Steam Nozzles and Turbines Questions

• The pressure velocity compounded impulse turbine allows a bigger pressure drop and hence __________ number of stages are required.
• In velocity compounding of an impulse turbine, the expansion of steam takes place in a nozzle or a set of nozzles from the boiler pressure to condenser pressure.
• If the critical pressure ratio for steam is 0.546, then the steam is initially
• In a Parson's turbine stage, blade velocity is 320 m/s at the mean radius and rotor blade exit angle is 30°. For minimum kinetic energy of the steam leaving the stage, the steam velocity at the exit of the rotor will be
• In an impulse turbine, steam expands
• A nozzle is said to be a convergent-divergent nozzle, when the cross-section of a nozzle first decreases from its entrance to throat and then increases from its throat to exit.
• In an ideal impulse turbine, the
• The effect of bleeding is that
• A single stage turbine is not used because it requires large reduction gearing due to very high rotational speed.
• Which of the following statement is wrong?
• During flow through a nozzle, no heat is supplied or rejected by the steam.
• Which of the following statement is correct?
• Steam turbines may be classified according to
• In a nozzle, the effect of supersaturation is to increase the dryness fraction of steam.
• In a nozzle, the effect of supersaturation is to
• For a Parson's reaction turbine, if α1 and α2 are fixed blade angles at inlet and exit respectively and β1 and β2 are the moving blade angles at entrance and exit respectively, then
• When the cross-section of a nozzle __________ continuously from entrance to exit, it is called a convergent nozzle.
• The efficiency of an impulse turbine is maximum when (where Vb = Blade speed, V = Absolute velocity of steam entering the blade, and α = Nozzle angle)
• The expansion of steam in a nozzle follows
• In a 50% reaction turbine stage, tangential component of absolute velocity at rotor inlet is 537 m/s and the blade velocity is 454 m/s. The power output in kW of steam will be