Chapter 6 Flashcards
What is the difference between a local convection heat transfer coefficient and an average heat transfer coefficient?
What are the units for local and average heat transfer coefficients?
What are the forms of Newton’s law of cooling for a heat flux and a heat rate? What are the analogous forms for convection mass transfer, expressed in molar and mass units?
Provide some examples for which species transfer by convection is pertinent
What is Fick’s Law?
What is the velocity boundary layer and under what conditions does it develop?
What is the thermal boundary layer and under what conditions does it develop?
What is the concentration boundary layer and under what conditions does it develop?
What quantities change with location in a velocity boundary layer?
What quantities change with location in a thermal boundary layer?
What quantities change with location in a concentration boundary layer?
Recognizing that convection heat (mass) transfer is strongly influenced by conditions associated with fluid flow over a surface, how is it that we may determine the convection heat (species) flux by applying Fourier’s (Fick’s) law to the fluid at the surface?
Do we expect heat and mass transfer to change with transition from a laminar to a turbulent boundary layer? If so, how?
What laws of nature are embodied by the convection transfer equations?
What physical processes are represented by the terms of the x-momentum equation (6.28)?
What physical processes are represented by the terms of the x-momentum equation (6.29)?
What physical processes are represented by the terms of the x-momentum equation (6.30)?
What special approximations may be made for conditions within thin velocity boundary layers?
What special approximations may be made for conditions within thin thermal boundary layers?
What special approximations may be made for conditions within thin concentration boundary layers?
How is the Reynold’s number defined?
What is the Reynold’s number’s physical interpretation?
What role is played by the critical Reynold’s number?
What is the definition of the Prandtl number?
How does the Prandtl number’s value affect relative growth of the velocity and thermal boundary layers for laminar flow over a surface?
What are representative room-temperature values of the Prandtl number for a liquid metal, a gas, water, and an oil?
What is the definition of the Schmidt number?
What is the physical interpretation of the Schmidt number?
How does the Schmidt number influence the relative velocity, thermal, and concentration boundary layer development for laminar flow over a surface?
What is the definition of the Lewis number?
What is the Lewis number’s physical interpretation?
How does the Lewis number influence the relative velocity, thermal, and concentration boundary layer development for laminar flow over a surface?
What is the coefficient of friction?
For flow over a prescribed geometry, what are the independent parameters that determine local and average friction coefficient values?
What is the Nusselt number?
For flow over a prescribed geometry, what are the independent parameters that determine local and average Nusselt number values?
What is the Sherwood number?
For flow over a prescribed geometry, what are the independent parameters that determine local and average Sherwood number values?
Under what conditions may velocity, thermal, and concentration boundary layers be termed analogous? What is the physical basis of analogous behavior?
What important boundary layer parameters are linked by the heat and mass transfer analogy?
What is the physical basis of the evaporative cooling effect? Have you ever experienced the effect?
What important boundary layer parameters are linked by the Reynolds analogy?
