"Compression Ratios" for pumping liquids
"Compression Ratios" for pumping liquids
(OP)
In compressible flow we use the very useful concept of "compression ratios" as a shorthand notation for the ratio (in absolute terms) of a compressor discharge pressure to the suction pressure. This ratio has significant physical characteristics in addition to being very concise for communications.
When talking about the differential head in a pump, does anyone know of a similar widely used term? When I talk about a centrifugul pump operating at 2-3 "ratios" per stage I get a blank stare because "ratios" implies "compression ratio" and most liquids are largely incompressible at low differential head. Calling it a "lift ratio" gets me even more blank stares.
When talking about the differential head in a pump, does anyone know of a similar widely used term? When I talk about a centrifugul pump operating at 2-3 "ratios" per stage I get a blank stare because "ratios" implies "compression ratio" and most liquids are largely incompressible at low differential head. Calling it a "lift ratio" gets me even more blank stares.
David Simpson, PE
MuleShoe Engineering
www.muleshoe-eng.com
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RE: "Compression Ratios" for pumping liquids
i would definitely have a quizical or questionable facial appearance and would ask for clarification.
regarding gas compressor terms, your statements are understandable.
good luck.
-pmover
RE: "Compression Ratios" for pumping liquids
PUMPDESIGNER
RE: "Compression Ratios" for pumping liquids
RE: "Compression Ratios" for pumping liquids
The reason why you talk of compression ration with gasses is that this is fairly constant with no regards to initial pressure but only for a limited inlet pressure range.
For a pump however the HEAD (as it is called) is constant when measured in height of liquid collumn - regardless of inlet pressure and medium. Providing that the casing dosnt burst i has the same head regardless of the inlet pressure beeing 1 or 10 barg.
The head is allways the same regardsless of liquid properties - but the outlet pressure (or even perssure rise) is no: Eg a pump with a head of 10 m (at a given flow rate) and a inlet pressure of 0 barg will have a outlet pressure of 1 barg when pumping water (density=1000 kg/m3) but out 0.8 barg if pumping a oil with a density of 800 kg/3m)
Best regards
Morten