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Air enters a diffuser witha velocity of 400 m/s, a pressure of 1 bar and temperature of 25 C. It exits with a temperature of 100 C. What is the exit velocity of the air? Assume there are no heat losses or change in potential energy Data:= 0.718 kJ/kg.°C. MW = 28.9 g/mol

Respuesta :

Answer:

Exit velocity of air is 96.43 m/s.

Explanation:

Given that

[tex]V_1=400\ m/s[/tex]

[tex]T_1=25C[/tex]

[tex]T_2=100C[/tex]

For air

[tex]C_p=1.005\ KJ/kg.K[/tex]

Now from first law of thermodynamics for open system at steady state

[tex]h_1+\dfrac{V_1^2}{2000}+Q=h_2+\dfrac{V_2^2}{2000}+w[/tex]

For diffuser

[tex]h_1+\dfrac{V_1^2}{2000}=h_2+\dfrac{V_2^2}{2000}[/tex]

We know that

[tex]h=C_pT[/tex]

[tex]h_1+\dfrac{V_1^2}{2}=h_2+\dfrac{V_2^2}{2000}[/tex]

[tex]1.005\times 25+\dfrac{400^2}{2000}=1.005\times 100+\dfrac{V_2^2}{2}[/tex]

[tex]V_2=96.43\ m/s[/tex]

So the exit velocity of air is 96.43 m/s.

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