Pipe support bottom temp

[Binoi]

Dear All,

i want to calculate temp on bottom of pipe shoe.I have Outside temp 20 degc,Pipe temp- 420 deg c and length of shoe-0.2m,width of shoe- 0.3m,thickness of shoe- 0.01m.Please help me out how i can arrive tempearure on bottom pipe shoe.

thanks in advance

 

[SNORGY]

What are:
(1) the diameter of the pipe
(2) the thickness and type of insulation on the pipe
(3) the height of the shoe (from which you will know the exposed area available for heat dissipation to ambient)
(4) the pipe and shoe materials (I assume it is not A106B pipe, for example, since 420 C is at or near the graphitization threshold for that material)
If you can, sill some water onto the exposed top surface of the shoe. If it doesn't boil off immediately, I'd be inclined to say its not hot enough to matter in the overall scheme of things.

 

[Binoi]

Dia-6 inch
thickness- 10mm
Mineral wool
Material - Low carbon steel

thanks
Binoi

 

[Binoi]

i have found some excel sheet showing some caluclation but i dont know what it is exactly in which heat and mass transfer formula



Te = Outside tEMP,


TO = Temp.Pipe





T
L **
l



TL = Temp. on Bottom


Temperature on Shoe ( bottom) L ** = Length Outside insulation


-ml
TL = Te + ( To - Te ) e


e = 2.718 ( Always )
p = 2 ( l +t )
s = l x t
he = 10 Kcal/h m2 C° ( Always )
y = 40 Kcal/h m2 C° ( for Low Carbon Steel )



l = 0.3 M Te = 20 °C
L = 0.2 M TO = 420 °C
T = 0.01 M
p = 0.62
s = 0.003 M2


M= SQURT he x p / y x s= 7.187953 e^-mL= 0.2375



TL = 115.0138838 C°

Let me know is it correct formula where is formula taken from.

 

[SNORGY]

I question the insulation thickness of 10 mm.

My initial guess was about 100 C on the pipe shoe...based solely and purely on knowing what I have occasionally burned myself on around hot steam lines (or hidden tracers) in the field.

On that basis the formula seems reasonable.

I will do some research.

 

[SNORGY]

Binoi,

Does this help at all?

http://books.google.ca/books?id=G1t...ulate heat loss from pipe shoes escoe&f=false

thread378-289166

 

[Binoi]

Dear Snorgy,

Thanks a lot thats what i am looking for many thanks to you for your kindness.

thanks a lot
Binoi.S

 

[SNORGY]

No worries. Glad to help.