Flash evaporation or flashing is an evaporation phenomenon caused by a sudden pressure drop sufficiently below the saturation pressure. Due to this sudden drop in pressure, the liquid undergoes a quick phase transition and the sensible heat of the liquid converts into latent heat of evaporation. An accidental release of pressurized liquid from supply pipelines or liquid storage tanks can generate a flashing jet with violent phase change. This fast phase change can cause rapid mixture with an oxidant like air, and if the liquid is flammable, disastrous effects such as explosions, fires, and damage to industrial equipment can occur. On the other side, flash evaporation can be beneficially employed in industrial applications. It can have a significant effect on the performance of many devices (e.g. injectors and reactors). The understanding of the fluid behavior of the flash evaporation and the resultant shock waves can help to prevent disastrous consequences that may occur due to accidental fluid release as well as can be useful to further develop the phenomena's industrial and technological applications such as utilize resulting shock waves in creating useful compression.This work investigates spray flashing evaporation phenomena and resulting shock waves experimentally and numerically, considering pure water as working fluid. 2D transient simulation was conducted by using Ansys Fluent to simulate the multiphase flow field in the evaporation zone. The Mixture model was applied using the concept of slip velocities to model multiphase flows as non-homogeneous multiphase model where the phases (liquid water and water vapor) move at different velocities. In addition, a rectangular vacuum chamber connected to a circular nozzle was used in the experiments. A z-type Schlieren technique with a Photron high-speed camera was used to observe the propagation of the moving shock wave and the flow. The numerical simulation results show that once the superheated water is injected in the low-pressure environment, the flashing phenomenon occurs and a shock wave is induced. This shock wave is a moving shock wave and it travels forward into the vacuum chamber. The two-phase mixture expands behind the moving shock wave that travels faster into the water vapor. The entire flow characteristics such as pressure, velocity, Mach number, speed of sound, density, and volume fraction are discontinuous across the shock wave. After the moving shock wave strikes the end of the vacuum chamber, it reflects from the wall as reflected shock wave that propagates back into the chamber, further increasing the pressure behind it. An experimental work was carried out with injected liquid water having an initial temperature ranging between 40 and 100°C and vacuum pressure ranging between 4000 Pa and 10000 Pa. To show the shock wave structure, the Schlieren technique was used and Schlieren photographs were mathematically filtered using the Image Processing and Analysis in Java (ImageJ). The experimental results were in good agreement with the numerical results, confirming that once the superheated water is injected in the vacuum chamber, it flashes directly and can induce a shock wave. The results confirm that with increasing superheat of the injected water, the flash evaporation accelerates. At low vacuum pressure, full flashing occurs, and a shock wave is induced especially with a high initial liquid temperature.

This comprehensive and carefully edited volume presents a variety of experimental methods used in Shock Waves research. In 14 self contained chapters this 9th volume of the “Shock Wave Science and Technology Reference Library” presents the experimental methods used in Shock Tubes, Shock Tunnels and Expansion Tubes facilities. Also described is their set-up and operation. The uses of an arc heated wind tunnel and a gun tunnel are also contained in this volume. Whenever possible, in addition to the technical description some typical scientific results obtained using such facilities are described. Additionally, this authoritative book includes techniques for measuring physical properties of blast waves and laser generated shock waves. Information about active shock wave laboratories at different locations around the world that are not described in the chapters herein is given in the Appendix, making this book useful for every researcher involved in shock/blast wave phenomena.

The Fourth American Physical Society Topical Conference on Shock Waves in Condensed Matter was held in Spokane, Washington, July 22-25, 1985. Two hundred and fifty scientists and engineers representing thirteen countries registered at the conference. The countries represented included the United States of America, Australia, Canada, The People's Repub lic of China, France, India, Israel, Japan, Republic of China (Taiwan), United Kingdom, U. S. S. R, Switzerland and West Germany. One hundred and sixty-two technical papers, cov ering recent developments in shock wave and high pressure physics, were presented. All of the abstracts have been published in the September 1985 issue of the Bulletin of the American Physical Society. The topical conferences, held every two years since 1979, have become the principal forum for shock wave studies in condensed materials. Both formal and informal technical discussions regarding recent developments conveyed a sense of excitement. Consistent with the past conferences, the purpose of this conference was to bring together scientists and engineers studying the response of condensed matter to dynamic high pressures and temperatures. Papers covering experimental, theoretical, and numerical studies of con densed matter properties were presented. A noteworthy feature of this conference was the participation by several leading scientists engaged in static high pressure research. Donald Curran served as the Master of Ceremonies at the conference banquet, which was at tended by two hundred and seventy-five conference participants and guests including Dr. Samuel Smith, the new President of Washington State University. Dr.

One of the main goals of investigations of shock-wave phenomena in condensed matter is to develop methods for predicting effects of explosions, high-velocity collisions, and other kinds of intense dynamic loading of materials and structures. Based on the results of international research conducted over the past 30 years, this book is addressed not only to experts in shock-wave physics, but also to interested representatives from adjacent fields of activity and to students who seek an introduction to the current issues. With that goal in mind, the book opens with a brief account of the theoretical background and a short description of experimental techniques. The authors then progress to a systematic treatment of special topics, some of which have not been fully addressed in the literature to date.

This book provides an elementary introduction to one-dimensional fluid flow problems involving shock waves in air. The differential equations of fluid flow are approximated by finite difference equations and these in turn are numerically integrated in a stepwise manner, with artificial viscosity introduced into the numerical calculations in order to deal with shocks. This treatment of the subject is focused on the finite-difference approach to solve the coupled differential equations of fluid flow and presents the results arising from the numerical solution using Mathcad programming. Both plane and spherical shock waves are discussed with particular emphasis on very strong explosive shocks in air. This expanded second edition features substantial new material on sound wave parameters, Riemann's method for numerical integration of the equations of motion, approximate analytical expressions for weak shock waves, short duration piston motion, numerical results for shock wave interactions, and new appendices on the piston withdrawal problem and numerical results for a closed shock tube. This text will appeal to students, researchers, and professionals in shock wave research and related fields. Students in particular will appreciate the benefits of numerical methods in fluid mechanics and the level of presentation.