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Questions (71 - 77)
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In this lesson, questions (71 - 77) 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

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  1. COURSE: Questions on Steam Turbine Lesson : Questions-(71-77)


  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: https://unacademy.in/user/harshit aggarwal


  3. Question 71 4 m's 9 Velocity diagram shown above is for an impulse turbine stage What is the, tangential force and axial thrust per kg/s of steam, respectively? (a) 450 N, 8 N (b) 560 N, 8 N (c) 680 N, 4 N (d) 910 N, 4 N V, 960 m/s 450 /s 910 m/s


  4. Solution 71 Tangential force= m >1 Vw 1x 910N = 910N Axial force = mx1K, = 1 4N-4N Ans :d


  5. Question 72 Consider the following statements regarding an impulse turbine: 1. Relatives velocity at the inlet and exit of the rotor blades are the same 2. Absolute velocity at the inlet and exit of the rotor blades are the same 3. Static pressure within the rotor blade channel is constant 4. Total pressure within the rotor blade channel is constant Of these statements: (a) 1 and 4 are correct (c) 1 and 3 are correct (b) 2 and 3 are correct (d) 2 and 4 are correct Ans c


  6. Question 73 Steam enters the rotor of a reaction turbine with an absolute velocity of 236 m/s and the relative velocity of 132 m/s. It leaves the rotor with a relative velocity of 232 m/s absolute velocity of 126 m/s. The specific work output is (a) 38.1 kW (b) 40.1 kW (c) 43.8 kW (d) 47.4 kW


  7. Solution 73 [Note V comes first] 2362-1262)+(2322132 38.1 KVW Ans a


  8. Question 74 In a simple impulse turbine, the nozzle angle at the entrance is 30 . What will be the blade-speed ratio for maximum diagram efficiency? (a) 0 433 (b) 0 25 (c) 0.5 (d) 0.75


  9. Solution 74 V cos u cos 30 2 2 4 Ans a


  10. Question 75 In the given figure, B1, B2, B3, and B4 represent blade passages in an impulse turbine. Consider the following statements in this regard 1. The solid line represents velocity variation. 2. The solid line represents pressure variation. 3. B and Ba are rotor passages. 4. Bi and Ba are rotor passages. Of these statements: (a) 1 and 4 correct (c) 2 and 3 are correct (b) 1 and 3 are correct (d 2 and 4 are correct Ans b


  11. Question 77 In a two-row Curtis stage with symmetrical blading, (a) Work done by both rows of moving blades are equal (b) Work done by the first row of moving blades is double of the work done by second row of moving blades (c) Work done by the first row of moving blades is three times the work done by second row of moving blades (d) Work done by the first row of moving blades is four times the work done by the second row of moving blades Ans c