Turbo Machinery · Turbo Machinery · GATE ME
Marks 1

The magnitude of absolute velocity at entry is $$300$$ $$m/s$$ at an angle of $${65^0}$$ to the axial direction, while the magnitude of the absolute velocity at exit is $$150$$ $$m/s.$$ The exit velocity vector has a component in the downward direction. Given that the axial (horizontal) velocity is the same at entry and exit, the specific work (in $$kJ/kg$$) is ______________.
Column $$I$$
$$P:$$ Centrifugal compressor
$$Q:$$ Centrifugal pump
$$R:$$ Pelton wheel
$$S:$$ Kaplan turbine
Column $$II$$
$$1:$$ Axial flow
$$2:$$ Surging
$$3:$$ Priming
$$4:$$ Pure impulse

Marks 2
Consider a Pelton wheel of 1 m diameter. The magnitude of relative velocity of water at the bucket inlet is same as the magnitude of relative velocity of water at the bucket exit. The absolute speed of water at the bucket inlet is $125.66 \mathrm{~m} \mathrm{~s}-1$. For maximum power output from the Pelton wheel, the rpm of the Pelton wheel is_______ (rounded off to 1 decimal place).
Consider an air-standard Brayton cycle with adiabatic compressor and turbine, and a regenerator, as shown in the figure. Air enters the compressor at 100 kPa and 300 K and exits the compressor at 600 kPa and 550 K. The air exits the combustion chamber at 1250 K and exits the adiabatic turbine at 100 kPa and 800 K. The exhaust air from the turbine is used to preheat the air in the regenerator. The exhaust air exits the regenerator (state 6) at 600 K. There is no pressure drop across the regenerator and the combustion chamber. Also, there is no heat loss from the regenerator to the surroundings. The ratio of specific heats at constant pressure and volume is $c_p/c_v$= 1.4. The thermal efficiency of the cycle is ________% (answer in integer).

Marks 5
(a) Find the power developed by the model assuming the efficiencies of the model and the proto-type are equal.
(b) Find the ratio of the heads and the ratio of mass flow rates between the proto-type and the model.
Power developed $$=430$$ $$kW;$$
Operating head $$=300$$ $$m;$$
Speed $$=600$$ $$rpm.$$