Download Free Numerical Study Of Mixing A Supercritical Jet In A Supercritical Environment Book in PDF and EPUB Free Download. You can read online Numerical Study Of Mixing A Supercritical Jet In A Supercritical Environment and write the review.

A numerical simulation campaign is conducted to better elucidate flow physics and modeling requirements of a supercritical (SC) nitrogen jet injected into a tank of quiescent sC nitrogen. The goals of this work are twofold: to inform the design of injectors and power combustion chambers for use in the direct-fired supercritical CO2 (s-CO2) generation cycle and cryogenic liquid propellant rockets, and to investigate the extent to which meaningful flow characterization can be achieved with computationally expedient methods, using commercial software. Reynolds-Averaged Navier-Stokes (RANS) and Large Eddy Simulation (LES) approaches are used in STAR-CCM+ versions 10.06.010 and 12.02.011. Jet disintegration is evaluated with velocity, density and temperature profiles, potential core penetration and identification of turbulent length scales. These data are compared with experimental data and evaluated against other modeling approaches. Mixing behavior is expected to mimic that of a single-phase jet, and be diffusion-driven, as there will be no droplet formation in the supercritical phase. Challenges are encountered in high computational requirements inherent to unsteady LES. Challenges are also encountered in simulation stability and convergence given large flow gradients near jet exit, large fluid property gradients near the critical point, and the small length scale of energetic flow features unique to this high-pressure thermodynamic regime. Simulation results over-predict core penetration compared to experiment and previous numerical efforts and show an overall slower transition to ambient conditions. It is shown however that commercial code can correctly synthesize the overall flow physics and trends of the single-phase gas jet behavior expected in purely supercritical turbulent mixing flow.
The objective of this study is the fundamental understanding of fuel disintegration and mixing in a supercritical environment (relative to the fuel) in order to determine parameter regimes advantageous to mixing. The approach is based on the future goal of developing a model for a supercritical, turbulent jet mixing with surrounding fluid. The method is one that combines the modeling of supercritical fluids with a systematic development based on the Large Eddy Simulation (LES) approach. This systematic development includes a consistent protocol based upon Direct Numerical Simulations (DNS) for developing a Subgrid Scale (SGS) Model appropriate to supercritical fluids, rather than choosing in an ad hoc manner an existing SGS model developed under assumptions inconsistent with supercritical fluid behavior. This SGS model should be used in future studies of supercritical turbulent jets utilizing the LES methodology.
The objective of this study is the fundamental understanding of fuel disintegration and mixing in a supercritical environment (relative to the fuel) in order to determine parameter regimes advantageous to mixing. The approach is based on developing a model of a supercritical, turbulent jet mixing with surrounding fluid. The method is one that combines the modeling of supercritical fluids with a systematic development based on the Large Eddy Simulation (LES) approach. This systematic development includes a consistent protocol based upon Direct Numerical Simulations (DNS) for developing a Subgrid Scale Model (SGS) appropriate to supercritical fluids, rather than choosing in an ad hoc manner an existing SGS model developed under assumptions inconsistent with supercritical fluid behavior. This SGS model will be used in the LES of a supercritical turbulent jet.
Atomization and sprays are used in a wide range of industries: mechanical, chemical, aerospace, and civil engineering; material science and metallurgy; food; pharmaceutical, forestry, environmental protection; medicine; agriculture; meteorology and others. Some specific applications are spray combustion in furnaces, gas turbines and rockets, spray drying and cooling, air conditioning, powdered metallurgy, spray painting and coating, inhalation therapy, and many others. The Handbook of Atomization and Sprays will bring together the fundamental and applied material from all fields into one comprehensive source. Subject areas included in the reference are droplets, theoretical models and numerical simulations, phase Doppler particle analysis, applications, devices and more.
