jimhokie
Mechanical
- Feb 16, 2005
- 50
I need to size a steam blowdown line to vent a pressure vessel initially at 100 psig. The flow will be initiated by opening a butterfly valve in the line near the pressure vessel. The blowdown line will be on the order of 10 to 15 feet long, then dump into a 36" duct. The backpressure at this point will be on the order of 20 psig. I expect the flow to choke either across the open butterfly valve or where the blowdown line joins the larger 36" duct.
I need to determine what size the blowdown line needs to be (as small as is feasible due to space limitations) such that it can pass at least 350 lbm/sec saturated steam (~40% quality). All the literature I read on the subject deals with pretty nozzles or clean orifices. How do I go about estimating mass flow capability vs. size in a real world pipe with a butterfly valve, a few bends, and an exit into a larger duct? Also, any thoughts on whether the choke point would be at the valve or at the exit into the larger duct?
Any assistance offered will be greatly appreciated!
I need to determine what size the blowdown line needs to be (as small as is feasible due to space limitations) such that it can pass at least 350 lbm/sec saturated steam (~40% quality). All the literature I read on the subject deals with pretty nozzles or clean orifices. How do I go about estimating mass flow capability vs. size in a real world pipe with a butterfly valve, a few bends, and an exit into a larger duct? Also, any thoughts on whether the choke point would be at the valve or at the exit into the larger duct?
Any assistance offered will be greatly appreciated!