Question 674Steam Plants - Assistant Engineer70% to pass
Steam passing through a multi-stage impulse turbine does not impart any appreciable axial thrust to the rotor. This is primarily due to the _______________.
AI Explanation
The correct answer is C) equalizing holes provided in the turbine wheel.
The equalizing holes in the turbine wheel allow the pressure on both sides of the wheel to equalize, preventing any appreciable axial thrust from being imparted to the rotor. This is because the pressure drop across the moving blades is balanced by the pressure drop through the nozzle diaphragms, resulting in a net zero axial force on the rotor.
The other answer choices are incorrect because:
A) The dummy piston and cylinder arrangement is not the primary reason for the lack of axial thrust.
B) The decreasing steam velocity through the nozzle diaphragms does not directly prevent axial thrust.
D) The pressure drop through the moving blades is not the main factor in preventing axial thrust.
Related Questions
#672 Which of the following statements represents the function the nozzle assembly performs in an impulse turbine? #673 The labyrinth packing ring in an interstage diaphragm of an impulse turbine is prevented from rotating by _______________.#675 In an impulse turbine, the fixed blades function to _______________.#676 The purpose of shroud bands secured to the tips of the turbine blades is to _______________.#677 Tenon peening is a technique employed by turbine manufacturers to _______________.