... Convection HeatandMassTransfer 457
7.5 The Sphere 465
7.6 Flow Across Banks of Tubes 468
7.7 Impinging Jets 477
7.7.1 Hydrodynamic and Geometric Considerations 477
7.7.2 Convection HeatandMassTransfer ... applicability ofheat exchanger analysis to heat
sink design and materials processing. Much of the coverage of compact heat exchangers
included in the previous edition was limited to a specific heat exchanger. ... ofheattransfer by free convection
and radiation exchange.
(b) To assess the trade-off between current-carrying
capacity, operating temperature, and bar diameter,
for diameters of 10, 20, and...
... Convection HeatandMassTransfer 457
7.5 The Sphere 465
7.6 Flow Across Banks of Tubes 468
7.7 Impinging Jets 477
7.7.1 Hydrodynamic and Geometric Considerations 477
7.7.2 Convection HeatandMassTransfer ... in heat transfer. It explains the
linkage between heattransferand thermodynamics, and it reveals the relevance and rich-
ness of the subject. It should be covered in its entirety. Much of the ... is 25ЊC and
the plate measures 0.3 ϫ 0.3 m with a massof 3.75 kg
and a specific heatof 2770 J/kg ⅐ K.
1.23 A transmission case measures W ϭ 0.30 m on a side
and receives a power input of P
i
ϭ...
... water-ice mixture.
Mass and specific heatof reference sphere.
FIND:
Specific heatof the test sphere of known mass.
SCHEMATIC:
ASSUMPTIONS:
(1) Spheres are of equal diameter, ... Electrical heater is perfectly insulated
from dryer wall, (3) Heater and switch are isothermal at T
set
, (4) Negligible heattransfer from
sides of heater or switch, (5) Switch surface, A
s
, loses heat ...
KNOWN: Power consumption, diameter, and inlet and discharge temperatures of a hair
dryer.
FIND: (a) Volumetric flow rate and discharge velocity of heated air, (b) Heat loss from case.
SCHEMATIC:...
...
value of the heat rate.
PROBLEM 1.39
KNOWN: Power consumption, diameter, and inlet and discharge temperatures of a hair
dryer.
FIND: (a) Volumetric flow rate and discharge velocity of heated ... Electrical heater is perfectly insulated
from dryer wall, (3) Heater and switch are isothermal at T
set
, (4) Negligible heattransfer from
sides of heater or switch, (5) Switch surface, A
s
, loses heat ...
KNOWN:
Dimensions, thermal conductivity and surface temperatures of a concrete slab. Efficiency
of gas furnace and cost of natural gas.
FIND:
Daily cost ofheat loss.
SCHEMATIC:
ASSUMPTIONS:
...
... symbols dQ and dW represent differential heattransferand work
done, respectively. The differential operator, d, is used as both heattransferand work
are path functions and the evaluation of integrals ... product
r(v
:
n) dA
34
Fundamentalsof Momentum,
Heat, andMass Transfer
5th Edition
The pressures that act on the various faces of the element are numbered 1 through 6.
To find the sum of the forces ... Molecular MassTransfer 399
24.2 The Diffusion Coefficient 407
24.3 Convective MassTransfer 428
24.4 Closure 429
25. Differential Equations ofMassTransfer 433
25.1 The Differential Equation for Mass...
... COMBINED MODES OFHEAT TRANSFER
Previous sections treated each mode ofheattransfer separately. But in practice all the three
modes ofheattransfer can occur simultaneously. Additionally heat generation ... blank type and true or false type
questions are provided to test the understanding of the basic principles.
Author
PREFACE vii
VED
c-4\n-demo\damo2-3
74 FUNDAMENTALSOFHEATANDMASS TRANSFER
0.1 ... Problem model.
VED
c-4\n-demo\demo1-1.pm5
12 FUNDAMENTALSOFHEATANDMASS TRANSFER
Solution: Refer equation 1.10
Heat convected + heat radiated = heat conducted considering 1m
2
,
h(T
1
– T
2
)...
...
components
Heat output
Fig. 9 Micro heat pipe [54]
Two-Phase Flow andHeatTransfer in Micro-Channels 57
17. In, S., Jeong, S.: Flow boiling heattransfer characteristics of R123 and R134a in ... knowledge ofheattransfer mechanisms at different
conditions. Investigations on flow boiling heattransfer in literature have revealed
numbers of criteria of system classification, flow instabilities and ... Microchannel Heat Sinks. J. Heat Transf. 129(10), 1341–1351 (2007)
37. Brutin, D., Tadrist, L.: Pressure drop andheattransfer analysis of flow boiling in a
minichannel: influence of the inlet...
... problems of
heat transferand sometimes mass transfer.
This large and very interesting area of fluid mechanics is still developing
rapidly. For further information there are a wide range of multiple ...
Generation
of
mass
of
a
species
Accumulation ofmassof a
species
Input
and
output ofmassof
a
species
Example
2.1.2-1
Macroscopic species
mass
balance with
zero
-0
rde
r
irreversible ... for mass transfer:
r
1
(1.1.2-3)
where
NA
is the
mass
flux
of species
A,
k,
is the single-phase
mass transfer coefficient,
ZA~
is the concentration of
A
at the
surface, and...
... Convention for Thermal andMassTransfer Boundary Conditions
A wide variety of thermal andmasstransfer boundary conditions can be encoun-
tered in practice. Standard thermal andmasstransfer boundary ... (m)
l
ent,ma
Mass transfer entrance length (m)
l
ent,th
Thermal (heat transfer) entrance length (m)
l
M
Turbulence mixing length ( m)
l
M, ma
Turbulence mixing length f or masstransfer (m)
l
heat
Heated ... (m)
l
th
Turbulence mixing length f or heattransfer (m)
M Molar mass (kg/kmol)
Ma Mach number
m Mass fraction; dimensionless constant
m Mass (kg); massof a single molecule (kg)
m
Mass flux (kg/m
2
s)
N Ratio...
... corresponds to that
of heat conduction, whilst masstransfer in a flowing fluid, known for short as
convective masstransfer corresponds to convective mass transfer. Mass transfer
by diffusion and convection ... only sorts ofmass transfer. Radiative heat
transfer has no corresponding masstransfer process.
1.4.1 Diffusion
The calculation ofmasstransfer by diffusion requires several definitions and rela-
tionships ... heattransfer in film condensation, cross current heattransfer
and the analogy between heatandmasstransfer in evaporation.
76 1 Introduction. Technical Applications
We consider a volume of...