JNTU Exam Papers,II B.Tech I Semester Supplimentary Examinations,FLUID MECHANICS AND HYDRAULIC MACHINERY February 2008
II B.Tech I Semester Supplimentary Examinations, February 2008
FLUID MECHANICS AND HYDRAULIC MACHINERY
(Electrical & Electronic Engineering)
1. (a) State Newton’s equation of viscosity and give examples of its application.
(b) An oil of viscosity 5 poise is used for lubrication between a shaft and sleeve. The diameter of shaft is 0.5 m and it rotates at 200 rpm. Calculate the horse power lost in the oil for a sleeve length of 100 mm. The thickness of the oil film is 1.0 mm.
2. (a) Define a stream line. Enumerate the properties of streamlines.
(b) A pipe 20 cm diameter is carrying water with a mean velocity of 3 m/sec. Calculate the discharge. If the pipe bifurcates into two pipes of 10 cm each, find the velocity of water in the 10 cm diameter pipe.
3. (a) Define Major Energy Loss and Minor Energy Loss.
(b) Briefly explain Hydraulic Gradiant Line and Total Energy Line.
(c) The rate of flow of water through a horizontal pope is 0.3m3/sec. The diameter of the pipe is suddenly enlarged fron 25cm to 50cm. The pressure intensity in the smaller pipe is 1.4Kgf/cm2. Determine loss of head due to sudden enlargement, pressure intensity in the large pipe and power lost due to enlargement.
4. (a) Derive the expressions for force and work done per second by the jet when it strikes a flat vertical plate moving in the direction of the jet and away from the jet.
(b) A jet of water of 75mm diameter strikes a curved vane at its center with a velocity of 20m/sec. The curved vane is moving with a velocity of 8m/sec in the direction of jet. Find the force exerted on the plate in the direction of the jet power and efficiency of the jet. Assume the plate to be smooth.
5. (a) Explain how power potential is estimated from known hydrological particulars at a hydropower plant site on a stream.
(b) Compare different types of hydroelectric power stations stating the features and merits. Use sketches wherever necessary. List out the elements of a typical hydroelectric power station
6. (a) What are the working proportions of a Kaplan turbine ? Explain why draft tube is provided for a Kaplan turbine when compared with a Pelton wheel.
(b) An inward flow reaction turbine has inlet and outlet diameters of 1.2m and 0.6 m respectively. The breadth at inlet is 0.25 m and at outlet it is 0.35m. The runner speed is 250 rpm. The relative velocity at inlet is 3.5m/sec and is radial. Determine
i. the absolute velocity at inlet and its inclination to the tangent of runner
ii. Discharge and
iii. the velocity of flow at outlet.
7. (a) What do you mean by scale ratio. What are the expressions for length scale ratio, area scale ratio and volume scale ratio ?
(b) A turbine installation develops an out put of 7000 Kw working under a head of 30m and at a speed of 200 rpm. What is its specific speed. Find its speed and power when the turbine works under a head of 10m.
8. (a) Derive the equation for work done by the impeller of a centrifugal pump on the fluid handled. What are different efficiencies of centrifugal pump ?
(b) Explain the working of a reciprocation pump with a neat sketch showing all the components.