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Design Optimization of Solid Rocket Propulsion: A Survey of Recent Advancements

JOURNAL OF SPACECRAFT AND ROCKETS 2020年第1期57卷 3-11页

作者： Mahjub, Ahmed Mazlan, Nurul Musfirah Abdullah, M. Z. Azam, Qummare Univ Sains Malaysia Sch Aerosp Engn Engn Campus Nibong Tebal 14300 Pulau Pinang Malaysia Univ Sains Malaysia Sch Mech Engn Engn Campus Nibong Tebal 14300 Pulau Pinang Malaysia AIAA Reston VA 20191 USA

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Tunnel ventilation during construction and diffusion of hazardous gases studied by numerical simulations

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BUILDING AND ENVIRONMENT 2020年 177卷

作者： Chang, Xiaoke Chai, Junrui Luo, Jipeng Qin, Yuan Xu, Zengguang Cao, Jing Xian Univ Technol State Key Lab Base Ecohydraul Engn Northwest Arid Xian 710048 Peoples R China China Three Gorges Univ Coll Hydraul & Environm Engn Yichang 443002 Peoples R China Beijing Engn Corp Ltd Beijing 100024 Peoples R China Xian Univ Technol State Key Lab Base Ecohydraul Engn Arid Area Xian 710048 Peoples R China

Proper ventilation of tunnels has remained a serious issue for many years. However, only empirical methods are currently utilised for estimating ventilation time scales in construction scheduling. In this study, the forced ventilation system used in tunnels under construction was investigated through computational fluid dynamics modelling. The effects of influencing factors, such as the duct position, distance between the ventiduct mouth and the working face, air velocity in the duct, and cross-sectional area of the tunnel, were examined, and the flow field and CO concentration distributions in the tunnel space were determined. The obtained results revealed that the zone near the working face can be divided into a jet zone, backflow zone, and vortex zone. Pollutant discharge was strongly related to the flow field distribution. The CO concentration distributions were calculated from the data sets generated by various models, and a ventilation time estimation function was derived for the entire tunnel construction period. The blasting cycle can be significantly shortened by allowing construction workers to enter the tunnel within the calculated entry periods, and necessary construction procedures can be reasonably implemented. The flow field distribution and time dependence of the CO concentration deduced in this study can be extended and applied to other similar projects.

关键词： Tunnel under construction Forced ventilation Pollutant transport computational fluid dynamics simulation

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Verification of Anisotropic Mesh Adaptation for Turbulent simulations over ONERA M6 Wing

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AIAA JOURNAL 2020年第4期58卷 1550-1565页

作者： Balan, Aravind Park, Michael A. Anderson, William K. Kamenetskiy, Dmitry S. Krakos, Joshua A. Michal, Todd Alauzet, Frederic NASA Langley Res Ctr Computat Aerosci Branch Hampton VA 23681 USA Boeing Co Boeing Commercial Airplanes Seattle WA 98204 USA Boeing Co Boeing Commercial Airplanes St Louis MO 63166 USA Boeing Co St Louis MO 63166 USA INRIA Paris Saclay GAMMA3 Team Alan Turing Bldg F-91120 Palaiseau France

Unstructured anisotropic mesh adaptation is known to be an efficient way to control discretization errors in computational fluid dynamics simulations. Method verification is required to provide the confidence for routine use in production analysis. The current work aims at verification of anisotropic mesh adaptation for Reynolds-averaged Navier-Stokes simulations over the ONERA M6 wing. The present verification study is performed using four different flow solvers, three different implementations of the metric field, and three mesh mechanics packages. Two of the flow solvers use stabilized finite element discretizations (FUN3D-SFE and general geometry Navier-Stokes), one uses finite volume discretization (FUN3D-FV), and the last one uses mixed finite volume and finite element discretizations (Wolf). The mesh adaptation is based on an error estimator that aims to control the quadratic error term in the linear interpolation of the Mach number. Two sets of adaptations were performed;the first one controls the interpolation error in the L2 norm, and the second one controls the interpolation error in the L4 norm. Convergence studies were performed on the forces and the pitching moment using all four solvers, and the results are compared with previously verified convergence studies on fixed (nonadapted) meshes. Both the forces and pitching moment on adapted meshes are found to be converging to the fine-mesh values faster than those on fixed meshes. In addition to forces and moments, the convergence of surface pressure and skin-friction coefficients at various measurement locations on the wing are also presented. Adapted-mesh surface pressure distributions agree with the fine fixed mesh pressure distributions. Adapted-mesh skin-friction distributions contain high-frequency noise with mean values approaching the fixed mesh pressure skin-friction distributions.

