The handle of a ladle used for pouring molten lead is 30 cm long. Originally the handle
Question:
The handle of a ladle used for pouring molten lead is 30 cm long. Originally the handle was made of 1.9 × 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.GIVENA steel handle of a ladle used for pouring molten leadHandle length (L) = 30 cm = 0.3 mOriginal handle: 1.9 by 1.25 cm mild steel bar stockNew handle: tubing 0.15 cm thick with the same shapeThe average heat transfer coefficient ( hc ) = 14 W/(m2 K)Air temperature (T??) = 21?CASSUMPTIONSThe lead is at the melting temperatureThe handle is made of 1% carbon steelThe ladle is normally in steady state during useThe variation of the thermal conductivity is negligibleOne dimensional conductionHeat transfer from the end of the handle can beneglected
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Principles of heat transfer
ISBN: 978-0495667704
7th Edition
Authors: Frank Kreith, Raj M. Manglik, Mark S. Bohn