Question No. 1 In which turbine tip leakage is a problem? Answer: Tip leakage is a problem in reaction turbines. Here, each vane forms a nozzle; steam must flow through the moving nozzle to the fixed nozzle. Steam escaping across the tips of the blades represents a loss of work. Therefore, tip seals are used…
Question No. 1 What is the function of a thrust bearing? Answer: Thrust bearings keep the rotor in its correct axial position. Question No. 2 What is done when cracks due to SCC or corrosion-fatigue are found? Answer: The damaged blade is usually replaced, as repairing is difficult. Question No. 3 What is a stage…
Question No. 1 In which section of the steam-turbine rotors is the problem of rotor failure mostly prevalent? Answer: Rotor failures occur mostly on the large low-pressure rotors. Question No. 2 In which turbines, is this pressure-velocity compounding principle employed? Answer: In the Curtis turbine. Question No. 3 What are the disadvantages of velocity compounding?…
Question No. 1 What is the possible cause of slow start up of a steam turbine? Answer: This may be due to high starting torque required by the driven equipment. Question No. 2 What is the remedy for rotor-surface cracking? Answer: Current rotor/shaft should be machined off (skin-peeling). Question No. 3 What is to be…
Question No. 1 What is the purpose of a turning gear? Answer: Heat must be prevented from warping the rotors of large turbines or high-temperature turbines of 400°C or more. When the turbine is being shut down, a motor-driven turning gearis engaged to the turbine to rotate the spindle and allow uniform cooling. Question No….
Question No. 1 What are the two basic types of steam turbines? Answer: 1. Impulse type. 2. Reaction type. Question No. 2 How can steam turbines be classified? Answer: The classification of steam turbine are as follows: By the action of steam: 1. Impulse. 2. Reaction. 3. Impulse and reaction combined. The number of step reductions involved: 1. Single…
Question No.1 Explain notch sensitivity. State the relation between stress concentration factor and notch sensitivity. Answer: Notch sensitivity (q) is the degree to which the theoretical effect of stress concentration is actually reached. The relation is, Kf = 1 + q (Kt-1) Question No.2 What are the factors that affect notch sensitivity? Answer: The factors effecting notch…
Question No.1 What are the types of fracture? Answer: The two types of fracture are 1. Ductile fracture 2. Brittle fracture Question No.2 Distinguish between brittle fracture and ductile fracture. Answer: In brittle fracture, crack growth is up to a small depth of the material. In ductile fracture large amount of plastic deformation is present to a…
Question No.1 Define Ductility. Answer: It is the property of the material enabling it to be drawn into wire, with the application of tensile force. It must be both strong and plastic. It is usually measured in terms of percentage elongation and reduction in area, (e.g.) Ni, Al, and Cu. Question No.2 Define fatigue. Answer:…
Question No. 1 What is the advantage of leaf spring over helical spring? Answer: The advantage of leaf spring over helical spring is that the end of the spring may be guided along a definite path as it deflects to act a structural member in addition to energy absorbing device. Question No. 2 Write notes…