Effect of Bionic Concave Surface to the Drag Reduction Performance of Cylinder Sealing Ring

2014 ◽  
Vol 1055 ◽  
pp. 152-156 ◽  
Author(s):  
Gang Zhao ◽  
Fang Li ◽  
Wei Xin Liu ◽  
Jian Ying Zhao ◽  
Hong Shi Bi
Keyword(s):  
Drag Reduction ◽  
Reduction Rate ◽  
Cylinder Block ◽  
Lubricating Oil ◽  
Concave Surface ◽  
Movement Speed ◽  
Piston Velocity ◽  
Friction Resistance ◽  
Sealing Ring ◽  
Maximum Drag Reduction

According to the problem of large friction resistance exists between the sealing ring and the cylinder block when the piston cylinder works, the drag reduction technology of bionic concave surface was applied in the sealing ring. By building a drag reduction motion model of sealing ring with concave surface of triangular arrangement, the effect of drag reduction performance decided by concave diameter and piston velocity was studied with the method of numerical simulation. The results show that: when the piston velocity is fixed, the maximum drag reduction rate can be achieved with the concave diameter is 1.5mm, and the maximum drag reduction rate is 15.72%. Meanwhile when the diameter of the concave is fixed, the drag reduction rate increased gradually with the increase of initial speed, the drag reducing effect is best at the speed of 0.6m/s. In the process of piston movement, lubricating oil in concave shakes, and makes the lubricating oil flow to the inside wall of cylinder, which play the role of lubrication, so as to achieve the effect of reducing friction and increasing the movement speed of piston.

scholarly journals Influence of Bionic Pit Structure on Friction and Sealing Performance of Reciprocating Plunger

2020 ◽  
Vol 2020 ◽  
pp. 1-10
Author(s):  
Tianyu Gao ◽  
Bo Su ◽  
Lei Jiang ◽  
Qian Cong
Keyword(s):  
Reduction Rate ◽  
Frictional Resistance ◽  
Lubricating Oil ◽  
Element Analysis ◽  
Friction Resistance ◽  
Sealing Performance ◽  
Maximum Drag Reduction ◽  
Lubrication Condition ◽  
Bionic Structure ◽  
Oil Film Pressure

A new kind of pit-shaped bionic plunger proposes to reduce the frictional resistance of the reciprocating plunger and improve its sealing performance. According to the dorsal pore of earthworm, the bionic pit structure with different parameters designed and processed. The friction resistance test, observation test, and finite element analysis carried out. The results show that the bionic pit structure can improve the lubrication condition of the plunger surface and reduce the frictional resistance with a maximum drag reduction rate of 14.32%. The pit-shaped bionic structure can increase the storage of lubricating oil, intercept the surface streamline, and decrease the flow rate. The bionic plungers’ mean contact pressure and oil film pressure increased significantly.

scholarly journals An investigation on the drag reduction performance of bioinspired pipeline surfaces with transverse microgrooves

2020 ◽  
Vol 11 ◽  
pp. 24-40 ◽  
Author(s):  
Weili Liu ◽  
Hongjian Ni ◽  
Peng Wang ◽  
Yi Zhou
Keyword(s):  
Numerical Simulation ◽  
Drag Reduction ◽  
Pressure Loss ◽  
Fluid Transport ◽  
Reduction Rate ◽  
Orthogonal Analysis ◽  
Maximum Drag Reduction ◽  
Reduction Effect ◽  
Save Energy ◽  
Microgrooved Surface

A novel surface morphology for pipelines using transverse microgrooves was proposed in order to reduce the pressure loss of fluid transport. Numerical simulation and experimental research efforts were undertaken to evaluate the drag reduction performance of these bionic pipelines. It was found that the vortex ‘cushioning’ and ‘driving’ effects produced by the vortexes in the microgrooves were the main reason for obtaining a drag reduction effect. The shear stress of the microgrooved surface was reduced significantly owing to the decline of the velocity gradient. Altogether, bionic pipelines achieved drag reduction effects both in a pipeline and in a concentric annulus flow model. The primary and secondary order of effect on the drag reduction and optimal microgroove geometric parameters were obtained by an orthogonal analysis method. The comparative experiments were conducted in a water tunnel, and a maximum drag reduction rate of 3.21% could be achieved. The numerical simulation and experimental results were cross-checked and found to be consistent with each other, allowing to verify that the utilization of bionic theory to reduce the pressure loss of fluid transport is feasible. These results can provide theoretical guidance to save energy in pipeline transportations.

