Download or read book Numerical Simulation of Rarefied Nozzle Plume Impingements written by and published by . This book was released on 2000 with total page 7 pages. Available in PDF, EPUB and Kindle. Book excerpt: This paper describes numerical simulation of rarefied nozzle plume impingements. Two different reservoir pressures 400 kPa and 4 kPa are considered, In the case of 400 kPa, the simulation of the nozzle flow was conducted by using the Navier-Stokes equation and then the analysis of the plume flow was carried out by the DSMC method employing the nozzle exit conditions obtained by Navier-Stokes equation. On the other hand., for 4 kPa both the nozzle flow and the plume impingement have been calculated using the DSMC method. Concerning the angle between the nozzle axis and the flat plate, three kinds of angle are selected, that is 90 degrees, 45 degrees and 0 degrees. In addition, we considered the case where there exists a flat plate behind the nozzle. Simulated results have been compared with the existing experiments for the pressure and shear stress distributions on the flat plate. A good agreement between the DSMC results and the experiments are shown. In the case of the oblique and parallel impingements, the location of the impingement pressure peak and the stagnation point shifted upstream with increasing rarefaction.

Download or read book Experimental and Numerical Study of Nozzle Plume Impingement on Spacecraft Surfaces written by and published by . This book was released on 2005 with total page 7 pages. Available in PDF, EPUB and Kindle. Book excerpt: An experimental and numerical effort was undertaken to assess the effects of a cold gas (To=300K) nozzle plume impinging on a simulated spacecraft surface. The nozzle flow impingement is investigated experimentally using a nano-Newton resolution force balance and numerically using the Direct Simulation Monte Carlo (DSMC) numerical technique. The Reynolds number range investigated in this study is from 0.5 to approximately 900 using helium and nitrogen propellants. The thrust produced by the nozzle was first assessed on a force balance to provide a baseline case. Subsequently, an aluminum plate was attached to the same force balance at various angles from 0 degrees (parallel to the plume flow) to 10 degrees. For low Reynolds number helium flow, a 16.5% decrease in thrust was measured for the plate at 0 degrees relative to the free plume expansion case. For low Reynolds number nitrogen flow, the difference was found to be 12%. The thrust degradation was found to decrease at higher Reynolds numbers and larger plate angles.

Download or read book Nozzle Plume Impingement on Spacecraft Surfaces Effects of Surface Roughness POSTPRINT written by and published by . This book was released on 2005 with total page 8 pages. Available in PDF, EPUB and Kindle. Book excerpt: An experimental and numerical effort was undertaken to assess the effects of a cold gas (To=300K) nozzle plume impinging on a simulated spacecraft surface. The nozzle flow impingement is investigated experimentally using a nano-Newton resolution force balance and numerically using the Direct Simulation Monte Carlo (DSMC) numerical technique. The Reynolds number range investigated in this study is from 0.5 to approximately 900 using helium and nitrogen propellants. The thrust produced by the nozzle was first assessed on a force balance to provide a baseline case. Subsequently, an aluminum plate was attached to the same force balance at various angles from 0? (parallel to the plume flow) to 10?. For low Reynolds number helium flow, a 16.5% decrease in thrust was measured for the plate at 0? relative to the free plume expansion case. For low Reynolds number nitrogen flow, the difference was found to be 12%. The thrust degradation was found to decrease at higher Reynolds numbers and larger plate angles. The roughness of the simulated spacecraft surface will be a variable in the testing to be performed for this manuscript.

Download or read book Numerical Simulation of the Dynamics of Large Fire Plumes and the Phenomenon of Puffing written by A. F. Ghoniem and published by . This book was released on 1996 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Analysis and Simulation of Rocket Exhaust Plume Models written by Matthew R. Maurer and published by . This book was released on 2014 with total page 100 pages. Available in PDF, EPUB and Kindle. Book excerpt: In this work we present mathematical models for a rocket nozzle exhaust plume expanding into a vacuum; specifically, models for plume density introduced by Simons and Cai. The models are discussed and compared to simulation results produced with the direct simulation Monte Carlo method. Simons' model, which is based in Prandtl-Meyer flow and boundary layer theory is discussed first. The model has several questionable assumptions and conclusions, which are analyzed. Cai's model, based on molecular gas dynamics, is described and offered as an alternative to Simons'. Numerical gas dynamic simulations utilizing the direct simulation Monte Carlo method were performed to validate Cai's model. These simulations are introduced and discussed. A description of the simulation's method and implementation is included. Literature review of articles related to simulating exhaust plumes is also discussed. Some results from those articles are compared to the aforementioned simulation results to further validate the model.

