Calculation of thermophysical properties of fluids

توضیحات

Calculation of thermophysical properties of fluids

Department of Linguistics and Foreign Languages

Ph.D Thesis in Chemistry (Physical Chemistry)

Calculation of thermophysical

properties of fluids

ABSTRACT

Tetrafluoromethane which is a low temperature refrigerant is employed in electronicsmicro-fabrication and neutron detectors. Although structurally similar to chlorofluorocarbons(CFCs), tetrafluoromethane does not deplete the ozone layer.

The most crucial advantage of the inversion procedure is that the values of one property that is known accurately can be used to predict other properties that are known less accurately from the experiment.

Keywords: Corresponding states principle; Diffusion; Inversion method; Kinetic theory of gases; Thermal conductivity; Transport properties; Viscosity

LIST OF CONTENTS

CONTENT PAGE

CHAPTER I : Introduction

Introduction………………………………………………………………………………………… 2

CHAPTER II : Transport Properties

2.1Transport Properties of Dilute Gases and Gaseous

Mixtures……………………………………………………………………………………………… 7

2.2 Equations for Transport Properties……………………………………………………. 11

2.2.1 Collision integrals for elastic collision……………………………………………. 11

2.2.2 Viscosity Coefficient………………………………………………………………. 13

2.2.3 Diffusion Coefficient……………………………………………………………… 14

2.2.4 Thermal Diffusion Factor………………………………………………………… 14

2.2.5 Thermal Conductivity…………………………………………………………………… 15

CHAPTER III: The Law of Corresponding States for

Transport Properties

3.1 Extended law of Corresponding States ……………………………………………. 20

3.2 Viscosity Collision Integrals, for Molecular Gases…………………….. 22

3.3 Viscosity Collision Integrals, for Noble Gases………………………….. 22

3.4 Diffusion Collision Integrals, for Molecular Gases……………………… 23

3.5 Diffusion Collision Integrals, for Noble Gases…………………………… 24

CHAPTER IV: Intermolecular Potential

4.1 Practical Models for Intermolecular Pair Potential………………………………. 27

4.2 Inversion Method…………………………………………………………………………… 35

4.2.1 Historical Background…………………………………………………………….. 35

4.2.2 The Direct determination of Intermolecular……………………………….. 36

CHAPTER V: Results, Discussion and Conclusions

Results, Discussion and Conclusions……………………………………………………… 41

REFERENCES…………………………………………………………………………………… 71

LIST OF TABLES

TABLE PAGE

Table 5.1. The reduced collision integrals and their ratios for CF4–

He system…………………………………………………………………………………………… 45

Table 5.2 The reduced collision integrals and their ratios for CF4-Ne

System………………………………………………………………………………………………. 46

Table 5.3 The reduced collision integrals and their ratios for CF4–

Ar system……………………………………………………………………………………………. 47

Table 5.4 The reduced collision integrals and their ratios for CF4–

Kr system……………………………………………………………………………………………. 48

Table 5.5 The reduced collision integrals and their ratios for CF4–

Xe system…………………………………………………………………………………………… 49

Table 5.6 The reduced collision integrals and their ratios for CF4-CO2

systemTable ……………………………………………………………………………………….. 50

5.7 The reduced collision integrals and their ratios for CF4-N2 system………… 51

Table 5.8 The reduced collision integrals and their ratios for CF4-O2

system……………………………………………………………………………………………….. 52

Table 5.9 The reduced collision integrals and their ratios for CF4-CO

System……………………………………………………………………………………………….. 53

Table 5.10 The reduced collision integrals and their ratios for CF4-SF6

System……………………………………………………………………………………………….. 54

Table 5.11 The reduced collision integrals and their ratios for CF4-CH4

System……………………………………………………………………………………………….. 55

Table 5.12 Least squares coefficients, correlation coefficients (R), and