Effect of Jet Hole Size on Drag Reduction Performance of Bionic Jet Surface

2014 ◽  
Vol 1022 ◽  
pp. 87-90
Author(s):  
Zhao Gang ◽  
Fang Li ◽  
Wei Xin Liu ◽  
Shu Zhang ◽  
Hong Shi Bi ◽  
...  
Keyword(s):  
Numerical Simulation ◽  
Drag Reduction ◽  
High Speed ◽  
Reduction Rate ◽  
Surface Model ◽  
Surface Boundary ◽  
Hole Size ◽  
Friction Resistance ◽  
Rectangular Jet ◽  
Flow Length

According to the problem of drag reduction on bionic jet surface, a rectangular jet surface model which is similar to shark branchial shape was built, and numerical simulation was processed by using SST k-ω turbulence model, moreover, influence of jet hole size on the drag reduction performance of jet surface was studied. The results show that: the effect of flow length of rectangular jet hole on the drag reduction is remarkable, with the increase of flow length, fluid friction resistance of the jet surface decreases, the maximum drag reduction rate was 14.38%, and the results of numerical simulation was verified by carrying out experiments. The jet fluid decreases the sweep on the wall of mainstream high speed fluid, which increases the thickness of jet surface boundary layer, thereby reducing the surface friction of the jet hole downstream.

LDV Measurement of Turbulent Pipe Flow With Traveling Wavy Elastic Wall for Drag Reduction

2019 ◽  
Author(s):  
Seiya Nakazawa ◽  
Takaaki Shimura ◽  
Akihiko Mitsuishi ◽  
Kaoru Iwamoto ◽  
Akira Murata
Keyword(s):  
Drag Reduction ◽  
Pipe Flow ◽  
Reduction Rate ◽  
Streamwise Velocity ◽  
Turbulent Pipe Flow ◽  
Deformation Control ◽  
Wall Deformation ◽  
Maximum Drag Reduction ◽  
Reduction Effect ◽  
Ldv Measurement

Abstract Drag reduction effect by traveling wavy wall deformation control in turbulent pipe flow was experimentally investigated. From the visualization, we confirmed the downstream traveling wave although it was not uniform in the circumferential direction. When the frequency is 110 Hz, the wall deformation amplitude and the wavelength indicated that the effective values for drag reduction. The wavespeed is approximately effective values for drag reduction. As a result, the maximum drag reduction rate of 6.8 % is obtained. The result of a LDV measurement shows that the mean streamwise velocity gradient decreased near the wall by the control, which leads to drag reduction.

Experimental Study of the Concave Bionic Drag Reduction Needles

2013 ◽  
Vol 461 ◽  
pp. 702-706
Author(s):  
Ji Yue Wang ◽  
Qian Cong
Keyword(s):  
Drag Reduction ◽  
Reduction Rate ◽  
Outer Wall ◽  
Comparative Test ◽  
Point Of View ◽  
National Standard ◽  
Reduction Mechanism ◽  
Laser Material ◽  
Maximum Drag Reduction ◽  
Smooth Design

In this paper, we have started from the point of view of bionics, doing surface bionic non-smooth design at the standard No.16 animal syringe needles. Then treating the concave as the bionic unit, we worked out the concave bionic drag reduction needles by use of the laser material remove processing means. In accordance with the national standard on the injection drag test of disposable needles, we did the puncture drag comparative test of the smooth needles and the bionic needles, getting the correspondence relationship between the drag reduction rate and the bionic unit parameters. We found that the maximum drag reduction rate up to 44.05%, and it appeared when the concave interval was 0.9mm and the concave diameter was 0.09mm. Then through discussing the drag reduction mechanism of the bionic needles, we knew that the bionic units reduced the actual contact area between the needle outer wall and the simulation skin, and it was the main reason of bionic needles puncture drag decreases.

