Discuss the below in detail:
Q: The handle of a ladle used for pouring molten lead is 30 cm long. Originally the handle was made of 1.9 A 1.25 cm mild steel bar stock. To reduce the grip temperature, it is proposed to form the handle of tubing 0.15 cm thick to the same rectangular shape. If the average heat transfer coefficient over the handle surface is 14 W/(m2 K), estimate the reduction of the temperature at the grip in air at 21°C.
GIVEN
A steel handle of a ladle used for pouring molten lead
Handle length (L) = 30 cm = 0.3 m
Original handle: 1.9 by 1.25 cm mild steel bar stock
New handle: tubing 0.15 cm thick with the same shape
The average heat transfer coefficient ( hc ) = 14 W/(m2 K)
Air temperature (T∞) = 21°C
ASSUMPTIONS
The lead is at the melting temperature
The handle is made of 1% carbon steel
The ladle is normally in steady state during use
The variation of the thermal conductivity is negligible
One dimensional conduction
Heat transfer from the end of the handle can beneglected