standard errors (ES) for Eq. (5.2) for CF4-noble gas mixtures……………………. 56

Table 5.13 Least squares coefficients, correlation coefficients and standard

errors for Eq. (5.3)……………………………………………………………………………….. 57

Table 5.14 Least squares coefficients, correlation coefficients and standard

errors for Eq. (5.4)………………………………………………………………………………. 58

Table 5.15 Least squares coefficients, correlation coefficients and standard

errors for Eq. (5.5)……………………………………………………………………………….. 58

LIST OF FIGURES

FIGURE PAGE

Figure 2.1 Trajectory of the particle in the central field…………………………….. 10

Figure 4.1 Pictorial representation of some spherically symmetrical

empirical potential functions…………………………………………………………………. 34

Figure 5.1 Deviations of the calculated viscosity values of CF4-He gaseous

system from those reported in [81] at different temperatures and mole

fractions x(He): 0.3748 (¿), 0.5209 (¢), 0.9134 (p)……………………………… 59

Figure 5.2 Deviations of the calculated viscosity values of CF4-Ne gaseous

system from those reported in [81] at different temperatures and

molefractions x (Ne): 0.1713 (¿), 0.3886 (¢), 0.5801 (r), 0.8041 (Í)……… 60

Figure 5.4 Deviations of the calculated viscosity values of CF4-Kr gaseous system from those reported in [82] at different temperatures and mole fractions x (Kr): 0.2122(¿),0.2899 (£), 0.5127 (p). 62

Tetrafluoromethane which is a low temperature refrigerant is employed in electronics micro-fabrication and neutron detectors. Although structurally similar to chlorofluorocarbons(CFCs), tetrafluoromethane does not deplete the ozone layer.

Table 5.1. The reduced collision integrals and their ratios for CF₄–

Table 5.2 The reduced collision integrals and their ratios for CF₄-Ne

Table 5.3 The reduced collision integrals and their ratios for CF₄–

Table 5.4 The reduced collision integrals and their ratios for CF₄–

Table 5.5 The reduced collision integrals and their ratios for CF₄–

Table 5.6 The reduced collision integrals and their ratios for CF₄-CO₂

5.7 The reduced collision integrals and their ratios for CF₄-N₂ system………… 51

Table 5.8 The reduced collision integrals and their ratios for CF₄-O₂

Table 5.9 The reduced collision integrals and their ratios for CF₄-CO

Table 5.10 The reduced collision integrals and their ratios for CF₄-SF₆

Table 5.11 The reduced collision integrals and their ratios for CF₄-CH₄

standard errors (E_S) for Eq. (5.2) for CF4-noble gas mixtures……………………. 56

Figure 5.1 Deviations of the calculated viscosity values of CF₄-He gaseous

Figure 5.2 Deviations of the calculated viscosity values of CF₄-Ne gaseous

Figure 5.4 Deviations of the calculated viscosity values of CF₄-Kr gaseous system from those reported in [82] at different temperatures and mole fractions x (Kr): 0.2122(¿),0.2899 (£), 0.5127 (p). 62

Figure 5.7 The comparison of the calculated viscosities with those calculated from Davidson’s method [84] CF₄-He (¿), CF₄-Ne (£), CF₄-Ar (p), CF₄-Kr (Ú), CF₄-Xe()……………………… 65

Figure 5.8 The comparison of the calculated viscosities with those calculated from Reichenberg’s method [85] CF₄-He (¿), CF₄-Ne (¢), CF₄-Ar (r), CF₄-Kr (Í),CF₄-Xe ()………………. 66

: for CF₄-CO₂ (¿), CF₄-N₂ (¢), CF₄-O₂ (p), CF₄-SF₆ (¯), CF₄-CH₄(£)

compared with [81], for CF₄-CH₄ (r) compared with [80], and for CF₄-CH₄

() compared with [83]………………………………………………………………………. 68

temperatures: for CF₄-He (¿), CF₄-Ne (p), CF₄-Ar(£) compared

with [81], for CF₄-Kr(r) compared with Ref [82]…………………………………… 69

Figure 5.12 Deviations for the thermal conductivity of CF₄-CH₄ mixture at temperature 303 K and different mole fractions compared with those given in

binary diffusion coefficient, m²s^-1

E_S standard error

kBoltzman constant, J K^-1

transport cross-section, m²