scholarly journals Vibration Reduction Performance of Damping-Enhanced Water-Lubricated Bearing Using Fluid-Saturated Perforated Slabs

2020 ◽  
Vol 33 (1) ◽  
Author(s):  
Yong Jin ◽  
Jianjun Lu ◽  
Wu Ouyang ◽  
Zhenglin Liu ◽  
Kunsheng Lao
Keyword(s):  
Liquid Phase ◽  
Vibration Amplitude ◽  
Volume Fraction ◽  
Vibration Reduction ◽  
Vertical Direction ◽  
Fluid Phase ◽  
Raw Material ◽  
Vibration Model ◽  
Optimal Value ◽  
Fluid Fraction

AbstractAs the first link element for the transmission of shaft vibration to the pedestal and even to the hull, water-lubricated bearing plays a key role in suppressing vibration. Although the porous structure is considered as one of the main methods for improving the wideband vibration and noise reduction performance of materials in many industrial fields, the studies in the field of water-lubricated bearing remain insufficient. To enhance vibration reduction performance, a fluid-saturated perforated slab is designed in this study, and via the establishment of a fluid-solid coupled vibration model, the influence law and impact levels were analyzed and verified by simulation and experiments. The results obtained verified that the total vibration amplitude of damping-enhanced stern bearing in the vertical direction was smaller than that of the normal stern bearing, and the reduction amplitude of the characteristic frequency agreed with the optimal value at approximately 0.1 of the volume fraction of the liquid phase when the solid-fluid phase was rubber–water. Additionally, the increase in fluid fraction did not enhance the damping effect, instead, it unexpectedly reduced the natural frequency of the raw material significantly. This research indicates that the design of the fluid-saturated perforated slab is effective in reducing the transmission of the vibration amplitude from the shaft, and presents the best volume fraction of the liquid phase.

SYNTHESIS OF HYDROGEN IN ACOUSTOPLASMA DISCHARGE IN A LIQUID-PHASE STREAM

2019 ◽  
pp. 42-48 ◽  
Author(s):  
N. A. Bulychev
Keyword(s):  
Liquid Phase ◽  
Organic Compounds ◽  
Electrode Materials ◽  
Solid Phase ◽  
Plasma Discharge ◽  
Raw Material ◽  
Two Phase ◽  
Reduced Pressure ◽  
External Power Source ◽  
Phase Medium

In this paper, the plasma discharge in a high-pressure fluid stream in order to produce gaseous hydrogen was studied. Methods and equipment have been developed for the excitation of a plasma discharge in a stream of liquid medium. The fluid flow under excessive pressure is directed to a hydrodynamic emitter located at the reactor inlet where a supersonic two-phase vapor-liquid flow under reduced pressure is formed in the liquid due to the pressure drop and decrease in the flow enthalpy. Electrodes are located in the reactor where an electric field is created using an external power source (the strength of the field exceeds the breakdown threshold of this two-phase medium) leading to theinitiation of a low-temperature glow quasi-stationary plasma discharge.A theoretical estimation of the parameters of this type of discharge has been carried out. It is shown that the lowtemperature plasma initiated under the flow conditions of a liquid-phase medium in the discharge gap between the electrodes can effectively decompose the hydrogen-containing molecules of organic compounds in a liquid with the formation of gaseous products where the content of hydrogen is more than 90%. In the process simulation, theoretical calculations of the voltage and discharge current were also made which are in good agreement with the experimental data. The reaction unit used in the experiments was of a volume of 50 ml and reaction capacity appeared to be about 1.5 liters of hydrogen per minute when using a mixture of oxygen-containing organic compounds as a raw material. During their decomposition in plasma, solid-phase products are also formed in insignificant amounts: carbon nanoparticles and oxide nanoparticles of discharge electrode materials.

scholarly journals Theoretical analysis and experimental research on multi-layer elastic damping track structure

2021 ◽  
Vol 13 (2) ◽  
pp. 168781402199497
Author(s):  
Guanghui Xu ◽  
Shengkai Su ◽  
Anbin Wang ◽  
Ruolin Hu
Keyword(s):  
Finite Element ◽  
Analytical Solution ◽  
Finite Element Simulation ◽  
Reaction Force ◽  
Vibration Reduction ◽  
Vertical Direction ◽  
Propagation Path ◽  
Track Structure ◽  
Test Results ◽  
Element Simulation

