Studies On Equation Of State And Opacity Of Liquid Argon

In this dissertation equation of state was measured for liquidargon compressed dynami ca11y to pressure of 17. 5-47. 3GPa by employingthe two-stage light gas gun, the liquid argon condensed by usingliquid nitrogen. The shock-compression parameters of liquid argonwere measured by using electrica1 probes which made in thi s laboratory.Shock temperature of liquid argon was measured by using opticalmeasure equ ipments.The main results can be summarized as follows:1. The shock wave velocity in shock-compressed liquid argon wasmeasured, so the mass velocity of shock-compressed liquid argonand shock volume can be obtained with impedance-matching method.According experimental results, the slope of Hugoniot curvechanged when mass velocity higher than 3. 4km/s. The slope ofHugoniot curve decreased above 30Gpa shock pressure. Data of massvelocity and shock wave velocity fitD =1 .387 + 1 .5l4Ï…p (0--30GPa)D = 3.02l + l.022U. (above 30GPa)2. Shock temperature of 1 iquid argon was measured in this work. TheShock temperature of l iquid argon betweens 4600--l l000K and shockpressure betweens l7. 5--33. 2GPa. For higher shock temperature, thepeak of 1ight radiaflce curve shift to ultraviolet wave band,however the measured wave band of pyrometer used in this work isi n vis ib le wave band, so the higher shock temperature have not beenmeasured in this work.3. According to the spectral radiance history data, the spectra1absorption coefficients x(l) were calcu1ated, and R(k) (thereKect ion coeffi cient at the baseplate/liquid argon interface)were a1so obtained. The va1ue of R(A) is near 1. 0 for anywavelength and states. R(A) is near perfect reflection value,much greater than it's va1ue of static. According to the signalof experiments and ana1yse to the experimental data, the energyradiance of shock compressed l iquid argon is a1most b1ack bodyradiance and the portion of shock compressed 1 iquid argon isuntransparence, so the method obtained spec tral absorpt ioncoefficients K(1) and R(l) form l ight radiance is unreasonable.4. Us ing the f1uid perturbat ion variational theory, the shockHugoniot of 1 iqui d argon have been ca1culated. Comparing toexperimenta1 data gi ven by Nel1 is and this work, the theoreticaIcd1Cu 1ated pressure and volume is in good agreement with those data.The theoret ica1 model has been extended to exami ne experimenta1data by inducing mo1ecu1ar dissociative factor. According totheoret ica1 and experimental analys is, we cou1d think that thephase transi t ion was mo1ecu1ar dissociative phase transition.5. Accordi ng experimenta1 data and theoreti cal data, l iqui d argon canbe treat as transparent before shock compression.