Experimental and Numerical Analysis of Flow Behavior for Reverse Circulation Drill Bit with Inserted Swirl Vanes

A swirling drill bit designed with an integrated vane swirler was developed to improve reverse circulation in down-the-hole hammer drilling. Its entrainment effect and influential factors were investigated by CFD simulation and experimental tests. The numerical results exhibit reasonable agreement with the experimental data, with a maximum error of 13.68%. In addition, the structural parameters of the swirler were shown to have an important effect on the reverse circulation performance of the drill bit, including the helical angle and number of spiral blades, swirler outlet area, and the flushing nozzles. The optimal parameters for the swirling drill bit without flushing nozzles include a helical angle of 60°, four spiral blades, and the area ratio of 2, while it is about 30°, 3, and 3 for the drill bit with flushing nozzles. Moreover, the entrainment ratio of the drill bit without flushing nozzles can be improved by nearly two times compared with one with flushing nozzles under the same conditions.

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Orthogonal experimental research on the structural parameters of a novel drill bit used for ice core drilling with air reverse circulation

Journal of Glaciology ◽

10.1017/jog.2019.76 ◽

2019 ◽

Vol 65 (254) ◽

pp. 1011-1022 ◽

Cited By ~ 1

Author(s):

Pinlu Cao ◽

Qi Zhao ◽

Zhuo Chen ◽

Hongyu Cao ◽

Baoyi Chen

Keyword(s):

Structural Parameters ◽

Ice Core ◽

Influential Factor ◽

Dominant Factor ◽

Orthogonal Experimental Design ◽

Drill Bit ◽

Entrainment Ratio ◽

Core Drilling ◽

Helical Angle ◽

Reverse Circulation

AbstractA new type of ice core drill bit, designed with a vane swirler, was developed for ice core drilling with air reverse circulation. An orthogonal experimental design method was employed to investigate the effects of the swirler structure parameters on the reverse circulation performance of the drill bit including helical angle, number of blades, blade length and blade central angle, etc. The entrainment ratio was used to evaluate the reverse circulation effectiveness of the drill bit. The results show that the helical angle is the dominant factor regardless of whether or not the flushing nozzles are part of the design of the drill bit. The number of blades is the least important factor for the drill bit designed with the flushing nozzles (referred to as drill bit I), while the outlet area of the swirling slot is the least influential factor for the drill bit without flushing nozzles (referred to as drill bit П). In addition, the appearance of the ice core has a certain effect on the air reverse circulation for both drill bits. Within the ranges of this study, the optimal structure of the drill bit was determined based on the range analysis of the orthogonal design.

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Experimental and Numerical Study on Air Flow Behavior for a Novel Retractable Reverse Circulation Drill Bit of Casing-while-Drilling (CwD)

Geofluids ◽

10.1155/2021/3586572 ◽

2021 ◽

Vol 2021 ◽

pp. 1-12

Author(s):

Bo Qi ◽

Pinlu Cao ◽

He Yang ◽

Wenbo He ◽

Mengke Wang ◽

...

Keyword(s):

Numerical Study ◽

Flow Behavior ◽

Nozzle Diameter ◽

Channel Structure ◽

Entrainment Rate ◽

Drill Bit ◽

Structure Parameters ◽

Channel Diameter ◽

Gas Channel ◽

Reverse Circulation

A reverse circulation Down-The-Hole (DTH) hammer drill bit in Casing-while-Drilling (CwD) processes is designed and applied to drilling under complicated formation. The drill bit is a special retractable drill bit with an exclusive reverse circulation gas channel. Using numerical simulations and experiments, the influence of the gas channel structure parameters of the drill bit, including the inner jet nozzles, flushing nozzles, suction channel, and other parameters, on its reverse circulation performance is analyzed, and the optimal gas channel structure parameters of the drill bit are determined to improve the reverse circulation effect. The results show that the flushing nozzles and inner jet nozzles have an important influence on entrainment performance. The entrainment rate η decreases as the flushing nozzle diameter increases and decreases as the inner jet nozzle diameter increases. An increase in the suction channel diameter can improve the reverse circulation effect of the drill bit. The spiral slot drill bit is more conducive to air being sucked into the central channel in the form of spiral flow, so it can improve the entrainment performance. The entrainment rate η can reach 23.4% with the optimum structured drill bit.

