Advances in heat transfer

Description

Copyright 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