Momentum Transfer Flashcards
The fluid property, due to which, mercury does not wet the glass is
a. surface tension
b. viscosity
c. cohesion
d. adhesion
Surface Tension
What is the SI unit of surface tension?
N/m
The viscosity of a gas
increases with increase in temperature
The dimensionless numver that characterizes fluid flows in a conduit is
Reynolds number
Natural convection
Grashof Number
Mass Transfer
Peclet number
Nu= hD/k in convective heat transfer is
Nusselt Number
Turbulent flow generally occurs for cases involving
a. viscous fluid
b. very narrow capillary tubes
c. very slow motions
d. none of these
None of these
The normal stress is the same in all directions at a point in a fluid when the fluid is
having no motion of one fluisnlayer relarive to the layer
Which of the following statements is TRUE about Newton’s law of viscosity
it applies only to Newtonian fluid
At high Reynolds numbers
inertial forces control and viscous forces are not significant
The dimension of dynamic viscosity is (t notation here is time)
ML^-1t^-1
The ratio of average fluid velocity to the maximum velocity in casebof laminar flow of a Newtonian fluid in a circular pipe is
0.5
The ratio od average fluid velocity to the maximum velocity in case of turbulent flow of a Newtonian fluid in a circular pipe is
1
If teo similar horizontal pipes are to be connceted, which od the following fittings should be used?
Union
If a pump delivers water to a destination tank at high elevation, which od the following valves will protect the pump from unintended fluid backflow?
Check valve
Which of the following phenomena describes the formation of bubbles in liquid flow when the local pressure falls to around the vapor pressure of the fluid?
Cavitation
If a piping system delivers corrosive and abrasive fluids, which od the following should ne used to control the flow?
Diaphragm valve
Which valve id used accurately to regulate the flow of liquids and gases at low flow rates?
Needle valve
When a fluid flows through a reducer in a piping system, the velocity at the outlet ens is ___ the velocity at the inlet
greater than
Which of the following statements is FALSE?
a. Potential flow is a flow of compressible fluids with no shear
b. Rotameters are variable head meters
c. There are 8 schedule numbers in use for standard pipes
d. Roughness has no appreciable effect on the friction factor when the flow is laminar
c. There are 8 schedule numbers in use for standard pipes
Which of the folloeinf statements is FALSE?
a. A pump will operate safely if its NPSHA is greater than NPSHR
b. Fans and blowers are used to transport gases
c. Pumps and blowers increase the mechanical energy of the fluid
d. The power loss due to friction in a venturi meter is greater than an orifice meter
d. The power loss due to friction in a venturi meter is greater than an orifice meter
For transport of air with pressure drops lessbtgan 0.03 bar, which od the following is used?
Fan (negligible pressure drop isipin mo ang electric fan, compressors have high pressure drops)
What do you call the input power delivered by the motor to the pump?
Brake horsepower
Which of the following meters will havr the highest permanent pressure loss?
Orifice meter
