scholarly journals Application of the Symmetric Model to the Design Optimization of Fan Outlet Grills

Symmetry ◽  
2019 ◽  
Vol 11 (8) ◽  
pp. 959 ◽  
Author(s):  
Lin ◽  
Cheng
Keyword(s):  
Wind Speed ◽  
Flow Field ◽  
Velocity Distribution ◽  
Simulation Analysis ◽  
Three Dimensional ◽  
Surface Flow ◽  
Simulation Software ◽  
Experimental Results ◽  
Symmetric Model ◽  
Airflow Rate

In this study, different designs of the opening pattern of computer fan grills were investigated. The objective of this study was to propose a simulation analysis and compare it to the experimental results for a set of optimized fan designs. The FLUENT computational fluid dynamics (CFD) simulation software was used to analyze the fan blade flow. The experimental results obtained by the simulation analysis of the optimized fan designs were analyzed and compared. The effect of different opening pattern designs on the resulting airflow rate was investigated. Six types of fans with different grills were analyzed. The airflow velocity distribution in the simulated flow channel indicated that the wind speed efficiency of the fan and its influence were comparable with the experimental model. The air was forced by the fan into the air duct. The flow path was separately measured by analog instruments. The three-dimensional flow field was determined by performing a wind speed comparison on nine planes containing the mainstream velocity vector. Moreover, the three-dimensional curved surface flow field at the outlet position and the highest fan rotation speed were investigated. The air velocity distribution at the inlet and the outlet of the fan indicated that among the air outlet opening designs, the honeycomb shaped air outlet displayed the optimal performance by investigating the fan characteristics and the estimated wind speed efficiency. These optimized designs were the most ideal configurations to compare these results. The air flow rate was evenly distributed at the fan inlet.

scholarly journals Three-dimensional hydrodynamics numerical of wind-driven circulations in Danjiangkou Reservoir

2018 ◽  
Vol 246 ◽  
pp. 02021
Author(s):  
Jie Zhu ◽  
Jin Quan ◽  
Xiaohui Lei ◽  
Xia Yue ◽  
Yang Duan
Keyword(s):  
Wind Speed ◽  
Flow Field ◽  
Potential Flow ◽  
Flow Direction ◽  
Three Dimensional ◽  
Surface Flow ◽  
Surface Velocity ◽  
Wind Condition ◽  
Reservoir Area ◽  
Danjiangkou Reservoir

This paper focuses on the analysis of the flow field of Danjiangkou Reservoir under the action of wind stress. Based on the analysis of the annual wind field data of Danjiangkou Reservoir, the three-dimensional hydrodynamic model of Danjiangkou Reservoir was established. The distribution of water flow field in the reservoir area under five different wind directions and two different wind speeds was studied. The simulation results were compared with the flow field without wind. The results show that when the wind speed in the reservoir area is 3.3m/s, the surface velocity and flow direction change less under the same wind conditions as the potential flow direction. Under the wind condition opposite to the potential flow direction, the reservoir area is locally generated. The small circulation and surface flow are more disordered; when the wind speed reaches 10.0m/s, under the same wind condition as the potential flow direction, the surface velocity of the reservoir area increases significantly. Under the wind condition opposite to the direction of the potential flow, a stable counterclockwise circulation is generated, and the wind direction dominates the surface layer. seriously affecting the flow field distribution in the reservoir area. The research results in this paper can provide support for the reservoir in the formulation of emergency water pollution emergency strategy and the formulation of real-time scheduling plan.

