Due to its comparatively large thermal conductivity, water is a preferred fluid for convection cooling. However, in applications involving electronic devices, watermust notcome into contact with the devices, whichwould therefore have to be hermetically sealed. To circumvent related design and operational complexities andto ensure that the devices are not rendered inoperable bycontact with the coolant, a dielectric fluid is commonlyused in lieu of water. Many gases have excellent dielectric characteristics, and despite its poor heal transferproperties, air is the common choice for electronic cooling. However, there is an alternative, which involves aclass of perfluorinated liquids that are excellentdielectrics and have heat transfer properties superior tothose of gases.Consider the microchannel chip cooling application of Problem 8.109 but now for a perfluorinatedliquid with properties of c p = 1050 J/kg ⋅ K , k = 0.065 W/m ⋅ K , μ = 0.0012 N ⋅ s/m 2 , and Pr = 15 . (a) For channel dimensions of H = 200 μ m, W = 50 μ m, and S = 20 μ m. a chip thermal conductivity of k c h = 140 W/m ⋅ K and width L = 10mm. a channel base temperature ( x = 0) of T s = 350 K , achannel inlet temperature of T m , i = 290 K , and aflow rate of m 1 = 10 − 4 kg/s per channel, determinethe outlet temperature and the chip power dissipation for the dielectric liquid. (b)Consider the foregoing conditions, but with air at a flow rate of m 1 = 10 − 6 kg/s used as the coolant. Using properties of c p = 1007 J/kg ⋅ K,k = 0.0263 W/m ⋅ K , and μ = 185 × 10 − 7 N ⋅ s/m 2 , determine the air outlet temperature and the chip power dissipation.
Due to its comparatively large thermal conductivity, water is a preferred fluid for convection cooling. However, in applications involving electronic devices, watermust notcome into contact with the devices, whichwould therefore have to be hermetically sealed. To circumvent related design and operational complexities andto ensure that the devices are not rendered inoperable bycontact with the coolant, a dielectric fluid is commonlyused in lieu of water. Many gases have excellent dielectric characteristics, and despite its poor heal transferproperties, air is the common choice for electronic cooling. However, there is an alternative, which involves aclass of perfluorinated liquids that are excellentdielectrics and have heat transfer properties superior tothose of gases.Consider the microchannel chip cooling application of Problem 8.109 but now for a perfluorinatedliquid with properties of c p = 1050 J/kg ⋅ K , k = 0.065 W/m ⋅ K , μ = 0.0012 N ⋅ s/m 2 , and Pr = 15 . (a) For channel dimensions of H = 200 μ m, W = 50 μ m, and S = 20 μ m. a chip thermal conductivity of k c h = 140 W/m ⋅ K and width L = 10mm. a channel base temperature ( x = 0) of T s = 350 K , achannel inlet temperature of T m , i = 290 K , and aflow rate of m 1 = 10 − 4 kg/s per channel, determinethe outlet temperature and the chip power dissipation for the dielectric liquid. (b)Consider the foregoing conditions, but with air at a flow rate of m 1 = 10 − 6 kg/s used as the coolant. Using properties of c p = 1007 J/kg ⋅ K,k = 0.0263 W/m ⋅ K , and μ = 185 × 10 − 7 N ⋅ s/m 2 , determine the air outlet temperature and the chip power dissipation.
Solution Summary: The author explains the water outlet temperature and chip power dissipation for dielectric liquid.
Due to its comparatively large thermal conductivity, water is a preferred fluid for convection cooling. However, in applications involving electronic devices, watermust notcome into contact with the devices, whichwould therefore have to be hermetically sealed. To circumvent related design and operational complexities andto ensure that the devices are not rendered inoperable bycontact with the coolant, a dielectric fluid is commonlyused in lieu of water. Many gases have excellent dielectric characteristics, and despite its poor heal transferproperties, air is the common choice for electronic cooling. However, there is an alternative, which involves aclass of perfluorinated liquids that are excellentdielectrics and have heat transfer properties superior tothose of gases.Consider the microchannel chip cooling application of Problem 8.109 but now for a perfluorinatedliquid with properties of
c
p
=
1050
J/kg
⋅
K
,
k
=
0.065
W/m
⋅
K
,
μ
=
0.0012
N
⋅
s/m
2
,
and
Pr
=
15
.
(a) For channel dimensions of
H
=
200
μ
m,
W
=
50
μ
m, and
S
=
20
μ
m. a chip thermal conductivity of
k
c
h
=
140
W/m
⋅
K
and width L = 10mm. a channel base temperature (x = 0) of
T
s
=
350
K
, achannel inlet temperature of
T
m
,
i
=
290
K
, and aflow rate of
m
1
=
10
−
4
kg/s per channel, determinethe outlet temperature and the chip power dissipation for the dielectric liquid. (b)Consider the foregoing conditions, but with air at a flow rate of
m
1
=
10
−
6
kg/s used as the coolant. Using properties of
c
p
=
1007
J/kg
⋅
K,k
=
0.0263
W/m
⋅
K
,
and
μ
=
185
×
10
−
7
N
⋅
s/m
2
, determine the air outlet temperature and the chip power dissipation.
PROBLEM 3.23
3.23 Under normal operating condi-
tions a motor exerts a torque of
magnitude TF at F. The shafts
are made of a steel for which
the allowable shearing stress is
82 MPa and have diameters of
dCDE=24 mm and dFGH = 20
mm. Knowing that rp = 165
mm and rg114 mm, deter-
mine the largest torque TF
which may be exerted at F.
TF
F
rG-
rp
B
CH
TE
E
1. (16%) (a) If a ductile material fails under pure torsion, please explain the failure
mode and describe the observed plane of failure.
(b) Suppose a prismatic beam is subjected to equal and opposite couples as shown
in Fig. 1. Please sketch the deformation and the stress distribution of the cross
section.
M
M
Fig. 1
(c) Describe the definition of the neutral axis.
(d) Describe the definition of the modular ratio.
using the theorem of three moments, find all the moments, I only need concise calculations with minimal explanations. The correct answers are provided at the bottom
Need a deep-dive on the concept behind this application? Look no further. Learn more about this topic, mechanical-engineering and related others by exploring similar questions and additional content below.
Principles of Heat Transfer (Activate Learning wi...Mechanical EngineeringISBN:9781305387102Author:Kreith, Frank; Manglik, Raj M.Publisher:Cengage Learning