Theory of Laminar Film Condensation

ISBN-13: 9781461278160 / Angielski / Miękka / 2011 / 213 str.

Tetsu Fujii

Opis

Since the petroleum crisis in the 1970s, a lot of effort to save energy was made in industry, and remarkable achievements have been made. In the research and development concerning thermal energy, however, it was clar ified that one of the most important problems was manufacturing con densing systems with smaller size and higher performance. To solve this problem we need a method which synthesizes selections_ of the type of con denser, cooling tube and its arrangement, assessment of fouling on the cooling surfaces, consideration of transient characteristics of a condenser, etc. The majority of effort, however, has been to devise a surface element which enhances the heat transfer coefficient in condensation of a single or multicomponent vapor. Condensation phenomena are complexly affected by a lot of physical property values, and accordingly the results of theo retical research are expressed with several dimensionless parameters. On the other hand, the experimental research is limited to those with some specified cooling surfaces and some specified working fluids. Hence, the basic research of condensation is necessary for criticizing the enhancement effect as well as for an academic interest."

Spis treści

1 Introduction.- References.- 2 Basic Equations for Laminar Film Condensation of a Binary Vapor.- References.- 3 Similarity Solution of Forced-Convection Condensation of Binary Vapors.- 3.1 Similarity Transformation.- 3.2 Procedure of Numerical Calculation.- 3.3 Examples of Numerical Solutions.- 3.3.1 Characteristics of the Boundary Values.- 3.3.2 Distributions of Velocity, Temperature, and Concentration.- 3.3.3 Possibility of the Appearance of Subcooling in the Vapor Boundary Layer.- 3.4 Formulas of the Boundary Values ?’FLw,?’FLi, and ?’FVi for Dimensionless Temperature.- 3.5 Formula of the Boundary Value ?’Fi for Normalized Concentration.- 3.6 Algebraic Method for Calculating Condensation Mass Flux and Heat Flux.- 3.7 Flow Resistance.- 3.8 Relations between Relevant Physical Quantities and Dimensionless Functions.- References.- 4 Similarity Solution for Free-Convection Condensation of Binary Vapors.- 4.1 Similarity Transformation.- 4.2 Procedure of Numerical Calculation.- 4.3 Examples of Numerical Solutions.- 4.3.1 Characteristics of the Boundary Values.- 4.3.2 Distributions of Velocity, Temperature, and Concentration.- 4.3.3 Possibility of the Appearance of Subcooling in the Vapor Boundary Layer.- 4.4 Formulas of the Boundary Values ?’GLw,?’GLi and ?’GVi for Dimensionless Temperature.- 4.5 Formula of the Boundary Value ?’Gi for Normalized Concentration.- 4.6 Algebraic Method for Calculating Condensation Mass Flux and Heat Flux.- 4.7 Relations between Relevant Physical Quantities and Dimensionless Functions for Free-Convection Condensation.- References.- 5 Condensation of Pure Vapors.- 5.1 Forced-Convection Condensation of Saturated Pure Vapors.- 5.2 Forced-Convection Condensation of Superheated Pure Vapors.- 5.3 Free-Convection Condensation of Saturated Pure Vapors.- 5.4 Free-Convection Condensation of Superheated Pure Vapors.- 5.5 Combined Forced- and Free-Convection Condensation of Saturated Pure Vapors.- 5.6 Discussion on the Shekriladze and Gomelauri’s Solution for Forced-Convection Condensation of Saturated Pure Vapors.- 5.7 Condensation of Saturated Pure Vapors in the Case of Uniform Heat Flux.- 5.7.1 Forced-Convection Condensation.- 5.7.2 Free-Convection Condensation.- References.- 6 Condensation of Binary Vapors.- 6.1 Forced-Convection Condensation of Mixtures of Vapor and Noncondensable Gas.- 6.1.1 Mixture of Air and Saturated Steam — Graphical Solution.- 6.1.2 Necessary Condition for the Appearance of Mist and its Effect on Condensation Characteristics.- 6.1.3 An Approximate Solution in the Case of Small Vapor Concentration.- 6.2 Free-Convection Condensation of Mixtures of Vapor and Noncondensable Gas.- 6.2.1 The Case of a Saturated Vapor and Negligible Convective Heat Transfer in the Vapor Phase.- 6.2.2 Single Phase Free-Convection with Simultaneous Heat and Mass Transfer —The Case of Very Small Condensation Mass Flux.- 6.3 Forced-Convection Condensation of Binary Vapors.- 6.3.1 Graphical Solution and Some Typical Examples.- 6.3.2 Accuracy of the Stagnant Film Theory.- 6.4 Free-Convection Condensation of Binary Vapors.- 6.5 Combined Forced- and Free-Convection Condensation of Binary Vapors.- References.- 7 Forced-Convection Condensation of Multicomponent Vapors.- 7.1 Basic Equations for Forced-Convection Condensation of a Multicomponent Vapor.- 7.2 Similarity Transformation.- 7.3 Orthogonal Transformation of the Ordinary Differential Equations using the Matrix Method.- 7.4 Algebraic Equations for a Multicomponent Vapor.- 7.5 Algebraic Equations for a Ternary Vapor.- 7.6 An Example for an Air-Methanol-Water Mixture.- References.- 8 Free-Convection Condensation of Multicomponent Vapors.- 8.1 Basic Equations, Transformations, and Algebraic Equations.- 8.2 Free-Convection Heat and Mass Transfer of Ternary Vapors.- 8.3 Free-Convection Condensation of Ternary Vapors.- References.- 9 Representative Physical Properties for the Condensate Film and the Vapor Boundary Layer.- 9.1 Representative Physical Properties for the Condensate Film.- 9.1.1 Approximate Analysis for Forced-Convection Condensation of a Saturated Pure Vapor.- 9.1.2 Numerical Analysis for Forced-Convection Condensation of Saturated Pure Vapors.- 9.1.3 Approximate and Numerical Analyses for Free-Convection Condensation of Saturated Pure Vapors.- 9.2 Representative Physical Properties for the Vapor Boundary Layer.- 9.2.1 Forced-Convection Condensation of Binary Vapors.- 9.2.2 Free-Convection Condensation of Binary Vapors.- References.- 10 Condensation of Pure Vapors in the Subcritical Region.- 10.1 Forced-Convection Condensation.- 10.1.1 Basic Equations and Similarity Transformation.- 10.1.2 Examples of Numerical Solutions.- 10.1.3 Wall Heat Flux and Condensation Mass Flux.- 10.2 Free-Convection Condensation.- 10.2.1 Basic Equations and Similarity Transformation.- 10.2.2 Examples of Numerical Solutions.- 10.2.3 Wall Heat Flux and Condensation Mass Flux.- References.- Appendix: Physical Properties.- A2 Phase Equilibrium.- A6 Thermal Conductivity ? [W/mK].- A9 Equations for Predicting Physical Properties of Mixtures.- A10 Viscosity of Mixtures of Polar Molecules.- References.- Author Index.