STUDY OF OILSEED MATERIAL RHEOLOGY DURING EXTRUSION PROCESSING

2021 ◽  
Author(s):  
А.В. ГУКАСЯН ◽  
Е.П. КОШЕВОЙ ◽  
В.С. КОСАЧЁВ ◽  
И.А. ШОРСТКИЙ
Keyword(s):  
Hydrostatic Pressure ◽  
Shear Rate ◽  
Structure Formation ◽  
Oil Content ◽  
Velocity Shear ◽  
Hydraulic Pressure ◽  
Rotational Viscometer ◽  
Measuring Cell ◽  
Extrusion Processing

Определены параметры течения пластичной жидкости при экструзионной переработке масличных культур. В качестве экспериментального материала использовали мезгу, выходящую из жаровни и поступающую в экструдер. Вязкость измеряли на ротационном вискозиметре при избыточном гидростатическом давлении 981 Па. Высота слоя материала в измеряемой ячейке составила 38 мм. Скорость сдвига в процессе измерения варьировали от 1 до 10 рад/с. Проведены эксперименты по определению зависимости вязкости от масличности материала, напряжения и скорости сдвига, а также гидравлического давления на исследуемый материал. Анализ результатов эксперимента свидетельствует о наличии структурообразования материала, поступающего в экструдер. Полученные параметры инженерной модели позволяют прогнозировать реологию вязкопластичного течения в широком диапазоне скоростей сдвига в каналах шнекового пресса. The parameters of the flow of plastic liquid during the extrusive processing of oilseed material are defined. The pulp coming from the brazier and into an extruder was used as experimental material. The viscosity was measured with rotational viscometer under excessive hydrostatic pressure of 981 PA. The height of the layer of material in the measuring cell was 38 mm. Shear rate during the measurement ranged from 1 to 10 rad/s. The experiments to determine the dependence of viscosity on oil content material, pressure, and velocity shear, and hydraulic pressure on the oilseed material were carrying out. Analysis of the results of the experiment indicates the presence of structure formation of the material coming into the extruder.

ENTROPY INFLUENCE ON THE DEPENDENCE OF THE NANOFLUIDS VISCOSITY ON TEMPERATURE AND SHEAR RATE

2021 ◽  
Vol 7 (3) ◽  
pp. 89-105
Author(s):  
Lyudmila P. SEMIKHINA ◽  
Daniil D. Korovin
Keyword(s):  
Activation Energy ◽  
Shear Stress ◽  
Shear Rate ◽  
Viscous Flow ◽  
High Reliability ◽  
Narrow Particle Size Distribution ◽  
Disperse Systems ◽  
Rotational Viscometer ◽  
Surfactant Micelles ◽  
Dispersed Systems

A Brookfield DV-II + Pro rotational viscometer was used to study the viscosity of 7 samples of concentrated nanodispersed systems (nanofluids) with a similar viscosity (6-22 mPa ∙ s), the particles of the dispersed phase in which are nanosized surfactant micelles and conglomerates from them. It was found that for 5 out of 7 studied reagents, there is a decrease in viscosity typical for dispersed systems with an increase in the shear rate, and their flow curves, that is, the dependence of the shear stress on the shear rate, correspond to the ideal plastic flow of non-Newtonian fluids. Moreover, with high reliability, R2 ≥ 0.999 is described by the Bingham equation with a small value of the limiting shear stress (less than 0.2 Pa). It is shown that all the studied reagents are also characterized by an increase in the activation energy of a viscous flow Е with an increase in the shear rate. As a result, a decrease in viscosity with an increase in shear rate, typical for disperse systems, including nanofluids, is provided by a more significant increase in entropy changes ΔS compared to Е. It has been substantiated that, depending on the ratio between the activation energy of viscous flow Е and the change in entropy ΔS, the viscosity of concentrated micellar dispersed systems with an increase in the shear rate can decrease, remain unchanged, and increase. The last two cases, not typical for disperse systems and nanofluids, were identified and studied using the example of two demulsifiers, RIK-1 and RIK-2, with a maximum of a very narrow particle size distribution at 160 ± 5 nm, corresponding to the size of a special type of very stable micelles Surfactant — vesicle.

