STEAM FLOW
STEAM FLOW
(OP)
I have a question about steam flow...
I have recieved specs from a steam turbine generator that the steam leaving it is at 4000 lb/hr. To find the velocity I simply divide by its density and the cross sectional area.
This steam is then going to be condensed to water. It seems that the mass flow rate should be constant and we will have 4000 lb/hr of water. And to find the velocity we do the same as above. but since water is some much more dense than steam there is a big difference in velocities in the pipe.
for example if i had 4000 lb/hr of steam at 100 psig, 0.25 lbm/ft3 going through a 1 ft diameter pipe the velocity is 5.6588 ft/s. When it condenses to liquid with 60.271 lbm/ft3 the calculated velocity is 0.023 ft/s.
Is this correct? is the mass flow rate of steam the same for water? what other factors are at work?
Thank you for any advice or references anyone can refer me to.
I have recieved specs from a steam turbine generator that the steam leaving it is at 4000 lb/hr. To find the velocity I simply divide by its density and the cross sectional area.
This steam is then going to be condensed to water. It seems that the mass flow rate should be constant and we will have 4000 lb/hr of water. And to find the velocity we do the same as above. but since water is some much more dense than steam there is a big difference in velocities in the pipe.
for example if i had 4000 lb/hr of steam at 100 psig, 0.25 lbm/ft3 going through a 1 ft diameter pipe the velocity is 5.6588 ft/s. When it condenses to liquid with 60.271 lbm/ft3 the calculated velocity is 0.023 ft/s.
Is this correct? is the mass flow rate of steam the same for water? what other factors are at work?
Thank you for any advice or references anyone can refer me to.





RE: STEAM FLOW
rmw
RE: STEAM FLOW
Doug
RE: STEAM FLOW
DKM, give us a little more description of your process, please. It might help us to better be able to offer meaningful advice. I still stand by my initial reply, however. Given your question, that is where I would start (or with a good set of steam tables.)
rmw
RE: STEAM FLOW
RE: STEAM FLOW
I assure you though the first places i looked was literature. I have 4 books on thermo and two on fluid and after looking through them the above is what i concluded. This forum was my last effort to get a proffesional opinion of what i have concluded.
The actual application is for a condenser and I am trying to get an idea of the flow of the steam and water in the tubes, constant diameter.
RE: STEAM FLOW
you will not ever see "steam and water" flowing in the "constant diameter" tubes - that's where the cooling water stays as a fluid.
For your problem, you're mixing up the inlet flow conditions (4000 lbm/hr steam at 100 psig in an unknown pipe diameter) with the outlet of the turbine conditions (12" dia pipe - AFTER the "work" of the turbine has been extracted by removing enthalpy at an unknown pressure and temperature for saturated water of unknown quality) with the condensate water conditions (still at 4000 lbm/hr water at some unknown pressure and temperature in an unknown diameter pipe) with the COOLING water conditions (an unknown nbr of tubes at an unknown diameter of unknown wall thickness pipe conducting an unknown mass of cooling water at an unknown pressure and temperature (unknown Reynolds nbr and unknown roughness factor further fouling up your problem.)
RE: STEAM FLOW
The condenser that we use is air cooled. the steam is distributed into the tubes and condenses and leaves the tubes as water. the steam/water is condensed inside the tubes and air cooles them on the outside.
RE: STEAM FLOW
RE: STEAM FLOW
The water that condenses naturally flows by gravity to the lower parts of the condenser (in the tubes with the steam that is entering and condensing all the while) where it is collected and pumped out. And yes, those lines are much smaller than the steam lines by several orders of magnitude.
Sorry for my initial response but your OP was pretty rough and I didn't want to waste time trying to explain engineering stuff to a non engineering professional. This site has lots of those. If you have 4 thermo books, you are ahead of me. Go to the head of the class. If you hadn't known what a thermo book was, I wouldn't have posted this.
rmw