scholarly journals Structure Optimization Design of Pulseoscillation Amplifier for Hydraulic Oscillator Based on Numerical Simulation

2021 ◽  
Vol 1 (1) ◽  
Author(s):  
Yuqiang Xu
Keyword(s):  
Numerical Simulation ◽  
Pressure Loss ◽  
Structural Parameters ◽  
Pulse Amplification ◽  
Amplification Effect ◽  
Nozzle Length ◽  
Outlet Pressure ◽  
Pressure Peak ◽  
Pulse Oscillator ◽  
Peak Value

Hydraulic oscillator is one of the effective tools to solve the problem of high friction in directional drilling and horizontal drilling. However, there are some problems with this kind of tools such as high pressure loss and insufficient vibration force. Because of its self-excited oscillation characteristics, pulse oscillation amplifier can realize the amplification of pulse jet pressure under the condition of lowpressure loss, which is one of the effective ways to solve the above problems of hydraulic oscillator. In this paper, according to the working characteristics of hydraulic oscillator and the demand of pulse amplification, the structure of pulse oscillator amplifier was optimized based on numerical simulation method. Firstly, the geometric and numerical models of the pulse oscillator amplifier were constructed, and the flow field distribution and pulse amplification effect of the pulse oscillation amplifier under different structural parameters were simulated and analyzed, and the influence of different structural parameters on the pulse amplification effect was explored. Secondly, the structure of the pulse oscillator amplifier was optimized by Response Surface Method, and the optimal structure based on the effect of outlet pressure amplification was obtained: upper nozzle diameter D1=22mm, upper nozzle length L1=26mm, lower nozzle diameter D2=28mm, lower nozzle length L2=28mm, cavity length L=58mm, cavity diameter d=80mm, angle 60°. Its pressure loss was 0.3MPa and outlet pressure peak value was 4.5MPa, which was 1.8 times of the inlet pressure peak value of 2.5MPa. Finally, the minimum relative error between the experimental results and the numerical simulation results was 4%, which has verified the credibility of the numerical simulation and structural optimization results.

Numerical Simulation of the Nozzle Angles Effect on the Pressure at Thrustwall and Nozzle Outlet of PDE

2014 ◽  
Vol 705 ◽  
pp. 92-95
Author(s):  
Zhi Wu Wang ◽  
Kun Zhang ◽  
Long Xi Zheng
Keyword(s):  
Numerical Simulation ◽  
Nozzle Outlet ◽  
Evacuation Time ◽  
Pressure Peak ◽  
Simulation Results ◽  
Peak Value

In order to investigate the effects of nozzles with different angles on PDE performance, PDE with nozzles of different convergent and divergent angles were simulated and propane-air mixture was used. The simulation results indicated that the effects of nozzles with different angles on the pressure at the thrustwall of PDE and nozzle outlet were not the same. The pressure at the thrustwall and nozzle outlet of PDE with convergent nozzles was higher than that with divergent nozzles, and the pressure peak appeared earlier in the case of convergent nozzles. The peak value of the pressure at the nozzle outlet increased and appeared ahead of time as the convergent angle increased. The peak value of the pressure at the nozzle outlet increased and the evacuation time was prolonged with convergent nozzles. The pressure at the nozzle outlet dropped quickly and the evacuation time was shortened with divergent nozzles.

scholarly journals Influence of Vortex Finder Structure on Separation Performance of Double-Overflow Three-Product Hydrocyclones

Separations ◽  
2021 ◽  
Vol 8 (6) ◽  
pp. 79
Author(s):  
Yuekan Zhang ◽  
Jiangbo Ge ◽  
Lanyue Jiang ◽  
Hui Wang ◽  
Junru Yang ◽  
...  
Keyword(s):  
Numerical Simulation ◽  
Flow Field ◽  
Experimental Research ◽  
Separation Efficiency ◽  
Structural Parameters ◽  
Separation Performance ◽  
Insertion Depth ◽  
Flow Field Characteristics ◽  
Vortex Finder ◽  
Fine Classification

