Question

A stainless-steel fin (k = 16 W/m. °C) has a length of 15 cm and a square cross section 12.5 by 12.5 mm attached to a wall maintained at 250 °C. The heat-transfer coefficient is 40 W/m. °C, and the environment temperature is 90 °C. Calculate the percentage increase in heat transfer after attaching the fin.

Answer #1

Consider an aluminum pin fin (k = 240 W/m·K) with a 2 mm by 2 mm
square cross-section and a length of 4 cm that is attached to a
surface at 100o C. The fin is exposed to air at 25o C with a
convection heat transfer coefficient of 20 W/m2 · o C. Determine
the rate of heat transfer and the tip temperature of the fin for
the following cases:
(a) Convection from the fin tip.
(b) Adiabatic tip...

An aluminum fin 1.6 mm thick surrounds a tube 2.5 cm
in diameter. The length
of the fin is 12.5 mm. The tube-wall temperature is 200◦C, and the
environment
temperature is 20◦C. The heat-transfer coefficient is 60 W/m2 · ◦C.
Consider the heat dissipated in a pipe 1.20 m long if the fins are
4.2 mm apart from center to center
Explain your procedure with formulas

It's a heat transfer question.
A stainless steel fin with a constant base temperature (900K)
and with an insulated end. Apply convection at all cylindrical
surfaces except the base and the tip. The convection coefficient, h
= 50 W/(m2·K), and fluid temperature of T∞ =
300K. Plot the temperature distribution along the center
axis line (T vs x). Include a contour plot across the
cross section of the fin. Assume zero contact resistance between
the sections.
K=19.8W/m-k Cp=557J/Kg-K Rho= 7900Kg/m^3...

Annular steel fins (k=56.7W/m· K) are attached to a steel tube
that is 30mm in external diameter. The fins are 2mm thick and 15mm
long. The tube wall temperature is 350K and the surrounding fluid
temperature is 450K with a heat-transfer coefficient of 75W/m2 · K.
There are 200 fins per meter of tube length. Calculate:
(a) The fin efficiency.
(b) The fin surface area per meter of tube length.
(c) The prime surface area per meter of the tube...

A fin of rectangular profile has a thermal conductivity of 14
W/m C, thickness of 2.0 mm, and length of 23 mm. The base of the
fin is maintained at a temperature of 220 o C while the fin is
exposed to a convection environment at 23 o C with h=25 W/m2 o C.
Calculate heat lost per meter of fin depth for the three tip
conditions. (a) Convection, (b) Adiabatic, and (c) T (x=L) = 23 o
C.

A long 10 cm × 20 cm rectangular cross section steel bar ݇ k=
63.9 W/mK and alpha=18.8*10^-6 m^2 /s was heated to an initial
temperature of 450°C. The steel bar is allowed to cool in a room
with a temperature of 25°C and convection heat transfer coefficient
of 25 W/m^2 K. The bottom surface of the bar is insulated while the
other surfaces are exposed to convection. With a uniform nodal
spacing of 5 cm, determine the duration required...

A pin fin, fabricated from an aluminum alloy (k = 185 W/m K),
has a diameter of D = 3 mm and a length of L = 15 mm. Its base
temperature is Tb = 100°C, and it is exposed to a fluid
for which T∞ = 20°C and h = 50 W/m2 K.
Provide a sketch and state your assumptions (1 point)
Use Table 3.5 in the book (grading is based on the use of
that particular table) to...

For a straight, rectangular fin that is 2 cm in length, and 1 cm
in thickness, with a thermal conductivity of 55 W/moC,
density = 8000 kg/m3, and a wall temperature of
500oC in an environment where h=50 W/m2oC and
Tair = 25oC, what is the heat dissipated from
the fin per meter of depth?

A house has a composite wall of wood (exterior) (k = 0.12 W m-1
K -1 , 20 mm thick), fibreglass insulation (k = 0.045 W m-1 K -1 ,
70 mm thick) and plasterboard (interior) (k = 0.25 W m-1 K -1 , 10
mm thick). Determine the total heat loss through the wall when the
inside temperature is 20 °C, the outside temperature is -10 °C, the
inside heat transfer coefficient is 15 W m-2 K -1 ,...

2.1Consider a solid cylindrical rod of length 0.15 m and
diameter 0.05 m. The top and bottom surfaces of the rod are
maintained at constant temperatures of 20oC and 95oC, respectively,
while the side surface is perfectly insulated. 2.1.1 Draw a diagram
to represent the situation described above. (3) 2.1.2 Determine the
rate of heat transfer through the rod if it is made of copper, k =
380 W/m? oC. (4) 2.1.3 Determine the rate of heat transfer through
the...

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