Question

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

Answer #1

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 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.

A finned heat exchanger tube is made of aluminum alloy
(k=186W/m· K) and contains 125 annular fins per meter of tube
length. The bare tube between fins has an OD of 50 mm. The fins are
4mm thick and extend 15mm beyond the external surface of the tube.
The outer surface of the tube will be at 200◦C and the tube will be
exposed to a fluid at 20◦C with a heat-transfer coefficient of
40W/m2 · K. Calculate:
(a) The...

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...

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...

Used engine oil flows at 0.025 m/s through a 12.5-mm-diameter
tube. The oil enters the tube at a temperature of 27 ºC, while the
tube surface temperature is maintained at 87º C. Determine the oil
outlet temperature for a 100-m and the total heat transfer.

Select 1 m / s for a wall-illuminated 3 mm, inner 10 mm, 100 m long pipe, the incoming fluid entering 85 is cooled to 75 ℃. Apart from the pipe, there is a heat transfer coefficient of 7.8 W / m2.K and cross flowing water.
a) Calculate the temperature before the fluid.
b) Is the fluid flow laminar in the pipe? Is it turbulent? Why?
c) Calculate the heat transfer coefficient between the fluid and the inner surface of...

Pressurized Water is heated in a thin tube with a diameter of 60
mm. water enters with a mass flow rate of 0.01 kg/s and an inlet
temperature of 20°C. a uniform heat flux of 2000 W/m2 is applied to
the tube. What is the required length of the tube to obtain an exit
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A square aluminum plate 5 mm thick and 150 mm on a side is
heated while vertically suspended in quiescent air at 75°C.
Determine the average heat transfer coefficient for the plate when
its temperature is 15°C by two methods: using results from the
similarity solution to the boundary layer equations, and using
results from an empirical correlation.
The answer should be close to 5.78 and 5.92 W/m^2K
Please show all work

An aluminum transmission line with a diameter of 20 mm has an
electrical resistance of R'elec= 2.636 × 10-4 Ω/m and
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severe cross winds, increasing the probability of contact between
adjacent lines, thereby causing sparks and creating a potential
fire hazard for nearby vegetation. The remedy is to insulate the
line, but with the adverse effect of increasing the conductor
operating temperature.
(a) Calculate the conductor temperature...

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