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Design and Experiment Using Flexible Bumps for Piezoelectric-Driven Hydraulically Amplified Braille Dot Display

Micromachines ◽

10.3390/mi12070795 ◽

2021 ◽

Vol 12 (7) ◽

pp. 795

Author(s):

Xiaochao Tian ◽

Yuze Sun ◽

Zhiyao Li ◽

Hu Wang ◽

Zhicong Wang ◽

...

Keyword(s):

Structural Parameters ◽

Water Discharge ◽

Experimental Tests ◽

Output Displacement ◽

Amplification Ratio ◽

Fluid Resonance ◽

Piezoelectric Vibrator ◽

Flexible Film ◽

Touch Sensitivity ◽

Sensitivity Standard

This paper describes the design of a piezoelectric-driven hydraulically amplified Braille-flexible bump device that enables the flexible formation of Braille characters. A piezoelectric vibrator is used to excite fluid resonance in a cavity, and displacement is realized by compressing the fluid, allowing Braille character dots to be formed. First, the structural design and working principle of the device, as well as the method used to drive the fluid, are explained. Expressions for the output displacement and amplification ratio of the flexible film and piezoelectric vibrator are then obtained through kinetic analysis of the system unit. Subsequently, the structural parameters that affect the output displacement and the liquid amplification are described. Finally, experimental tests of the system are explained. The results indicate that the output displacement of the contact formed by the flexible film reaches 0.214 mm, satisfying the requirements of the touch sensitivity standard for the blind, when the fluid cavity diameter measures 31 mm and the resonance frequency is 375.4 Hz. The corresponding water discharge is 8.8 mL. This study proves that constructing a Braille bump device in this way is both feasible and effective.

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CFD Simulation of a Hyperloop Capsule Inside a Low-Pressure Environment Using an Aerodynamic Compressor as Propulsion and Drag Reduction Method

Applied Sciences ◽

10.3390/app11093934 ◽

2021 ◽

Vol 11 (9) ◽

pp. 3934

Author(s):

Federico Lluesma-Rodríguez ◽

Temoatzin González ◽

Sergio Hoyas

Keyword(s):

Shock Waves ◽

Power Consumption ◽

High Speed ◽

Cfd Simulation ◽

Aerodynamic Drag ◽

Flow Behavior ◽

Critical Conditions ◽

Vehicle Speed ◽

Blockage Ratio ◽

The Cost

One of the most restrictive conditions in ground transportation at high speeds is aerodynamic drag. This is even more problematic when running inside a tunnel, where compressible phenomena such as wave propagation, shock waves, or flow blocking can happen. Considering Evacuated-Tube Trains (ETTs) or hyperloops, these effects appear during the whole route, as they always operate in a closed environment. Then, one of the concerns is the size of the tunnel, as it directly affects the cost of the infrastructure. When the tube size decreases with a constant section of the vehicle, the power consumption increases exponentially, as the Kantrowitz limit is surpassed. This can be mitigated when adding a compressor to the vehicle as a means of propulsion. The turbomachinery increases the pressure of part of the air faced by the vehicle, thus delaying the critical conditions on surrounding flow. With tunnels using a blockage ratio of 0.5 or higher, the reported reduction in the power consumption is 70%. Additionally, the induced pressure in front of the capsule became a negligible effect. The analysis of the flow shows that the compressor can remove the shock waves downstream and thus allows operation above the Kantrowitz limit. Actually, for a vehicle speed of 700 km/h, the case without a compressor reaches critical conditions at a blockage ratio of 0.18, which is a tunnel even smaller than those used for High-Speed Rails (0.23). When aerodynamic propulsion is used, sonic Mach numbers are reached above a blockage ratio of 0.5. A direct effect is that cases with turbomachinery can operate in tunnels with blockage ratios even 2.8 times higher than the non-compressor cases, enabling a considerable reduction in the size of the tunnel without affecting the performance. This work, after conducting bibliographic research, presents the geometry, mesh, and setup. Later, results for the flow without compressor are shown. Finally, it is discussed how the addition of the compressor improves the flow behavior and power consumption of the case.

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The analysis on the influence of mixed sliding-rolling motion mode to precision degradation of ball screw

Proceedings of the Institution of Mechanical Engineers Part C Journal of Mechanical Engineering Science ◽

10.1177/0954406220982018 ◽

2021 ◽

pp. 095440622098201

Author(s):

Qiang Cheng ◽

Baobao Qi ◽

Hongyan Chu ◽

Ziling Zhang ◽

Zhifeng Liu ◽

...

Keyword(s):

Structural Parameters ◽

Experimental Tests ◽

Theoretical Models ◽

Operating Conditions ◽

Ball Screw ◽

Rolling Motion ◽

Degradation Model ◽

Sliding Motion ◽

Factors Analysis ◽

Motion Mode

The combination of sliding/rolling motion can influence the degree of precision degradation of ball screw. Precision degradation modeling and factors analysis can reveal the evolution law of ball screw precision. This paper presents a precision degradation model for factors analysis influencing precision due to mixed sliding-rolling motion. The precision loss model was verified through the comparison of theoretical models and experimental tests. The precision degradation due to rolling motion between the ball and raceway accounted for 29.09% of the screw precision loss due to sliding motion. Additionally, the total precision degradation due to rolling motion accounted for 21.03% of the total sliding precision loss of the screw and nut, and 17.38% of the overall ball screw precision loss under mixed sliding-rolling motion. In addition, the effects of operating conditions and structural parameters on precision loss were analyzed. The sensitivity coefficients of factors influencing were used to quantitatively describe impact degree on precision degradation.

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Research on CFD Simulation of the Cement Slurry Mixer

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.621.196 ◽

2012 ◽

Vol 621 ◽

pp. 196-199

Author(s):

Shui Ping LI ◽

Ya Li Yuan ◽

Lu Gang Shi

Keyword(s):

Flow Field ◽

High Performance ◽

Cfd Simulation ◽

Structural Parameters ◽

Internal Flow ◽

Simulation Method ◽

Cement Slurry ◽

Fluid Machinery ◽

Computational Fluid Dynamics Cfd ◽

Machinery Design

Numerical simulation method of the internal flow field of fluid machinery has become an important technology in the study of fluid machinery design. In order to obtain a high-performance cement slurry mixer, computational fluid dynamics (CFD) techniques are used to simulate the flow field in the mixer, and the simulation results are studied. According to the analysis results, the structural parameters of the mixer are modified. The results show the mixer under the revised parameters meet the design requirements well. So CFD analysis method can shorten design period and provide valuable theoretical guidance for the design of fluid machinery.

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Numerical and Experimental Approaches to Investigate the Stability of a Motorcycle Vehicle

Volume 2: Automotive Systems, Bioengineering and Biomedical Technology, Fluids Engineering, Maintenance Engineering and Non-Destructive Evaluation, and Nanotechnology ◽

10.1115/esda2006-95311 ◽

2006 ◽

Cited By ~ 1

Author(s):

Federico Cheli ◽

Marco Bocciolone ◽

Marco Pezzola ◽

Elisabetta Leo

Keyword(s):

