Important Question And Answer: civil - Applied Hydraulic Engineering - Part 3

91.Define open channel flow?

The term open channel flow denotes the gravity-driven flow of a liquid with a free surface.

92.What do you mean by stream lining?

`Streamlining is adding a faired tail section to reduce the  extent of separated flow on the downstream portion of an object .

93.What is centrifugal pump?

The hydraulic machines which convert mechanical energy in to pressure energy by means of centrifugal force is called centrifugal pump.It acts a reverse of inward radial flow  turbine.

94.What do you know about Hub or Boss?

It is the core part of the axial flow turbine where the vanes are attached.

95.Under what head the propeller turbine take water?

About 100 m head the propeller turbine take water.

When the vanes are fixed to the hub and they are not adjustable the turbine is called propeller turbine.

96.What are the uses of Kaplan turbine?

1.To produce more out put.

2.The efficiency of the turbine is more

97.Define unit speed:

It is defined as the speed of the turbine under unit head

Where

Nu = N/?H

Nu -unit speed

N -number of rotations

H- head of the turbine

98.Define unit discharge

It is defined as the discharge passing through the turbine which is working under unit head.

Qu = Q/ ?H Where

Qu - unit discharge Q - Total discharge H- head of the turbine

99.Define unit power:

It is defined as the power developed by the turbine working under unit head.

Pu = P/H^3/2

Where  Pu - unit power.

P  - Total power.

H- head of the turbine.

100.What are the main parts of centrifugal pump?

1.Suction pipe with foot valve and strainer

2.Impeller

3.casing

4.delivery pipe

101.What are fluid machines?

The machines which use the liquid or gas for the transfer of energy from fluid to rotor or from rotor to fluid, are known as fluid machines.

102. What are hydraulic machines and thermal turbo machines?

If  liquid  is  used  for  the  transfer  of  energy,  then  machines  are known as hydraulic machines whereas if gas is used then machnes are known as thermal turbo machines.

103.How are fluid machines classified?

Fluid machines are classified into 2 categories depending upon the direction of

1.       Turbines

2.       Pumps or compressors..

104.What is the purpose of an air vessel fitted in the pump?

1.To obtain a continuous supply of liquid at a uniform rate.

2.To save a considerable amount of work in overcoming the frictional resistance in the suction and delivery pipes, and

3.To run the pump at a high speed with out separation.

105. What is the work saved by fitting a air vessel in a single acting ,double acting pump?

Work saved by fitting air vessels in a single acting pump is 84.87%, In a double acting pump the work saved is 39.2%.

106.What is Discharge through a Reciprocating Pump in Per sec ?

For Single acting

Discharge (Q)=ALN/60 Where

A=Area of the Cylinder in m²

L=Length of Stroke in m. N=Speed of Crank in RPM

For Double acting Q=2ALN/60

107. What is the Workdone by Reciprocating Pump Per sec.?

Workdone = ?gALN(hs+hd)/60 (for single acting)

For Double acting:

Work done= 2?gALN(hs+hd)/60 Where

          ?=Density of Water in kg/m³                     

          A=Area of the Cylinder in m²                    

          L=Length of Stroke in m                           

          N=Speed in rpm                     

          hs,hd=Suction and Delivery head in m                         

108.  What is the Pressure head due to acceleration in the Suction & Delivery Pipe ?                     

 hf=4fl(A/a*?r sin?)2/2gd      

 where         A = Area of piston in m2.   a = Area of pipe in m2.     

f=Co-efficient of friction.                 

? = Angular speed         r = Radius of crank       

109. What is the relation between Work done of a Pump and Area of Indicator Diagram ?

Work done by the pump is Proportional to the area of the Indicator diagram.

110. What is the Work done by the Pump per sec due to acceleration and friction in the suction and delivery Pipes ?

For single acting

W= ?gALN(hs+hd+0.67hfs+0.67hfd)/60 For Double acting

W=2?gALN(hs+hd+0.67hfs+0.67hfd)/60

Where hfs, hfd =loss of head due to acceleration in the suction and delivery Pipe.

111. What is the Mean Velocity of Single acting reciprocating pump ?

v=A? r/3.14a

Where

? =Angular velocity in rad/sec r =Radius of the crank in m

A and a =Area of cylinder and Pipe in m2

mp and rotating cylinder pump.