The increase of axle load and train speed would cause intense wheelrail interactions, and lead to potential vibration related problems in train operation. For the low-frequency vibration reduction of a track system, a multi-layer track structure was proposed and analyzed theoretically and experimentally. Firstly, the analytical solution was derived theoretically, and followed by a parametric analysis to verify the vibration reduction performance. Then, a finite element simulation is carried out to highlight the influence of the tuned slab damper. Finally, the vibration and noise tests are performed to verify the results of the analytical solution and finite element simulation. As the finite element simulation indicates, after installation of the tuned slab damper, the peak reaction force of the foundation can be reduced by 60%, and the peak value of the vertical vibration acceleration would decrease by 50%. The vibration test results show that the insertion losses for the total vibration levels are 13.3 dB in the vertical direction and 21.7 dB in the transverse direction. The noise test results show that the data of each measurement point is smoother and smaller, and the noise in the generating position and propagation path can be reduced by 1.9 dB–5.5 dB.

scholarly journals Quantification of shear viscosity and wall slip velocity of highly concentrated suspensions with non-Newtonian matrices in pressure driven flows

2021 ◽  
Author(s):  
Patrick Wilms ◽  
Jan Wieringa ◽  
Theo Blijdenstein ◽  
Kees van Malssen ◽  
Reinhard Kohlus
Keyword(s):  
Shear Stress ◽  
Liquid Phase ◽  
Shear Rate ◽  
Shear Viscosity ◽  
Slip Velocity ◽  
Volume Fraction ◽  
Solid Volume Fraction ◽  
Wall Slip ◽  
Flow Index ◽  
Concentrated Suspensions

AbstractThe rheological characterization of concentrated suspensions is complicated by the heterogeneous nature of their flow. In this contribution, the shear viscosity and wall slip velocity are quantified for highly concentrated suspensions (solid volume fractions of 0.55–0.60, D4,3 ~ 5 µm). The shear viscosity was determined using a high-pressure capillary rheometer equipped with a 3D-printed die that has a grooved surface of the internal flow channel. The wall slip velocity was then calculated from the difference between the apparent shear rates through a rough and smooth die, at identical wall shear stress. The influence of liquid phase rheology on the wall slip velocity was investigated by using different thickeners, resulting in different degrees of shear rate dependency, i.e. the flow indices varied between 0.20 and 1.00. The wall slip velocity scaled with the flow index of the liquid phase at a solid volume fraction of 0.60 and showed increasingly large deviations with decreasing solid volume fraction. It is hypothesized that these deviations are related to shear-induced migration of solids and macromolecules due to the large shear stress and shear rate gradients.

Solid–liquid–liquid phase envelopes from temperature-scanned refractive index data

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Alcides J. Sitoe ◽  
Franco Pretorius ◽  
Walter W. Focke ◽  
René Androsch ◽  
Elizabeth L. du Toit
Keyword(s):  
Refractive Index ◽  
Liquid Phase ◽  
Volume Fraction ◽  
Solution Temperature ◽  
Linear Behavior ◽  
Upper Critical Solution Temperature ◽  
Novel Method ◽  
Using Data ◽  
Solid Liquid ◽  
Liquid Liquid Phase Separation

Abstract A novel method for estimating the upper critical solution temperature (UCST) of N,N-diethyl-m-toluamide (DEET)-polyethylene systems was developed. It was validated using data for the dimethylacetamide (DMA)-alkane systems which showed that refractive index mixing rules, linear in volume fraction, can accurately predict mixture composition for amide-alkane systems. Furthermore, rescaling the composition descriptor with a single adjustable parameter proved adequate to address any asymmetry when modeling the DMA-alkane phase envelopes. This allowed the translation of measured refractive index cooling trajectories of DEET-alkane systems into phase diagrams and facilitated the estimation of the UCST values by fitting the data with an adjusted composition descriptor model. For both the DEET- and DMA-alkane systems, linear behavior of UCST values in either the Flory–Huggins critical interaction parameter, or the alkane critical temperature, with increasing alkane molar mass is evident. The UCST values for polymer diluent systems were estimated by extrapolation using these two complimentary approaches. For the DEET-polyethylene system, values of 183.4 and 180.1 °C respectively were obtained. Both estimates are significantly higher than the melting temperature range of polyethylene. Initial liquid–liquid phase separation is therefore likely to be responsible for the previously reported microporous microstructure of materials formed from this binary system.

