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2 years ago

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Two AISI 304 stainless steel plates 10 mm thick are subjected to a contact pressure of 1 bar under vacuum conditions for which t

here is an overall temperature drop of 100°C across the plates. What is the heat flux through the plates? What is the temperature drop across the contact plane?

1 answer:

Travka [436]2 years ago

7 0

The heat flux through the plates is $36297.6 \mathrm{W} / \mathrm{m}^{2}$ and temperature drop across the contact plane is $56^{\circ} \mathrm{C}$

<u>Explanation</u>:

The thermal conduction resistance in stainless-steel plates,

$R_{1}=R_{2}=\frac{L}{k}=\frac{10 \times 10^{-3}}{16.6 \times 1}=6.024 \times 10^{-4} \mathrm{m}^{2} \cdot \mathrm{K} / \mathrm{W}\\$

From thermal contact resistance for metallic interfaces under vacuum condition table,

the average thermal contact resistance for stainless steel,

$R_{\text {contact }}=15.5 \times 10^{-4} \mathrm{m}^{2} \cdot \mathrm{K} / \mathrm{W}$

The total Thermal resistance,

$R=R_{1}+R_{\text {conteet }}+R_{2}$

$=6.024 \times 10^{-4}+15.5 \times 10^{-4}+6.024 \times 10^{-4}$

$=27.55 \times 10^{-4} \mathrm{m}^{2} \cdot \mathrm{K} / \mathrm{W}$

Heat flux through the plates,

$q=\frac{T_{1}-T_{2}}{R}$

$=\frac{100}{27.55 \times 10^{-4}}$

$=36297.6 \mathrm{W} / \mathrm{m}^{2} \approx 36.3 \mathrm{kW} / \mathrm{m}^{2}$

Temperature drop across the contact plates,

$q=\frac{T_{i, 1}-T_{i, 2}}{R_{\text {contact }}}$

$T_{i, 1}-T_{i, 2} \approx 56^{\circ} \mathrm{C}$

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Answer:

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Explanation:

Heat flux is the rate at which thermal (heat) energy is transferred per unit surface area. It is measured in W/m2

Heat transfer(loss or gain) is unit of energy per unit time. It is measured in W or BTU/hr

1W = 3.41 BTU/hr

Given parameters:

thickness, t = 7.5mm = 7.5/1000 = 0.0075m

Temperatures 150 C = 150 + 273 = 423 K

50 C = 50 + 273 = 323 K

Temperature difference, T = 423 - 323 = 100 K

We are assuming steady heat flow;

a.) Heat flux, Q" = kT/t

K= thermal conductivity of the material

The thermal conductivity of brass, k = 109.0 W/m.K

Heat flux, $Q" = \frac{109 * 100}{0.0075} = 1,453,333.33 W/m^{2} \\ Heat flux, Q" = 1.453MW/m^{2} \\$

b.) Area of sheet, A = 0.5m2

Heat loss, Q = kAT/t

Heat loss, $Q = \frac{109*0.5*100}{0.0075} = 726,666.667W$

Heat loss, Q = 726,666.667 * 3.41 = 2,477,933.33 BTU/hr

c.) Material is now given as soda lime glass.

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Heat loss, Q = 6,666.67 * 3.41 = 22,733.33 BTU/hr

d.) Thickness, t is given as 15mm = 15/1000 = 0.015m

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2 years ago

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Answer:

Lets check each statement for the errors.

Explanation:

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The following error message will be displayed when this program statement will be compiled:

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String literals use double quotes. So to correct this syntax error, the statement should be changed as follows:

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The output of this corrected line is as following:

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The error message displayed when this line is compiled is as following:

Main.java:15: error: ; expected

Main.java:15: error: not a statement

So in order to correct this syntax error the statement should be changed as following:

System.out.println("about the future.");

The output of this corrected line is as following:

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System.out.println("Num is: " - userName);

There is a syntax error in this statement because of - symbol used instead of +

+ symbol is used to join together a variable and a value a variable and another variable in a single print statement.

The error message displayed when this line is compiled is as following:

Main.java:13: error: bad operand types for binary operator '-'

So in order to correct this syntax error the statement should be changed as following:

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Answer:

$Re=\dfrac{\rho\ v\ l}{\mu }$

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$Re=\dfrac{\rho\ v\ l}{\mu }$

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2 years ago

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Answer:

Here is the recursive function summation:

def summation(n, term):

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The screen shot of recursive function along with the output of explained examples is attached.

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