In: Mechanical Engineering

An aluminum plate with a thickness of 2L=0.22m is initially at a temperature of To=250°C. The plate is suddenly brought into contact with a fluid at a temperature of T∞=50°C, where the convection heat transfer coefficient is h=500 W/ m2K. Determine

a. the mid-plane temperature at t=300 seconds.

b. the total heat transfer from the plate to the fluid in 300 seconds if the surface area of one side of the plate is 1 m2 .

A thin plate is initially at a uniform temperature of 200°C. At
a certain timet = 0 the temperature of the east side of
the plate is suddenly reduced to 0°C. The other surface is
insulated. Use the explicit finite volume method in con- junction
with a suitable time step size to calculate the transient
temperature distribution of the slab and compare it with the
analytical solution at time (i) t = 40 s, (ii) t
= 80 s and...

You have 520 g of aluminum at an initial temperature of 350 °C.
(Aluminum has a specific heat capacity c = 0.214 cal/(g°C).) You
place it into a beaker filled with 860 g of water at an initial
temperature of 18 °C. (Water has a specific heat capacity c = 1.0
cal/(g°C).) Assume that no phase changes or chemical reactions
occur during this time.
Calculate the final temperature of the
aluminum~and water.
Calculate the amount of heat that enters the...

. A 20 mm diameter sphere made of aluminum alloy 2024 initially
at a uniform temperature of 500 ºC is suddenly immersed in a
saturated water bath maintained at atmospheric pressure. The
surface of the sphere has an emissivity or 0.25. Determine.
a.) the total heat transfer coefficient for this initial
condition, and
b.) what fraction of the total coefficient is contributed by
radiation. (~180 W/m2 -K, ~ 7%)

The air, which has a temperature of 120 ° C, flows
over a plate with a length of 1.2 m and a constant temperature of
30 ° C across the surface, and its speed flows at a speed of 2 m /
s. According to this,
a.) Calculate the speed and temperature boundary layer thickness at
the end of the plate.
b.) Find the local heat transfer coefficient and heat flux at the
end of the plate.
c.) Find the...

12a. A 0.260-kg piece of aluminum that has a temperature of -159
°C is added to 1.0 kg of water that has a temperature of 2.7 °C. At
equilibrium the temperature is 0 °C. Ignoring the container and
assuming that the heat exchanged with the surroundings is
negligible, determine the mass of water that has been frozen into
ice. Number Units
b. If the price of electrical energy is $0.09 per kilowatt·hour,
what is the cost of using electrical energy...

100 people enter a room that is initially at a temperature of 15
C and pressure of 1bar. Each person losses heat to the air in the
room at a constant rate of 300 W at a constant temperature of 37 C.
The air mass in the room is 750 Kg, remains constant and its cv =
0.79 kJ/(Kg K), cp = 1.08 kJ/(Kg K) and the gas constant is 0.287
kJ/(Kg K). Air enters the room at a temperature...

Two moles of helium are initially at a temperature of 29.0 ∘C
and occupy a volume of 2.90×10−2 m3 . The helium first
expands at constant pressure until its volume has doubled. Then it
expands adiabatically until the temperature returns to its initial
value. Assume that the helium can be treated as an ideal gas.
Part A
What is the total heat supplied to the helium in the
process?
Q
Q
=
nothing
J
SubmitRequest Answer
Part B
What is...

1. An aluminum circular cylinder 50 mm in diameter with ends
insulated is initially at 100◦C. Approximate the temperature at the
center of the cylinder after 2 s if the lateral surface is kept at
0◦C.For aluminum, k = 8.6 × 10−5m2 /s.
2. A circular cylinder 1 m in radius is completely insulated and
has an initial temperature distribution 100r ◦C. Find an expression
for the temperature as a function of r and t. Write integral
expressions for at...

Calculate the final temperature of a mixture of 180.0 g of ice
initially at -16.00 °C and 377.0 g of water initially at 92.50
°C

Part A.
A volume of 125 mL of H2O is initially at room temperature
(22.00 ∘C). A chilled steel rod at 2.00 ∘C is placed in the water.
If the final temperature of the system is 21.20 ∘C , what is the
mass of the steel bar? Use the following values: specific heat of
water = 4.18 J/(g⋅∘C) specific heat of steel = 0.452 J/(g⋅∘C)
Express your answer to three significant figures and include the
appropriate units.

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