9.9.Blowers are used with many diesel engines to supply the air necessary for combustion to the
engine’s cylinders. When the pressure of this air is increased above atmospheric pressure,
referred to as supercharging, the power output of engine is increased. In addition, in a two-stroke
engine the air supplied by the blower helps to purge the engine’s cylinders of exhaust gas. This is
referred to as scavenging. Based on these descriptions, please specify the correct statement.
(A)The scavenging and supercharging processes share identical purpose of increasing the static
pressure in the intake pipes.
(B)The use of blow for scavenging and supercharging is due to its characteristics of high-pressure
and low volumetric flow rate.
(C)The blower for marine application is always the centrifugal type as it offers the high speed
(D)The scavenging in a two-stroke engine assists to purge the engine’s exhaust gas which has
beneficial effect for combustion.
20.20.Which type of boiler depends on the heat input to establish differential densities between the
steam-and-water mixture flowing in the riser or generating circuits and the water flowing downward
in the downcomer circuits?
(D)Two-furnace, forced circulation superheat
21.21.When the fluid is moved over the heat transfer surface by an external force, such as that provided
by a pump, which type of heat transfer is referred to?
(C)Centrifugal heat transfer
22.22.Which phenomenon will take place in a steam turbine when the nozzle-passing frequency stimulus
is coincident with a turbine blade natural frequency?
40.40.Which device in the fuel injection system of a diesel engine has a spring loaded fuel valve mounted
on the fuel nozzle?
(B)Fuel injection pump
(C)Plunger pump driven by camshaft
(D)Discharge check valve