1.)What is pitting ? How it is caused ?
Ans: Non uniform corrosion over the entire metal surface, but occurring only in small pits is called pitting. It is caused by lack of uniformity in metal.
2.)What is caustic embrittlement ?
Ans: It is the actual physical change in metal that makes it extremely brittle and filled with minute cracks. It occurs particularly in the seams of riveted joints and around the rivet holes.
3.)Why efficiency of gas turbines is lower compared to I.C. engines?
Ans: In gas turbines, 70% of the output of gas turbine is consumed by compressor. I.C. engines have much lower auxiliary consumption. Further combustion temperature of I.C. engines is much higher compared to gas turbine.
4.)Why pistons are usually hollowed at top ?
Ans: Pistons are usually hollowed at top to (i) provide greater space for combustion, (ii)increase surface for flue gases to act upon, and (iii) better distribution of stresses.
source : Mechanical Engineers Page on Facebook
Ans: Non uniform corrosion over the entire metal surface, but occurring only in small pits is called pitting. It is caused by lack of uniformity in metal.
2.)What is caustic embrittlement ?
Ans: It is the actual physical change in metal that makes it extremely brittle and filled with minute cracks. It occurs particularly in the seams of riveted joints and around the rivet holes.
3.)Why efficiency of gas turbines is lower compared to I.C. engines?
Ans: In gas turbines, 70% of the output of gas turbine is consumed by compressor. I.C. engines have much lower auxiliary consumption. Further combustion temperature of I.C. engines is much higher compared to gas turbine.
4.)Why pistons are usually hollowed at top ?
Ans: Pistons are usually hollowed at top to (i) provide greater space for combustion, (ii)increase surface for flue gases to act upon, and (iii) better distribution of stresses.
source : Mechanical Engineers Page on Facebook
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