Download or read book Measurement and Analysis of a Small Nozzle Plume in Vacuum written by P. F. Penko and published by . This book was released on 1993 with total page 22 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Numerical Simulation of a Thrust Augmented Rocket Nozzle written by and published by . This book was released on 2006 with total page 11 pages. Available in PDF, EPUB and Kindle. Book excerpt: Numerical results are presented from a reacting-flow Navier-Stokes simulation of a rocket nozzle in which fuel is injected downstream of the nozzle throat for the purposes of augmenting the thrust. The numerical results are compared with experimental data in terms of overall thrust and specific impulse as well as pressure distribution along the nozzle wall. The flow physics associated with the thrust augmentation is also described. The investigation shows that propellant injection downstream of the throat is a viable method for augmenting rocket thrust. In addition, the augmented thrust levels increase with increasing levels of injected mass flow. Finally, the investigation shows that the numerical predictions are in good agreement with the experimental results.

Download or read book Numerical Investigation of Twin Nozzle Rocket Plume Phenomenology written by Houshang Ebrahimi and published by . This book was released on 1997 with total page 13 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Generalized Implicit Flow Solver (GIES) computer program, developed under sponsorship of the Air Force Phillips Laboratory, Edwards Air Force Base, CA, has been modified and used for three-dimensional reacting two-phase flow problems. The intent of the original GIFS development effort was to provide the JANNAF community with a standard computational methodology to simulate multiple nozzle/plume flow-field phenomena and other three-dimensional effects. Recent development efforts have concentrated on improving the run time and robustness of the algorithm. The GIFS computer program was originally released as an untested research version. Since that time, several corrections and enhancements have been made to the model. The Van Leer Flux Splitting option has been successfully implemented into the existing GIFS model and provides a more robust solution scheme. A Parabolized Navier-Stokes (PNS) version of the GIFS algorithm is currently under development and is intended to substantially improve the run-time requirements for flow fields dominated by supersonic flow regimes. These improvements and enhancements will foster the application of the GIFS model in the CFD community. This paper reports the significant results of several twin-nozzle/plume applications of the GIFS code. Six simulations of Titan II plume flow fields have been completed to assess the effects of three-dimensionality, turbulent viscosity, afterburning, near-field shock structure, finite-rate kinetic chemistry, intranozzle geometric spacing, and initial nozzle exit plane profile effects on the subsequent plume exhaust flow field. The results of these calculations indicate that the viscous stress model, kinetic chemistry, and nozzle exit profile are significant parameters that should be considered in analyses and interpretation of the calculations.

Download or read book Numerical Simulation of an Advanced Airblast Fuel Nozzle Under Rich burn Condition written by S. L. Yang and published by . This book was released on 1994 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Numerical Simulation of Chemical Reactions in Point source Plumes written by John Peter Meeder and published by . This book was released on 1998 with total page 105 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Velocity Measurements in Rarefied Nozzle Plumes written by C. Dankert and published by . This book was released on 1988 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Probabilistic Design of a Rocket Nozzle written by and published by . This book was released on 2008 with total page 59 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Numerical Simulation of Plume Fumigation During Nocturnal Inversion Break up written by P. J. Hurley and published by . This book was released on 1990 with total page 44 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Plume Simulation Contamination and Microfluidics Preprint written by and published by . This book was released on 2006 with total page 12 pages. Available in PDF, EPUB and Kindle. Book excerpt: This research project pursues basic understanding of rarefied gas flows, leading to Air Force tools for plumes, spacecraft, and micro-devices. It develops, applies, and validates kinetic and molecular-level models of improved physical realism for nonequilibrium processes such as collisional interaction of gases, gas-particulate mixtures, and gas surface interaction that arise in high temperature, multi-species, chemically reacting rarefied flowfields such as rocket plumes. These phenomena are not accurately addressed by standard engineering tools and require improved understanding of the basic physics. A number of closely related research issues arise in the area of rarefied flows on the micro length scales, including micropropulsion flows. The key computational tool used in this effort is the direct simulation Monte Carlo (DSMC) method and related kinetic solvers. Recently, a 3D multi-phase DSMC capability has been developed and applied to study the interaction of solid propellant plumes with rarefied atmosphere. A parallel 3D Monte Carlo numerical tool for modeling radiation in multi-phase flows has been developed; the integration of fluid and radiation tools is planned in the future. New optical micropropulsion concepts have been formulated based on non-resonant interaction of optical lattice and carrier gas. Spacecraft contamination effects have been studied, and efficient numerical models for surface roughness were proposed.

Download or read book Nozzle Lip Effects on Gas Expansion Into the Plume Backflow Region written by D. P. Weaver and published by . This book was released on 1988 with total page 23 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Direct Simulation Monte Carlo technique has been used to investigate the detailed flow structure in the region near the lip of a nozzle flowing to vacuum. The results for a range of nozzle lip thicknesses and shapes for argon are presented. Keywords: Monte Carlo, Rarefied gas dynamics, Plume, Nozzle flow, Contamination, Plume signature.

Download or read book Direct Numerical Simulation of Buoyant Reacting Plumes written by Vijayanand Rajandram and published by . This book was released on 2004 with total page 402 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Direct Numerical Simulation for Turbulent Dispersion of Buoyant Plumes in a Pressure driven Channel Flow written by Alexandre Fabregat Tomàs and published by . This book was released on 2007 with total page 109 pages. Available in PDF, EPUB and Kindle. Book excerpt: