In the final stages of production, a pharmaceutical is sterilized by heating it from 25 to 75C as it moves at 0.2 m/s through a straight thin-walled stainless steel tube of 12.7-mm diameter. A uniform heat flux is maintained by an electric resistance heater wrapped around the outer surface of the tube. If the tube is 10 m long, what is the required heat flux

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Answer:

The answer is "[tex]12682.267\ \ \frac{W}{m^2}[/tex]"

Explanation:

Calculating the mass flow rate of fluid:

[tex]m= \rho AV[/tex]

   [tex]= \rho \frac{\pi}{4} D^2\ V\\\\= 100 \times \frac{\pi}{4} \times (0.0127)^2\times 0.2\\\\=0.0253 \ \frac{kg}{s}\\\\[/tex]

Calculating the amount of heat transfer.

[tex]q =m\timesC_p(T_{m,0}-T_{m,i})[/tex]

  [tex]=0.0253 \times 4000 (75-25)\\\\=0.0253 \times 4000(50)\\\\=0.0253 \times 200,000 \\\\= 5060 \ W[/tex]

Calculating the required value for heat flux:

[tex]q"=\frac{q}{A_s}[/tex]

   [tex]=\frac{q}{\pi DL}\\\\= \frac{5060}{\pi \times 0.0127 \times 10}\\\\= 12682.267 \frac{W}{m^2}\\[/tex]