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Questions (64 - 70)
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In this lesson, questions (64 - 70) have been explained.

Harshit Aggarwal
Cleared UPSC ESE twice with Rank 63 and 90 in mechanical engg. Got 99 percentile in GATE. Cracked ONGC, BHEL,ISRO, SAIL, GAIL successfully

Unacademy user
waiting for your next class thank you ma'am
  1. COURSE: Questions on Steam Turbine Lesson : Questions-(64- 70

  2. About me Graduated from NIT Nagpur in 2008 A. Cleared Engineering Services Examination (ESE-UPSC) Exam Got the offer letter from most of the Maharatna and Navratna Companies Cleared GATE Exam Rate, Review, Recommend, Share <* Follow me on Unacademy at: aggarwal

  3. Question 64 Match List I (Blades) with List II (Features) and select the correct answer using the codes given below the Lists: List I List II (Features) 1. High creep strength 2. Forged and machined 3. Precision cast 4. Thick at mid chord 5. Thin trailing edge (Blades) A. Ceramic blades B. Steam turbine blades C. Alloy steel blades D. Compressor blades A B C D (a) 2154(b) 3 451 (c) 2 435(d) 3215 Codes: A Ans a

  4. Question 65 At a particular section of a reaction turbine, the diameter of the blade is 1.8 m, the velocity of flow of steam is 49 m/s and the quantity of steam flow is 5.4 m3/s. The blade height at this section will be approximately: (a) 4 cm (b) 2 cm (c) 1 cm (d) 0.5 cm

  5. Solution 65 Steam flow D x height of blade xV 5.4 100 3.14 1.8 49 or height of blade- cm . Ans b

  6. Question 66 Assertion (A): During the operation of a steam turbine, it is necessary to maintain the moisture content of steam below 10%. Hence, the steam quality at turbine exit must be greater than 0.9. Reason (R): The precaution has to be taken in order to prevent corrosion and the consequent damage to the turbine. (a) Both A and R are individually true and R is the correct explanation of A (b) Both A and R are individually true but R is not the correct explanation of A (c) A is true but R is false (d) A is false but R is true Ans: c

  7. Question 67 In a surface condenser used in a steam power station, under cooling of condensate is undesirable at this would (a) Not absorb the gases in steam (b) Reduce efficiency of the plant. (c) Increase the cooling water requirements. (d) Increase thermal stresses in the condenser Ans: C

  8. Question 68 If in an impulse turbine designed for free vortex flow, tangential velocity of steam at the root radius of 250 mm is 430 m/s and the blade height is 100 mm, then the tangential velocity of steam at the tip will be (a) 602 m/s(b) 504 m/s (c) 409 m/s (d) 307 ms

  9. Solution 68 For free vortex V.r const Vr. 2503 -307m/s (250+100) Ans d

  10. Question 69 Consider the following statements: In an impulse turbine 1. The relative velocity of steam at inlet and outlet of moving blades are equal. 2. The moving blades are symmetrical 3. The outlet area of the moving blades is smaller than the inlet area. Of these statements: (a) 1, 2 and 3 are correct (c) 1 and 2 are correct (b) 2 and 3 are correct (d) 1 and 3 are correct Ans: c