surrounding air temperature close to a hot vessel. 1

[jtseng123]

I have a vertical 304SS vessel, 42" diameter 7' tall. No insulation in order to cool internal powder which is continuously flowing through. The estimated vessel skin temperature is about 900 F.
Our instrument supplier wants to know the air temperature 1' away and 2' away from the vessel to select proper instrument.
Considering ambient air is 80F with 3 MPH wind speed, can anyone advise the air temperature both 1' away and 2' away ?

 

[IRstuff]

Downwind or upwind?

A temperature rise results from the convective heat transfer equation. You would then diffuse that heat over some volumetric mass flow of air.

TTFN
faq731-376

 

[MintJulep]

And do not neglect radiation.

 

[jtseng123]

the flow is downward, it is catalyst powder, through this vessel then go into a storage tank. I am not a heat exchanger engineer, knowing the air is a good heat blocker, but to calcualte the temp when you stand 1' and 2' away, that got me.

 

[MiketheEngineer]

Almost impossible to answer. Go to Radio Shack and for about $70 buy an infrared thermometer. It is your best bet.

 

[jtseng123]

Plant is brand new, commissioning will be next year. We are requested to providing the temperature. I thought there will have some way to calculate, or a temperature profile curve to look for.

 

[IRstuff]

It ought not be that hard to construct a scenario, just depends on what you want to do.

Your comment about flow was confusing. I was referring to the 3 mph cooling air only.

TTFN
faq731-376

 

[jtseng123]

the wind will be considered parallell to the ground, sweeping through the vessel at 3 miles per hour.

 

[Twoballcane]

Why don't you tell them a max of 900F? At this temperature 1 or 2 inches away at worst case of no cross wind (natural convection) should be close, especially at the top of the vessel where the convection film is the thickest. At least you have margin.

Tobalcane
"If you avoid failure, you also avoid success."
“Luck is where preparation meets opportunity”
"People get promoted when they provide value and when they build great relationships"

 

[jtseng123]

it is one foot and two feet away.

 

[Twoballcane]

whoops sorry...dam eyes...getting too old...

Tobalcane
"If you avoid failure, you also avoid success."
“Luck is where preparation meets opportunity”
"People get promoted when they provide value and when they build great relationships"

 

[IRstuff]

The bulk air temperature is probably no worse than ~115°F, but the radiometric temperature is probably considerably higher, say, on the order of about 450°F at one foot. The equations appear to be quite messy. Radiometric temperature is highly dependent on the emissivity of the surface looking at your vessel and its emissivity.

TTFN
faq731-376