Numerical Simulation and Experimental Verification of the Deposition Concentration of an Unmanned Aerial Vehicle

2019 ◽  
Vol 35 (3) ◽  
pp. 367-376 ◽  
Author(s):  
Qiang Shi ◽  
Hanping Mao ◽  
Xianping Guan
Keyword(s):  
Numerical Simulation ◽  
Flow Field ◽  
Unmanned Aerial Vehicle ◽  
Simulation Analysis ◽  
Three Dimensional ◽  
Laser Scanner ◽  
Utilization Rate ◽  
Droplet Deposition ◽  
Aerial Vehicle ◽  
Motion Characteristics

Abstract. To analyze the droplet deposition under the influence of the flow field of an unmanned aerial vehicle (UAV), a hand-held three-dimensional (3D) laser scanner was used to scan 3D images of the UAV. Fluent software was used to simulate the motion characteristics of droplets and flow fields under the conditions of a flight speed of 3 m/s and an altitude of 1.5 m. The results indicated that the ground deposition concentration in the nonrotor flow field was high, the spray field width was 2.6 m, and the droplet deposition concentration was 50 to 200 ug/cm2. Under the influence of the rotor flow field, the widest deposition range of droplets reached 12.8 m. Notably, the droplet deposition uniformity worsened, and the concentration range of the droplet deposition was 0 to 500 ug/cm2. With the downward development of the downwash flow field, the overall velocity of the flow field gradually decreased, and the influence interval of the flow field gradually expanded. In this article, the droplet concentration was verified under simulated working conditions by a field experiment, thereby demonstrating the reliability of the numerical simulation results. This research could provide a basis for determining optimal UAV operating parameters, reducing the drift of droplets and increasing the utilization rate of pesticides. Keywords: Unmanned aerial vehicle (UAV), Aerial application, Downwash flow field, Droplet deposition, Simulation analysis.

The effect analysis of an engine jet on an aircraft blast deflector

2018 ◽  
Vol 41 (4) ◽  
pp. 990-1001
Author(s):  
Song Ma ◽  
Jianguo Tan ◽  
Xiankai Li ◽  
Jiang Hao
Keyword(s):  
High Temperature ◽  
Flow Field ◽  
High Speed ◽  
Deflection Angle ◽  
Stokes Equations ◽  
Three Dimensional ◽  
Aircraft Engine ◽  
Experimental Results ◽  
Exhaust Gases ◽  
The Impact

This paper establishes a novel mathematical model for computing the plume flow field of a carrier-based aircraft engine. Its objective is to study the impact of jet exhaust gases with high temperature, high speed and high pressure on the jet blast deflector. The working condition of the nozzle of a fully powered on engine is first determined. The flow field of the exhaust jet is then numerically simulated at different deflection angle using the three-dimensional Reynolds averaged Navier–Stokes equations and the standard [Formula: see text]-[Formula: see text] turbulence method. Moreover, infra-red temperature tests are further carried out to test the temperature field when the jet blast deflector is at the [Formula: see text] deflection angle. The comparison between the simulation results and the experimental results show that the proposed computation model can perfectly describe the system. There is only 8–10% variation between them. A good verification is achieved. Moreover, the experimental results show that the jet blast deflector plays an outstanding role in driving the high-temperature exhaust gases. It is found that [Formula: see text] may be the best deflection angle to protect the deck and the surrounding equipment effectively. These data results provide a valuable basis for the design and layout optimization of the jet blast deflector and deck.

Computational and experimental investigations in a cyclone dust separator

1997 ◽  
Vol 211 (4) ◽  
pp. 247-257 ◽  
Author(s):  
S M Fraser ◽  
A M Abdel-Razek ◽  
M Z Abdullah
Keyword(s):  
Flow Field ◽  
Richardson Number ◽  
Swirling Flow ◽  
Laser Doppler Anemometry ◽  
Experimental Studies ◽  
Three Dimensional ◽  
Experimental Results ◽  
Experimental Investigations ◽  
Cyclone Chamber ◽  
Dust Separator

Three-dimensional turbulent flow in a model cyclone has been simulated using PHOENICS code and experimental studies carried out using a laser Doppler anemometry (LDA) system. The experimental results were used to validate the computed velocity distributions based on the standard and a modified k-∊ model. The standard k-∊ model was found to be unsatisfactory for the prediction of the flow field inside the cyclone chamber. By considering the strong swirling flow and the streamlined curvature, a k-∊ model, modified to take account of the Richardson number, provided better velocity distributions and better agreement with the experimental results.

Study of Blade Sweep Effects of Compressor

2005 ◽  
Author(s):  
C. Xu ◽  
R. S. Amano
Keyword(s):  
Flow Field ◽  
Turbine Blade ◽  
Experimental Studies ◽  
Three Dimensional ◽  
Experimental Results ◽  
Numerical Analyses ◽  
Blade Design ◽  
3D Flow ◽  
Efficient Manner ◽  
Blade Row

The three dimensional blading had been used for years in the process of turbomachine designs. In need of turbine blade designs in an efficient manner, the current advancement of CFD technologies allows effective 3D predictions of a complex 3D flow field in turbine blade passages, which can improve the turbine blade performances. Since numerous advantages of 3-D CFD usage had been reported in the open literature, many industries already started to use 3D blading in their turbomachines. In addition, a blade lean and a sweep for the blade design had been also implemented to increase the blade row efficiency. Experimental studies have shown some advantages of these lean and sweep features. Most of the experimental results combine many other features together. However, it is difficult to determine what the effects of different features should be. In this study, detailed numerical analyses were developed and these were used to present the results to gain better understanding of different feature of 3D blading for turbine designers and engineers. Throughout this paper performance impacts on different 3D features are presented and the superiority of the present approach is discussed.

Experimental Testing and Finite Element Modeling of Bump Wafer Probing

2013 ◽  
Vol 284-287 ◽  
pp. 748-753
Author(s):  
Hao Yuan Chang ◽  
Kao Hua Chang ◽  
Yi Shao Lai
Keyword(s):  
Finite Element ◽  
Solder Bump ◽  
Experimental Testing ◽  
Three Dimensional ◽  
Element Model ◽  
Simulation Software ◽  
Experimental Results ◽  
Height Variation ◽  
Bump Height ◽  
Wafer Probing

The purpose of this paper is mainly to develop a method to simulate the bump height variation and probe mark profile for Eutectic (Sn63/ Pb37) bump wafer probing with continuing-touchdown probing. Certainly, the bump height variation and probe mark area on the solder bump influence the quality of the wafer probing and further impacts reliability of the packaging process after wafer probing to cause issues of cold-joint and needle damage. A three-dimensional computational model of was developed to analyze the contact phenomena between the vertical needle and the solder bump. Finite element simulation software, ANSYS, is used to analyze the loading force distributed on the vertical needle with various overdrives. In addition, the results of the bump height variation and probe mark area, which predicted by the finite element method (FEM), were verified against the on-line experimental results. Finally, the results predicted by the finite element model is consistent with experimental results and the numerical method presented in the paper can be used as a useful evaluating method to support the choice of suitable probe geometry and wafer probe testing parameters.

scholarly journals Thermal Effect on a CIGS Thin-Film Solar Cell P2 Layer by Using a UV Laser

2014 ◽  
Vol 6 ◽  
pp. 723136 ◽  
Author(s):  
Dyi-Cheng Chen ◽  
Ming-Fei Chen ◽  
Ming-Ren Chen
Keyword(s):  
Stainless Steel ◽  
Solar Cell ◽  
Simulation Analysis ◽  
Processing System ◽  
Base Plate ◽  
Simulation Software ◽  
Experimental Results ◽  
Uv Laser ◽  
Cigs Solar Cell ◽  
Laser Apparatus

This study used ANSYS simulation software for analyzing an ultraviolet (UV) (355 nm) laser processing system. The laser apparatus was used in a stainless steel CIGS solar cell P2 layer for simulation analysis. CIGS films process order according to S iO2 layer, molybdenum electrode, CIGS absorbed layer, CdS buffered layer, i-ZnO penetrate light layer, TCO front electrode, MgF resist reflected materials, andelectrode materials. The simulation and experimental results were compared to obtain a laser-delineated P2 laser with a low melting and vaporization temperature. According to the simulation results, the laser function time was 135 μs, the UV laser was 0.5 W, and the P2 layer thin films were removed. The experimental results indicated that the electrode pattern of the experiment was similar to that of the simulation result, and the laser process did not damage the base plate. The analysis results confirm that the laser apparatus is effective when applied to a stainless steel CIGS solar cell P2 layer.

