Anna University Chennai B.E Mechanical Engineering Fluid mechanics and machinery - MODEL QPAPER (AUT) 2009 Question paper

MODEL QUESTION PAPER – CE 1208 FLUID MECHANICS AND MACHINERY
(AS PER THE LATEST SYLLABUS OF ANNA UNIV TRICHY)
PART A
ANSWER ALL THE QUESTIONS: 10X2=20

1. A flat plate of area 1.5X106 mm2 is pulled with a speed of 0.4m/s relative to another plate located at a distance of 0.15mm from it. Find the force required to maintain this speed, if the fluid separating them is having viscosity as 1 poise.

2. State the Continuity equation for compressible and incompressible fluids.

3. Define hydraulic grade line?

4. Write the Darcy-weisbach equation used to find loss of head due to friction in pipe.

5. What do you mean by dynamic similarity?

6. Define Weber's number?

7. A turbine develops 7225 kW power under a head of 25 m at 135 rpm. Calculate the specific speed of the turbine and state the type of the turbine.

8. Define specific speed of a turbine?

9. What is negative slip? How it occurs?

10. What is meant by suction head and delivery head?

PART B

ANSWER ALL THE QUESTIONS: 5X16=80
11. (a) If 5.27 m3 of certain oil weighs 44 kN , Calculate the specific speed , mass density and specific gravity of the oil. (6)
(b) What are the physical phenomena which are responsible for the property of viscosity? How these factors contribute to viscosity of fluid? (4)
(c) A body weighing 441.5 N with a flat surface area of 0.093 m2 slides down lubricated inclined plane making a 30° angle with the horizontal. For a viscosity of 3 m/s , determine the lubricant film thickness. (6)

12. State and prove the Bernoulli's Equation and write the applications of Bernoulli's Equation. (16)

13. Derive an expression for Darcy – weisbach formula to determine the head loss due to friction. Give the expression for relation between friction factor 'f' and Reynold's number for laminar and turbulent flow. (16)

14. A30 cm diameter pipe, conveying water, branches into two pipes of diameters 20 cm and 15 cm respectively. If the average velocity in the 30 cm diameter pipe is 2.5 m/s, find the discharge in the pipe. Also determine the velocity in 15 cm pipe if the average velocity in 20 cm pipe is 2 m/s. (16)

15.The pressure difference ?p in a pipe of diameter D and length 'l' due to turbulent flow depends on the velocity V , viscosity µ , density ? , and roughness k. Using Buckingham's p - theorem , obtain an expression for ?p. (16)

16. Using Buckingham's p – theorem, show that the discharge Q consumed by an oil ring is given by
Q = Nd3? [µ/?Nd2, s/?N2d3, w/ ?N2d]
Where'd' is the internal diameter of the ring, N is rotational speed , ? is density , µ is viscosity , s is surface tension and w is the specific weight of oil. (16)

17. Explain the main parts of a centrifugal pump with neat sketch. Also discuss about manometric efficiency, Mechanical efficiency and overall efficiency. (16)

18. Describe the working of Pelton Wheel with neat sketch and state the difference between impulse and reaction turbine. (16)

19. Describe the working of reciprocating pump with the aid of a sketch. (16)

20. A single acting reciprocating pump, running at 50 rpm delivers 0.01m3/s of water. The diameter of the piston is 200mm and stroke length 400mm. Determine
(i) The theoretical discharge of the pump
(ii) Co-efficient of discharge
(iii) Slip and percentage of slip of the pump.