A Comparative Study of the Flow Field of High Viscosity Media in Conventional/Rotary Hydrocyclones

The flow fields inside conventional and rotary hydrocyclones were simulated respectively. In these simulations, water only and oil-water mixture, with distinctly different viscosities, were used as continuous phases. Simulation results agreed well with the experimental measurements. Simulation results showed that the conventional hydrocyclone could effectively separate sand from water, but could not separate sand from high viscosity water/oil emulsion. This showed that the viscosity of continuous phases influenced greatly both the separation efficiency and the flow field distribution in the conventional hydrocyclone. For high viscosity oil/water sand dispersion （mixture）, the rotary hydrocyclone has better separation performance than the conventional one, with a more favorable flow field distribution.

A Flexible Valve Based Piezoelectric Pump for High Viscosity Cooling Liquid Transportation

A piezoelectric pump with flexible valve has been developed to pump high viscosity cooling liquid in the nanosats thermal control system. The structure of the flexible valve is designed according to the characteristics of the human aortic shape with the aim to simulate the bionic pumping function of the human heart. Dynamic stress-strain features of the flexible valve are analyzed by the finite element method,and the results show that the proposed flexible valve is suitable and functional for the piezoelectric pump. Then the cylinder and diffuser/nozzle piezoelectric pumps based on flexible valves have been developed and fabricated. Experimental results of the output performance indicate that the maximum flow rate of the cylinder piezoelectric pump with flexible valve is 15.38 mL/min,170.77% higher than the diffuser/nozzle piezoelectric pump with flexible valve. The ability of the cylinder piezoelectric pump with flexible valve for transmitting high viscosity liquid has been validated. The piezoelectric pump with flexible valve has potential applications in the nanosats thermal control system.

Preparation of high viscosity average molecular mass poly-L-lactide

Poly-L-lactide（PLLA） was synthesized by ring-opening polymerization fi＇om high purity L-lactide with tin octoate as initiator, and characterized by means of infi＇ared, and ^1H-nuclear magnetic resonance. The influences of initiator concentration, polymerization temperature and polymerization time on the viscosity average molecular mass of PLLA were investigated. The effects of different purification methods on the concentration of initiator and viscosity average molecular mass were also studied. PLLA with a viscosity average molecular mass of about 50.5×1^04 was obtained when polymerization was conducted for 24 h at 140℃ with the molar ratio of monomer to purification initator being 12 000. After purification, the concentration of tin octoate decreases; however, the effect of different purification methods on the viscosity average molecular mass of PLLA is different, and the obtained PLLA is a typical amorphous polymeric material. The crystallinity of PLLA decreases with the increase of viscosity average molecular mass.

Aging effects on rheological properties of high viscosity modified asphalt

This work investigated the aging effects on the rheological properties of high viscosity modified asphalt(HVMA).First,the high-and low-temperature rheological properties were measured by a dynamic shear rheometer and a bending beam rheometer,respectively.The aging mechanism was then tested using an Fourier transform infrared spectroscopy and a scanning electron microscope.Besides,a study was performed to compare the aging effects on the rheological properties of HVMA,crumb rubber modified asphalt(CRMA),and neat asphalt(SK-90).The experimental results showed that the effects of the long-term aging on HVMA exceeded those of short-term aging.The complex shear modulus of the HVMA was improved by the aging in the whole frequency range.The complex shear modulus of the HVMA after the long-term aging was larger than after the short-term aging.Thus,the aging improved the high-temperature viscoelastic performance of HVMA.With a decrease in temperature from-12℃to-24℃,the low-temperature viscoelastic performance of HVMA decreased since its stiffness modulus and low continuous grading temperature increase.Both of the short-and long-term aging of HVMA were caused by an oxidation reaction,while modifier swelling also happened after long-term aging.Compared to CRMA and SK-90,aging had a limited influence on the high-and low-temperature rheological properties of HVMA.

Effect of different high viscosity modifiers on rheological properties of high viscosity asphalt

High viscosity asphalt(HVA)has been a great success as a drainage pavement material.However,the larger porosity of drainage asphalt mixtures weakens the cohesion and adhesion and leads to premature rutting,water damage,spalling and cracking.The purpose of this study was to investigate the rheological properties of HVA prepared using different high viscosity modifiers through conventional tests,Brookfield viscosity tests,dynamic shear rheometer tests and bending beam rheometer tests.The conventional performance results demonstrated SBS+rubber asphalt(SRA1/2)exhibited excellent elastic recovery and low-temperature flexibility.The 60℃ dynamic viscosity results indicated TPS+rubber asphalt(TRA)had the excellent adhesion.The rotational viscosity results and rheological results indicated that SRA-2 not only exhibited excellent temperature stability and workability,as well as excellent resistance to deformation and rutting resistance,but also exhibited excellent low-temperature cracking resistance and relaxation performance.Based on rheological results,the PG classification of HVA was 16%rubber+asphalt for PG76-22,20%rubber+asphalt for PG88-22,TRA and SRA-1/2 for PG88-28.From comprehensive evaluation of the viscosity,temperature stability and sensitivity,as well as high/low temperature performance of HVA,SRA-2 was found to be more suited to the requirements of drainage asphalt pavement materials.

