# Fluid Mechanics (Gas through a pipe)

1. Mar 17, 2010

### Thiendrah

1. The problem statement, all variables and given/known data
Hot CO₂ gas enters a pipe at pressure P₁ and exits at atmospheric pressure (P₂ = 1 bar) and T₂ = 0°C. The pipe has a constant diameter D = 1 cm. The input temperature is T₁ = 100°C and the mass flow rate ṁ = 0.5 g/min. There is a significant change in mechanical energy due to friction with a loss factor of 2500 m²/s².

Calculate the average flow velocities, input pressure and gas densities using the given data.

V₁ = ?
P₁ =?
T₁ = 100°C
ρ₁ =?

V₂ = ?
P₂ = 1 bar
T₂ = 0°C
ρ₂ = ?

2. Relevant equations
1. row2 = p2/RT2
2. V= m/(row2)A
3. Bernouliies eqn with loss.

3. The attempt at a solution
I followed those three equations. The problem begins when when V1 comes out as a new negative number. That's not possible. FYI - flow is from 1 to 2.

I'm not sure where I am missing a negative sign. I dont think it can be negative considering pressure and density values.