Question

An electrical heater 150 mm long and 5mm in diameter is inserted into a hole drilled normal to the surface of a large block of material having a thermal conductivity of 10W/mK. The temperature of the electrical heater is 70 oC and the temperature of block surface is 40 oC. Estimate the power dissipation of the electrical heater. (in W)

Answer 1

Step-by-step explanation:

From the table of conduction shape factor and dimensionless conduction rates for selected systems, for vertical cylinder in a semi-infinite medium

`S=& (2 \pi L)/(\ln \left((4 L)/(D)\right))`

`S=& (2 \pi L)/(\ln \left((4 L)/(D)\right))`

`(2 \pi * 0.1)/(\ln \left((4 * 0.1)/(0.005)\right))`

`=0.1433 \mathrm{m}`