Question

Consider a pipe with an inner radius of 5cm and an outer radius of 7cm.The inner surface is kept at 100C, and the outer surface at 80C. Determine the heat loss per meter length of the pipe if the pipe is made of pure copper [k=387W/m.oC], pore aluminum [k=200W/m.C], and pure iron [k=62W/m.C].

Answer 1

Answer:

Explanation:

given data:

innner radius r_i = = 5cm

outer radius r_0 = 7 cm

temperature at outer surface = 80 degree celcius

temperature at inner surface = 100 degree celcius

thermal resistance per unit length is given as

$R _{th} = \frac{1}{ 2\pi kl} ln \frac{ ro}{ri}$

           $= \frac{1}{ 2\pi k*1} ln \frac{ 7}{5}$

           $= \frac{0.053}{k}$

heat loss rate per unit length $q = \frac{Ti-To}{R_{th}}$

$q = \frac{100-80}{\frac{0.053}{k}}$

q = 373.474 K

1) for pure COPPER

k  = 387 W/m degree celcius

q = 373.474 * 387  = 144534.438 W

2) for pure ALUMINIUM

k  = 200 W/m degree celcius

q = 373.474 * 200  = 74694.84 W

3)

1) for pure IRON

k  = 62W/m degree celcius

q = 373.474 * 62  = 23155.416 W