Heat Transfer 11-1a1 Conduction R = L Fouriers Law of Conduction - - PowerPoint PPT Presentation

▶
heat transfer 11 1a1
SMART_READER_LITE
LIVE PREVIEW

Heat Transfer 11-1a1 Conduction R = L Fouriers Law of Conduction - - PowerPoint PPT Presentation

Jan 21, 2024 535 likes •599 views

Heat Transfer 11-1a1 Conduction R = L Fouriers Law of Conduction Thermal Resistance: kA Rate of Heat Transfer: Through a composite wall: Through a wall: R total = R 1 + R 2 = L 1 k 1 A + L 2 k 2 A Q = Qt Professional

slide-1
SLIDE 1

Professional Publications, Inc.

FERC

11-1a1 Heat Transfer

Conduction

Fourier’s Law of Conduction Rate of Heat Transfer:

  • Through a wall:

Thermal Resistance: R = L kA

  • Through a composite wall:

Rtotal = R1 +R2 = L1 k1A + L2 k2A Q = Qt

slide-2
SLIDE 2

Professional Publications, Inc.

FERC

11-1a2 Heat Transfer

Conduction

  • Through a cylindrical wall of length L:

R = lnr2 r1 2kL

slide-3
SLIDE 3

Professional Publications, Inc.

FERC

11-2 Heat Transfer

Convection

Convection Heat Transfer For a straight fin: P = exposed perimeter k = thermal conductivity Ac = cross-sectional area Tb = temperature of fin base T = fluid temperature

slide-4
SLIDE 4

Professional Publications, Inc.

FERC

11-3 Heat Transfer

Radiation

Black Body vs. Gray Body Black Body: Gray Body: = emissivity = 5.6710

8 W/m 2 K 4 (Stefan-Boltzmann constant)

emissivity() = absorptivity () = 1 = , and both are between 0 and 1

slide-5
SLIDE 5

Professional Publications, Inc.

FERC

11-4 Heat Transfer

Radiant Heat Transfer

For any body, radiation must be absorbed, reflected, or transmitted through: