Discover new perspectives and gain insights with IDNLearn.com. Join our community to access reliable and comprehensive responses to your questions from experienced professionals.

An electrical device is insulated on all sides except one face. That face is bonded to a 4mm thick aluminum plate which is cooled by air. The electrical device dissipates 10^4 W m2 The resistance of the joint between the device and aluminum plate is 0.5E-4 m2K W The conductivity of the aluminum is 238 W mK The temperature of the air is 278 K and the convection coefficient from the aluminum plate to the air is 100 W m2K What is the operating temperature of the device

Sagot :

Answer:

t₁ = 378.668 K

Explanation:

From the given information:

The heat dissipated (q) from the electrical device = [tex]10^4 W/m^2[/tex]

The contact resistance between device and aluminium;

(R_{const} ) = 0.5× 10⁻⁴ m² K/W

Conductivity of aluminum (k)  = 238 \ W/mK

The thickness of aluminum plate (L) = 0.004 m

Convection coefficient (h) = 100 \ W/m^2 K

Surrounding temperature (t_2) = 278 \ k

According to Fourier's law of heat conduction.

[tex]q = \dfrac { t_1- t_2 }{R_{const} + \dfrac{L}{k} + \dfrac{1}{h} }[/tex]

[tex]10^4 = \dfrac{t_1 - 278}{0.5 \times 10^{-4} + \dfrac{0.004}{238} + \dfrac{1}{100} }[/tex]

[tex]10^4 *( 0.5 \times 10^{-4} + \dfrac{0.004}{238} + \dfrac{1}{100}) = t_1 - 278[/tex]

[tex]100.668 = t_1 -278[/tex]

t₁ = 378.668 K