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Wang Y.,Hubei University of Automotive Technology | Wang Y.,State Key Laboratory of Automotive Simulation and Control | Xin Y.,Hubei University of Automotive Technology | Gu Z.,State Key Laboratory of Advanced Design and Manufacturing for Vehicle Body | And 3 more authors.
Journal of Applied Fluid Mechanics | Year: 2014

The numerical simulation and wind tunnel experiment were employed to investigate the aerodynamic characteristics of three typical rear shapes: fastback, notchback and squareback. The object was to investigate the sensibility of aerodynamic characteristic to the rear shape, and provide more comprehensive experimental data as a reference to validate the numerical simulation. In the wind tunnel experiments, the aerodynamic six components of the three models with the yaw angles range from -15° and 15° were measured. The realizable k-ε model was employed to compute the aerodynamic drag, lift and surface pressure distribution at a zero yaw angle. In order to improve the calculation efficiency and accuracy, a hybrid Tetrahedron-Hexahedron-Pentahedral-Prism mesh strategy was used to discretize the computational domain. The computational results showed a good agreement with the experimental data and the results revealed that different rear shapes would induce very different aerodynamic characteristic, and it was difficult to determine the best shape. For example, the fastback would obtain very low aerodynamic drag, but it would induce positive lift which was not conducive to stability at high speed, and it also would induce bad crosswind stability. In order to reveal the internal connection between the aerodynamic drag and wake vortices, the turbulent kinetic, recirculation length, position of vortex core and velocity profile in the wake were investigated by numerical simulation and PIV experiment.


Wang Y.-P.,Hunan University | Wang Y.-P.,Wuhan University of Technology | Gu Z.-Q.,Hunan University | Yang X.,Wuhan Ordnance Noncommissioned Officers School
Kongqi Donglixue Xuebao/Acta Aerodynamica Sinica | Year: 2012

Based on the road test of the reference model, the CFD technology was used to analyze the side windows buffeting characteristics, and the results showed that the rear window buffeting is much higher than the front one. Furthermore, the effects of several parameters on buffeting frequency and intensity were also studied. These parameters include vehicle speed, interior volume, the location of windows and numbers of opened windows. According to the mechanism of wind buffeting, two improvements were employed to reduce the rear window buffeting, and the maximal noise was reduced by 9 dB.


Wang Y.,Hubei University of Automotive Technology | Wang Y.,Jilin University | Zhen X.,Hubei University of Automotive Technology | Wu J.,Hubei University of Automotive Technology | And 3 more authors.
Science China Technological Sciences | Year: 2013

Flow passing a vehicle may lead to the increase of the cabin interior noise level through a variety of mechanisms. These mechanisms include vibrations caused by aerodynamic excitations and re-radiation from the glass panels, exterior noise transmitted and leaked through door seals including gaps and glass edge, and transmission of airborne noise generated by the interaction of flow with body panels. It is of vital importance to predict both the flow fields and the acoustic sources around the vehicle to accurately assess the impact of wind induced noise inside the cabin. In the present study, an unstructured segregated finite volume model was used to calculate the flow fields in which a hexahedron grid is used to simplify the vehicle geometry. A large eddy simulation coupled with a wall function model was applied to predict the exterior transient flow fields. The mean flow quantities were thus calculated along the symmetry plane and the vehicle's side windows. A coupled FEM/BEM method was used to compute the vehicle's interior noise level. The total contribution of the interior noise level due to the body panels of the vehicle was subsequently analyzed. © 2013 Science China Press and Springer-Verlag Berlin Heidelberg.


Wang Y.,Wuhan University of Technology | Wang Y.,Hunan University | Wang Y.,Hubei University of Automotive Technology | Deng Y.,Wuhan University of Technology | And 4 more authors.
Proceedings of the Institution of Mechanical Engineers, Part D: Journal of Automobile Engineering | Year: 2013

Numerical computation was conducted to investigate the flow-induced sunroof buffeting noise at low Mach numbers. In order to avoid the stiffness problem which occurs in solving the compressible fluid equations at low Mach numbers, new governing equations were derived with the assumption that there is a slight compressibility effect. The mechanisms of the flow-induced sunroof buffeting noise were investigated by considering a three-dimensional model cavity. Extensive wind tunnel tests were conducted to verify the computational scheme developed in the present study. The results demonstrated that strong pressure fluctuations will be generated inside the cavity and that the modal resonant frequencies are in good agreement with the Rossiter formula and experimental data. Moreover, the results reveal that the sunroof buffeting noise is attributed to the periodicity of flow separation, vortex shedding, vortex impingement and pressure wave feedback, with the addition of the Helmholtz resonance locked effect. Therefore, the current computational approach was validated to have the capability to predict the flow-induced buffeting noise in low-Mach-number flows. © 2013 IMechE.