In view of the difficulty of traditional hydrocyclones to meet the requirements of fine classification, a double-overflow three-product (internal overflow, external overflow and underflow) hydrocyclone was designed in this study. Numerical simulation and experimental research methods were used to investigate the effects of double-overflow flow field characteristics and structural parameters (i.e., internal vortex finder diameter and insertion depth) on separation performance. The research results showed that the larger the diameter of the internal vortex finder, the greater the overflow yield and the larger the cut size. The finest internal overflow product can be obtained when the internal vortex finder is 30 mm longer than the external vortex finder. The separation efficiency is highest when the internal vortex finder is 30 mm shorter than the external vortex finder.

Design of Novel Sensitive Terahertz Biosensors Based on Graphene-Plasmonic Nanostructures

2021 ◽  
Author(s):  
Atefeh Chahkoutahi ◽  
Farzin Emami
Keyword(s):  
Structural Parameters ◽  
Absorption Peak ◽  
Plasmonic Nanostructures ◽  
Aluminum Layer ◽  
Absorption Factor ◽  
Peak Wavelength ◽  
Blood Samples ◽  
Chemical Potentials ◽  
Sensing Characteristics ◽  
Peak Value

Abstract In this paper, four different configurations of sensitive biosensors based on graphene-plasmonic combinations are designed and proposed. The nanostructures are made of graphene, SiO2, aluminum and gold layers on a silicon substrate. Graphene-ring shaped structures with diagonal strips in vertical and horizontal directions are considered in the structures which greatly affect the absorption characteristics (absorption peak value and wavelength). Aluminum layer is used in the structure to prevent the transmission of light throughout some layers and improving the absorption factor. To promote the functionality of the structures, effects of the structural parameters (R1 and R2) and chemical potentials (Ef1, Ef2, Ef3 and Ef4) on the absorption peak-wavelength and its value, are also studied. The four individual configurations with different layers and strip directions demonstrate distinct and different wavelength ranges; structure-1: 45-60 µm, structure-2: 50-70 µm, structure-3: 70-85 µm, and structure-4: 80-100 µm. Thus, they can be utilized for wide categories of applications. Sensitivities of 1500nm/RIU, 2250/RIU, 3750nm/RIU and 4850nm/RIU are obtained for four types, respectively. The proposed structures indicate more sensitivities and they can be used in acceptable sensing characteristics for different applications like hemoglobin and glucose concentrations in blood samples and can be utilized as refractive index bio-sensing sensors.

Dynamic Test of Bird Strike on a Flat Plate Made from LY-12 Aluminium

2013 ◽  
Vol 765-767 ◽  
pp. 3158-3161
Author(s):  
Jun Liu ◽  
Zheng Li Zhang
Keyword(s):  
Numerical Simulation ◽  
Dynamic Response ◽  
Dynamic Test ◽  
Time History ◽  
Aircraft Design ◽  
Bird Strike ◽  
Test Results ◽  
Valuable Data ◽  
Good Agreement ◽  
Peak Value

Tests of bird strike have been carried out on plate made from LY-12 Aluminium. The test was down with the projectile impacting the target perpendicularly at velocity of 40m/s, 80m/s, 120m/s respectively. The displacement-time history curves and strain-time history curves of on LY-12 Aluminium plate were measured. The good agreement of the results between two specimens in one group indicated that the results tested in the presnet paper are reliable. The dynamic response of the plate and damage modes of the bird influenced by striking velocity were analyzed. The peak value of the displacement linear enlarged with the increasing of the striking velocity. The test results in the present paper provided valuable data for aircraft design impacted by bird, and also provided abundant test datas for the numerical simulation model applied in bird striking.

