A plane wall of thickness 150 mm has its area as 4.5 m². If its conductivity is 9.35 W/m'C and
surface temperature are steady at 150°C and 4°C, determine:
A) Heat flow across the wall.
B) Temperature gradient in the flow direction.
Answers
A) Heat flow across the wall = 29452.5 w/m^2
B) Temperature gradient in the flow direction= -700℃/m
Solution:
Wall thickness , dx= 150mm = 0.15 m
Area (A) = 4.5 m^2
Temperature difference = dt = 40- 150 = -105 C
Thermal conductivity , k = 9.35 w/m.℃
Applying the Fourier's Law of Heat Conduction,
Q = - K × A × dt/dx
=> Q = -(9.35) × 4.5 × (-105)/0.15
Q = 29452.5 w/m^2
( ii ) dt/dx. = -Q/KA
=. - 29452.5/(9.35×4.5)
= -700℃/m
Given:
A plane wall of thickness 150 mm has its area as 4.5 m². If its conductivity is 9.35 W/m'C and
surface temperature are steady at 150°C and 4°C
Find:
A) Heat flow across the wall = 29452.5 w/m^2
B) Temperature gradient in the flow direction= -700℃/m
Solution:
Wall thickness , dx= 150mm = 0.15 m
Area (A) = 4.5 m^2
Temperature difference = dt = 40- 150 = -105 C
Thermal conductivity , k = 9.35 w/m.℃
Applying the Fourier's Law of Heat Conduction,
Q = - K × A × dt/dx
=> Q = -(9.35) × 4.5 × (-105)/0.15
Q = 29452.5 w/m^2
( ii ) dt/dx. = -Q/KA
= - 29452.5/(9.35×4.5)
= -700℃/m