关键词： Aerodynamic Force Coefficients FUN3D Reynolds Averaged Navier Stokes computational fluid dynamics simulation Skin Friction Coefficient Linear Interpolation Turbulence Models Lagrange Multipliers External Flows Unstructured Grid

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Local-Turning Osculating Cones Method for Waverider Design

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AIAA JOURNAL 2020年第8期58卷 3499-3513页

作者： Zheng, Xiaogang Hu, Zhancang Li, Yiqing Zhu, Chengxiang You, Yancheng Song, Wenjia Xiamen Univ Dept Power Engn Sch Aerosp Engn Xiamen 361005 Fujian Peoples R China Nanchang Hangkong Univ Jiangxi Key Lab Micro Aeroengine Sch Aircraft Engn Nanchang 330063 Jiangxi Peoples R China Ludwig Maximilians Univ Munchen Dept Earth & Environm Sci Theresienstr 41 D-80333 Munich Germany

To expand the selection of preassigned shock surfaces, a new inverse design method called the local-turning osculating cones method has been proposed for waverider design. The new method discretizes the three-dimensional preassigned shock surface into a multitude of stream surfaces, which are composed of multiple local osculating planes. The flowfield within each stream surface is computed on the same fictional meridian plane based on a new schematic of method of characteristics. In this way, the constraint of obligating the streamline initiating from the discrete leading edge point to flow within the same osculating plane is removed. Two types of shock waves with distinct three-dimensional characteristics are specified as input to demonstrate the validity of the new proposed method. At the same time, two typical waveriders, which are not easily generated by the past waverider design methods, are derived and validated by the inviscid computational fluid dynamics simulation (Euler code). The results indicate that waveriders based on the new method can successfully reproduce the preassigned shock waves and the original flowfields with errors less than 2%. Thus, the local-turning osculating cones method offers a far-improved capability to design waveriders, and it is favorable for hypersonic airframe propulsion integration.

关键词： Waverider Shock Wave Profiles computational fluid dynamics simulation Lift to Drag Ratio Airframes Freestream Mach Number Aerodynamic Performance Two Dimensional Flow Space Shuttle Cartesian Coordinate System

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Investigation of the Chain Formation Effect on Thermal Conductivity of Magnetorheological fluids

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JOURNAL OF THERMOPHYSICS AND HEAT TRANSFER 2020年第1期34卷 3-12页

作者： Maroofi, J. Hashemabadi, S. H. Rabbani, Y. Iran Univ Sci & Technol Sch Chem Petr & Gas Engn Tehran *** Iran Iran Univ Sci & Technol CFD Res Lab Sch Chem Petr & Gas Engn Tehran *** Iran Univ Tehran Sch Chem Petr & Gas Engn Tehran *** Iran

Chain formation is one of the factors influencing the changes in the rheological properties of magnetorheological (MR) fluids as thermal conductivity. After applying the magnetic field, the particles make some clusters in the direction of the applied field. In this work, a variation of thermal conductivity of the MR fluid was investigated experimentally, and the cluster formation inside the fluid was visualized by appropriate computational fluid dynamics simulations. The experimental results show that with the increase in magnetic field strength and dispersed particle volume fraction, as well as the decrease in the size of dispersed particles, more particles joined together in the direction of the external applied magnetic field. It was found that the more and longer chains of particles are formed, the variation of thermal conductivity of the MR fluid is more considerable. The experimental results showed that the thermal conductivity of the MR fluid with 15% dispersed particle volume fraction is increased up to 117% by applying an 11.16 kA/m magnetic field. The increase in the thermal conductivity has been observed in experimental studies, and the longer and the more strong chain formations have shown in computational fluid dynamics simulation that its trend is in good agreement with experimental results.

关键词： Thermal Conductivity Measurement Magnetorheological fluid Magnetic Field Intensity computational fluid dynamics simulation Apparent Viscosity Convection Heat Transfer Electrical Resistance Shear Stress Yield Stress Magnetic Permeability

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Performance Assessment of a Building Integrated Photovoltaic Thermal System in Mediterranean Climate-A Numerical simulation Approach

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ENERGIES 2020年第11期13卷

作者： Bot, Karol Aelenei, Laura Gomes, Maria da Gloria Silva, Carlos Santos Lab Nacl Energia & Geol LNEG P-1649038 Lisbon Portugal Univ Lisbon Inst Super Tecn Dept Civil Engn Architecture & Georesources DECiv CERIS P-1049001 Lisbon Portugal Univ Lisbon Inst Super Tecn Dept Mech Engn DEM INCtr Innovat Technol & Policy Res LARSyS P-1049001 Lisbon Portugal

