Liquid hydrogen is flowing through an insulated pipe ( k = 23 W/m .K, D i =3 cm, D o =4 cm and L= 20 m) . The pipe is situated in a chemical plant, where the average air temperature is 40°C. The convection heat transfer coefficients of the liquid hydrogen and the ambient air are 200 W/m 2 K and 50 W/m 2 .K, respectively. If the oilier surface temperature of the insulated pipe is 5°C, determine the thickness of the pipe insulation ( k = 0.6 W/m .K) and in order to keep the liquid hydrogen flowing at an average temperature of -300°C.
Liquid hydrogen is flowing through an insulated pipe ( k = 23 W/m .K, D i =3 cm, D o =4 cm and L= 20 m) . The pipe is situated in a chemical plant, where the average air temperature is 40°C. The convection heat transfer coefficients of the liquid hydrogen and the ambient air are 200 W/m 2 K and 50 W/m 2 .K, respectively. If the oilier surface temperature of the insulated pipe is 5°C, determine the thickness of the pipe insulation ( k = 0.6 W/m .K) and in order to keep the liquid hydrogen flowing at an average temperature of -300°C.
Solution Summary: The author explains the thickness of the pipe insulation in order to keep the liquid hydrogen flowing at an average temperature of -300 o C.
Liquid hydrogen is flowing through an insulated pipe
(
k
=
23
W/m
.K,
D
i
=3 cm, D
o
=4 cm and L= 20 m)
. The pipe is situated in a chemical plant, where the average air temperature is 40°C. The convection heat transfer coefficients of the liquid hydrogen and the ambient air are 200 W/m2 K and 50 W/m2 .K, respectively. If the oilier surface temperature of the insulated pipe is 5°C, determine the thickness of the pipe insulation
(
k
=
0.6
W/m
.K)
and in order to keep the liquid hydrogen flowing at an average temperature of -300°C.
A
ә
レ
shaft fitted with a flywheel rotates at 300 rpm. and drives a machine. The torque
required to drive the machine varies in a cyclic manner over a period of 2 revolutions. The torque drops
from 20,000 Nm to 10,000 Nm uniformly during 90 degrees and remains constant for the following 180
degrees. It then rises uniformly to 35,000 Nm during the next 225 degrees and after that it drops to
20,000 in a uniform manner for 225 degrees, the cycle being repeated thereafter.
Determine the power required to drive the machine and percentage fluctuation in speed, if the driving
torque applied to the shaft is constant and the mass of the flywheel is 12 tonnes with radius of gyration of
500 mm. What is the maximum angular acceleration of the flywheel.
35,000
TNm
20,000
10,000
495
Crank angle 8 degrees
270
0
90
か
---20125
750 X 2.01
44
720
s
The gas tank is made from A-36 steel (σy = 250 MPa) and has an inner diameter of 3.50 m. If
the tank is designed to withstand a pressure of 1.2 MPa, determine the required minimum wall
thickness to the nearest millimeter using
(a) The maximum-shear-stress theory
(b) Maximum distortion- energy theory.
Apply a factor of safety of 1.5 against yielding.
ә
レ
Figure below shows a link mechanism in which the link OA rotates uniformly in an
anticlockwise direction at 10 rad/s. the lengths of the various links are OA=75 mm, OB-150 mm,
BC=150 mm, CD-300 mm. Determine for the position shown, the sliding velocity of D.
A
A
B
#
Space Diagram
o NTS (Not-to-Scale)
C
10
=--20125
735)
750 x2.01
اه
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