Fluid-Solid Coupling Numerical Simulation Analysis of Impermeable Rock Mining Seam Floor Failure

2014 ◽  
Vol 1010-1012 ◽  
pp. 1527-1530
Author(s):  
Chun Jie Song ◽  
Cheng Fan
Keyword(s):  
Numerical Simulation ◽  
Simulation Analysis ◽  
Water Inrush ◽  
Three Dimensional ◽  
Deep Understanding ◽  
Simulation Method ◽  
Relevant Information ◽  
Simulation Software ◽  
Pressurized Water ◽  
Floor Failure

Based on a deep understanding of FLAC 3D numerical simulation software and the solid-liquid coupling theory and calculation method, this paper established a mining three-dimensional mechanical model under the pressurized water .Using the numerical simulation method, this paper systematically analysis deformation Laws of stress distribution of mining floor, bottom stress, its plastic zone and floor failure depth. By analyzing water inrush flow-solid coupling seepage problem under the conditions of coal mining, and compares with relevant information, verify the rationality of the existing theories and engineering measures, provide a theoretical basis for seeking security and economic exploitation of technical measures.

Surface flow field around three-dimensional bluff bodies

1983 ◽  
Vol 11 (1-3) ◽  
pp. 405-420 ◽  
Author(s):  
B.H.L. Gowda ◽  
H.J. Gerhardt ◽  
C. Kramer
Keyword(s):  
Flow Field ◽  
Three Dimensional ◽  
Surface Flow ◽  
Bluff Bodies

Volumetric Three-Dimensional Wind Measurement Using a Single Mobile-Based LiDAR

2015 ◽  
Vol 138 (1) ◽  
Author(s):  
M. Zendehbad ◽  
N. Chokani ◽  
R. S. Abhari
Keyword(s):  
Wind Speed ◽  
Flow Field ◽  
Measurement Technique ◽  
Complex Terrain ◽  
Wind Farm ◽  
Three Dimensional ◽  
Wind Flow ◽  
Lidar System ◽  
Scanning Lidar ◽  
Utility Scale

A novel approach to measure the wind flow field in a utility-scale wind farm is described. The measurement technique uses a mobile, three-dimensional scanning LiDAR system to make successive measurements of the line-of-sight (LOS) wind speed from three different positions; from these measurements, the time-averaged three-dimensional wind velocity vectors are reconstructed. The scanning LiDAR system is installed in a custom-built vehicle in order to enable measurements of the three-dimensional wind flow field over a footprint that is larger than with a stationary scanning LiDAR system. At a given location, multiple series of plan position indicator (PPI) and velocity azimuthal display scans are made to average out turbulent fluctuations; this series is repeated at different locations across the wind farm. The limited duration of the total measurement time period yields measurements of the three-dimensional wind flow field that are unaffected by diurnal events. The approach of this novel measurement technique is first validated by comparisons to a meteorological mast and SODAR at a meteorological observatory. Then, the measurement technique is used to characterize the wake flows in two utility-scale wind farms: one in complex terrain and the other in flat terrain. The three-dimensional characteristics of the wakes are described in the measurements, and it is observed that in complex terrain the wake has a shorter downstream extent than in flat terrain. A maximum deficit in the wind speed of 20–25% is observed in the wake. The location of the maximum deficit migrates upward as the wake evolves; this upward migration is associated with an upward pitching of the wake flow. A comparison of the measurements to a semi-empirical wake model illustrates how the measurements, at full-scale Reynolds numbers, can support further development of wake models.

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