This volume continues previous DLES proceedings books, presenting modern developments in turbulent flow research. It is comprehensive in its coverage of numerical and modeling techniques for fluid mechanics. After Surrey in 1994, Grenoble in 1996, Cambridge in 1999, Enschede in 2001, Munich in 2003, Poitiers in 2005, and Trieste in 2009, the 8th workshop, DLES8, was held in Eindhoven, The Netherlands, again under the auspices of ERCOFTAC. Following the spirit of the series, the goal of this workshop is to establish a state-of-the-art of DNS and LES techniques for the computation and modeling of transitional/turbulent flows covering a broad scope of topics such as aerodynamics, acoustics, combustion, multiphase flows, environment, geophysics and bio-medical applications. This gathering of specialists in the field was a unique opportunity for discussions about the more recent advances in the prediction, understanding and control of turbulent flows in academic or industrial situations.
ABSTRACT: Liquid jet injection into quiescent gaseous environment was investigated experimentally and analytically. This is the first comprehensive experimental study covering subcritical to supercritical conditions. The research was focused on investigating the surrounding gas pressure and temperature influence on the jet break-up mechanisms. Subcritical, transcritical and supercritical jet break-up mechanisms were observed. The map of break-up modes was plotted in the P-T space. Under the subcritical conditions first and second wind-induced break-up regimes were observed. The break-up in this case was controlled by surrounding gas inertia and surface tension forces. Apparent decrease of surface tension influence on the jet surface behavior was observed under transcritical conditions. Ligament formation was significantly reduced under these conditions with only occasional drop formation observed. A significantly different jet break-up was observed in the transcritical mixing region. Further increase of pressure and temperature led to supercritical break-up modes. This manifested through a smoothening of the liquid - gas interface. Ligament formation was not observed under supercritical conditions; this indicates that surface tension did not play any role in the supercritical jet break-up. Despite the apparent absence of the surface tension, the density gradients values observed under supercritical conditions were comparable to those observed under subcritical conditions. A linear jet stability analysis was performed to gain physical insight into the jet break-up mechanisms. The results showed good correlation with experiments for subcritical mixing but did not match for the transcritical and supercritical regimes.
A work on turbulent premixed combustion is important because of increased concern about the environmental impact of combustion and the search for new combustion concepts and technologies. An improved understanding of lean fuel turbulent premixed flames must play a central role in the fundamental science of these new concepts. Lean premixed flames have the potential to offer ultra-low emission levels, but they are notoriously susceptible to combustion oscillations. Thus, sophisticated control measures are inevitably required. The editors' intent is to set out the modeling aspects in the field of turbulent premixed combustion. Good progress has been made on this topic, and this cohesive volume contains contributions from international experts on various subtopics of the lean premixed flame problem.
This proceeding comprises peer-reviewed papers of the 2021 Asia-Pacific International Symposium on Aerospace Technology (APISAT 2021), held from 15-17 November 2021 in Jeju, South Korea. This book deals with various themes on computational fluid dynamics, wind tunnel testing, flow visualization, UAV design, flight simulation, satellite attitude control, aeroelasticity and control, combustion analysis, fuel injection, cooling systems, spacecraft propulsion and so forth. So, this book can be very helpful not only for the researchers of universities and academic institutes, but also for the industry engineers who are interested in the current and future advanced topics in aerospace technology.
This book presents a collection of the best papers from the Seventh Asian Joint Workshop on Thermophysics and Fluid Science (AJWTF7 2018), which was held in Trivandrum, India, in November 2018. The papers highlight research outputs from India, China, Japan, Korea and Bangladesh, and many of them report on collaborative efforts by researchers from these countries. The topics covered include Aero-Acoustics, Aerodynamics, Aerospace Engineering, Bio-Fluidics, Combustion, Flow Measurement, Control and Instrumentation, Fluid Dynamics, Heat and Mass Transfer, Thermodynamics, Mixing and Chemically Reacting Flows, Multiphase Flows, Micro/Nano Flows, Noise/NOx/SOx Reduction, Propulsion, Transonic and Supersonic Flows, and Turbomachinery. The book is one of the first on the topic to gather contributions from some of the leading countries in Asia. Given its scope, it will benefit researchers and students working on research problems in the thermal and fluid sciences.