A steel ball l of radius 30 mm is initially in thermal equilibrium at 1000anddeg;C in the furnace. It is then suddenly removed and cooled in ambient air at 30anddeg;C with convection heat transfer coefficient h = 20 W/m2K. find the time required in seconds to cool the steel ball in air from 1000anddeg;C to 450anddeg;C, (Take thermophysical properties of steel: density andrho; = 7600 kg/m3, Conductivity k = 40 W/mK, specific heat Cp = 500 J/kg K.)a)519b)519c)1590d)2144Correct answer is option 'C'. Can you explain this answer?

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A steel ball l of radius 30 mm is initially in thermal equilibrium at 1000°C in the furnace. It is then suddenly removed and cooled in ambient air at 30°C with convection heat transfer coefficient h = 20 W/m²K. find the time required in seconds to cool the steel ball in air from 1000°C to 450°C, (Take thermophysical properties of steel: density ρ = 7600 kg/m³, Conductivity k = 40 W/mK, specific heat C_p = 500 J/kg K.)

a)
519
b)
519
c)
1590
d)
2144

Correct answer is option 'C'. Can you explain this answer?

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A steel ball l of radius 30 mm is initially in thermal equilibrium at ...

Given, R = 30 x 10^-3 m.

T0 = 1000 °C

T∞ = 30 ° C

T = 450 ° C

h = 20 W/m²K

ρ = 7600 kg/m³

k = 40 W/mK

C_p = 500 J/kg K.

Now, biot number <0.1, applying="" limped="" analysis:="" ----------------="" (eq="">

Where,

Now applying ‘b’ in first equation (eq 1):

Therefore: τ = 1590.819 secs.

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A steel ball l of radius 30 mm is initially in thermal equilibrium at 1000°C in the furnace. It is then suddenly removed and cooled in ambient air at 30°C with convection heat transfer coefficient h = 20 W/m2K. find the time required in seconds to cool the steel ball in air from 1000°C to 450°C, (Take thermophysical properties of steel: density ρ = 7600 kg/m3, Conductivity k = 40 W/mK, specific heat Cp = 500 J/kg K.)a)519b)519c)1590d)2144Correct answer is option 'C'. Can you explain this answer?

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