JNTU B.Tech III MECHANICS OF FLUIDS AND HYDRAULIC MACHINES Previous Question Paper (November/December - 2018 - R13)

Distinguish between cohesion and adhesion by giving examples.

Explain atmospheric, gauge and vacuum pressures.

Differentiate between surface and body forces.

Explain what momentum equation is.

Give the concept of boundary layer.

Describe HGL and TEL with a neat sketch.

Explain what hydrodynamic force is.

Write about water hammer.

Explain what NPSH is.

Distinguish between pipes in series and pipes in parallel.

Distinguish between (i) dilatant and pseudo-plastic, (ii) thixotropic and rheopectic fluids and (iii) dynamic and kinematic viscosities.

A thin flat plate of size 60 cm by 60 cm moves centrally between two large stationary boundaries. The plane of the plate is parallel to the two boundaries which are 7 cm apart. The space between the plate and one boundary is filled with a fluid of viscosity twice that of another fluid which fills the space on the other side of the plate. If the plate moves with a uniform speed of 20 cm/s by the application of a force of 6 N parallel to the plane of the plate, determine the fluid viscosities.

Distinguish between (i) standard and local atmospheric pressures, (ii) barometric pressure and absolute pressure and (iii) absolute pressure and gauge pressure.

Explain the working of a Bourdon pressure gauge.

Explain the terms: (i) Path line (ii) Streak line (iii) Stream line, and (iv) Stream tube.

A 40 cm diameter pipe, conveying water, branches into two pipes of diameter 30 cm and 20 cm respectively. If the average velocity in the 40 cm diameter pipe is 3 m/s. Find the discharge in this pipe. Also determine the velocity in 20 cm pipe if the average velocity in 30 cm diameter pipe is 2 m/s.

Distinguish between: (i) Steady flow and un-steady flow, (ii) Uniform and non-uniform flow, (iii) Compressible and incompressible flow, (iv) Rotaional and irrotational flow (v) Laminar and turbulent flow.

A pipe, through which water is flowing is having diameters 40 cm and 20 cm at the cross-sections 1 and 2 respectively. The velocity of water at section 1 is 5.0 m/s. Find the velocity head at the sections 1 and 2 and also rate of discharge.

Derive an expression for the loss of head due to friction in pipes.

The water is flowing through a pipe of diameter 30 cm. The pipe is inclined and a venturimeter is inserted in the pipe. The diameter of venturimeter at throat is 15 cm. The difference of pressure between the inlet and throat of the venturimeter is measured by a liquid of specific gravity 0.8 in an inverted U-tube which gives a reading of 40 cm. The loss of head between the inlet and throat is 0.3 times the kinetic head of the pipe. Find the discharge.

Define and explain the following: (i) Pipes connected in series and (ii) Pipes connected in parallel.

An oil of Kinematic Viscosity 0.5 stoke is flowing through a pipe of diameter 300 mm at the rate of 320 litres per sec. Find the head lost due to friction for a length of 60 m of the pipe.

Differentiate between an inward and an outward flow reaction turbine with neat sketches.

A Kaplan turbine working under a head of 25 m develops 16000 kW shaft power. The outer diameter of the runner is 4 m and hub diameter is 2 m. The guide blade angle is 35 degrees. The hydraulic and overall efficiency are 90% and 85% respectively. If the velocity of whirl is zero at outlet, determine runner vane angles at inlet and outlet, and speed of turbine.

Compare and contrast impulse and reaction turbines.

The following data refers to a Pelton wheel installation: net head = 250 m, speed ratio = 0.45, nozzle coefficient = 0.98, jet ratio = 18, overall efficiency = 76%, frequency of generation = 50 Hz and pairs of poles of alternator = 6. Compute the wheel diameter, jet diameter and the power output in KW.

Draw a typical layout and explain the working of centrifugal pump. Also indicate various components.

Explain the method of selection of centrifugal pumps with the aid of characteristic curves.

Why is priming necessary for centrifugal pumps. What are the various methods of priming a centrifugal pump?

A centrifugal pump delivers 10 litres of water per second under a head of 20m. The speed of the shaft is 1200 rpm. Find its specific speed.