An electrical heater has a shape of a thinwalled square duct

An electrical heater has a shape of a thin-walled square duct. The duct cross section is 2cm x 2cm square; the length is 10cm. The duct is suspended vertically in air of temperature 20C. The ends of the duct are open. The inner and outer surfaces of the duct could be modeled as isothermal black surfaces. Calculate the power of the heater required to maintain the surface temperature at 580C. List all of your assumptions.

Solution

From the given data power required can be calculated as follows

powerpower required to maintain the temprature =48 KW