Degrees Of Freedom ◽

Structural Parameters ◽

Experimental Tests ◽

Roll Angle ◽

Longitudinal Motion ◽

Reference Trajectory ◽

Steering Angle ◽

Steady State Condition ◽

The Stability ◽

Linearized Model

The study of motorcycle’s stability is an important task for the passenger’s safety. The range of frequencies involved for the handling stability is lower than 10 Hz. A numerical model was developed to access the stability of a motorcycle vehicle in this frequency range. The stability is analysed using a linearized model around the straight steady state condition. In this condition, the vehicle’s vertical and longitudinal motion are decoupled, hence the model has only four degrees of freedom (steering angle, yaw angle, roll angle and lateral translation), while longitudinal motion is imposed. The stability was studied increasing the longitudinal speed. The input of the model can be either a driver input manoeuvre (roll angle) or a transversal component of road input able to excite the vibration modes. The driver is introduced in the model as a steering torque that allows the vehicle to follow a reference trajectory. To validate the model, experimental tests were done. To excite the vehicle modes, the driver input was not taken into account considering both the danger for the driver and the repeatability of the manoeuvre. Two different vehicle configurations were tested: vehicle 1 is a motorcycle [7] and vehicle 2 is a scooter. Through the use of the validated model, a sensitivity analysis was done changing structural (for example normal trail, steering angle, mass) and non structural parameters (for example longitudinal speed).

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Experimental Investigation of Factors Influential for the Flexible Blade Based Prototyping Process

Volume 4: 4th Design for Manufacturing Conference ◽

10.1115/detc99/dfm-8960 ◽

1999 ◽

Author(s):

Bram de Smit ◽

Johan J. Broek ◽

Imre Horváth

Keyword(s):

Order Approximation ◽

Experimental Tests ◽

Influential Factors ◽

Free Form ◽

Process Characteristics ◽

Novel Technology ◽

Large Numbers ◽

First Results ◽

Manufacturing Technologies ◽

Balanced Optimization

Abstract Due to the need for large numbers of layers and size limitations, current layered manufacturing technologies are not suitable for the fabrication of large sized free-form objects. For this purpose a novel technology of thick layered object manufacturing is being developed, based on higher order approximation of the initial geometry, and the application of a flexible curved cutting tool. The method allows us to produce physical prototypes with less or without any finishing. The technology of cutting foams by means of a heated flexible blade in polystyrene foam offers new possibilities. However to achieve the optimum output, optimization of the process parameters is needed. In this paper a closer look is taken into the process characteristics and the influential factors which are decisive for productive cutting. The authors summarize the results of the executed experimental tests. In these experiments the values of the most influential parameters were systematically changed and the effects were carefully investigated. The first results indicate that the cutting technology is practically feasible, but further research is needed in order to achieve a balanced optimization of the technology from all aspects.

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A Mathematical Calculation Method for Hysteresis Characteristics Analysis of Arc-Shaped Finger Seal

10.21203/rs.3.rs-126112/v1 ◽

2020 ◽

Author(s):

Chun-Hua Du ◽

Yan-Chao Zhang ◽

Ya-Hui Cui ◽

Shu-Na Dong ◽

Hong-Hu Ji ◽

...

Keyword(s):

Mathematical Model ◽

Structural Parameters ◽

Maximum Error ◽

Calculation Model ◽

Correction Coefficient ◽

Research Results ◽

Characteristics Analysis ◽

Leakage Characteristics ◽

The Mathematical Model ◽

Hysteresis Characteristics

Abstract In order to accurately predict the hysteresis characteristics of finger seal, the minimum hysteresis which can directly reflect the hysteresis of finger seal is proposed to characterize the hysteresis of finger seal. The mathematical model for calculating the minimum hysteresis of finger seal is established, the correction coefficient in the mathematical model is determined, and the mathematical model is verified by experiments. The influence of the structure and working condition parameters of finger laminates on the hysteresis characteristics is studied based on the modified calculation model, and the rule of influence is obtained in the end. Research results show that the maximum error between the leakage characteristics numerical calculation of finger seal base on modified calculation model and the experiment results is 7.64%, and the mathematical model of the minimum hysteresis is reasonable and reliable. The descending order of influence degree of structural parameters on the hysteresis characteristics of finger seal is: thickness of each finger laminate, finger repeat angle, arc radius of the finger beam arcs‘ centers, diameter of the finger base circle, width of the interstice between fingers, arc radius of finger beam. The research results provide a theoretical basis for further research on the influence of hysteresis on the finger seal leakage characteristics and the optimal design of finger seal structure.

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