A cylindrical tank must be designed to contain 5 kg of compressed nitrogen at a pressure of 200 atm (gage) and 20°C. The design constraints are that the length must be twice the diameter and the wall thickness must be 0.5 cm. What are the external dimensions?

Respuesta :

Answer:

[tex]D_o = 0.249 m[/tex]

Explanation:

Given data:

Mass of cylinder is 5 kg

Pressure  = 200 atm

Temperature = 20 degree celcius = 293 K

wall thickness  = 0.5 cm = 0.005 m

we know that Gas constant for nitrogen is calculated as

[tex]\frac{\bar{R}}{M}[/tex]

[tex]R = \frac{8314}{28.01} = 296.82 J/kg.K

FROM IDEAL GAS EQUATION

PV =mRT

[tex]V = \frac{mRT}{P}[/tex]

[tex]= \FRAC{5\times 296.82\times 293}{200\times 101325}[/tex]

V = 0.021457 m^3

internal diameter  by using volume formula

[tex]V =\frac{\pi}{4} D_i^2 L[/tex]

[tex]0.021457 = \frac{\pi}{4} D_i^2 (2D_i)[/tex]

solving for [tex]D_i[/tex]

[tex]D_i = 0.239 m[/tex]

calculate the outer diameter

[tex]D_o = D_i + 2t[/tex]

[tex]= 0.239  + 2\times 0.005[/tex]

[tex]D_o = 0.249 m[/tex]