Xi Z.,Wuhan Ordnance Noncommissioned Officers School | Bo W.,Wuhan Ordnance Noncommissioned Officers School
Advanced Materials Research | Year: 2014

A fluorescent markers based two-dimensional parallel detection technique of Micro-fluidic chip is studied. In a special designed fluid field of test sample, excite fluorescence of micro-spheres probe by pulse-laser and employ high sensitivity CCD to catch it. The entire information from micro-fluidic chip can be obtained via a computer post-processing of the caught signal of fluorescence. Analyzed the probe flow state and fluorescence signal intensity of detection program. Established the expressions of fluorescence signal intensity and the parameters of detection system. Validation experiments indicate that this detection method has the advantages of rapid, accurate and high sensitivity. © (2014) Trans Tech Publications, Switzerland.


Wang Y.,Hubei University of Automotive Technology | Li S.,Hubei University of Automotive Technology | Zhang Y.,Hubei University of Automotive Technology | Yang X.,Wuhan Ordnance Noncommissioned Officers School | And 2 more authors.
Energy Conversion and Management | Year: 2016

The waste heat of automotive exhaust gas would be directly transferred into electricity by thermoelectric modules (TEM) because of the temperature difference between heat exchanger and water tank. For the vehicle thermoelectric generator (TEG), the electrical power generation was deeply influenced by temperature difference, temperature uniformity and topological structure of TEG. In previous works, increasing the difference of temperature would significantly enhance the power generation of TEG and inserted fins were always applied to enhance heat transfer in heat exchanger. However the fins would result in a large unwanted back pressure which went against to the efficiency of the engine. In current studies, in order to enhance heat transfer rates and to avoid back pressure increase, a heat exchanger containing cylindrical grooves (the depth-to-width ratio is 0.25) on the interior surface of heat exchanger was proposed. The cylindrical grooves could increase the heat transfer area and enhance the turbulence intensity, meanwhile there was no additional inserts in the fluid to block the flow. The surface temperatures of water tank and heat exchanger with three internal structures, such as grooved surface, flat surface and inserted fins, were studied by numerical simulation at each row of thermoelectric modules. The results showed that comparing to other structures, heat exchanger with cylindrical grooves could improve the TEG efficiency at a low back pressure. The influence of the channel height on the TEG performance was investigated and the TEG with a channel height of 8 mm showed the best overall performance. It was also found that a portion of heat exchanger uncovered with thermoelectric modules at the downstream section could make the upstream section hotter and make full use of each TEM. © 2016 Elsevier Ltd


Wang Y.,Hubei University of Automotive Technology | Wu C.,Hubei University of Automotive Technology | Tang Z.,Hubei University of Automotive Technology | Yang X.,Wuhan Ordnance Noncommissioned Officers School | And 2 more authors.
Journal of Electronic Materials | Year: 2015

Thermoelectric generators (TEGs) are currently a topic of interest for energy recovery in vehicles. By applying TEGs to the outside surface of the exhaust tailpipe, a small amount of electrical power can be generated because of the temperature difference between the hot exhaust gases and the automobile coolant. The amount of power is anticipated to be a few hundred watts based on the expected temperature difference and the properties of the thermoelectric materials used in TEGs. It is well know that, for thermoelectric exhaust energy recovery, the temperature uniformity of the heat exchangers has a strong influence on the electric power generation. In the current research, the temperature uniformity of a heat exchanger was improved by optimizing the fin distribution to maximize the electric power generated for a given vehicle TEG. A computational fluid dynamics (CFD) model of the heat exchanger was constructed to assess the influence of different fin distributions on the temperature uniformity and the pressure drop in the exhaust system. For the fin distributions, four factors were considered: the length of, spacing between, angle of, and thickness of the fins. Based on these four factors, a design of experiments study using the orthogonal experimental method was conducted to analyze the sensitivity to the design variables and build a database to set up a surrogate model using the Kriging response surface method. A multi-island genetic algorithm was used to optimize the fin distribution based on this surrogate model. To validate the accuracy of the CFD model, a generic heat exchanger module was manufactured and a related testbed constructed, then the temperature distribution on the surface of the exchanger was measured to compare with the results obtained by CFD. © 2014, The Minerals, Metals & Materials Society.


