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Evaluation of Cryogenic Force Balance Calibration Methodologies Relative to Wind Tunnel Results

JOURNAL OF AIRCRAFT 2019年第4期56卷 1398-1406页

作者： Burns, Devin E. Toro, Kenneth G. Parker, Peter A. Rivers, S. Melissa Quix, Harald Wright, Martin NASA Langley Res Ctr Adv Measurement & Data Syst Branch Hampton VA 23681 USA NASA Langley Res Ctr Syst Engn & Engn Methods Branch MS290 Hampton VA 23681 USA NASA Langley Res Ctr Configurat Aerodynam Branch Mail Stop 267 Hampton VA 23681 USA European Transon Windtunnel GmbH Test & Data Syst Grp Ernst Mach Str 51147 D-51147 Cologne Germany European Transon Windtunnel GmbH Aerodynam & Testing Ernst Mach Str 51147 D-51147 Cologne Germany

Independent tests of the NASA Common Research Model at NASA's National Transonic Facility and the European Transonic Windtunnel reveal differences at low operating temperatures and high Reynolds numbers that warrant further investigation. Since each facility used their own wind tunnel balance for their tunnel entry, one suggestion for the differences was the temperature compensation methodology developed and applied for each balance. This hypothesis is explored through simulation and experiment. Independent calibrations of NASA's NTF-118A balance at NASA Langley Research Center and European Transonic Windtunnel reveal differences in the thermal compensation of the normal force and pitching moment primary sensitivities with temperature, while the axial force primary sensitivities are in good agreement. The application of the balance calibrations performed at NASA and European Transonic Windtunnel to the prior wind tunnel data suggests that the thermal compensation differences are an order of magnitude lower than the differences observed between the wind tunnel aerodynamic coefficients. Thus, the balance temperature compensation methodologies used by NASA and European Transonic Windtunnel are not a major contributor to the wind tunnel differences.

关键词： Wind Tunnel Balances National Transonic Facility Aerodynamic Coefficients NASA Langley Research Center Angle of Attack Cryogenic Temperature Linear Interpolation Temperature Effects computational fluid dynamics simulation Temperature Control

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Mutual Effect Between Swept-and-Leaned Vanes and Acoustic Liners on Fan Interaction-Noise Reduction

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AIAA JOURNAL 2019年第6期57卷 2479-2488页

作者： Zhang, Weiguang Wang, Xiaoyu Du, Lin Sun, Xiaofeng Commercial Aircraft Corp China Ltd COMAC Beijing Aeronaut Sci & Technol Res Inst Aerodynam & Acoust Grp Beijing 102211 Peoples R China Beihang Univ Sch Energy & Power Engn Beijing 100191 Peoples R China

The swept-and-leaned vanes and acoustic liners can both be used to reduce the turbofan noise. In this work, an analytical model was proposed under an idealized condition, in which an annular stator cascade and a locally reacting liner exist in an infinite duct at the same time, to study the mutual effect between these two techniques. Based on the transfer element method, the system matrix of multi-elements can be established based on the continuity of disturbance pressure and velocity at the interfaces. The acoustic elements for a stator and a liner were established, respectively, by employing the three-dimensional lifting-surface method and the equivalent surface source method, which are both the so-called methods of singularity. The interface matching pattern between adjacent elements was improved in this paper with more physics included, which can also be combined with the numerical methods easier. Because the technologies for fan-noise reduction, which are the swept-and-leaned vanes and acoustic liners in this paper, are both closely related to the modal acoustic field in the duct, the coupling effect can be strong in some conditions. The results showed that the noise reduction gained by these two techniques cannot be superposed simply. They should not be considered isolatedly. Further discussions on the transmission and reflection between different kinds of acoustic elements should be made to achieve the system optimization in the nacelle.

关键词： computational Aeroacoustics Nacelles Turbofan Noise Acoustic Scattering Rotor Stator Interactions computational fluid dynamics simulation Sweep Angle Computing Power Potential Flow Turbofan Engines

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Experimental and simulation study of thermal accumulation in an enclosed vehicle

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PROCEEDINGS OF THE INSTITUTION OF MECHANICAL ENGINEERS PART D-JOURNAL OF AUTOMOBILE ENGINEERING 2019年第14期233卷 3621-3629页

作者： Chua, Sing Ngie David Chan, Boon Kean Lim, Soh Fong Univ Malaysia Sarawak Fac Engn Kota Samarahan 94300 Malaysia

