heat exchanger Flashcards
heat exchanger for gas to gas
intercool and aftercool
heat exchanger to liquid to gas
shell and tube
liquid or gas in the tubes of shell and tube heat exchanger
liquid
heat transfer through contact of the fluid with a metal surface
conduction
heat transfer as a result of movement of gas or fluid from a warm location to a cooler one
convection
rate conductor best to worst
metal, liquid, gas
metal
liquid
gas
heat transfer from electromagnetic wave moving across a space
radiation
flow path arrangement have both fluids flowing in the same direction
parallel flow
flow path much more efficient than parallel flow
counter flow
flow path that can create turbulance and used for efficiency
crossflow
flow path often using baffles
mixed flow
heat exchanger that has continually curving passage creating turbulance, scrubbing effect to reduce fouling and is true counterflow
spiral heat exchanger
efficiency of water tower depends on
area of water surface
length of contact time between air and water
relative humidity
water tower using fan
mechanical draft
water tower without fans
natural draft
mechanical cooling tower use fan to push air through the tower
force draft
mechanical cooling tower has fan at top of tower that pulls the air up
induced draft
induced draft or forced draft cooling tower is more efficicient
induced
heat exchanger for high pressure, low temperatures
double pipe
heat exchanger for higher pressure, high temperatures
shell and tube
tubesheet layout for most tubes
30 degrees
tubesheet layout for easy cleaning
45 and 90
tubesheet layout offers least resistance and least pressure drop
in line square
purpose of baffles
cause turbulence and provide support to tubes
dirty fluid in fixed tubesheet shell and tube heat exchanger
tube
dirty fluid in u tube heat exchanger
shell
2 determining factors of shell tube efficiency
tube length and shell diameter
standard for hydrotesting
1.5 times working pressure
