Air enters the compressor of a gas-turbine plant at ambient conditions of 100 kPa and 25°C with a low velocity and exits at 1 MPa and 347°C with a velocity of 90 m/s. The compressor is cooled at a rate of 1500 kJ/min, and the power input to the compressor is 254 kW. Determine the mass flow rate of air through the compressor. (Round the final answer to the nearest three decimal places.)

Respuesta :

Answer:

The mass flow rate of the air through the compressor

m'=0.6857

Explanation:

The law of gases help to find the mass flow in the gas-turbine

Ein=Eout

[tex]E_{in} =E_{out}\\W_{in}+m'*(h_{i}+\frac{v_{i}^{2}}{2})=Q_{out}+m'*(h_{o}+\frac{v_{o}^{2}}{2})\\W_{in}-Q_{out}=m'*(h_{o}-h_{i}+\frac{v_{o}^{2}-v_{i}^{2}}{2})[/tex]

Pressure determinate the 'h' the gas turbine move so

[tex]h_{i}=T1\\T1=25 C= 298K=h_{i}=298.2 \frac{kj}{kg}\\h_{o}=T2\\T2=347 C= 620K=h_{o}=628.07 \frac{kj}{kg}[/tex]

revolving for m'

[tex]m'=\frac{W_{in}-Q_{out}}{h_{o}-h_{i}+(\frac{vi^{2} -0}{2})(\frac{1\frac{kj}{kg} }{1000} \frac{m^{2} }{s^{2} } )} \\m'=\frac{254\frac{ki}{s} -1500\frac{ki}{60s}}{628.07-298.2+(\frac{90^{2} -0}{2s})(\frac{1\frac{kj}{kg} }{1000} \frac{m^{2} }{s^{2} } )} \\m'=\frac{229}{333.92}\\m'=0.6857[/tex]

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