Thermal accumulation in a car cabin under direct exposure to sunlight can be extremely critical due to the risk of heatstroke especially to children who are left unattended in the car. There are very limited studies in the literature to understand the thermal behaviour of a car that is parked in an open car park space and the findings are mostly inconsistent among researchers. In this paper, the studies of thermal accumulation in an enclosed vehicle by experimental and computational fluid dynamics simulation approaches were carried out. An effective and economical method to reduce the heat accumulation was proposed. Different test conditions such as fully enclosed, fully enclosed with sunshade on front windshield and different combinations of window gap sizes were experimented and presented. Eight points of measurement were recorded at different locations in the car cabin and the results were used as the boundary conditions for the three-dimensional computational fluid dynamics simulation. The computational fluid dynamics software used was ANSYS FLUENT 16.0. The results showed that the application of sunshade helped to reduce thermal accumulation at car cabin by 11.5%. The optimum combination of windows gap size was found to be with 4-cm gap on all four windows which contributed to a 21.1% reduction in car cabin temperature. The results obtained from the simulations were comparable and in agreement with the experimental tests.

关键词： Car cabin temperature thermal comfort computational fluid dynamics simulation

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JAXA's and KHI's Contribution to the Third High Lift Prediction Workshop

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JOURNAL OF AIRCRAFT 2019年第3期56卷 1080-1098页

作者： Ito, Yasushi Murayama, Mitsuhiro Yokokawa, Yuzuru Yamamoto, Kazuomi Tanaka, Kentaro Hirai, Tohru Yasuda, Hidemasa Tajima, Atsushi Ochi, Akio Japan Aerosp Explorat Agcy Tokyo 1810015 Japan Ryoyu Syst Co Ltd Aerosp Engn Solut Div Minato Ku Nagoya Aichi 4550024 Japan Kawasaki Heavy Ind Co Ltd Gifu 5048710 Japan Kawaju Gifu Engn Co Ltd Gifu 5040971 Japan Kawasaki Heavy Ind Co Ltd Gifu 5048710 Japan Aeronaut Technol Directorate Mitaka Tokyo Japan Aerodynam Engn Sect Kakamigahara Japan

This paper is based on results presented at the Third High Lift Prediction Workshop. The Japan Aerospace Exploration Agency provided computer-aided design models and experimental results of the Japan Aerospace Exploration Agency Standard Model to the workshop as a test case. An unstructured hybrid mesh generator, MEGG3D, was applied to the Japan Aerospace Exploration Agency Standard Model wing-body and wing-body-nacelle-pylon configurations to generate grids, which were provided for the use of workshop participants by the committee. This paper presents details of experimental results and the method for deforming the computer-aided design models and volume grids based on the experiment. The Japan Aerospace Exploration Agency and Kawasaki Heavy Industries, Ltd., performed computational fluid dynamics simulations of the test case as workshop participants. Kawasaki Heavy Industries also generated custom participant-generated grids. Their computational results using the TAS code and Cflow are discussed.

关键词： computational fluid dynamics simulation Aircraft Configurations Computer Aided Design Japan Aerospace Exploration Agency Laminar Turbulent Transition Low Speed Wind Tunnel Angle of Attack Aerodynamic Coefficients Flow Conditions Reynolds Averaged Navier Stokes

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Design, analysis, and performance verification of a water jet thruster for amphibious jumping robot

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PROCEEDINGS OF THE INSTITUTION OF MECHANICAL ENGINEERS PART C-JOURNAL OF MECHANICAL ENGINEERING SCIENCE 2019年第15期233卷 5431-5447页

作者： Mo, Jixue Miao, Zhihuai Li, Bing Zhang, Yunlu Song, Zhendong Harbin Inst Technol State Key Lab Robot & Syst Harbin Heilongjiang Peoples R China Harbin Inst Technol Sch Mech Engn & Automat Shenzhen Peoples R China Shenzhen Polytech Coll Mech & Elect Engn Shenzhen 518055 Peoples R China

In nature, certain aquatic animals and seabirds are capable of leaping from water surface and overcoming aquatic obstacles with ease. Inspired by that, researchers have developed various underwater robots, which can perform the aquatic jumping motion. Although there are several ways to achieve it, the water jet propulsion is the most appropriate approach for the amphibious jumping robot, which is under development. In this paper, a high-performance water jet thruster powered by liquid nitrogen is proposed to be the potential actuator for the amphibious jumping robot. The theoretical jumping model is built to optimize the initial volume fraction of water inside thruster and analyze its parameters' variation during water jet. Then the computational fluid dynamics simulations by ANSYS FLUENT software are carried out to analyze the self-pressurization process of liquid nitrogen as well as the water jet process. Finally, the proof-of-concept outdoor experiments present that the 3.7 kg thruster's maximum aquatic and terrestrial jumping heights are 25.1 m and 24.4 m, respectively. A simple heat transfer analysis between water and liquid nitrogen is also conducted, and the order of magnitude estimation of heat transfer coefficient is given to be 265W/ (m(2)center dot K) based on the experimental reaction time.

