<i>Simulation analysis and test for flow field and deposition concentration of small size unmanned plant protection helicopter</i>

2018 ◽  
Author(s):  
Qiang Shi ◽  
Hanping Mao ◽  
Xianping Guan
Keyword(s):  
Flow Field ◽  
Simulation Analysis ◽  
Plant Protection

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.

scholarly journals Simulation and experimental research based on carrier gas flow rate on the influence of four-channel coaxial nozzle flow field

2020 ◽  
pp. 002029402096423
Author(s):  
Shi Rui Guo ◽  
Qian Qian Yin ◽  
Lu Jun Cui ◽  
Xiao Lei Li ◽  
Ying Hao Cui ◽  
...  
Keyword(s):  
Flow Field ◽  
Gas Flow ◽  
Simulation Analysis ◽  
Two Phase ◽  
Carrier Gas ◽  
Coaxial Nozzle ◽  
Convergence Point ◽  
Flow Convergence ◽  
Fluent Software ◽  
Carrier Gas Flow

This paper investigates the influence of carrier gas flow on the external flow field of coaxial powder feeding nozzle. FLUENT software was adopted to establish gas-solid two-phase flow. The simulation of powder stream field under different carrier gas flow was also carried out. Results show that the larger the flow of carrier gas is, the higher the gas flow field velocity at the nozzle outlet is. At the same time, the concentration at the convergence point is lower, and the convergent point is maintained at 0.015 m. Under the condition of 4 L/min, the powder flow convergence is good. When it exceeds 4 L/min, powder spot diameter increases. The experiment of powder aggregation and laser cladding forming were completed, which shows that the forming effect is the best one under the condition of 4 L/min. It is consistent with the simulation analysis results and has a high reference to the optimization of the process parameters of coaxial nozzle.

Flow Field Analysis and Structure Optimization of Water Hydraulic Poppet Valve Based on the CFD

2013 ◽  
Vol 791-793 ◽  
pp. 734-737 ◽  
Author(s):  
Qiu Xia ◽  
Xiang Pan Guang
Keyword(s):  
Flow Field ◽  
Simulation Analysis ◽  
Internal Flow ◽  
Turbulent Energy ◽  
Field Analysis ◽  
Value Differences ◽  
Poppet Valve ◽  
Traditional Structure ◽  
Fluent Software ◽  
Water Hydraulic

This paper builds two water hydraulic poppet valve models which are of different structure, and simulation analysis used by FLUENT software on it’s internal flow field. The analysis results show that, after improving the structure of water hydraulic poppet valve, import and export pressure value differences decreased, effectively restrains the generation of cavitation, reduces the vibration amplitude and turn down noise, reduces loss of turbulent energy, the overall performance is superior to the traditional structure.

Simulation Analysis of Temperature Field of Permanent Magnet Governor

2014 ◽  
Vol 1044-1045 ◽  
pp. 422-425 ◽  
Author(s):  
Yan Jie Wang ◽  
San Ping Zhou
Keyword(s):  
Fluid Dynamics ◽  
Temperature Field ◽  
Flow Field ◽  
Permanent Magnet ◽  
Simulation Analysis ◽  
Eddy Current Loss ◽  
Ansys Fluent ◽  
Operation Process ◽  
Fluent Software ◽  
Computational Fluid Dynamics Cfd

In the operation process of permanent magnet governor, the temperature rises due to eddy current loss, and demagnetization of permanent magnet occurs at high temperature. The numerical simulation of fluid flow field and temperature field was carried out with the method of computational fluid dynamics (CFD) and ANSYS-Fluent software. And then we improved the structure of permanent magnet governor on the basis of analysis of the flow field and temperature distribution. The result indicates that the flow of improved structure increases, and temperature drops 46.°C, fulfilling the desired temperature range of permanent magnet can bear, which provides a theory basis for the design of ventilation-cooling structure of permanent magnet governor.

scholarly journals Design of UAV Downwash Airflow Field Detection System Based on Strain Effect Principle

Sensors ◽  
2019 ◽  
Vol 19 (11) ◽  
pp. 2630 ◽  
Author(s):  
Yalei Wu ◽  
Lijun Qi ◽  
Hao Zhang ◽  
Elizabeth M. Musiu ◽  
Zepeng Yang ◽  
...  
Keyword(s):  
Wind Speed ◽  
Flow Field ◽  
Strain Gauge ◽  
Wind Field ◽  
Output Voltage ◽  
Plant Protection ◽  
Strain Effect ◽  
Sampling Point ◽  
Field Detection ◽  
Finite Element Software

Accurate measurement of the downwash flow field of plant protection unmanned aerial vehicles (UAVs) is essential for analyzing the spatial distribution of droplets. To realize on-line rapid detection of the downwash flow field of a multi-rotor UAV, a flexible polypropylene detection device based on the principle of full bridge strain effect was proposed. Its performance principle was based on the physical deformation caused by wind pressure. The Fluid Flow and Static Structural modules of ANSYS 16.0 finite element software were used to simulate one-way fluid-solid coupling interaction. The surface of the resistive strain gauge embedded in the flexible detecting structure responded well to wind speed variation, hence it was suitable for downwash airflow wind field detection. By solving the strain force on the surface of the flexible detection structure, the length and layout of the grating wire of the strain gauge on the surface of the flexible detection structure were optimized. Meanwhile at 4 m·s−1 wind speed, the output voltage at varied bridge flexible acquisition systems in the acquisition card was measured. Results indicated coefficient of variation of 3.67%, 1.63% and 1.5%, respectively, which proved the good data acquisition consistency of the system. Through calibration test, the regression equation for the relationship between output voltage and wind speed for three unique sensor signal measuring circuits was established. The determination coefficients R2 for single bridge, half bridge and full bridge circuits were 0.9885, 0.9866 and 0.9959, respectively. In conclusion, by applying the multi-rotor plant protection UAV test platform, the results indicated the maximum relative error of the wind speed at each sampling point of the system at 1.0 m altitude was below 5.61%. Simulated and measured value had an RMSE maximum error of 0.1246 m·s−1. Moreover, downwash airflow detection not only has high accuracy but also has high sensitivity. Thus, there is convenience and practicability in the plant protection offered by this approach. The rapid measurement of UAV wind field and the established two-dimensional wind field model can provide a basis for precise application of agricultural aviation.

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