Calibration model and numerical simulation of a 7-hole probe based on pressure–velocity parameterization equation

2021 ◽  
Author(s):  
Tao Yao ◽  
Shu-dao Zhou ◽  
Min Wang ◽  
Yang-chun Zhang ◽  
Song Ye
Keyword(s):  
Numerical Simulation ◽  
Flow Field ◽  
Middle Atmosphere ◽  
Detection System ◽  
Three Dimensional ◽  
Calibration Method ◽  
Calibration Model ◽  
System A ◽  
Probe Calibration ◽  
3D Information

Abstract As a sensor of a flow field detection system, a 7-hole probe can detect the flow field velocity and retrieve three-dimensional (3D) information of the flow field. Owing to its simple structure and strong environmental adaptability, it is particularly important to calibrate it when it is widely used in turbine machinery, aerospace, and other fields. To detect the 3D flow field in the middle atmosphere, a novel calibration method based on the potential flow theory is designed using a hemispherical 7-hole probe. The hemispherical 7-hole probe was numerically calibrated through numerical simulation, and the coefficients of the calibration equation are provided. In comparison with the traditional 7-hole probe calibration method, the calibration process is significantly shortened while maintaining good measurement accuracy. The velocity error was less than 5% and the angle error was approximately 0.5°.

Fabrication of Three-Dimensional Micro-Structures with Two-Photon Absorption by Femtosecond Laser

2006 ◽  
Vol 532-533 ◽  
pp. 568-571
Author(s):  
Ming Zhou ◽  
Hai Feng Yang ◽  
Li Peng Liu ◽  
Lan Cai
Keyword(s):  
Photonic Crystal ◽  
Femtosecond Laser ◽  
Detection System ◽  
Three Dimensional ◽  
Photon Absorption ◽  
Micro Fabrication ◽  
Two Photon Absorption ◽  
Two Photon ◽  
Photo Polymerization ◽  
System A

The photo-polymerization induced by Two-Photon Absorption (TPA) is tightly confined in the focus because the efficiency of TPA is proportional to the square of intensity. Three-dimensional (3D) micro-fabrication can be achieved by controlling the movement of the focus. Based on this theory, a system for 3D-micro-fabrication with femtosecond laser is proposed. The system consists of a laser system, a microscope system, a real-time detection system and a 3D-movement system, etc. The precision of micro-machining reaches a level down to 700nm linewidth. The line width was inversely proportional to the fabrication speed, but proportional to laser power and NA. The experiment results were simulated, beam waist of 0.413μm and TPA cross section of 2×10-54cm4s was obtained. While we tried to optimize parameters, we also did some research about its applications. With TPA photo-polymerization by means of our experimental system, 3D photonic crystal of wood-pile structure twelve layers and photonic crystal fiber are manufactured. These results proved that the micro-fabrication system of TPA can not only obtain the resolution down to sub-micron level, but also realize real 3D micro-fabrication.

Two-Phase Flow Field Numerical Simulation in Scrubber for Exhaust Gas Desulfurization

2014 ◽  
Vol 541-542 ◽  
pp. 1288-1291
Author(s):  
Zhi Feng Dong ◽  
Quan Jin Kuang ◽  
Yong Zheng Gu ◽  
Rong Yao ◽  
Hong Wei Wang
Keyword(s):  
Numerical Simulation ◽  
Flow Field ◽  
Flue Gas ◽  
Two Phase Flow ◽  
Three Dimensional ◽  
Flue Gas Desulfurization ◽  
Parameter Design ◽  
Phase Flow ◽  
Two Phase ◽  
Entrance Angle

Calculation fluid dynamics software Fluent was used to conduct three-dimensional numerical simulation on gas-liquid two-phase flow field in a wet flue gas desulfurization scrubber. The k-ε model and SIMPLE computing were adopted in the analysis. The numerical simulation results show that the different gas entrance angles lead to internal changes of gas-liquid two-phase flow field, which provides references for reasonable parameter design of entrance angle in the scrubber.

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.