Experimental Study on the Performance of Constrained Damped Rail Vibration Reduction

2011 ◽  
Vol 42 (10) ◽  
pp. 9-14
Author(s):  
L.Y. Liu ◽  
J.Y. Li ◽  
X.J. Yin
Keyword(s):  
Experimental Study ◽  
Time Domain ◽  
Vibration Amplitude ◽  
Impact Load ◽  
Vibration Reduction ◽  
Time Domain Analysis ◽  
Experimental Basis ◽  
Vibration Acceleration ◽  
The Time Domain ◽  
Vibration Performance

To study the vibration reduction performance of damped rail, we take the standard rail and labyrinth constrained damped rail as the study target. By testing the vibration performance of both standard rail and labyrinth constrained damped rail in an anechoic room, we use the time-domain analysis to study the vibration changes with time passing. The results showed that: the labyrinth constrained damped rail vibration can effectively reduce the vibration amplitude and duration. Under the radial impact load, compared to the standard rail, vibration acceleration attenuation of the labyrinth constrained damped rail is 5% −19%, time of vibration and attenuation greater than 94%; under the axial impact load, compared to the standard rail, vibration acceleration attenuation of the labyrinth constrained damped rail is 9% −21%, time of vibration and attenuation greater than 92%. The results have provided an experimental basis for the design of new constrained damped rail.

Study on Vibration Reduction of Finishing Lapping Machine for Bearing Race

2011 ◽  
Vol 199-200 ◽  
pp. 1496-1500
Author(s):  
Jia Man ◽  
Lian Hong Zhang ◽  
Yong Liang Chen
Keyword(s):  
Vibration Amplitude ◽  
Vibration Reduction ◽  
Experimental Studies ◽  
Machining Efficiency ◽  
Bearing Race ◽  
Excitation Force ◽  
Lapping Machine ◽  
Light Material ◽  
Vibration Performance

It is key to improve the machining efficiency of finishing lapping machine to restrain the vibration that raise with work speed. The vibration amplitude is influenced by the excitation force of unbalanced crank-rocker mechanism and the anti-vibration performance of guide. Following improving schemes as adding counterweight to crank-rocker mechanism, adopting the light material motion components and enhancing the anti-vibration performance of guide are proposed based on theoretical and experimental studies. The improving schemes are verified by the experiment.

scholarly journals Flow analysis of particulate suspension on an asymmetric peristaltic motion in a curved configuration with heat and mass transfer

2018 ◽  
Vol 19 (4) ◽  
pp. 401 ◽  
Author(s):  
Ahmed Zeeshan ◽  
Nouman Ijaz ◽  
Muhammad Mubashir Bhatti
Keyword(s):  
Volume Fraction ◽  
Biological Fluids ◽  
Particle Volume Fraction ◽  
Flow Analysis ◽  
Volumetric Flow Rate ◽  
Fluid Phase ◽  
Peristaltic Motion ◽  
Particle Volume ◽  
Two Phase ◽  
Peristaltic Pumping

This article addresses the influence of particulate-fluid suspension on asymmetric peristaltic motion through a curved configuration with mass and heat transfer. A motivation for the current study is that such kind of theory is helpful to examine the two-phase peristaltic motion between small muscles during the propagation of different biological fluids. Moreover, it is also essential in multiple applications of pumping fluid-solid mixtures by peristalsis, i.e., Chyme in small intestine and suspension of blood in arteriole. Long wavelength, as well as small Reynolds number, have been utilized to render the governing equations for particle and fluid phase. Exact solutions are presented for velocity (uf,p), temperature (θf,p) and concentration distributions (φf,p). All the parameters such as Prandtl number (Pr), particle volume fraction (C), suspension parameter (M1), curvature parameter (k), volumetric flow rate (Q), Schmidt number (Sc), phase difference (φ), Eckert number (Ec), and Soret number (Sr) discussed graphically for peristaltic pumping (Δp), pressure gradient (dp/dx), velocity (uf,p), temperature (θf,p) and concentration distributions (φf,p). The streamlines are also plotted with the aid of contour.