This study addresses the thermal and energy performance assessment of a Building Integrated Photovoltaic Thermal (BIPVT) system installed on the facade of a test room in Solar XXI, a Net Zero Energy Building (NZEB) located in Lisbon, Portugal. A numerical analysis using the dynamic simulation tool EnergyPlus was carried out for assessing the performance of the test room with the BIPVT integrated on its facade through a parametric analysis of 14 scenarios in two conditions: a) receiving direct solar gains on the glazing surface and b) avoiding direct solar gains on the glazing surface. Additionally, a computational fluid dynamics (CFD) analysis of the BIPVT system was performed using ANSYS Fluent. The findings of this work demonstrate that the BIPVT has a good potential to improve the sustainability of the building by reducing the nominal energy needs to achieve thermal comfort, reducing up to 48% the total energy needs for heating and cooling compared to the base case. The operation mode must be adjusted to the other strategies already implemented in the room (e.g., the presence of windows and blinds to control direct solar gains), and the automatic operation mode has proven to have a better performance in the scope of this work.

关键词： building integrated photovoltaic thermal system whole-building dynamic energy simulation computational fluid dynamics simulation

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Single-Shot Temperature Measurements in a Scramjet Combustor Using Thermally Assisted Laser-Induced Fluorescence

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AIAA JOURNAL 2020年第8期58卷 3486-3498页

作者： Sopek, Tamara Brieschenk, Stefan Vanyai, Tristan Morgan, Richard G. McIntyre, Timothy J. Univ Queensland Brisbane Qld 4072 Australia Univ Queensland Sch Mech & Min Engn Ctr Hyperson Brisbane Qld Australia Univ Queensland Sch Math & Phys Ctr Hyperson Brisbane Qld Australia Univ Oxford London England

The knowledge of the temperature in the flowfield of the scramjet is critical to the understanding of its performance. This study represents the application of an optical diagnostic technique, thermally assisted laser-induced fluorescence, to the temperature measurements in the combustor of a supersonic combustion engine. The experiments were conducted in the T4 shock tunnel using a scramjet model. Experimental data were obtained by focusing a laser beam into the combustor and exciting the OH radical. A detailed numerical model that simulates all radiative and collisional processes of relevance with the appropriate system of differential equations was developed for the analysis of the influence of energy transfer processes on the fluorescence signal. The population distributions achieved with numerical modeling of the LIF process validated the approach proposed to deduce temperatures. By evaluating the scramjet LIF spectra with a full spectral fit, a temperature distribution across the combustor width was obtained. The experimental results were compared with the computational fluid dynamics simulations of the combustion process.

关键词： Combustors Scramjet Engines Laser Induced Fluorescence Rayleigh Scattering computational fluid dynamics simulation Temperature Distribution Linear Multistep Method Vibrational Energy Supersonic Combustion Shock Tunnels

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Assessment of Model Validation and Calibration Approaches in the Presence of Uncertainty

Assessment of Model Validation and Calibration Approaches in...

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AIAA Science and Technology (SciTech) Forum and Exposition

作者： Whiting, Nolan W. Roy, Christopher J. Duque, Earl Lawrence, Seth Virginia Tech Crofton Dept Aerosp & Ocean Engn Blacksburg VA 24060 USA Intelligent Light Rutherford NJ 07070 USA Intelligent Light Appl Res Grp Rutherford NJ 07070 USA

ISBN: (数字)9781624105784

ISBN: (纸本)9781624105784

Model validation is the process of determining the degree to which a model is an accurate representation of the true value in the real world. The results of a model validation study can be used to either quantify the model form uncertainty or to improve/calibrate the model. However, the model validation process can become complicated if there is uncertainty in the simulation and/or experimental outcomes. These uncertainties can be in the form of aleatory uncertainties due to randomness or epistemic uncertainties due to lack of knowledge. We will use four different approaches for addressing model validation and calibration: 1) the area validation metric, 2) a modified area validation metric with confidence intervals, 3) the standard validation uncertainty from ASME V&V 20, and 4) Bayesian updating of a model discrepancy term. To provide an unambiguous assessment of these different approaches, synthetic experimental values were generated from computational fluid dynamics simulations of a multi-element airfoil. A simplified model was then developed using a combination of thin airfoil theory and lifting line theory. This simplified model was then assessed using the synthetic experimental data. The quantities examined include the lift and moment coefficients for the wing with varying angles of attack and flap deflection angles. Each of these validation/calibration approaches will be assessed for their ability to tightly encapsulate the true value in nature at locations both where experimental results are provided and prediction locations to which the validation metric results are extrapolated.

