>> terrible here and
>>> getting worse. I want to put a piece of perforated
>>> metal behind the
>>> grill guard to catch the bugs. If it cuts the air down,
>>> it can still
>>> come in between the screening and the grill. I don't
>>> think it will make
>>> a lot of difference in the amount of air entering the
>>> radiator, but
>>> maybe catch the bugs and fluffy crap in the air...
>>> When we figure
>>> airflow into a home, we cut the flow through a window in
>>> half when a
>>> screen is used. I am looking at a peforated metal
>>> with holes .188in
>>> in diameter and offset centers so it gets the most holes
>>> per square
>>> inch. Does anyone have any experience with this type
>>> of screening or
>>> have a formula to determine if it will cut the airflow
>>> too much. I think
>>> the area behind the grill guard and the grill is wide
>>> enough to keep
>>> from cutting down the air flow. Traveling down the road
>>> at 60mph it may
>>> deflect some air around the grill instead of through..
>>>
>>> I just don't want to have to remove this radiator
>>> again. I have to use
>>> a stepladder to work on the d&%$^d thing it is so tall.
>>> It is stock for
>>> that year, but the manufacturers want to see how far the
>>> drivers can
>>> jump to get into a pickup nowdays. I remember a 63 and
>>> 66 chevy 1/2 ton
>>> pickup we worked out of on the farm every day. Hauled
>>> 20 head of cows
>>> in a bumper trailer with no brakes into OKC
>>> Stockyards. Loaded 60
>>> bushels of wheat to haul to the elevator when the lines
>>> were long and
>>> the grain truck had not returned. Now, I have a 3/4 ton
>>> that I have to
>>> jump into or pull myself in with the steering wheel and
>>> 30 bushels of
>>> rye in the bed causes it to squat, with twice as much
>>> tire under it than
>>> the old ones had.. It doesn't ride all that much
>>> better, just cooler
>>> when the A/C works. OK rant off.....
>>>
>>> Cecil
>>>
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