气体热动力润滑与密封

CHAPTER 1 Properties of gases.1

1.1 Gas equations 1

1.1.1 Ideal gas equations.. 2

1.1.2 Gas index equation.. 3

1.1.3 Actual gas equation. 5

1.1.4 Degree of gas molecular freedom .. 5

1.1.5 Specific heat capacity 7

1.2 Viscosity ..7

1.3 Property of wet gas .11

1.3.1 Pressure .. 12

1.3.2 Humidity. 13

1.3.3 Dew point temperature 14

References 14

CHAPTER 2 Gas lubrication equations. 15

2.1 Reynolds equation 15

2.1.1 Derivation of Reynolds equation.. 16

2.1.2 Reynolds equation in the polar coordinate system . 19

2.1.3 Reynolds equation in the cylindrical coordinate system.. 19

2.1.4 Lubrication parameters .. 20

2.2 Energy equation.22

2.2.1 Chang of gas inner energy 23

2.2.2 External work on gas and energy loss 24

2.3 Solid heat conduction equation and the interface equation ..26

2.4 Numerical analysis method.27

2.4.1 Finite difference method 27

2.4.2 Flow conservation. 28

2.4.3 Friction force balance . 34

References 35

CHAPTER 3 Isothermal gas lubrication .. 37

3.1 Sliders .37

3.1.1 Lubrication equation 38

3.1.2 Pressure boundary condition 40

3.1.3 Lubrication performance parameters.. 40

VI Contents

3.2

3.3

CHAPTER 4

4.1

4.2

4.3

4.4

3.1.4 Hydrodynamic lubrication characteristics of sliders.. 41

3.1.5 Hydrodynamic lubrication characteristics of divergent sliders .. 43

3.1.6 Lubrication characteristics of the magnetic head slider . 45 Journal bearing and radial seal .51

3.2.1 Lubrication equations.. 52

3.2.2 Boundary conditions 52

3.2.3 Lubrication parameters .. 53

3.2.4 Lubrication characteristics 55

Spiral groove thrust bearing56

3.3.1 Gas lubrication equations.. 59

3.3.2 Pressure boundary conditions . 60

3.3.3 Lubrication parameters .. 60

3.3.4 Lubrication characteristics 61

3.3.5 Spiral groove face seal 64

3.3.6 Lubrication equations.. 65

3.3.7 Pressure boundary conditions . 65

3.3.8 Seal performance parameters.. 66

3.3.9 Lubrication regularity . 66

References 71

Gas thermohydrodynamic lubrication of rigid surfaces.. 73 Sliders .73

4.1.1 Gas lubrication equations.. 73

4.1.2 Boundary conditions 75

4.1.3 Thermal lubrication characteristics . 75

Journal bearing and radial seal .79

4.2.1 Lubrication equations.. 79

4.2.2 Thermal boundary condition 80

4.2.3 Lubrication property 80

Spiral groove thrust bearing83

4.3.1 Lubrication equations.. 83

4.3.2 Boundary conditions 85

4.3.3 Lubrication property 86

Spiral groove face seal..86

4.4.1 Temperature characteristics of gas film 91

4.4.2 Lubrication property 94

References 99

Contents VII

CHAPTER 5 Gas thermoelastohydrodynamic lubrication of face seals . 101

5.1 Fundamental equations101

5.1.1 Lubrication equations 101

5.1.2 Boundary conditions . 104

5.2 Choked fluid effect107

5.2.1 Model validation . 107

5.2.2 Pressure distribution characteristics . 109

5.3 Characteristics of thermoelastic distortions of seal faces..109

5.4 Characteristics of gas thermoelastohydrodynamic lubrication..111

5.4.1 Mechanical distortions . 111

5.4.2 Thermal distortions 115

5.4.3 Thermoelastic distortions 117

References. 120

CHAPTER 6 Transient thermoelastohydrodynamic gas lubrication of face seals 121

6.1 Fundamental equations121

6.1.1 Dynamic equations. 122

6.1.2 Lubrication equations 122

6.1.3 Boundary conditions . 123

6.1.4 Dynamic characteristic parameter . 123

6.2 Dynamic characteristics of isothermal gas lubrication .124

6.2.1 Axial stiffness and damping . 124

6.2.2 Angular stiffness and damping 126

6.2.3 Amplitude-frequency characteristics of gas film .. 129

6.3 Dynamic characteristics of thermal gas lubrication of rigid surfaces 130

6.3.1 Axial stiffness and damping . 131

6.3.2 Angular stiffness and damping 134

6.3.3 Amplitude-frequency characteristics of gas film .. 137

6.4 Dynamic characteristics of gas thermoelastohydrodynamic lubrication..137

6.4.1 Axial stiffness and damping . 137

6.4.2 Angular stiffness and damping of gas film .. 139

6.4.3 Amplitude-frequency characteristics of gas film. 140 References. 141

VIII Contents

CHAPTER 7 Vapor-condensed gas lubrication of face seals .. 143

7.1 Fundamental equations143

7.1.1 Wet gas equations .. 143

7.1.2 Vapor-condensed parameter . 145

7.2 Characteristics of vapor condensation in gas lubrication film 145

7.3 Laws of vapor condensation in gas lubrication film..146

7.3.1 Humidity.. 146

7.3.2 Seal clearance 147

7.3.3 Seal pressure . 148

7.3.4 Rotational speed.. 148

7.4 Movement of liquid drops on gas lubrication surfaces.150

7.4.1 Surface wetting model . 150

7.4.2 Surface-texture geometry parameters and wettability 152

7.4.3 Droplet motion . 158

7.4.4 Drop adsorption on seal surface . 164

References. 164

CHAPTER 8 Cryogenic gas lubrication of face seals 167

8.1 Fundamental equations167

8.1.1 Lubrication equations 168

8.1.2 Boundary conditions . 171

8.2 Phase change in gas lubrication film..172

8.3 Characteristics of thermoelastic distortions of seal faces 173

8.4 Characteristics of cryogenic gas lubrication173

8.4.1 Ambient temperature 174

8.4.2 Rotation speed.. 174

References. 177

CHAPTER 9 Surface grooves of gas face seals and testing technology.. 179

9.1 Surface grooves of gas face seals .179

9.2 Testing technology of gas face seals ..185

9.2.1 Experimental setup. 185

9.2.2 Face groove machining 185

9.2.3 Face morphology test 187

9.3 Experimental characteristics of gas face seals ..188

9.3.1 Seal opening characteristic 188

9.3.2 Hydrodynamic characteristics.. 190

Contents IX

9.3.3 Surface wear.. 192

References. 195

CHAPTER 10 Design of gas face seals 197

10.1 Force analysis of gas seals197

10.1.1 Opening force. 198

10.1.2 Closing force.. 198

10.1.3 O-ring friction force 199

10.2 Geometric parameters of gas face seals 199

10.2.1 Seal clearance. 199

10.2.2 Seal face width.. 199

10.2.3 Balance diameter.. 200

10.2.4 Seal face and shaft (shaft sleeve) clearance.. 200

10.3 Performance parameters of gas face seals201

10.3.1 Leakage rate 201

10.3.2 Gas film stiffness . 201

10.4 Materials of the seal couple .202

10.5 Dimension design of seal rings..202

10.5.1 Design of rotor dimension .. 202

10.5.2 Design of stator dimension . 203

10.5.3 Design of the face groove 204

10.6 Design of the secondary seal ..205

10.7 Process of seal design and illustration205

10.7.1 Process of seal design 205

10.7.2 Design conditions. 206

10.7.3 Design steps 206

References. 218

Index .219