JNTU, B-Tech,I-Semester,Hydraulics And Hydraulic Machinery, November 2008
Hydraulics And Hydraulic Machinery
, November 2008
(Electrical & Electronic Engineering)
1. (a) Explain how vacuum pressure is measured with the help of a U-tube manometer.
(b) The barometric pressure at sea level is 760 mm of Hg while on a mountain top it is found to be 735 mm of Hg. If the specific weight of air is assumed constant at 11.8N/m3, calculate the height of the mountain.
2. (a) Briefly explain the classification of flows.
(b) What type of acceleration is to be expected if
i. Streamlines are parallel and equidistant
ii. Streamlines are straight and converging
iii. Streamlines are curved but equispaced
iv. Streamlines are curved and converging.
3. A pipe 300 m long has a slope of 1 in 100 and tapers from 1.25 m diameter at the
high end to 0.625m diameter at the low end. Quantity of water flowing is 0.1m3/s. If the pressure at the high end is 98.1kN/m2, find the pressure at the low end.
4. Two reservoirs with a difference in water surface elevation of 10 m are connected
by a pipeline ABC, which consists of two pipes AB and BC joined in series. Pipe
AB is 10 cm in diameter, 20 m long and has a value of f = 0.02. Pipe BC is of 16
cm diameter, 25 m long and has a f = 0.018. The junctions with the reservoirs and
between the pipes are abrupt.
(a) calculate the discharge,
(b) what difference in water elevations is necessary to have a discharge of 15
litres/sec. (include all minor losses).
5. (a) Explain the working principle of a pitot-static tube with a neat sketch?
(b) Bring out clearly the differences between venturi meter and orifice meter.
6. A square plate weighing 115N and of uniform thickness and 30 cm edge is hung so
that horizontal jet 2 cm diameter and having a velocity of 15 m/s impinges on the plate. The center line of the jet is 15 cm below the upper edge of the plate, and when the plate is vertical the jet strikes the plate normally and at its center. Find what force must be applied at the lower edge of the plate in order to keep plate vertical.If the plate is allowed to swing freely, find the inclination to vertical which the plate will assume under the action of jet.
7. (a) Define ‘unit toque’ and derive an expression for it
(b) Prove that specific speed can be expressed as Ns = 3.13Nu pQu?o
Where, Nu and Qu are the unit speed and unit discharge and ?o is the overall
8. (a) Derive an expression for the minimum starting speed of a centrifugal pump.
(b) Discuss the performance of multistage pumps.