dynamic compressors Flashcards
how to increase effieciency and capcity in single stage compressor
diffuser vanes fit to inside of the housing
increasing the speed in the single stage compressor will also increase the ______
volume
adding additional impellers also known as multistaging will have this effect
increase volume and overall pressure ratio
multistaging with intercooling between stages with 4-5 impellers can be achieved using this _____
bull gear
impeller is used to accelerate or decelerate
accelerate
volute and diffuser is used to accelerate or decelerate
decelerate
3 types of centrifugal casings
sectional
horizontally split
vertically split
casing usually on small units for low pressure ratio and small volumes
sectional
casing most easily removed and limited to less than 1000 psi
horizontally split
casing used for high pressure up to 10 000 psi
vertically split
3 types of impellers
open
semi closed
closed
impeller used in single stage and used in rough service environment
open
impeller used in single and multi stage or final stage stage in axial compressor. blades may be straight radial, backwards leaning
semi closed
impeller used in single and multi stage or final stage stage in axial compressor. enclosure of vanes allow you to achieve higher pressure ratio
closed
directs gas flow into the compressor or from one stage to the next
guide elements
controls compressor output and increase effieciency
inlet guide vanes
stationary guides in a compressor
diaphragm
result of the differential pressure between the impeller front and the back shroud
axial thrust
thrust load is on this end of the compressor
suction end
3 ways to minimize axial thrust
balance piston, thrust bearing, impeller arranged
where is the balance piston located
discharge end immediately behind last impeller
what end is the thrust collar installed
suction end
impeller arrangement for high pressure
back to back
impeller arrangement for maximum flow
double flow arrangement