Advances in heat transfer

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List of contributors
Analyses of buoyancy-driven convection
Introduction
Prediction of Nusselt number
Lessons from forced convection
Governing equations
Reynolds averaged equations for the mean flow and heat transport
Laminar DHVC solution
Dimensional analysis of buoyancy-driven convection
Dimensional analysis of laminar DHVC
Dimensional analysis of turbulent DHVC
Review of scaling patch approach
Layer structure of turbulent channel flow
Steps in scaling patch approach
Scaling analysis of laminar DHVC
Scaling analysis of the mean momentum equation in turbulent DHVC
Layer structure of the mean momentum balance equation
Properties of the Reynolds shear stress
Outer scaling of the mean momentum equation
Inner scaling of the mean momentum equation
7.5 Meso scaling of the mean momentum equation
Scaling analysis of the mean heat equation
Layer structure of the mean heat equation
Properties of the turbulent temperature flux Rwθ
Outer scaling of the mean heat equation
Alternative scaling of the turbulent temperature flux
Inner scaling of the mean heat equation
Scaling patches in the mean heat equation
New prediction of Nusselt number
Summary and conclusions
Acknowledgments
References
Convective heat transfer in different porous passages
Introduction
The governing equations
Physical interpretation of relaxation times
Energy equations with dimensionless coordinates and time
Micro-scale bio-heat diffusion
Boundary and initial conditions
Uncoupling-based solution method
Dual-phase lag bio-heat diffusion equation
Transformations of the dependent variable: The DPL equation
Temperature solution in finite regular tissues
Temperature solution in a laser-irradiated biological tissue
Transient thermal diffusion in porous devices
Transient temperature field with a moving fluid
Transient temperature field with stationary fluid
Steady state heat transfer to flow in porous passages
Formulation of heat transfer in porous ducts
Porous ducts with no-axial conduction
First solution
Second solution
Circular pipes
An alternative method of solution
Porous ducts with axial conduction
Parallel plate ducts
Solution
Circular ducts
Solution
Orthogonality condition and the determination of coefficients
Parallel plate channels
Circular pipes
Frictional heating effects
Rapidly switched heat regenerators in counterflow
Mathematical formulation for cyclic steady operation
Slowly- and rapidly-switched heat regenerators
General solution of the gas energy equation
``Cold´´ particles
Blow period
Reverse period
``Hot´´ particles
Reverse period
Blow period
``Internal´´ particles
Blow period
Reverse period
Fluid temperature solution
Effectiveness and heat stored in the regenerator
Concluding remarks
References
Heat exchange between the human body and the environment: A comprehensive, multi-scale numerical simulation
Introduction
Overall solution domain geometry
Numerical methods
Bioheat modeling
Pennes´ solution geometry
Numerical methods for the investigation into Pennes´ model
Pennes´ model boundary conditions
Pennes´ model computational grid and convergence
Pennes´ model thermophysical properties
Pennes´ model results
Heat transfer from the skin surface
Quantitative Pennes´ model temperature comparisons
Computational grid and convergence of the wind chill model
Boundary conditions
Thermophysical properties
Initial conditions
Results
Comparison of published Nusselt number correlations
Simulation validation using cylinder Nusselt number correlations
New facial Nusselt number correlation
Comparison of predicted facial temperatures with measured values
Temperature contour diagrams
Discussion of wind chill
Predicted facial temperatures
Concluding remarks
References
Pressure drop and heat transfer in the entrance region of microchannels
Introduction
Entrance length
Hydrodynamic entrance length
Thermal entrance length
Circular microchannels
Parallel plate microchannels
Rectangular microchannels
Continuous flow in the entrance region
Slip flow in the entrance region
Developing velocity profiles
Effects of aspect ratio and Knudsen number
Hydrodynamic development length
Elliptical microchannels
Fully developed flow and heat transfer
Laminar flow in the entrance region
Heat Transfer in the entrance region
Simultaneously developing flow
Hydrodynamically fully developed flow
Entrance length
Simultaneously developing flow
Hydrodynamically fully developed flow
Microchannel plate fin heat sinks
Liquid slip entrance flow
Nanofluid entrance flow
Effect of Reynolds number
Effect of aspect ratio
Effect of particle volume fraction
Acknowledgments
References
Predicting mesoscale spectral thermal conductivity using advanced deterministic phonon transport techniques
Introduction
The phonon gas
Frequency-dependent phonon transport
Thermal interfacial resistance
Convergence performance of phonon transport methods
Methodology
The Boltzmann transport equation for phonons
Spectral phonon transport
Multigroup gray phonon transport
Frequency-independent gray phonon transport
Spectral phonon diffusion
Weak forms of the multigroup phonon transport equations
Self-adjoint angular flux formulation
Spatial discretization
Multigroup gray method
Frequency-independent gray method-Finite difference
Weak form of the multigroup phonon diffusion equation
Spatial discretization
Derivation of energy conservation
Interface conditions
Diffuse mismatch model
Uncertainty quantification
Material property development
First-order phonon transport properties
Determination of the phonon mean free path
Decomposition into transport groups
Results
Spectral phonon transport
Spectral phonon transport in silicon
Frequency-independent gray phonon transport
Single crystal uranium dioxide
Thermal conductivity in z-axis graphite
Thermal conductivity of Si with uncertainty quantification
Silicon nanowires in germanium superstructure
Xenon bubble in uranium dioxide
Convergence studies
Four-group data set
Test problem A
Test problem B
Conclusions
Acknowledgments
References
An overview of mathematical models and modulated-heating protocols for thermal ablation
Introduction
The clinical aspect: Why induced hyperthermia is so important
What is thermal ablation?
How to quantify damage
Ablation procedures
Scope of the present chapter
Modeling
Thermal problem
Heat source term modeling
Modulated-heating protocols
Radiofrequency ablation
Microwave ablation
Conclusions
References
Thermal stimulation of targeted neural circuits via remotely controlled nano-transducers: A therapy for ne ...
Introduction
Neurodegenerative disorders
Magnetothermal stimulation
Thermal field characterization
Blood flow analysis
Blood flow homogeneity
Blood rheology
Pulsatile blood flow
Brain capillary analysis
Average thermophysical properties
Thermal models for nano transducers injected into brain capillaries
Single phase approach; homogenous method
Two-phase approach; Eulerian-Lagrangian method
Nanoparticle dynamics
Drag force
Gravity force
Lift force
Brownian force
Thermophoretic force
Pressure gradient force
Virtual mass force
Neuro-signaling model
Concluding remarks
Acknowledgment
References