Heat Exchangers Flashcards
Which flow path arrangement within a heat exchanger will reach equilibrium in tempature halfway between the two temperature extremes?
Parallel flow
Which flow path arrangement within a heat exchanger will reach the two temperatures extremes if given enough time?
Counter flow
What is the primary purpose of the fins on a dinner tube heat exchanger?
To increase surface area
What heat exchanger can have its capacity changed the easiest?
Plate
Within cooling towers, the heat exchanger is dependant on?
Evaporation
What is the purpose of the zinc anodes in a shell and tube heat exchanger?
To minimize electrolytic action (galvanic corrosion) within a shell and tube heat exchanger
Which baffle is used to reduce erosion by entering fluids?
Impingement
Is a fixed tube heat sheet heat exchanger limited to chemical cleaning on the shell side?
Yes
Which fluid should be “tube side” in a U-tube exchanger?
The clean fluid
On the tube side do you normally have Low pressure or High pressure fluid?
Typically on the tube side you have high pressure so the tubes don’t collapse on themselves
When the condition of fouling occurs with a heat exchanger, what symptoms are observed?
A drop in efficiency and an increase in pressure drop
Which methods of cleaning are suitable for tubes?
- Hot wash oil
- Mechanical
- Chemical
- High pressure water
Don’t use steam because it is too hot.
When rigging a tube bundle for a lift, where should you sling it?
From the Tube sheet and Baffles
When hydrostatic testing a heat exchanger for leaks, what pressure is used?
1 1/2 times the working pressure
What are the three basic means of heat transfer?
-Conduction
Transfer of heat from one molecule to another molecule through direct contact of the molecules
-Convection
When a fluid moves and mixes with another because of density differences caused by temperature differentials between two fluids
-Radiation
Electromagnetic waves moving across a space. It requires no medium of transport (no fluid or solid) and travels across a vacuum.