Process Intensification of VOC Removal from High Viscous Media by Rotating Packed Bed

The removal of a volatile organic compound (VOC) from high viscous liquid was carried out in a rotat-ing packed bed (RPB) in this study. The mixed liquid of syrup and acetone was used as simulated high viscous polymer solution with acetone as the volatile compound. The influence of the rotating speed of RPB, liquid viscos-ity, liquid flow rate, vacuum degree, and initial acetone content in the liquid on acetone removal efficiency was in-vestigated. The experimental results indicated that the removal efficiency increased with increasing rotating speed and initial acetone content in the viscous liquid and decreased with increasing liquid viscosity and flow rate. It was also observed that acetone removal efficiency increased with an increasing vacuum degree and reached 58% at a vacuum degree of 0.1 MPa. By the comparison with a flash tank devolatilizer, it was found that acetone removal ef-ficiency in RPB increased by about 67%.

Wall Sticking of High Water-Cut, Highly Viscous and High Gel-Point Crude Oil Transported at Low Temperatures

Some crude oils with high water cut have the capability to flow below the oil gel point, while the oil particles adhere to the pipe wall in the form of paste, also called "wall sticking". Wall sticking is a serious problem during the pipeline transportation, leading to partial or total blockage of the pipeline and energy wastage. In this paper, a series of laboratory flow loop experiments were conducted to observe the wall sticking characteristics of crude oil with high water cut, high viscosity and high gel point at low transportation temperatures. The effects of shear stress and water cut on the wall sticking rate and occurrence temperature were investigated. Experimental results indicated that the wall sticking rate and occurrence temperature were lower under stronger shear stress and higher water cut conditions. A criterion of wall sticking occurrence temperature(WSOT) and a regression model of wall sticking rate were then established. Finally, the software was developed to calculate the pressure drop along the pipelines of crude oils with high water-cut. It was able to predict the wall sticking thickness of gelled oil and then calculate the pressure drop along the pipelines. A typical case study indicated that the prediction results obtained from the software were in agreement with actual measured values.

A NEW EXPLICIT SIMULATION FOR MOULD FILLING WITH HIGH VISCOUS FEEDSTOCK

In the simulation of the metal injection moulding (MIM), the behaviours of feedstock are much di?erent from which of the polymer injection. It is a mixture of the metallic powder in high concentration and some plastic binder. The advance in simulation of the mould ?lling with such high viscous feedstock is featured by the development of a fully explicit vectorial algorithm. On the basis of previous explicit software realized by the authors, the new algorithm avoids the global solution for pressure ?elds and the use of MINI elements to improve its e?ciency. Except for the operations at element level, neither global solution nor the construction of global matrix is required in simulation. A special strategy is used to regulate the incompressibility condition in ?lled domain at each time step. In case of the MIM problems, this method provides a fast way to simulate the ?lling processes. The computational cost is about linearly proportional to the degree of freedom number. Moreover, this vectorial algorithm can be easily parallelized for high performance computation with multi-clusters. The comparison of numerical results with previous simulations on 3D cases proves the validity and e?ciency of new algorithm.

Influence of Viscosity in Fluid Atomization with Surface Acoustic Waves

In this work, aqueous glycerol solutions are atomized to investigate the influence of the viscosity on the droplet size and the general atomization behavior in a setup using standing surface acoustic waves (sSAW) and a fluid supply at the boundary of the acoustic path. Depending on the fluid viscosity, the produced aerosols have a monomodal or polymodal size distribution. The mean droplet size in the dominant droplet fraction, however, decreases with increasing viscosity. Our results also indicate that the local wavefield conditions are crucial for the atomization process.

