Heat and Mass Transfer Exam II

Chapter 5: Transient Conduction Summary of transient heat transfer results for constant surface temperature 푇

Heat and Mass Transfer Exam II

Summary of transient heat transfer results for constant surface heat flux 푞

Heat and Mass Transfer Exam II

Chapter 6: Introduction to Convection Dimensionless Parameters for heat and mass transfer. 퐿 refers to the geometry of the system

Number Definition Number Definition

Biot 퐵푖 ℎ퐿푘

Nussult 푁푢 ℎ퐿푘

Mass Biot 퐵푖 ℎ 퐿퐷

Peclet 푃푒 푉퐿훼

Friction Coefficient 퐶

휏휌 푉 2⁄

Prandtl 푃푟 휈훼

Fourier 퐹표 훼푡퐿

Reynolds 푅푒 휌푉퐿휇

Mass Fourier 퐹표

퐷 푡퐿

Schmidt 푆푐 휈퐷

Grashof 퐺푟 푔훽(푇 − 푇 )퐿휈

Sherwood 푆ℎ ℎ 퐿퐷

Boundary Layer equations and their y-direction boundary conditions

Evaporative Cooling: energy consumed by a combination of heat and mass transfer and occurs when a gas flows

over a liquid and is dependent on the flux of the species

푞 = 푛 ℎ ℎ(푇 − 푇 ) = ℎ ℎ (휌∗(푇 ) − 휌 , )

Reynolds Analogy: relates velocity, thermal, and concentration boundary layers, restricted by the accuracy of the boundary layer which is depended on 푃푟and 푆푐 ≈ 1 and Δ푃 ≈ 0, 푺풕 = Stanton number

퐶2

= 푆푡 = 푆푡 푆푡 =푁푢푅푒푃푟

푆푡 =푆ℎ

푅푒푆푐

Heat and Mass Transfer Exam II

Chapter 7: External Flow Summary of convection heat transfer correlations for external flow

Heat and Mass Transfer Exam II

Chapter 8: Internal Flow Summary of convection heat transfer correlations for internal flow

Chapter 9: Free Convection Fluid motion is due to buoyancy forces within the fluid – buoyancy occurs due to a density gradient Methodology for convection calculation

1. Identify flow geometry/geometries for the system 2. Specify the appropriate reference temperature to evaluate fluid properties 3. For mass transfer, fluid properties refer to species 퐵 for binary mixtures 4. Calculate 푅푒 number 5. Decide whether a local or surface average coefficient is required 6. Select appropriate correlation(s) for the system