2.) A fluid moves in a steady manner between two sections in a flow
line. At section 1: A2 = 10 ft?, V = 100 fpm, vl = 4 ftp/lb
At section 2: A2 = 2 ft², P2 = 0.20 lb/ft?
Calculate (a.) the mass flow rate, and
(b.) the speed at section 2

Respuesta :

Answer:

[tex]250\ \text{lbm/min}[/tex]

[tex]625\ \text{ft/min}[/tex]

Explanation:

[tex]A_1[/tex] = Area of section 1 = [tex]10\ \text{ft}^2[/tex]

[tex]V_1[/tex] = Velocity of water at section 1 = 100 ft/min

[tex]v_1[/tex] = Specific volume at section 1 = [tex]4\ \text{ft}^3/\text{lbm}[/tex]

[tex]\rho[/tex] = Density of fluid = [tex]0.2\ \text{lb/ft}^3[/tex]

[tex]A_2[/tex] = Area of section 2 = [tex]2\ \text{ft}^2[/tex]

Mass flow rate is given by

[tex]m=\rho A_1V_1=\dfrac{A_1V_1}{v_1}\\\Rightarrow m=\dfrac{10\times 100}{4}\\\Rightarrow m=250\ \text{lbm/min}[/tex]

The mass flow rate through the pipe is [tex]250\ \text{lbm/min}[/tex]

As the mass flowing through the pipe is conserved we know that the mass flow rate at section 2 will be the same as section 1

[tex]m=\rho A_2V_2\\\Rightarrow V_2=\dfrac{m}{\rho A_2}\\\Rightarrow V_2=\dfrac{250}{0.2\times 2}\\\Rightarrow V_2=625\ \text{ft/min}[/tex]

The speed at section 2 is [tex]625\ \text{ft/min}[/tex].

(a) The mass flow rate will be "250 lbm/min".

(b) At section 2, the speed will be "625 ft/min".

Speed and Mass

According to the question,

Section 1 area, A₁ = 10 ft²

Section 2 area, A₂ = 2 ft²

Water's velocity, V₁ = 100 ft/min

Volume at section 1, v₁ = 4 ft³/lbm

(a) We know the formula,

Mass flow rate, m = ρA₁V₁

                              = [tex]\frac{A_1 V_1}{v_1}[/tex]

By substituting the values,

                              = [tex]\frac{10\times 100}{4}[/tex]

                              = [tex]\frac{1000}{4}[/tex]

                              = 250 lbm/min

(2) The speed will be:

→ m = ρA₂V₂

or,

  V₂ = [tex]\frac{m}{\rho A_2}[/tex]

By substituting the values,

       = [tex]\frac{250}{0.2\times 2}[/tex]

       = [tex]\frac{200}{0.4}[/tex]

       = 625 ft/min

Thus the responses above are correct.  

Find out more information about speed here:

https://brainly.com/question/4931057