关键词： Amphibious jumping robot water jet thruster liquid nitrogen computational fluid dynamics simulation

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A practical CFD modeling approach to estimate outlet boundary conditions of industrial multistage spray dryers: Inert particle flow field investigation

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DRYING TECHNOLOGY 2019年第7期37卷 824-838页

作者： Afshar, Sepideh Metzger, Lloyd Patel, Hasmukh Selomulya, Cordelia Woo, Meng Wai Monash Univ Dept Chem Engn Clayton Campus Clayton Vic 3800 Australia South Dakota State Univ Dept Dairy Sci Brookings SD 57007 USA Land OLakes Inc Dairy Foods Res & Dev Brookings SD USA

Industrial multistage spray drying systems often have limited in situ process measurements to provide sufficient information for computational fluid dynamics (CFD) simulations of the primary drying chamber. In this case study on the spray dryer at Davis Dairy Plant (South Dakota State University), uncertainties were encountered in specifying the outlet boundary conditions of the spray drying chamber with two outlets: the side outlet and the bottom outlet leading to the second stage external vibrating bed. Using the available data on the vacuum pressure of the chamber, a numerical framework was introduced to approximate suitable outlet boundary conditions for the drying chamber. The procedure involved analyzing the ratio of the airflow rate between the two outlets and using a pseudo-tracer inert particle injection analysis. The goal of this approach was to determine a suitable range of outlet vacuum pressure that will lead to realistic particle movement behaviors during the actual plant operation. The protocol developed here will be a useful tool for CFD modeling of large scale multistage spray drying systems.

关键词： Boundary conditions computational fluid dynamics simulation multistage spray drying

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computational Investigation of Vertical Stabilizer with Vortex Generators and Dorsal Fin

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JOURNAL OF AIRCRAFT 2019年第5期56卷 1833-1848页

作者： Ito, Yasushi Murayama, Mitsuhiro Koike, Shunsuke Yamamoto, Kazuomi Nakakita, Kazuyuki Kusunose, Kazuhiro Japan Aerosp Explorat Agcy Aeronaut Technol Directorate Chofu Tokyo 1828522 Japan

This paper describes methods to improve the performance of a vertical stabilizer in terms of yawing moment with corotating blade-type vortex generators and a dorsal fin over a wide range of sideslip angles. A vertical stabilizer designed by ONERA was mounted on the NASA Common Research Model to investigate the performance of sets of vortex generators and dorsal fins at several rudder deflection angles. computational fluid dynamics simulations were performed to reveal basic flow characteristics of the vertical stabilizer, including its rudder, and to understand how vortices generated around the vortex generators and dorsal fins interact with the leading-edge separation vortex and boundary layer on the vertical stabilizer and how the vortices improve the lateral performance of the vertical stabilizer. Wind-tunnel tests were also conducted to validate the computational results. Vortex generators improved the performance of the vertical stabilizer slightly at low sideslip angles by reducing flow separation on the rudder, and a dorsal fin assisted greatly at high sideslip angles due to two vortices it induced: the primary dorsal fin vortex and the leading-edge separation vortex.

关键词： Vertical Stabilisers Vortex Generators computational fluid dynamics simulation Vortices Mean Aerodynamic Chord Boundary Layer Thickness Low Speed Wind Tunnel Rudder Angle of Sideslip Flow Characteristics

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Turbulence Modeling Effects on Fuel Regression Rate in Hybrid Rocket Numerical simulations

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JOURNAL OF PROPULSION AND POWER 2019年第6期35卷 1127-1142页

作者： Durand, Jean-Etienne Raynaud, Florent Lestrade, Jean-Yves Anthoine, Jerome ONERA French Aerosp Lab Rocket Prop Lab Unit Multiphys Energet Dept F-31410 Mauzac France

A new fuel regression model, based on the mass/energy balance at the fuel surface, is implemented in the computational fluid dynamics software CEDRE. The modeling aims at generalizing a practical use of the fuel regression model to improve, by means of numerical simulations, the knowledge about aerothermochemical phenomena in hybrid rocket engines. The present study focuses on the analysis of the turbulent boundary layer with wall blowing, modeled by k-omega with the shear stress transport formulation, to assess the impact of a turbulence model wall correction on the fuel regression. A discussion about the matching between numerical simulations and experimental data from hydrogen peroxide/high-density polyethylene hybrid rocket engine tests in an axial injection configuration for a pressure range of 1.1-3.6 MPa is reported to assess the improvement in the fuel regression and pressure reproduction provided by the turbulence wall correction.