Wang Y.,Hubei University of Automotive Technology | Li S.,Hubei University of Automotive Technology | Yang X.,Wuhan Ordnance Noncommissioned Officers School
Applied Acoustics | Year: 2016

Computational investigations are conducted to determine the effectiveness of a passive control technique, which was employed to decay the pressure oscillations induced by a subsonic flow over a cavity. This work focuses on a cavity with a small opening but a large volume. The passive control technique is employed by introducing a dimpled non-smooth surface, which is installed at the upstream of the cavity. Large eddy simulation is used to investigate the flow field and flow instability around the cavity for the smooth and non-smooth cases. Experiments are conducted in an acoustic wind tunnel for the smooth case to validate the computational scheme. Flow visualizations revealed that the dimpled surface located upstream effectively suppresses cavity flow oscillations. Finally, the control mechanism of cavity oscillation with the dimpled non-smooth surface is also determined based on the comparison of the flow field structure between the smooth and non-smooth cases. © 2016 Elsevier Ltd. All rights reserved.


Wang Y.,Hubei University of Automotive Technology | Li S.,Hubei University of Automotive Technology | Yang X.,Wuhan Ordnance Noncommissioned Officers School | Deng Y.,Hubei University of Automotive Technology | Su C.,Hubei University of Automotive Technology
Journal of Electronic Materials | Year: 2015

For vehicle thermoelectric exhaust energy recovery, the temperature difference between the heat exchanger and the coolant has a strong influence on the electric power generation, and ribs are often employed to enhance the heat transfer of the heat exchanger. However, the introduction of ribs will result in a large unwanted pressure drop in the exhaust system which is unfavorable for the engine’s efficiency. Therefore, how to enhance the heat transfer and control the pressure drop in the exhaust system is quite important for thermoelectric generators (TEG). In the current study, a symmetrical arrangement of dimpled surfaces staggered in the upper and lower surfaces of the heat exchanger was proposed to augment heat transfer rates with minimal pressure drop penalties. The turbulent flow characteristics and heat transfer performance of turbulent flow over the dimpled surface in a flat heat exchanger was investigated by numerical simulation and temperature measurements. The heat transfer capacity in terms of Nusselt number and the pressure loss in terms of Fanning friction factors of the exchanger were compared with those of the flat plate. The pressure loss and heat transfer characteristics of dimples with a depth-to-diameter ratio (h/D) at 0.2 were investigated. Finally, a quite good heat transfer performance with minimal pressure drop heat exchanger in a vehicle TEG was obtained. And based on the area-averaged surface temperature of the heat exchanger and the Seeback effect, the power generation can be improved by about 15% at Re = 25,000 compared to a heat exchanger with a flat surface. © 2015 The Minerals, Metals & Materials Society


Zhu C.-W.,Wuhan Ordnance Noncommissioned Officers School | Chen X.-Q.,Wuhan Ordnance Noncommissioned Officers School | Zheng Y.,Wuhan Ordnance Noncommissioned Officers School | Cai X.-Y.,Wuhan Ordnance Noncommissioned Officers School | Zeng C.-Z.,Wuhan Ordnance Noncommissioned Officers School
Proceedings of 2015 IEEE Advanced Information Technology, Electronic and Automation Control Conference, IAEAC 2015 | Year: 2015

Based on Multiple View Semi-supervised Dimensionality Reduction (MVSSDR), this thesis will propose Multiple View Dimensionality Reduction via Harmonic Function (MVDRHF), which substitutes the soft label gained in the harmonic-function-based label propagation technique for the link information in MVSSDR, thus avoids the transformation from label information to link information to preserve the prior information as much as possible and finally guarantee better dimensionality reduction power. © 2015 IEEE.

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