Numerical Analysis for Bolt Length Based on the Stress Response of Anchorage Surrounding Rock

2012 ◽  
Vol 204-208 ◽  
pp. 4481-4485
Author(s):  
Bin Wang ◽  
Fu Jun Zhao ◽  
Wen Bin Peng
Keyword(s):  
Numerical Simulation ◽  
Stress Response ◽  
Numerical Analysis ◽  
Bearing Capacity ◽  
Distribution Curve ◽  
Surrounding Rock ◽  
Effective Length ◽  
Plastic Failure ◽  
Deep Rock ◽  
Peak Value

The current researches on bolt length are rarely concerned with self-bearing characteristics of anchorage surrounding rock，its stress response is seldom used to analyze the bolt effective length. Tangential stress σθ of surrounding rock is sensitive to mechanical variation of surrounding rock plastic failure fields. When surrounding rock bolted, the distribution curve of σθ presents internal and external peak values from the surface rock to the deep rock, which is verified by numerical simulation. Internal peak value of σθ curve increases with the bolt length, which means the bearing capacity of surrounding rock in plastic failure division is improved, correspondingly, external peak value decreases which shows the supporting behavior of the deep rock is weakened. The results of numerical simulations prove that there exists an effective value of bolt length. If bolt length beyond it, the bearing capacity of anchorage surrounding rock cannot be improved obviously.

Vacuum Forming Refrigerator Inner Liner Structural Optimization

2011 ◽  
Vol 291-294 ◽  
pp. 1069-1073
Author(s):  
Wen Bin Su ◽  
Xiang Bing Sun ◽  
Tao Li ◽  
Bao Jian Liu
Keyword(s):  
Numerical Simulation ◽  
Structural Optimization ◽  
Structural Parameters ◽  
Forming Process ◽  
Significance Level ◽  
Orthogonal Experiments ◽  
Combination Scheme ◽  
Vacuum Forming ◽  
Validation Experiment

Thickness thinning is the principal quality problem in the vacuum forming process of the refrigerator inner liner. In this paper, the structural parameters of refrigerator inner liner were analyzed based on orthogonal experiments and numerical simulation. Optimized structural parameters combination scheme and the significance level of structural parameters to thickness were obtained by analyzing the results of orthogonal experiments. Validation experiment results shown that the quality of refrigerator inner liner based on the optimized structural parameters combination scheme improved effectively.

Numerical Simulation of Pressure Loss and Heat Transfer Characteristics for Additively Manufactured Channels

2020 ◽  
Author(s):  
Bryan Arko ◽  
Chad Iverson ◽  
Nicholas Staudigel
Keyword(s):  
Heat Transfer ◽  
Numerical Simulation ◽  
Surface Roughness ◽  
Nusselt Number ◽  
Pressure Loss ◽  
Reynolds Numbers ◽  
Measured Data ◽  
Transfer Effects ◽  
Micro Channels ◽  
Heat Transfer Effects

Abstract This body of work provides an initial study of modeling both surface roughness and heat transfer concurrently in a numerical simulation of micro-channels representative of those that might be found in a turbine cooling application. Increased use of additive manufacturing (AM) or 3D printing techniques for turbomachinery components enable the manufacture of complex features to achieve higher operational performance. Accurate modeling of flow losses and heat transfer effects are critical to designing parts which achieve optimal efficiency paired with durability. Surface finish is rougher with AM compared to more traditional manufacturing techniques; therefore enhancing the pressure loss and heat transfer effects. Proper implementation of surface roughness within the computational model and correct modeling of the near wall boundary mesh must be maintained to produce accurate results. This study focuses on the comparison of near wall mesh treatment coupled with surface roughness to determine a practice for obtaining accurate pressure loss and heat transfer within a cooling passage, as compared to measurements. Steady-state computational fluid dynamics (CFD) models consisting of a wind tunnel inlet nozzle and outlet diffuser, along with internal cooling passages represented using micro-channels, has been run for a range of Reynolds numbers and simulated roughness levels. Analysis of a baseline configuration with aerodynamically smooth walls is first compared to the measured data to verify the assumption of aerodynamically smooth walls. Surface roughness is then added to the channel walls, from published test coupon measurements, and compared to published experimental data for a range of Reynolds numbers. The metal surrounding the passages is also included as a conjugate heat transfer model providing heat addition to the fluid. Pressure loss and heat transfer is compared to the measured data as a friction factor and Nusselt number for the range of Reynolds numbers. Since surface roughness units and measurements vary, an effect of surface roughness values on pressure loss and heat transfer will also be investigated to determine the importance of using and converting to the correct units for the numerical model. This serves as a starting point for a guideline that will help when both heat transfer and surface roughness are included in a CFD model. Further study is recommended to understand the diminishing levels of increase in friction factor and Nusselt number observed as surface roughness was continually increased in the numerical simulation.

scholarly journals Experimental Research and Numerical Simulation of Ejector Precipitator in a Fully Mechanized Mining Face

2020 ◽  
Vol 45 (11) ◽  
pp. 9815-9833
Author(s):  
Guodong Zhai ◽  
Wentao Zhang ◽  
Yaozong Li ◽  
Xinghao Lu ◽  
Wenyuan Hu
Keyword(s):  
Numerical Simulation ◽  
Flow Field ◽  
Negative Pressure ◽  
Coal Dust ◽  
Structural Parameters ◽  
Dust Concentration ◽  
Dust Removal ◽  
Measuring Point ◽  
Mining Face ◽  
Supply Water

AbstractIn order to effectively reduce the coal dust concentration in a fully mechanized mining face, this research used laboratory experiment, numerical simulation, and field test to conduct an in-depth exploration of the ejector precipitator installed at the low-level caving coal hydraulic support. Firstly, through the experimental platform in the laboratory, the dust removal effect of the nozzle with different structural parameters was tested, and the 3D particle dynamic analyzer was adopted to verify its atomization characteristics; then, the structural parameters corresponding to the nozzle in the best test results were obtained. Secondly, by using Fluent, the negative pressure flow field in the ejector barrel was numerically simulated. The results indicated that when the pressure of supply water was 12 MPa, the negative pressure value formed in the flow field was the lowest and the inspiratory velocity was the largest, which was conducive to dust removal. Finally, the tests of liquid–gas ratio and dust removal ratio were carried out in a fully mechanized mining face. The results showed that when the nozzle specification recommended by the experiment and the pressure of supply water recommended by the numerical simulation were used, the removal ratios of the total coal dust and the respirable coal dust were 89.5% and 91.0%, respectively, at the measuring point of the highest coal dust concentration. It indicates that the ejector precipitator has a good application effect in reducing the coal dust concentration in a fully mechanized mining face and improving the work environment of coal mine workers.

The Sensitivity of Inner Nozzle Flow in Gasoline Direct Injection Injector to the Nozzle Geometry Parameters

2019 ◽  
Vol 141 (6) ◽  
Author(s):  
Xinhai Li ◽  
Yong Cheng ◽  
Xiaoyan Ma ◽  
Xue Yang
Keyword(s):  
Structural Parameters ◽  
Direct Injection ◽  
Large Diameter ◽  
Small Diameter ◽  
Flow Characteristics ◽  
Gasoline Direct Injection ◽  
Nozzle Geometry ◽  
Nozzle Flow ◽  
Nozzle Length ◽  
Injector Nozzle

The inner-flow of gasoline direct injection (GDI) injector nozzles plays an important role in the process of spray, and affects the mixture process in gasoline engine cylinder. The nozzle structure also affects the inner-flow of GDI injector. In order to obtain uniform performance of GDI injector, the size consistency of injector nozzle should be ensured. This paper researches the effect of nozzle length and diameter on the inner flow and analyzes the sensitivity of inner flow characteristics to these structural parameters. First, this paper reveals the process of inception, development, and saturated condition of cavitation phenomenon in injector nozzle. Second, the inner-nozzle flow characteristics are more sensitive to small diameter than large diameter under the short nozzle length, while the sensitivity of the inner-nozzle flow characteristics to large nozzle diameter becomes strong as the increase of the nozzle length. Finally, the influence of nozzle angle on the injection mass flow is studied, and the single nozzle fuel mass will increase as the decrease of nozzle angle α. And the sensitivity of inner-flow characteristic to nozzle angle becomes strong as the decrease of α.

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