39.What is the main function of labyrinth packing in a steam turbine engine?
(A)To improve dynamic balance
(B)To increase critical speed
(C)To reduce vibration
(D)To minimize leakage of working fluid
36.When the situations occurred in the machine space that could affect the speed, maneuverability, power supply or other essentials for ensuring the safe operation of the ship, which authority should be informed as soon as possible?
(A)Chief marine engineer
(B)Captain
(C)The bridge
(D)Ship owner
36.The energy added by a pump to the liquid passing through it is often referred to as the total head, which
is equal to the total suction head of the liquid when it enters the pump subtracted from the total
discharged head of the liquid when it leaves the pump. With the total discharge and suction heads of 10
m and – 0.5 m, what is the total head of the pump?
(A)20 m
(B)10.5 m
(C)9.5 m
(D)5 m