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3 years ago

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2- A 2-m3 insulated tank containing ammonia at -20 C, 80% quality, is connected by a valve to a line flowing ammonia at 2 MPa, 6

0 C. The valve is opened, allowing ammonia to flow into the tank. At what pressure should the vale be closed if the manufacturer wishes to have 15 kg of ammonia inside at the final state?

1 answer:

alekssr [168]3 years ago

8 0

Answer:

The valve should be closed at 1081 kPa ⇒ 11 bar

Explanation:

$Q_{C_V} + m_ih_i = m_2u_2 - m_1u_1 + W_{C_V}$

$Q_{C_V} = W_{C_V} = 0$

$m_1 = \frac{V}{v_1} = \frac{2}{0.49927} = 4.006 kg$

$m_i = m_2 - m_1 = 15 - 4.006 = 10.994 kg$

$u_1 = 1057.5, h_i = 1509.9$

$u_2 = m_ih_i + m_1u_1$

$m_2 = \frac{[10.994*1509.9] + [4.006*1057.5]}{15} = 1389.1 kJ/kg$

$v_2 = \frac{V}{m_2} = \frac{2}{15} = 0.1333 m^3/kg$

Therefore, v₂, u₂ fix state 2.

By trial and error, P₂ = 1081 kPa & T₂ = 50.4° C

1081 kPa ⇒ 11 bar

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Answer:

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Here, heat transfer is taking placfenly in radial direction, so this is case of one dimentional conduction, hence Fourier's law of conduction is applicable.

Now, according to Fourier's law:

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Putting the values from the equations (ii) and (iii) in the equation (i), we have

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An incandescent light bulb can be regarded as a resistor. If its power output is 100W, calculate the resistance of the light bul

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