Synergistic effects of multiple rotors and hydrogen-bond interactions lead to sensitive near-infrared viscosity probes for live-cell microscopy

Changes in cellular viscosity are associated with various physiological processes and pathological conditions.To study these cellular processes and functions,highly sensitive fluorescent probes that detect subtle changes in viscosity are urgently needed but remain lacking.In this study,we present a series of viscosity-responsive near-infrared(NIR)fluorescent probes based on styrene-coated boron dipyrromethene(BODIPY).The probe modified with dimethylaminostyrene and piperazine at the two terminals of the BODIPY scaffold showed extremely high viscosity sensitivity values(x,around 1.54),with excellent performance for detecting viscosity below 20 c P.This outstanding property is attributed to the synergistic effects of multiple rotatable bonds and hydrogen-bond interactions.Additionally,this probe has been successfully deployed to monitor viscosity changes in various cellular compartments(i.e.,cytoplasm)and processes(such as during autophagy).This work provides a rational molecular design strategy to construct fluorescent probes with high viscosity sensitivity for exploring cell functions.

Experimental investigation of viscous oil-water-sand flow in horizontal pipes:Flow patterns and pressure gradient

Fluid production from unconsolidated reservoirs often leads in sand production,which poses a number of issues.Sand deposition in flowlines can result in significant pressure dips,pipe and facility damage,and obstructions that decrease productivity.More research is needed to understand the movement and deposition of sand in oil-water-sand(O-W-S) fluxes.This article focuses on O-W-S flows in a 6-meter-long horizontal pipe with an inner diameter of 0.0381 m.The study looks at the flow behavior of high viscosity oil-water(O-W),water-sand(W-S),and oil-water-sand(O-W-S) flows.Experiments were carried out at 250 psig pressure in a laboratory flow test facility using various heavy synthetic oils(viscosities ranging from 3500 cP to 7500 cP at 25℃) and tap water.The sand concentration varied from 1% to 10%,with an average sand particle diameter of 145 μm and material density of 2630 kg/m~3.Water cuts ranged from 0.0 to 1.0.The experimental results revealed a minor change in pressure gradient between(O-W) and(O-W-S) flows.However,increasing the sand concentration in(O-W-S) flow resulted in higher pressure losses.The reduction factor of pressure gradient indicated that the highest decrease in pressure drop occurred at higher superficial oil velocities.Furthermore,a direct relationship was observed between the reduction factor and the decrease in water cut.The results also showed that the minimum required transportation velocity for sand slurry decreased with increasing superficial oil velocity,while the minimum transportation condition increased with higher sand concentration.The comparison between the expected pressure gradient from Bannwart and McKibben et al.and the actual experimental data demonstrated significant accuracy for the oil viscosities and superficial oil velocities used in the study.

Impact of Semen Liquefaction and Viscosity on the Outcomes of in vitro Fertilization

Objective To compare the outcomes of in vitro fertilization （IVF） and intracytoplasmic sperm injection （ICSI） between semen liquefaction and viscosity with normal and abnormal. Methods Semen that liquefied within 60 min and normal viscosity was assigned to the normal group, while semen that unliquefied more than 60 min or high viscosity was assigned to abnormal group. Equal volumes of culture medium were added to abnormal group and normal control group, followed by repeated pipetting, to induce liquefaction. Sperm parameters, fertilization and cleavage rates, good-quality embryo rate, im- plantation rate and pregnancy rate were analyzed. Results The abnormal group ratio was much higher in the ICSI group （30.5%） than in the IVF group （21.9%） （P〈0.05）. The age of the husbands and total progressive motility （PR） sperm in abnormal IVF group were higher than those in normal IVF group （P〈0.05）. Fertilization rate （80.7%） in the abnormal IVF group was higher than that in the normal IVF group （75.6%） and normal control group （P〈0.05）. There were no differences in outcomes of the ICSI patients between the normal and abnormal groups. There was no difference between normal group and normal control group. Conclusion Equal volume of culture media was added to non-liquefied semen may be used to high viscosity and unliquefied semen, and may have a positive effect on fertilization outcomes.

Viscosity and Structure Changes of CaO-SiO_2-Al_2O_3-CaF_2 Melts with Substituting Al_2O_3 for SiO_2

During the smelting process of the high Al steels,the reaction between SiOin molten slag and dissolved aluminum in liquid steel always takes place.This aluminathermic reduction reaction will lead to the substitution of 1mol SiOfor 2/3mol AlO.Therefore,the investigations about the influence of the ratio of AlOto SiOon viscosity and structure changes of mould flux during this process are very necessary.The viscosity variation of CaO-SiO-AlO-CaFv2 melts was studied by changing compositions considering the aluminathermic reduction reaction.It was found that viscosity increased monotonously with gradually increasing the substitution extent.According to the Raman analysis,the substitution of AlOfor SiOleads to the decrease of non-bridging oxygen but the increase of bridging oxygen.Therefore,degree of polymerization and viscosity increase as the substitution extent increases.By comparing the measured viscosities with the model calculated values,it was found that both the recently developed Zhang′s model and Roboud model could describe the viscosity variation behavior of CaO-SiO-AlO-CaFmelts very well.