scholarly journals Bionic Nonsmooth Drag Reduction Mathematical Model Construction and Subsoiling Verification

2021 ◽  
Vol 2021 ◽  
pp. 1-13
Author(s):  
Baoguang Wu ◽  
Ruize Zhang ◽  
Pengfei Hou ◽  
Jin Tong ◽  
Deyi Zhou ◽  
...  
Keyword(s):  
Mathematical Model ◽  
Drag Reduction ◽  
Field Experiments ◽  
Design Method ◽  
Reduction Rate ◽  
Movement Speed ◽  
Surface Drag ◽  
Movement Model ◽  
Surface Design ◽  
Pangolin Scale

In this study, a bionic nonsmooth drag-reducing surface design method was proposed; a mathematical model was developed to obtain the relationship between the altitude of the nonsmooth drag-reducing surface bulges and the spacing of two bulges, as well as the speed of movement, based on which two subsoiler shovel tips were designed and verified on field experiments. The mechanism of nonsmooth surface drag reduction in soil was analyzed, inspired by the efficient digging patterns of antlions. The nonsmooth surface morphology of the antlion was acquired by scanning electron microscopy, and a movement model of the nonsmooth surface in soil was developed, deriving that the altitude of the nonsmooth drag-reducing surface bulge is proportional to the square of the distance between two bulges and inversely proportional to the square of the movement speed. A flat subsoiler shovel tip and a curved tip were designed by applying this model, and the smooth subsoiler shovel tips and the pangolin scale bionic tips were used as controls, respectively. The effect of the model-designed subsoilers on drag reduction was verified by subsoiling experiments in the field. The results showed that the resistance of the model-designed curved subsoiler was the lowest, the resistance of the pangolin scale bionic subsoiler was moderate, and the resistance of the smooth surface subsoiler was the highest; the resistance of the curved subsoiler was less than the flat subsoilers; the resistance reduction rate of the model-designed curved subsoiler was 24.6% to 33.7% at different depths. The nonsmooth drag reduction model established in this study can be applied not only to the design of subsoilers but also to the design of nonsmooth drag reduction surfaces of other soil contacting parts.

scholarly journals Investigation on drag reduction performance of pipeline with bioinspired microgrooved surface

2019 ◽  
Author(s):  
Weili Liu ◽  
Hongjian Ni ◽  
Peng Wang ◽  
Yi Zhou
Keyword(s):  
Numerical Simulation ◽  
Drag Reduction ◽  
Pressure Loss ◽  
Fluid Transport ◽  
Fluid Dynamic ◽  
Reduction Rate ◽  
Orthogonal Analysis ◽  
Maximum Drag Reduction ◽  
Reduction Effect ◽  
Microgrooved Surface

Novel surface morphology of pipeline with transverse microgrooves was proposed for reducing the pressure loss of fluid transport. Numerical simulation and experimental research efforts were undertaken to evaluate the drag reduction performance of bionic pipeline. The computational fluid dynamic calculation, using SST κ-ω turbulent model, shown that the “vortex cushioning effect” and “driving effect” produced by the vortexes in the microgrooves were the main reason for the drag reduction. The shear stress of the microgrooved surface was reduced significantly owing to the decline of the velocity gradient; then bionic pipeline achieved drag reduction effect in the pipe and concentric annulus flow. The primary and secondary order of effect on the drag reduction and optimal microgroove geometric parameters were obtained by orthogonal analysis method. The comparative experiments were conducted in a water tunnel, and a maximum drag reduction rate of 3.21% was achieved. The numerical simulation and experimental results were cross-checked and consistent with each other to verify that the utilization of bionic theory to reduce the pressure loss of fluid transport is feasible. Results can provide theoretical guidance for the energy saving of pipeline transportation.

