Air at 30°C and 2 MPa flows at steady state in a horizontal pipeline with a velocity of 25 m/s. It passes through a throttle valve where the pressure is reduced to 0.3 MPa. The pipe is the same diameter upstream and downstream of the valve. What is the outlet temperature and velocity of the gas

The outlet velocity is 159.9m/s

The outlet temperature = 290.6K

Explanation:

At initial condition

P=2 MPa

T=30°C

V=25 m/s

At final condition

P=0.3 MPa

Now from first law for open system

We know that for air

h= 1.010 x T  KJ/kg

Now from mass balance

Now from equation 1 and 2

So we can say that

The outlet velocity is 159.9m/s

Now by putting the values in equation 2

The outlet temperature = 290.6K