It is required to heat oil to about 500°C for quenching purpose. A ladder is used in the furnace. The section of ladder is (10 x 20) mm². The sourroundings are at 27°C.
It is required to heat oil to about 500°C for quenching purpose. A ladder is used in the furnace. The section of ladder is (10 x 20) mm². The sourroundings are at 27°C. The temperature of ladder at 400 mm from oil should not reach 50°C, then what is the value of heat transfer coefficient. [k = 205 W/m°C]
Heat transfer coefficcient, h = \[\frac{T_{0}-T_{\infty}}{T-T_{\infty}}=e^{mx}\]
\[\Rightarrow e^{m\left ( 0.40 \right )} = \frac{500-27}{50-27}\]
\[\Rightarrow m = 7.55\]
\[\Rightarrow \sqrt{\frac{hP}{kA}}=7.55\]
\[\Rightarrow \frac{h \times \left [ \left ( 0.010 + 0.020 \right )\times2 \right ]}{205\times\left ( 0.010\times 0.020 \right )}=57.13\]
\[h = 39.03\,W/m^{2\circ}C\]
