Heat generated by Gland Packing Calc? 2

[sprintcar]

Anyone have a easy way to determine the potential heat developed in a stuffing box or gland packing? I've got the rpm, swept area of packing, diameter of sleeve, etc. I'm trying to estimate the temperature rise of the flush water. I figure a kinetic coef of friction to be 0.1 worst case. Thanks! Keep the wheels on the ground
Bob
showshine@aol.com

 

[fredb]

Hello sprintcar

The heat generated at the packing is given by:

Q = f (pi sq)PN (D sq)L/Cj

where:
Q = Btu/min
f = coefficient of friction
P = liquid pressure at packing lb/in sq (gage)
N = Shaft speed (rpm)
D = Sleeve OD or packing ID in inches
L = Sleeve length covered by packing in inches
C = 12
j = Mechanical equivalent of heat, 778 ft lb/Btu

Typical coefficients of friction are:

Plain cotton = 0.22
TFE-impregnated asbestos = 0.17
Grease-lube asbestos = 0.10

 

[sprintcar]

THANKS!!!!! Keep the wheels on the ground
Bob
showshine@aol.com

 

[sprintcar]

Fred - I'm getting some weird results
Would you please run the following and see what you get?
f =.17
P = 125psi gland water pressure
N = 500 rpm
D = 11 inches
L = 5 inches
Thanks!
Keep the wheels on the ground
Bob
showshine@aol.com

 

[fredb]

Hi sprintcar

I get 6,789 btu/min, if you plug this into Q = m Cp (T2-T1)where m = mass flowrate Cp = specific heat of water then knowing your inlet water temp T1 you can solve for the outlet water temp = T2.

fredb

 

[sprintcar]

OK - had a problem with the spreadsheet - (missing () )
I'll add the Temp - I assume it's in Deg F, right?

Actually - this will work even better to determine the flow required to keep the water at a safe discharge temperature

Thanks again Fred!
Any other good stuff in your Pump Bag of Tricks?
email me direct if you'd like
showshine@aol.com Keep the wheels on the ground
Bob
showshine@aol.com