Download or read book Droplet Evaporation in an Active Turbulence Grid Wind Tunnel written by Ferran Marti Duran and published by . This book was released on 2012 with total page 104 pages. Available in PDF, EPUB and Kindle. Book excerpt: In this thesis, we develop and test an experimental apparatus capable of examining the effect of turbulence on the evaporation of droplets when the Kolmogorov scale is smaller than the size of the drop (where size refers to the nominal droplet diameter). Traveling drop and suspended drop cases have been studied experimentally and the evaporation rate has also been predicted based on classical computations of transport rates. Cases involving still air, a mean flow with turbulence, and a mean flow without turbulence have been tested. The experimental data matches the theoretical computations for the case of still air and mean flow with no turbulence. There is no accepted computational model that can account for turbulent flow, but the experimental conditions tested so far do not show any measurable effect of turbulence on the evaporation rate. These findings suggest that turbulence is a much smaller factor in evaporation than is mean flow over the droplet. Hence, one suggestion for future work is to study traveling droplets with zero relative velocity to the air in order to focus the analysis on the effects of turbulence with no mean flow.
Download or read book On the Generation of Unsteady Mean and Turbulent Flows in a Wind Tunnel Using an Active Grid written by Abdullah Azzam and published by . This book was released on 2018 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Unsteady flows are pervasive in nature and engineering applications such as UAVs. Simulating these flows in an experimental setting is key to avoiding detrimental changes in the performance of such applications. This study explores the capabilities of an active grid in producing unsteady flows in a recirculating wind tunnel. The grid is operated in different modes that allow control over the flow frequency, amplitude and turbulence intensity. Hot-wire measurements demonstrate the grid's capabilities in generating flows typical of those used in experiments of unsteady aerodynamics. Mean grid blockage, freestream speed and tunnel size were all found to be factors influencing the resulting flow. The response of turbulence to the oscillating flow was also investigated and results showed a modulation of the turbulence intensity and dissipation rate that is dependent on the frequency of the imposed oscillations. A change in the scaling behaviour of the dissipation rate was also noted.
Download or read book Droplet Vaporization in Turbulent Flow written by Jung-Kyu Park and published by . This book was released on 1987 with total page 382 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Generation of Atmospheric Turbulence in a Wind Tunnel written by Elena Muñiz Pladellorens and published by . This book was released on 2017 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: This report aims to contribute to the knowledge and characterization of grid generated turbulence in a wind tunnel. It starts with a theory introduction to turbulence where we bring together the classic approaches (Richardson-Kolmogorov equilibrium cascade) and more recent research. The latter includes the nonequilibrium dissipation law developed by [Valente and Vassilicos, 2011] and calculus methods such as set forth by [Puga and LaRue, 2017]. The study is based on two grids: an active grid in two different modes (open and random) and a regular and irregular passive grids. In terms of the means employed, the data is gathered using a hot-wire anemometer which makes it possible to have a high time resolution even though only one point and 1D turbulence is collected. In addition, the software used in the mathematical processing is MATLAB. The crucial parameters analyzed are the variations, the lengthscales (as well as their interaction) and dissipation rate constants, both equilibrium and nonequilibrium definitions. Some significant results have been found. In the first place Kolmogorov hypotheses are justified to hold true. Furthermore, there are some signs that the nonequilibrium law seems a plausible answer to some instabilities perceived. Finally, the vertical profiles of the irregular grid clearly show that the turbulence generated is inhomogeneous, which ushers in new lines of investigation.
Download or read book The Evaporation of Liquid Droplets in Highly Turbulent Gas Streams written by Richard Gould and published by . This book was released on 1998 with total page 8 pages. Available in PDF, EPUB and Kindle. Book excerpt: Single acetone and heptane droplets were suspended from a hypodermic needle in turbulent airflow, and the Nusselt number was obtained from direct measurements of the droplet diameter and evaporation rate. Acetone was selected because it fluoresces when irradiated with ultraviolet laser radiation while heptane was selected because of its high volatility compared with water, methanol, and ethanol which were used previously. Planar laser induced fluorescence (PLIF) measurements were made to obtain qualitative concentration measurements of gaseous acetone in the boundary layer surrounding the droplet. The goal of these measurements was to give insight as to why the evaporation rate is increased by 50 % when the gas phase turbulence is increased from the laminar flow case to the case where the freestream turbulence is 10%. The use of acetone droplets required that the influence of humidity on droplet evaporation rate be considered. Measurements of the turbulence intensity of heated freestream air were also made. Finally, many modifications to improve the experimental apparatus were made during this research project.
Download or read book Effect of Turbulence on Droplet Evaporation and Drag written by Carlos Pereira Salvador and published by . This book was released on 2000 with total page 320 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book The Effect of Stable Stratification on Decaying Grid generated Turbulence written by Kyunghwan Yoon and published by . This book was released on 1989 with total page 362 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Grid Effects Upon the Power density Spectrum of Wind Tunnel Turbulence written by Timothy Leonard Vogt and published by . This book was released on 1962 with total page 48 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Computations of Turbulent Droplet Dispersion for Wind Tunnel Icing Tests written by Brian Charles DeAngelis and published by . This book was released on 1996 with total page 246 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Syllabus medicamentorum compositorum in Pharmacopoea Wirtenbergica comprehensorum juxta quem pharmacopolia commode visitari possunt written by and published by . This book was released on 1785 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Effect of Grid Location on Wind Tunnel Turbulence Characteristics written by Yung-che Fang and published by . This book was released on 1993 with total page 212 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book The Effect of Various Grids on Wind tunnel Turbulence written by William R. Patterson and published by . This book was released on 1950 with total page 74 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Evaporation and Droplet Growth in Gaseous Media written by N. A. Fuks and published by Pergamon. This book was released on 1959 with total page 88 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Investigation of a Grid Induced Turbulent Environment for Wind Tunnel Testing written by Timothy A. Reinhold and published by . This book was released on 1975 with total page 150 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Fluid Mechanics and Heat Transfers in Sprays written by American Society of Mechanical Engineers. Winter Annual Meeting and published by . This book was released on 1993 with total page 202 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Effect of Flow Turbulence on Evaporation Rate of a Single Droplet written by A. V. Eckartsberg and published by . This book was released on 2000 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Application of Dynamic Light Scattering to the Study of Grid generated Turbulence in a Wind Tunnel written by Michael Alexander Dumesh and published by . This book was released on 2001 with total page 142 pages. Available in PDF, EPUB and Kindle. Book excerpt:
