《THE SHOCK TUBE IN HIGH-TEMPERATURE CHEMICAL PHYSICS》

Ⅰ．THE SIMPLE SHOCK TUBE1

Introduction1

Historical3

Applications in chemistry4

Applications in physics6

Astrophysical applications7

Ⅱ．THE SHOCK WAVE IN AN IDEAL GAS9

Sound waves and shock waves9

The growth of a shock wave10

Rarefaction waves12

PRIMARY SHOCK WAVES13

Basic equations13

Derivation of shock parameters in an ideal gas15

Dependence of shock strength on diapbragm pressure ratio18

Comparison between shock-wave and isentropic heating21

REFLECTED SHOCK WAVES23

Reflected shock parameters in an ideal gas24

Comparison of the states behind incident and reflected shocks27

Ⅲ．THE SHOCK WAVE IN A REAL GAS29

Specific heat of a real gas30

Variation of shock parameters in areal gas31

Valid shock relations for a real gas34

The enthaipy of a non-dissociating real gas35

Calculation of the equilibrium state of a non-disociating real gas37

The enthalpy of a real dissociating gas39

Calculation of the equilibrium state of areal dissociating gas41

The equllibrium state of an ionised gas46

Enthalpy contribution from electronic excitation49

Enthalpy values at high temperatures51

Summary51

Ⅳ．GAS FLOWS AND ASSOCIATED EFFECTS IN SHOCK TUBES57

FLOW DURATION IN AN INVISCID GAS57

General considerations57

Interaction of a rarefaction wave with the contact surface58

Flow duration in the incident shock60

Minimum length of tube for working in the incident shock63

Interaction of the reflected shock and contact surface63

Observation time in the reflected shock66

Reduction of flow duration due to real-gas effects67

Laboratory and gas particle times69

VISCOUS FLOW AND BOUNDARY-LAYER LIMITATIONS70

Effect on flow duration and speed of the incident shock72

Closure of the boundary layer74

Effect on observation time and conditions in the reflected shock74

Flow duration at low initial pressure76

The nature and width of the contact surface77

INFLUENCE OF DIAPHRAGM-OPENING PROCESS ON SHOCK SPEED79

Influence of diaphragm-opening time79

Influence of initial three-dimensional flow81

Ⅴ．SHOCK-TUBE DESIGN AND TECHNIQUES83

The basic tube83

Shock-tube diaphragms and bursting techniques88

Improvement of shock-tube performance by heating driver gas92

Improvement of shock performance by area reduction in tube96

Improvement in performance by combined modification97

The tailored-interface shock tube98

Overall length of shock tube and optimum position of observation station99

Converging shock waves103

Electromagnetically driven shocks105

Shock-tube hazards106

Ⅵ．THE MEASUREMENT OF SHOCK SPEED108

Pressure-transducer detectors109

Optical detectors(light-screen schlieren and reflection)110

Temperature-sensitive resistance detectors113

Positive-ion beam detector116

Glow-discharge detector117

Ionisation detectors118

Detector noise levels,impedances and response times119

Measurement of time intervals121

Continuous measurement of shock speed127

Ⅶ．THE MEASUREMENT OF PRESSURE AND DENSITY133

Pressure measurement134

Diaphragm pressure transducers134

Limitations of diaphragm transducers136

Piezo-electric transducers138

Pressure calibration and display142

Density measurement142

Schlieren recording143

Shadow recording145

Light sources and time-resolved schlieren and shadowgraph recording147

Interferometric measurement150

The Mach-Zehnder interferometer152

X-ray and particle-absorption densitometry159

Ⅷ．MEASUREMENT OF TEMPERATURE162

Introduction162

The spectrum-line reversal method163

The sensitivity and accuracy of the reversal method168

The choice of line for spectrum reversal174

Background sources for reversal176

The brightness and emissivity method180

The two-line method182

Rotational temperatures183

Vibrational temperatures185

The breadth and shape of spectrum lines186

Ⅸ．RELAXATION PROCESSES AND TIMES189

Introduction189

Rotational relaxation193

Vibrational relaxation194

Dissociation rates202

Ionisation207

Radiation relaxation211

Relaxation processes in expanded flows211

Ⅹ．EMISSION AND ABSORPTION SPECTRA213

The nature of spectra213

Photography of shock-wave spectra215

Time resolution of spectra216

Spectra of inert gases219

Spectra of O2,N2 and air221

Molecular spectra226

Atomic spectra229

Excitation processes229

Absorption spectra234

Determination of oscillator strengths237

Ⅺ．CHEMICAL STUDIES IN THE SHOCK TUBE241

Experimental techniques241

Carbon formation245

Oxides of nitrogen247

Simple chemical reactions249

Determination of dissociation energies251

Ablation254

Ⅻ．SHOCK-IGNITED DETONATIONS257

The nature of detonation257

Shock and detonation waves261

The speed of a detonation wave262

The Chapman-Jouguet plane267

Calculation of the state of the gas in a detonation269

The shock initiation of detonations273

The structure of an established detonation wave275

Spectra of detonations279

Initiation of detonation with weak shocks282

References288

Author Index297

Subject Index301