[AT] Airflow calculations of perforated metal for radiator screens

Fri Jun 18 02:55:57 PDT 2021

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> 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>
> Date: 6/17/21 11:34 PM (GMT-05:00)
> To: 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>
> 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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