FFT Flashcards
(30 cards)
An ideal fluid is one that is
a. compressible
b. incompressible
c. incompressible and viscous
d. compressible and inviscid
Incompressible & Inviscid
The requirement by which the pressure of the liquid at the suction of the pump must
exceed the vapor pressure of the liquid to avoid cavitation of pump is
a. Net Positive Suction Head
c. Cavitational Limit
c. Cavitation Head
d. Suction Head
a. Net Positive Suction Head
Orifice has the highest permanent pressure loss among all meters. Which of the
following increases the pressure drop across an orifice for a given flow rate?
a. Decrease in orifice flow area
b. Decrease in orifice thickness
c. Both a and b
d. Neither a nor b
c. Both a and b
Which of the following fittings exhibits the highest pressure drop for the same flow
conditions?
a. 90-degree long radius elbow
b. 90-degree standard elbow
c. 45-degree standard elbow
d. square-corner elbow
d. square-corner elbow
A dimensionless group that is used to analyze transport phenomena and shows the
ratio of inertial forces to gravitational forces
a. Euler number
b. Froude number
c. Newton number
d. Reynolds number
b. Froude number
The laminar flow regime can be characterized by
a. parabolic profile
b. exponential profile
c. flat profile
d. hyperbolic profile
a. parabolic profile
Hydraulic radius is the ratio of
a. wetted perimeter to flow area
b. flow area to square of wetted perimeter
c. flow area to wetted perimeter
d. square root of flow area to wetted perimeter
c. flow area to wetted perimeter
Which of the following factors does not contribute to the pressure drop in a pipeline?
a. velocity of fluid
b. size of pipe
c. length of pipe and number of bends
d. none of these
d. none of these
It is a non-newtonian fluid which shoes an apparent viscosity that decreases with
increases rate of shear. Examples are solutions of high polymers, paper pulp, and
mayonnaise.
a. Thixotropic fluids
b. dilatant fluids
c. rheopectic fluids
d. pseudoplastic fluids
d. pseudoplastic fluids
Ninety-eight percent sulfuric acid (viscosity = 25 x 10 -3 Ns/m2, density = 1840kg/m3) is pumped at 1.25kg/s through a 25mm diameter pipe, 30m long, to a reservoir 12m higher than the feed point. Calculate the pressure drop in the pipeline.
Use mild steel pipe as the pipe.
a. 320kPa
b.240kPa
c. 480kPa
d. 560kPa
a. 320kPa
Natural gas which is essentially methane is being pumped through a 1.016m ID
wrought iron pipeline for a distance of 1.609 x 10 5 m at a rate of 2.077kmol/s. It
can be assumed that the line is isothermal at 288.8K. The pressure P2 at the
discharge end of the line is 170.3 x 10 3 Pa absolute.
Calculate the pressure P1 at
the inlet of the line.
a. 694 x10 3 Pa
b.680 x 10 3 Pa
c. 724 x 10 3 Pa
d. 433 x 10 3 Pa
b.680 x 10 3 Pa
The rate of flow of water in a 150mm diameter pipe is measured with a venturi
meter with a 50mm diameter throat. When the pressure drop over the converging section is 121mm of water, the flow rate is 2.91kg/s. What is the coefficient for the converging cone of the meter at this flow rate?
0.985
Water flows 10ft/s through a pipe 1000ft long with a diameter of 1in the inlet
pressure P1 = 200psig, and the exit section is 100ft higher than the inlet. What is the exit pressure P2 if the friction head loss is 350ft?
5 psig
Six thousand liters per second (6000L/s) of waer at 320K is pumped in a 40mm inside diameter pipe through a length of 150m in a horizontal direction and up through a vertical height of 10m. In the pipe there is a control valve which may be taken as equivalent to 200 pipe diameters and other pipe fittings equivalents to 60 pipe diameters. Also in the line there is a heat exchanger across which there is a loss in head of 1.5m of water. If the main pipe has a roughness of 0.0002m, what power must be delivered to the pump of the unit is 60% efficient?
128 W
A centrifugal pump is to be used to extract water from a condenser in which the
vacuum is 640mmHg. At the rated discharge, the net positive suction head must be at least 3 above the cavitation vapor pressure of 710mmHg vacuum. If losses in the suction pipe account for a head of 1.5m, what must be the least height of the liquid level in the condenser above the pump inlet?
3.55m
For an isothermal process the internal energy of a gas
a. Increases
b. decreases
c. remains unchanged
d. data insufficient can’t be predicted
c. remains unchanged
During Joule-Thomson expansion of gases
a. enthalpy remains constant
b. entropy remains constant
c. temperature remains constant
d. none of these
a. enthalpy remains constant
Which of the following is not a intensive property
a. Volume
b. Density
c. Temperature
d. Pressure
a. Volume
Entropy of an ideal gas depends upon its
a. pressure
b. temperature
c. both (a) & (b)
d. neither (a) nor (b)
c. both (a) & (b)
Coefficient of Performance (COP) of refrigerator is the ratio of:
a. work required to refrigeration obtained
b. refrigeration obtained to the work obtained
c. lower to higher temperature
d. higher to lower temperature
b. refrigeration obtained to the work obtained
Work in the amount of 12kJ is done on a closed system, and its internal energy decreases by 25kJ. How much heat is removed from the system?
37kJ
An ideal gas with CV = (7/2)R enters a process at 300K and 2 bar and leaves the process at 600K and 9 bar. Calculate its entropy change.
13.4 J/mol-K
Calculate the work necessary to compress air in an insulated cylinder from a volume of 6 ft 3 to a volume of 1.2 ft 3. The initial temperature and pressure are 50⁰F and
30psia, respectively.
-75 BTU
Saturated steam at 630K is throttled to a pressure of 15bar. What is the quality of the steam after the throttling process?
0.856
