Dense gas shock tube: Design and analysis

The study of BZT fluids in the single-phase vapor region is largely unexamined experimentally. To date, only one experimental study focused on nonclassical behavior in the single-phase vapor region. A new experimental program is proposed to examine the possibility of generating nonclassical behaviors in a shock tube apparatus. A design methodology is developed to identify the most important experimental characteristics and provide appropriate analytical and computational tools for subsequent study. Analysis suggests initial conditions, viscous effects, and wave interference as critical experimental characteristics. A shock tube design is proposed based on the results of the methodology.; An algorithm is developed and applied to classical state equations to generate experimentally feasible initial conditions which maximize the possibility of detecting a single-phase rarefaction shock wave within experimental accuracy and precision. The algorithm was applied to a commercially available fluid thought to exhibit dense gas behavior. It was found that the range of possible initial conditions generating dense gas phenomena is larger than previously assumed.; The shock tube is computationally modeled to validate the triple-discontinuity initial conditions and investigate the appropriate design dimensions. A two-step, flux-limited, total variation diminishing scheme was implemented to integrate the unsteady Navier-Stokes equations using three independent gas models. The triple-discontinuity flow field was verified with simulations.; A novel shock tube was constructed based on the previous analysis. A sixteen-foot stainless steel pipe with a single diaphragm was placed within a series of electric ovens. The test section thermal environment was controlled utilizing sixteen independent PID control loops. Initial conditions similar in pressure and temperature to dense gas conditions were generated for nitrogen gas. The nitrogen test results were compared with classical one-dimensional Riemann theory and two-dimensional Navier-Stokes simulations. The expansion fan pressure loss is found to be within 2% of the expected values. The average wave speed is calculated to be consistently lower than theory, but within experimental uncertainty. Error estimates predicted the apparatus is capable of conclusively proving single-phase nonclassical behavior.