Research on Drag Reduction Performance of Bionic Shark Gill Jet Surface

2014 ◽  
Vol 654 ◽  
pp. 57-60 ◽  
Author(s):  
Zhao Gang ◽  
Fang Li ◽  
Wei Xin Liu ◽  
Ming Ming Liu ◽  
Hong Shi Bi
Keyword(s):  
Numerical Simulation ◽  
Boundary Layer ◽  
Drag Reduction ◽  
Fluid Velocity ◽  
Reduction Rate ◽  
Frictional Resistance ◽  
Normal Velocity ◽  
Main Field ◽  
Maximum Drag Reduction ◽  
Pressure Resistance

According to the problem of bionic shark gill jet can reduce friction on shark surface, a model of bionic jet surface was established based on shark surface was analyzed by measurements, and its numerical simulation was processed by using RNG k-ε turbulence model. The results show that: the gill jet can reduce frictional resistance on shark surface, and the best drag reduction can be got when the speed of main field is 5m/s, furthermore the maximum drag reduction rate can be up to 17.15%. The pressure of jet hole upstream is reduced which due to the barrier to the facing fluid by the jet, so that the pressure resistance of jet surface is reduced as well. Besides, jet fluid is blocked in the boundary layer by mainstream fluid, which caused the fluid velocity of jet hole downstream is reduced, the thickness of boundary layer is increased, and the normal velocity gradient of wall is reduced, so as to achieve the effect of drag reduction.

scholarly journals Global effect of local skin friction drag reduction in spatially developing turbulent boundary layer

2016 ◽  
Vol 805 ◽  
pp. 303-321 ◽  
Author(s):  
A. Stroh ◽  
Y. Hasegawa ◽  
P. Schlatter ◽  
B. Frohnapfel
Keyword(s):  
Boundary Layer ◽  
Turbulent Boundary Layer ◽  
Drag Reduction ◽  
Control Region ◽  
Reduction Rate ◽  
Wall Turbulence ◽  
Local Skin ◽  
Control Schemes ◽  
Local Skin Friction ◽  
Friction Drag Reduction

A numerical investigation of two locally applied drag-reducing control schemes is carried out in the configuration of a spatially developing turbulent boundary layer (TBL). One control is designed to damp near-wall turbulence and the other induces constant mass flux in the wall-normal direction. Both control schemes yield similar local drag reduction rates within the control region. However, the flow development downstream of the control significantly differs: persistent drag reduction is found for the uniform blowing case, whereas drag increase is found for the turbulence damping case. In order to account for this difference, the formulation of a global drag reduction rate is suggested. It represents the reduction of the streamwise force exerted by the fluid on a plate of finite length. Furthermore, it is shown that the far-downstream development of the TBL after the control region can be described by a single quantity, namely a streamwise shift of the uncontrolled boundary layer, i.e. a changed virtual origin. Based on this result, a simple model is developed that allows the local drag reduction rate to be related to the global one without the need to conduct expensive simulations or measurements far downstream of the control region.

Drag Reduction of the Flow Past a Circular Cylinder in Surfactant Solution

2001 ◽  
Author(s):  
Satoshi Ogata ◽  
Keizo Watanabe
Keyword(s):  
Circular Cylinder ◽  
Drag Reduction ◽  
Sodium Salicylate ◽  
Tap Water ◽  
Pressure Coefficient ◽  
Surfactant Solution ◽  
Reduction Ratio ◽  
Number Range ◽  
Surfactant Solutions ◽  
Maximum Drag Reduction

Abstract The flow around a circular cylinder in surfactant solution was investigated experimentally by measurement of the pressure and velocity profiles in the Reynolds number range 6000 < Re < 50000. The test surfactant solutions were aqueous solutions of Ethoquad O/12 (Lion Co.) at concentrations of 50, 100 and 200 ppm, and sodium salicylate was added as a counterion. It was clarified that the pressure coefficient of surfactant solutions in the range of 10000 < Re < 50000 at the behind of the separation point was larger than that of tap water, and the separation angle increased with concentration of the surfactant solution. The velocity defect in surfactant solutions behind a circular cylinder was smaller than those in tap water. The drag coefficients of a circular cylinder in surfactant solutions were smaller than those of tap water in the range 10000 < Re < 50000, and no drag reduction occurred at Re = 6000. The drag reduction ratio increased with increasing concentration of surfactant solution. The maximum drag reduction ratio was approximately 35%.

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