Aircraft Power Plant - Turbine

In an axial flow turbine, the total temperature of the flow through nozzle always

• decreases

• increases

• remain constant

• None of the above

The space between two nozzle guide vanes form a

• Divergent duct

• Convergent duct

• Convergent - Divergent duct

• None of the above

For an axial flow turbine, absolute velocity at exit of the rotor is ______________ the same at the inlet.

• higher than

• lower than

• remain constant

• can't comment

The blade shroud is fitted in an attempt to

• reduces the vibration of the blades

• reduces gas leakage

• minimize losses due to to leakage across the turbine blade tips

• control the velocity of the gas stream

Definition of a free turbine or free power turbine

• has its own optimum speed

• a turbine which is not connected to the compressor

• it's connected only either to the propeller or to the rotor reduction gearbox

• All of the above

The power output of a turbine can be increased with an _____________ number of stages with a ________________ in turbine diameter.

• decrease, smaller

• increase, larger

• increase, reduction

• decrease, larger

It's a fact that the efficiency of the turbine blades ____________ as its rotational speed ______________.

(a)  

Turbine blades are classified into __________ types, namely _______________ .

• two: impulse and reaction

• three: impulse, reaction and impulse-reaction

• one: impulse-reaction

Within the convergent duct between the two nozzle guide vanes, some of the potential or pressure energy in the gas stream is converted to

• thermal energy

• kinetic energy

• velocity energy

• All of the above

On average the energy loss in the turbine is about _______ percent which comprised of approximately _______ percent aerodynamic losses in the _______________ and _______ percent in the ________________ .

(a)