Free Discharge (Liquid to Gas) Loss Coefficients
Free Discharge (Liquid to Gas) Loss Coefficients
(OP)
Hello All,
My question is, are there any losses associated directly with the exit of a pipe when liquid flows from the pipe to a gas, as with a garden hose?
I am trying to model a fluid network that discharges liquid to the atmosphere from a small pipe (40mm - 50mm diameter), I have the pipe frictional losses accounted for. I am aware that there are loss coefficients associated with inlet/outlet losses of a submerged pipe but what about an un-submerged pipe? Are the losses negligible? What is the pressure at the end of the pipe, at the min I am assuming it is atmospheric, is this suitable for the purposes of modelling such a scenario?
Kind Regards.
My question is, are there any losses associated directly with the exit of a pipe when liquid flows from the pipe to a gas, as with a garden hose?
I am trying to model a fluid network that discharges liquid to the atmosphere from a small pipe (40mm - 50mm diameter), I have the pipe frictional losses accounted for. I am aware that there are loss coefficients associated with inlet/outlet losses of a submerged pipe but what about an un-submerged pipe? Are the losses negligible? What is the pressure at the end of the pipe, at the min I am assuming it is atmospheric, is this suitable for the purposes of modelling such a scenario?
Kind Regards.





RE: Free Discharge (Liquid to Gas) Loss Coefficients
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"Pumping accounts for 20% of the world's energy used by electric motors and 25-50% of the total electrical energy usage in certain industrial facilities."-DOE statistic (Note: Make that 99% for pipeline companies) http://virtualpipeline.spaces.live.com/
RE: Free Discharge (Liquid to Gas) Loss Coefficients
Depending on where you measured your upstream pressure this might have to be regarded as a loss. If the upstream pressure was measured in a pressurised tank upstream of the pipe then some of that pressure would have to be used in accelerating the water (one velocity head). However, if you measured the upstream pressure in the pipe then the acceleration loss would have already been suffered and you would only be interested in the friction loss along the pipe and fittings.
In a free jet exit like this there is no additional exit loss the way there is in a sudden pipe expansion because the jet retains its diameter and there is no chance of eddies or detached boundary layers.
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