A large slab of steel at a uniform tempering temperature of 200°C and suddenly quenching, and it surface temperature lowered to 70°C. calculate the required time when the temperature at a depth 4.0 cm has dropped to 120°C? Given: steel [k =45 W/m°C, a=1.4×10³ m²/s, c=0.46 kJ/kg]

A large slab of steel at a uniform tempering temperature of 200°C and suddenly quenching, and it surface temperature lowered to 70°C. calculate the required time when the temperature at a depth 4.0 cm has dropped to 120°C? Given: steel [k =45 W/m°C, a=1.4×10³ m²/s, c=0.46 kJ/kg]

Principles of Heat Transfer (Activate Learning with these NEW titles from Engineering!)

8th Edition

ISBN:9781305387102

Author:Kreith, Frank; Manglik, Raj M.

Publisher:Kreith, Frank; Manglik, Raj M.

Chapter6: Forced Convection Over Exterior Surfaces

Section: Chapter Questions

Problem 6.26P

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Concept explainers

Work and Heat Transfer

It is generally related to thermal engineering which tells about the use, creation, conversion and transfer of heat energy between the systems. It is also considered that to transfer heat from one source to another, transfer of masses is also required. There are various mechanisms by which, transfer of heat takes place i.e. thermal conduction, convection, radiation or by change of phase. All these mechanisms have their own specific features which sometimes occur simultaneously within the same system.

Question

A large slab of steel at a uniform tempering temperature of 200°C and suddenly
quenching, and it surface temperature lowered to 70°C. calculate the required time when
the temperature at a depth 4.0 cm has dropped to 120°C?
Given: steel [k =45 W/m°C, a=1.4×10-5 m²/s, c=0.46 kJ/kg]

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