关键词： Turbulence Models Fuel Regression computational fluid dynamics simulation Hybrid Rocket Turbulent Boundary Layer High Density Polyethylene Hybrid Rocket Engines Shear Stress Mass Flow Rate Fuel Pyrolysis

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computational and Experimental Investigation of a Flapping-Wing Micro Air Vehicle in Hover

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JOURNAL OF AIRCRAFT 2019年第4期56卷 1610-1625页

作者： Badrya, Camli Govindarajan, Bharath Baeder, James D. Harrington, Aaron Kroninger, Christopher M. Univ Maryland Dept Aerosp Engn College Pk MD 20742 USA US Army Res Lab Aberdeen Proving Ground MD 21005 USA

Experimental and computational study of flapping-wing insect at low Reynolds number is conducted in this work. The paper is broadly divided into two sections: experiments and computational fluid dynamics-based numerical analysis. A dynamically scaled wing is simulated using Overset Transonic Rotor Unsteady Navier-Stokes (OVERTURNS) computational platform, a three-dimensional Navier-Stokes solver. The computational results are compared with experimental results of an isolated flapping wing performed in an oil tank. Good agreement was observed between the experiments and numerical simulations in terms of magnitude and trend of the unsteady instantaneous lift and drag forces over the flapping cycle. A parametric study was performed to observe the influence of the kinematic, flapping frequency and pitch angle, on the force production and power requirements. As a consequence of the study, lift-to-power ratio versus average lift was identified as a principal efficiency metric to assess the performance of flapping-wing vehicles for given geometry and kinematic parameters. A clear advantage for a wing pitch angle of 40 degrees was observed compared with that of 30 degrees or 60 degrees.

关键词： Flapping Frequency Micro Air Vehicle Free Stream Velocity computational fluid dynamics simulation Navier Stokes Solver Aerodynamic Efficiency Vortices Reynolds Averaged Navier Stokes Wing Span Flapping Kinematics

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Numerical investigation on flow mechanisms of a squirrel cage fan

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PROCEEDINGS OF THE INSTITUTION OF MECHANICAL ENGINEERS PART A-JOURNAL OF POWER AND ENERGY 2019年第1期233卷 3-16页

作者： Wang, Ke Ju, Yaping Zhang, Chuhua Xi An Jiao Tong Univ Sch Energy & Power Engn 28 West Xianning Rd Xian 710049 Shaanxi Peoples R China Xi An Jiao Tong Univ State Key Lab Strength & Vibrat Mech Struct Xian Shaanxi Peoples R China

Squirrel cage fan has found wide applications in heating, ventilation and air-conditioning as well as other cooling systems. Although many studies have been conducted to investigate the performance of the squirrel cage fan, the complex flows and the associated flow mechanisms have not been fully elucidated. In this paper, computational fluid dynamics simulations are performed for a comprehensive analysis of the flow throughout a whole squirrel cage fan. A novel representation technique is proposed for a vivid and quantitative description of the flow velocity distributions at the impeller inlet and outlet to aid a heuristic analysis of the complex flows in squirrel cage fan. The pressure gradient distributions, together with the pressure itself, along the volute wall are also extracted and analyzed to explore the local flow conditions of the volute profile with four segmental arcs. The results show that the proposed representation technique is capable of effectively measuring the circumferentially nonuniform flow conditions at both the impeller inlet and outlet. The strong interaction between the impeller and the volute tongue induces reversed flows at both the impeller inlet and outlet, which further aggravates the circumferential nonuniformity of inactive zone and the upstream impeller flow field. Despite the first-order continuity of the volute profile itself, there are strong variations of tangential pressure gradients and sudden diffusion-expansion effects at the junctions of adjacent arcs. These findings benefit a deep understanding of the complex flow mechanisms within the squirrel cage fan.

关键词： Squirrel cage fan computational fluid dynamics simulation inactive zone sudden diffusion-expansion effects

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