WorksheetsHeat exchanger:
Total questions: 15
Worksheet time: 8mins
In a shell-and-tube heat exchanger used as a jacket water cooler, the main reason seawater passes through the tubes is to:
Reduce fouling on shell surfaces
Allow easier cleaning and corrosion inspection
Maintain higher pressure on the cooling side
Prevent thermal shock on the tube plates
A plate-type heat exchanger transfers heat more effectively than a shell-and-tube type mainly because of its:
Larger surface area per volume
Higher seawater flow velocity
Thicker plates for better conduction
Use of double-pass circulation
The fundamental operating principle of any shipboard heat exchanger is to:
Mix two fluids of different temperatures
Exchange heat between fluids without mixing
Store thermal energy for later use
Convert heat into mechanical work
When the seawater temperature rises, the efficiency of a jacket water cooler typically:
Increases due to higher convection rate
Decreases due to reduced temperature gradient
Remains unchanged because flow is constant
Improves with lower pressure drop
Why is counter-flow arrangement commonly used in marine heat exchangers?
It achieves higher mean temperature difference
It minimizes thermal stress on tube plates
It equalizes fluid pressure on both sides
It prevents backflow of cooling water
Designers select counter-flow heat exchangers for shipboard cooling mainly to:
Enhance overall heat recovery efficiency
Simplify piping layout
Reduce fouling in seawater passages
Limit pressure variation across the shell
As seawater temperature increases, the performance of a jacket water cooler generally:
Improves from faster convection
Declines due to smaller temperature difference
Stays constant if flow rate is unchanged
Rises with reduced pressure drop
Counter-flow heat exchangers are commonly used onboard because they:
Increase turbulence along the flow path flow
Maximize the average temperature difference
Reduce pressure drop along the inner tubes
Minimize the frequency of cleaning
Designers select counter-flow heat exchangers for shipboard cooling mainly to:
Enhance overall heat recovery efficiency
Simplify piping layout
Reduce fouling in seawater passages
Limit pressure variation across the shell
A plate-type heat exchanger achieves higher heat transfer efficiency than a shell-and-tube type primarily due to its:
Greater surface area-to-volume ratio
Increased seawater flow rate
Thicker plates that enhance conduction
Incorporation of double-pass flow arrangement
The fundamental operating principle of any shipboard heat exchanger is to:
Mix two fluids of different temperatures
Store thermal energy for later use
Exchange heat between fluids without mixing
Convert heat into mechanical work
The ship’s air cooler in the main engine works on the same principle as a:
Condenser — removing latent heat
Cooler — removing sensible heat
Evaporator — adding heat to vapor
Reheater — increasing exhaust temperature
A heat exchanger begins to lose effectiveness when:
Flow velocity increases
Temperature difference widens
Heat transfer surfaces foul
Pressure drop decreases
The temperature difference between the fluids in a heat exchanger is maintained to:
Keep the fluids at equal flow rates
Control pressure differential
Drive heat transfer efficiently
Minimize corrosion potential
In a condenser used for the main engine FWG system, the latent heat of vapor is removed primarily by:
Radiation through the shell
Conduction through tube walls
Convection of cooling seawater
Combination of conduction and convection
