Thermal Contact Conductance

Introduction.- Mechanism of Contact Heat Transfer.- Significance of Contact Heat Transfer.- Scope of Present work.- Thermal Constriction Resistance.- Circular Disc in Half Space.- Resistance of a Constriction Bounded by a Semi-Infinite Cylinder.- Constriction in a Gaseous Environment.- Other Types of Constrictions.- Solid Spot Conductance of a Joint.- Multiple Spot Contact Conductance.- Estimation of the Number and Average Size of Contact Spots.- Gaussian Distribution of Surface Heights and Slopes.- Deformation Analysis.- The Plasticity Index.- Ratio of Real to Apparent Area of Contact.- Theoretical Expressions for Thermal Contact Conductance.- Solid Spot Conductance for Fully Plastic Deformation.- Solid Spot Conductance for Elastic Deformation.- Effect of Macroscopic Irregularities.- Correlations for Solid Spot Conductance.- Numerical Example: Solid Spot Thermal Conductance.- A Generalised Approach to Determine Solid Spot Conductance.- Gas Gap Conductance.- Factors Affecting Gas Gap Conductance.- The Thermal Accommodation Coefficient.- Effect of Temperature on Accommodation Coefficient.- Summary of Observations.- Effect of Gas Pressure on Gas Gap Conductance.- Correlations for Gas Gap Conductance.- Periodic and Transient Contacts.- Experimental Aspects.- Axial Heat Flow Apparatus.- Radial Heat Flow Apparatus.- Periodic Contacts.- Transient Measurements.- Discussion of Transient Vs Steady-State Measurements.- Analogue Methods.- Experimental Accuracy.- Summary.- Control of Thermal Contact Conductance Using Interstitial Materials.- Solid Interstitial Materials.- Metallic Films.- Wire Screens.- Surface Coatings.- Constriction Resistance of a Plated Contact.- Effective Hardness of Coated Surfaces.- Thermal Contact Conductance of Coated Surfaces.- Insulating Interstitial Materials.- Lubricating Films and Greases.- Carbon Based Interstitial Materials.- Special Topics.... Mehr