关键词： Lift Coefficient Flap Deflection Thin Airfoil Theory computational fluid dynamics simulation Lifting Line Theory Cumulative Distribution Function Mean Camber Line Computing Maximum Likelihood Estimation Heat Transfer

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Analysis of RCG-Coated Tile Tests in the PTF: Surface Heating Distribution in a Rectangular Cavity

Analysis of RCG-Coated Tile Tests in the PTF: Surface Heatin...

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AIAA Aviation Forum and Exposition

作者： Gokcen, Tahir Skokova, Kristina A. NASA AMA Inc Ames Res Ctr MS 230-2 Moffett Field CA 94035 USA NASA AMA Inc Ames Res Ctr MS 234-1 Moffett Field CA 94035 USA

ISBN: (数字)9781624105890

ISBN: (纸本)9781624105890

Tile calibration tests are conducted in the NASA Ames 20-MW Panel Test Facility to characterize the surface heating distribution of a test article, which contains a rectangular cavity with beveled side walls. The arc-jet test data include measurements of surface pressure and heat flux on a water-cooled calibration plate, and measurements of surface temperatures of the reaction-cured glass coated tile plates. Both flat and cavity tile plates instrumented with surface thermocouples are tested to measure heating augmentations at various locations in the cavity and to provide hot-wall calibration data for the test article. The present tile-cavity flow is characterized as a closed cavity as the incoming high-enthalpy flow is able to turn into the cavity and attach to the floor before reaching the cavity trailing edge. computational fluid dynamics simulations are performed to characterize the arc-jet test environment and estimate its parameters consistent with the facility and calibration measurements. The present analysis comprises simulations of the nonequilibrium flowfield in the facility nozzle, test box, and flowfield over test articles, including comparisons with the experimental measurements. While comparisons of computed results with the water-cooled calibration plate data (surface pressure and heat flux) show good agreement, computed surface temperatures of both flat and cavity tile plates using RCG catalysis reactions are consistently lower than the thermocouple measurements. However, the heating distributions, i.e., normalized computed and measured surface temperatures, are in good agreement, and including the facility imagery, they all confirm that the maximum heating augmentation is not on the cavity centerline but at two downstream corners of the cavity.

关键词： Enthalpy Heat Flux Trailing Edges Surface Thermocouples computational fluid dynamics simulation Catalysis NASA Ames Research Center Hypersonic Flows Emissivity Mach Number

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Noise Reduction of Regional Jet Two-Wheel Main Landing Gear 25

Noise Reduction of Regional Jet Two-Wheel Main Landing Gear

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25th AIAA/CEAS Aeroacoustics Conference

作者： Ito, Yasushi Yokokawa, Yuzuru Takaishi, Takehisa Yamamoto, Kazuomi Hirai, Tohru Ueno, Yosuke Isotani, Kazuhide Hayama, Kenji Shimada, Akihisa Kumada, Toshiyuki Hayashi, Kensuke Japan Aerosp Explorat Agcy Aeronaut Technol Directorate Mitaka Tokyo 1810015 Japan Ryoyu Syst Co Ltd Aerosp Engn Solut Div Minato Ku Nagoya Aichi 4550024 Japan Kawasaki Heavy Ind Co Ltd Dev Technol Dept Aerosp Syst Co Kakamigahara Gifu 5048710 Japan Sumitomo Precis Prod Co Ltd Engn & Dev Dept Aerosp Amagasaki Hyogo 6600891 Japan Mitsubishi Aircraft Corp Aircraft Integrat Dept Komaki Aichi 4800287 Japan

ISBN: (数字)9781624105883

ISBN: (纸本)9781624105883

To reduce noise from regional jet two-wheel main landing gear, a 10% scale wind tunnel model was fabricated and tested in a low-speed anechoic wind tunnel. Six types of noise reduction devices were prepared: a porous-plate cover around the tire axle and the lower half part of the strut, a plate between the mid door and strut, a plate on the side brace, wheel holes sealed with aluminum tape, a wind deflector and porous material with open cells affixed to the inner surfaces of the inboard gear door. In the wind tunnel test, significant noise reduction was achieved with the combination of the noise reduction devices except the wind deflector. computational fluid dynamics simulations were also performed to see if they were able to predict the effect of the noise reduction devices with a reasonable amount of computational time, and to deepen understanding of their effect. Although the effect of the noise reduction in the computational result with the devices is smaller than the experimental result, their qualitative trends in the difference of the lowest noise configuration from the baseline configuration in sound pressure level and the polar directivity patterns at the mid-frequency range are similar.

关键词： Landing Gear Sound Pressure Level Wind Tunnel Models computational fluid dynamics simulation Porous Materials Flight Test Vehicle Japan Aerospace Exploration Agency Band Pass Filter Accelerating Flow Aircraft Noise

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