A cryogenic fluid flows through a 35mm diameter tubewhich is concentric with a tube of 90mm diameter, surface emmisivities of inner and outer tube are 0.02 & 0.05 while temperature are 100^oK & 300^oK respectively. Find:
Percentage reduction in heat gained, if a radiation shield with diameter 54mm (emissivity is 0.03 for inner surface and 0.04 for outer surface) is introduced between the tubes. Refer the image in simulation.
$$Percentage\ Reduction\ in\ heat\ gain = \frac{Q_w - Q_s}{Q_w} * 100$$

A cryogenic fluid flows through a 35mm diameter tubewhich is concentric with a tube of 90mm diameter, surface emmisivities of inner and outer tube are 0.02 & 0.05 while temperature are 100^oK & 300^oK respectively. Find:
Steady state temperature attained by the shield. Refer the image in simulation.
$$T_3 = (\frac{-Q_s(\frac{1 - \epsilon_1}{A_1 \epsilon_1} + \frac{1}{A_1 F_{13}} + \frac{1-\epsilon_3}{A_3 \epsilon_3})}{\sigma} + T_1^4)^{1/4}$$