scholarly journals Functional Application for the Corn Leaf Fibre to Make Reinforced Polymer Composites Sheet

2021 ◽  
Author(s):  
Ramratan Guru ◽  
Anupam Kumar ◽  
Rohit Kumar
Keyword(s):  
Volume Fraction ◽  
Agricultural Waste ◽  
Matrix Material ◽  
Research Work ◽  
Weight Fraction ◽  
Natural Fibre ◽  
Raw Material ◽  
Corn Husk ◽  
The Matrix ◽  
Composite Product

This research work has mainly utilized agricultural waste material to make a good-quality composite sheet product of the profitable, pollution free, economical better for farmer and industries. In this study, from corn leaf fibre to reinforced epoxy composite product has been utilized with minimum 35 to maximum range 55% but according to earlier studies, pulp composite material was used in minimum 10 to maximum 27%. Natural fibre-based composites are under intensive study due to their light weight, eco-friendly nature and unique properties. Due to the continuous supply, easy of handling, safety and biodegradability, natural fibre is considered as better alternative in replacing many structural and non-structural components. Corn leaf fibre pulp can be new source of raw material to the industries and can be potential replacement for the expensive and non-renewable synthetic fibre. Corn leaf fibre as the filler material and epoxy as the matrix material were used by changing reinforcement weight fraction. Composites were prepared using hand lay-up techniques by maintaining constant fibre and matrix volume fraction. The sample of the composites thus fabricated was subjected to tensile, impact test for finding the effect of corn husk in different concentrations.

Determination of Methanol Concentration in Ethanol in Liquid Phase by a Phononic Crystal Mach-Zehnder Interferometer

2021 ◽  
Author(s):  
Aysevil Salman Durmuşlar ◽  
Emine Ates ◽  
Ahmet Biçer ◽  
Sualp Deniz ◽  
Ahmet Cicek ◽  
...  
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Liquid Phase ◽  
Volume Fraction ◽  
Phononic Crystal ◽  
High Sensitivity ◽  
Zehnder Interferometer ◽  
Pure Ethanol ◽  
Interferometric Sensor ◽  
Polyethylene Tubing

Abstract A practical and portable ultrasonic interferometric sensor to detect methanol concentration in ethanol in the liquid phase is numerically investigated. For high-sensitivity operation, the sensor is designed as a Mach-Zehnder interferometer based on a linear-defect waveguide in a two-dimensional phononic crystal, which consists of square array of cylindrical steel rods in water. The waveguide core comprises polyethylene tubing, impedance-matched with water, filled with either pure ethanol or ethanol-methanol binary mixture, allowing fast replacement of the analyte. Band structure analyses through the finite-element method are carried out to obtain guiding modes at frequencies around 200 kHz. With 50x21 cells with 4.2 mm periodicity, the total sensor area is 210-by-88.2 millimeters, which can be significantly reduced by increasing the operating frequency to megahertz range. The interferometer is constructed via T junctions of the waveguide, which facilitates low-loss equal splitting and recollection of ultrasonic waves. Sample and reference wave paths are constructed by filling polyethylene tubing on the upper and lower halves of the interferometer with the ethanol-methanol mixture and pure ethanol, respectively. Frequency-domain finite-element method simulations reveal that the sensor output is characterized by several transmission peaks, one of which is centered at 203.35 kHz with a full-width at half-maximum of 20 Hz, resulting in a quality factor of 10167. The peak frequency of this peak redshifts at a rate of 7.24 Hz per percent volume fraction change in methanol. The peak shift is linear when the methanol volume fraction is below 10%. Besides, the interferometric sensor has a figure of merit around 0.35. The proposed ultrasonic sensor offers rapid detection of methanol content in ethanol with high sensitivity.

Sign in / Sign up

Export Citation Format

Share Document