Effects of High Hydrostatic Pressure Treated Mung Bean Starch on Characteristics of Batters and Crusts from Deep-Fried Pork Nuggets

2014 ◽  
Vol 10 (2) ◽  
pp. 261-268 ◽  
Author(s):  
Lingwen Zhang ◽  
Hongfang Ji ◽  
Mingduo Yang ◽  
Hanjun Ma
Keyword(s):  
Hydrostatic Pressure ◽  
High Hydrostatic Pressure ◽  
Mung Bean ◽  
Oil Content ◽  
Dry Weight ◽  
Water Retention Capacity ◽  
Starch Granules ◽  
Retention Capacity ◽  
Mung Bean Starch

Abstract Influences of mung bean starches treated with different high hydrostatic pressure (HHP) on the properties of batters and crusts from deep-fried pork nuggets were explored. HHP-treated starch increased water retention capacity of batter and consequently the batter pick-up. The increase in pressure at 150–450 MPa could facilitate hydration and swelling of starch granules during gelatinization. The crusts containing HHP-treated starches had higher moisture and less oil content, and the oil content was 15.82 g/100 g dry weight (DW) for 450 MPa treated starch, which was much lower than that of native starch (18.39 g/100 g DW) (p<0.05). Additionally, HHP-treated starches changed the crispness of crusts with increases in the slope and decrease in the shearing distance. Results indicated that mung bean starch treated with HHP in the range of 150–450 MPa could improve the quality of deep-fried battered food.

scholarly journals Size-Dependent Distribution of Patient-Specific Hemodynamic Factors in Unruptured Cerebral Aneurysms Using Computational Fluid Dynamics

Diagnostics ◽  
2020 ◽  
Vol 10 (2) ◽  
pp. 64 ◽  
Author(s):  
Ui Yun Lee ◽  
Gyung Ho Chung ◽  
Jinmu Jung ◽  
Hyo Sung Kwak
Keyword(s):  
Fluid Dynamics ◽  
Shear Rate ◽  
Blood Viscosity ◽  
Cerebral Aneurysms ◽  
Velocity Shear ◽  
Patient Specific ◽  
Complex Flow ◽  
Size Dependent ◽  
Unruptured Cerebral Aneurysms ◽  
Small Aneurysms

Purpose: To analyze size-dependent hemodynamic factors [velocity, shear rate, blood viscosity, wall shear stress (WSS)] in unruptured cerebral aneurysms using computational fluid dynamics (CFD) based on the measured non-Newtonian model of viscosity. Methods: Twenty-one patients with unruptured aneurysms formed the study cohort. Patient-specific geometric models were reconstructed for CFD analyses. Aneurysms were divided into small and large groups based on a cutoff size of 5 mm. For comparison between small and large aneurysms, 5 morphologic variables were measured. Patient-specific non-Newtonian blood viscosity was applied for more detailed CFD simulation. Quantitative and qualitative analyses of velocity, shear rate, blood viscosity, and WSS were conducted to compare small and large aneurysms. Results: Complex flow patterns were found in large aneurysms. Large aneurysms had a significantly lower shear rate (235 ± 341 s−1) than small aneurysms (915 ± 432 s−1) at peak-systole. Two times higher blood viscosity was observed in large aneurysms compared with small aneurysms. Lower WSS was found in large aneurysms (1.38 ± 1.36 Pa) than in small aneurysms (3.53 ± 1.22 Pa). All the differences in hemodynamic factors between small and large aneurysms were statistically significant. Conclusions: Large aneurysms tended to have complex flow patterns, low shear rate, high blood viscosity, and low WSS. The hemodynamic factors that we analyzed might be useful for decision making before surgical treatment of aneurysms.

Numerical simulation of the 3D flow field in a ring die pellet mill considering viscous heating

2020 ◽  
Vol 11 (03) ◽  
pp. 2050025
Author(s):  
Yong-Mei Wang ◽  
Xiao-Peng Huang ◽  
Jin-Feng Wu ◽  
Wan-Xia Yang
Keyword(s):  
Numerical Simulation ◽  
Shear Rate ◽  
Flow Field ◽  
Velocity Shear ◽  
Viscous Heating ◽  
Powder Materials ◽  
Extrusion Force ◽  
3D Flow ◽  
Forming Process ◽  
Extrusion Forming

Viscous heating has a substantial influence on the extrusion forming process and product quality of powder materials. This study selected the MUZL420 ring die pellet mill as the research object, from which a 3D flow physical model was established. The numerical simulation of 3D nonisothermal flow in the extrusion pelletizing process of granulated alfalfa was performed with POLYFLOW. The distribution laws of pressure, velocity, shear rate, viscosity, viscous heating and temperature in the flow field were revealed to thoroughly investigate the pelletizing process and provide a reference for structural optimization and process control. The results showed that two extrusion zones in the pelleting chamber were symmetrical with respect to the center, and the significant pressure gradient along the rotating direction of the ring die and the roller caused the material to flow back in the opposite direction. There were larger velocity gradients, shear rates and viscous heating levels in the deformation and compaction zone, the negative pressure zone behind the extrusion zone and the die holes. The distribution of viscosity was opposite to that of the shear rate. The temperature increase area caused by viscous heating gradually expanded from the material inlet to the bottom of the extrusion chamber along the [Formula: see text]-axis direction, and the temperature increased accordingly. The extrusion force and the forming temperature in the extrusion forming zone were captured in the numerical simulation. The extrusion forming density was calculated with the regression prediction model established through the simulation experiment of pelletizing with a ring die. Through a comparison with the results of mean alfalfa pellet density from the ring die pellet mill experiment, the relative error was less than 5%, which indicated that the numerical simulation method was reliable.

