A thin metal pipe of 1 meter length and 1 cm radius carries steam at 100∘C. This is covered by two layers of lagging. The thermal conductivity of outer layer, which is 2 cm thick is 3.6×10−4 cal/cm∘C sec while that of inner layer, which is 1 cm thick is 1.2×10−4 cal/m∘C sec. If the outer surface of the laggings is at 30∘C, find (a) temperature of the cylindrical interface of two lagging materials (b) the mass of steam condensed per second. Given loge=0.6931.

A thin metal pipe of 1 meter length and 1 cm radius carries steam at 1

1.	A thin metal pipe of 1 meter length and 1 cm radius carries steam at 100∘C. This is covered by two layers of lagging. The thermal conductivity of outer layer, which is 2 cm thick is 3.6×10−4 cal/cm∘C sec while that of inner layer, which is 1 cm thick is 1.2×10−4 cal/m∘C sec. If the outer surface of the laggings is at 30∘C, find (a) temperature of the cylindrical interface of two lagging materials (b) the mass of steam condensed per second. Given loge=0.6931.
Answer» A thin metal pipe of 1 meter length and 1 cm radius carries steam at $100^{\circ} C$ . This is covered by two layers of lagging. The thermal conductivity of outer layer, which is 2 cm thick is $3.6 \times 10^{- 4} c a l / c m^{\circ} C$ sec while that of inner layer, which is 1 cm thick is $1.2 \times 10^{- 4} c a l / m^{\circ} C$ sec. If the outer surface of the laggings is at $30^{\circ} C$ , find (a) temperature of the cylindrical interface of two lagging materials (b) the mass of steam condensed per second. Given $l o g_{e} = 0.6931$ .