Study on the Principle of Yarn Splicing of Pneumatic Splicer Using Numerical Simulation

2012 ◽  
Vol 588-589 ◽  
pp. 1355-1358
Author(s):  
Xiao Xing ◽  
Guo Ming Ye
Keyword(s):  
Numerical Simulation ◽  
Flow Field ◽  
Three Dimensional ◽  
Numerical Results ◽  
Simulation Results

During the splicing process of pneumatic splicer, the principle of yarn splicing is closely related to the flow field inside the splicing chamber. This paper presents a numerical simulation of the flow char-acteristics inside the splicing chamber of the pneumatic splicer. A three-dimensional grid and the realizable tur¬bulence model are used in this simulation. The numerical results of veloc¬ity vectors distribution inside the chamber are shown. Streamlines starting from the two air injectors are also acquired. Based on the simulation, the principle of yarn splicing of the pneumatic splicer is discussed. The airflow in the splicing chamber can be divided into three regions. In addition, the simulation results have well sup¬ported the principle of yarn splicing of pneumatic splicer claimed by the splicing chamber makers.

Numerical Simulation on Cylinder Flow Field of Diesel

2013 ◽  
Vol 712-715 ◽  
pp. 1330-1334
Author(s):  
Yin Dong Song ◽  
Yin Nan Yuan ◽  
Chun Ping Wu ◽  
Yong Wang Li ◽  
Peng Zhe Qi ◽  
...  
Keyword(s):  
Numerical Simulation ◽  
Flow Field ◽  
Three Dimensional ◽  
Swirl Flow ◽  
Mixing Rate ◽  
Air Mixing ◽  
Reduce Emissions ◽  
Diesel Cylinder ◽  
Cylinder Flow ◽  
Transient Numerical Simulation

Three dimensional transient numerical simulation on cylinder flow field of 4B26 diesel was done by AVL FIRE. Detailed flow field structure of diesel cylinder was calculated. The typical swirl flow and squish flow were established in 4B26 diesel engine chamber. swirl flow and squish flow can increase the fuel and air mixing rate, and can improve diesel combustion and can reduce emissions of pollutants. Oil beam could accelerate the air around it.

Numerical simulation of three-dimensional airflow in a novel dual-feed rotor spinning box

2016 ◽  
Vol 88 (3) ◽  
pp. 237-253 ◽  
Author(s):  
Nicholus Tayari Akankwasa ◽  
Huiting Lin ◽  
Yuze Zhang ◽  
Jun Wang
Keyword(s):  
Numerical Simulation ◽  
Flow Field ◽  
Three Dimensional ◽  
Internal Flow ◽  
Velocity Variation ◽  
Positive Pressure ◽  
Three Dimensional Model ◽  
Air Velocity ◽  
Rotor Spinning ◽  
Pressure Profiles

In order to regulate turbulence strength and determine airflow characteristics in a new dual-feed rotor spinning unit, the internal flow field is investigated. A computational fluid dynamics technique is employed to numerically study the three-dimensional model of the internal airflow in the new design. The effects of air velocity variation on turbulence strength, negative pressure, Re, and wall pressure distribution are investigated based on simulation data and previous studies. The results show that the turbulence strength and Re increased with increase in inlet air velocity. Pressure profiles inside the rotor varied significantly with positive pressure observed at the channel exits. Minimal inlet velocity maintains the flow field in the rotor interior below 100 m/s, which gives the ideal turbulence required to minimize yarn quality deterioration. The dual-feed rotor spinning unit showed more orderly streamline patterns with fewer vortices compared to the conventional one. The numerical simulation can provide insights on airflow studies and some guidelines for future prototyping and experiments to further improve the new design.

Simulation and Experimental Analysis of the Effect of Channel Width on Flow Field in Laser Cutting

2009 ◽  
Vol 626-627 ◽  
pp. 171-176 ◽  
Author(s):  
X.J. Sheng ◽  
Jun Hu
Keyword(s):  
Numerical Simulation ◽  
Flow Field ◽  
Laser Cutting ◽  
Cone Angle ◽  
Three Dimensional ◽  
Channel Width ◽  
Gas Jet ◽  
Channel Surface ◽  
Symmetrical Model ◽  
Cutting Experiment

A three-dimensional axial symmetrical model of laser cutting is established by adopting N-S equation in the paper, and numerical simulation is put up to analyze the flow field of assist gas in cutting channel. The investigation reveals the law about how channel width affects the dynamic characteristic of gas jet in the cutting process, and the distributions of pressure and velocity of gas jet with different channel widths are shown in the study. The study shows that the intensity of compressed wave and expanded wave in cutting channel declines remarkably with channel width increasing, and the kinetic energy at channel surface drops while the cutting quality is deteriorated. A taper nozzle with cone angle of 30°and a convergence nozzle comprised a parabola equation of are designed for the laser cutting experiment. The experimental results are given at the end of the paper.

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