Relationship between microvascular blood velocity and pressure distribution

1977 ◽  
Vol 232 (4) ◽  
pp. H400-H405 ◽  
Author(s):  
H. N. Mayrovitz ◽  
R. F. Tuma ◽  
M. P. Wiedeman
Keyword(s):  
Blood Pressure ◽  
Shear Rate ◽  
Pressure Distribution ◽  
Blood Velocity ◽  
Volume Flow ◽  
Myotis Lucifugus ◽  
Velocity Shear ◽  
Cell Velocity ◽  
Red Blood Cell Velocity ◽  
Good Agreement

Red blood cell velocity and diameter were measured in vessels of the wing of the unanesthetized bat (Myotis lucifugus) from the supplying artery to the capillaries. These data were used to determine the manner in which velocity, shear rate, volume flow, and blood pressure depend on the vessel's hierarchical position within the vascular network. The results show that velocity decreases in an almost linear fashion as the capillary is approached but that the shear rate increases as one progresses distally from the supplying artery. Blood volume flow was found to decrease as an exponential function of the branching order. Comparison with available date in some animal species, including man, indicates some agreement in capillary velocity, although significantly lower values have been reported in some preparations. Using a method whereby blood pressure distribution could be obtained from anatomical data and center-line blood velocity, the rheologic alterations accompanying consecutive vessel branching were deduced and found to be in good agreement with data available in the literature.

Impact of acute exposure to increased hydrostatic pressure and reduced shear rate on conduit artery endothelial function: a limb-specific response

2009 ◽  
Vol 297 (3) ◽  
pp. H1103-H1108 ◽  
Author(s):  
Jaume Padilla ◽  
Ryan D. Sheldon ◽  
Diana M. Sitar ◽  
Sean C. Newcomer
Keyword(s):  
Hydrostatic Pressure ◽  
Shear Rate ◽  
Endothelial Function ◽  
Pressure Gradient ◽  
Brachial Artery ◽  
Popliteal Artery ◽  
Lower Limbs ◽  
Acute Exposure ◽  
Specific Response ◽  
Conduit Artery

Unlike quadrupeds, humans exhibit a larger hydrostatic pressure in the lower limbs compared with the upper limbs during a major part of the day. It is plausible that repeated episodes of elevated pressure in the legs may negatively impact the endothelium, hence contributing to the greater predisposition of atherosclerosis in the legs. We tested the hypothesis that an acute exposure to increased hydrostatic pressure would induce conduit artery endothelial dysfunction. In protocol 1, to mimic the hemodynamic environment of the leg, we subjected the brachial artery to a hydrostatic pressure gradient (∼15 mmHg) by vertically hanging the arm for 3 h. Brachial artery flow-mediated dilation (FMD) was assessed in both arms before and following the intervention. In protocol 2, we directly evaluated popliteal artery FMD before and after a 3-h upright sitting (pressure gradient ∼48 mmHg) and control (supine position) intervention. Our arm-hanging model effectively resembled the hemodynamic milieu (high pressure and low shear rate) present in the lower limbs during the seated position. Endothelium-dependent vasodilation at the brachial artery was attenuated following arm hanging ( P < 0.05); however, contrary to our hypothesis, upright sitting did not have an impact on popliteal artery endothelial function ( P > 0.05). These data suggest an intriguing vascular-specific response to increased hydrostatic pressure and reduced shear rate. Further efforts are needed to determine if this apparent protection of the leg vasculature against an acute hydrostatic challenge is attributable to posture-induced chronic adaptations.

The Influence of Base Oil and Thixotropy on Magnetorheological Property of MRF

2013 ◽  
Vol 320 ◽  
pp. 19-24
Author(s):  
Jian Jian Yang ◽  
Hua Yan ◽  
Zhi De Hu ◽  
Shi Xiang Xu
Keyword(s):  
Shear Stress ◽  
Shear Rate ◽  
Magnetorheological Fluid ◽  
Mineral Oil ◽  
Dispersed Phase ◽  
Zero Field ◽  
Rotational Viscometer ◽  
Base Oil ◽  
Low Shear

Adopting carbonyl iron powder and silicone/mineral oil as suspend phase and dispersed phase separately,and silica, kaolin as lubricant additives,magnetorheological (MR) fluid was prepared by ball milling. The apparent viscosity of base oil and shear stress were measured on a modified rotational viscometer. The experimental results demonstrated that an appropriate viscosity of base oil contributed to the rheology of MRF. Adding a small amount of thixotropy into MRF had little influence on zero-field viscosity, which facilitated the application of MRF to maintain adequate liquidity. Under low shear rate conditions, the shear stress was improved by adding thixotropy to some extent, especially in the mineral oil-based magnetorheological fluid, in which the role of silica was superior to kaolin.

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