Analysis of the extrusion pressure of a cylindrical extruder for extruding highly viscous fluids

Zhibin Sun,Baojun Shen,Yu He,Jiecai Long,Xiaobin Zhan,Yujin Li,Xiwen Li 한국화학공학회 2022 Korean Journal of Chemical Engineering Vol.39 No.10

Extrusion pressure is crucial for the security and performance of a cylindrical extruder during the extrusion process. In this study, a validated CFD model was adopted to evaluate the relationship between the extrusion velocity, fluid viscosity, and the extrusion pressure of a cylindrical extruder while extruding highly viscous fluids. The simulated and experimental results of the extrusion pressure and velocity profiles show good agreement. This study reveals that extrusion pressure evolution can be divided into two stages during the extrusion process. At stage I, the distance between the ram and the bottom of the vessel (liquid height) is greater than the critical height and the extrusion pressure remains almost constant. At stage II, the distance is less than the critical height and the extrusion pressure increases exponentially. The results indicate that an increase in extrusion velocity and fluid viscosity leads to a linear increase in the extrusion pressure at stage I. Furthermore, by introducing a pressure number, Np, and a pressurerelated Reynolds number, Rep, a novel correlation of the extrusion pressure with the extrusion velocity, viscosity of highly viscous fluids and liquid height has been developed.

Mixed organic acids improve nutrients digestibility, volatile fatty acids composition and intestinal microbiota in growing-finishing pigs fed high-fiber diet

Miao Li,Shenfei Long,Qianqian Wang,Lianhua Zhang,Jiangxu Hu,Jie Yang,Zhibin Cheng,Xiang Shu Piao 아세아·태평양축산학회 2019 Animal Bioscience Vol.32 No.6

Objective: The objective of this study was to investigate effects of mixed organic acids (MOA) on nutrient digestibility, volatile fatty acids composition and intestinal microbiota in growing-finishing pigs fed high wheat bran diet. Methods: Six crossbred barrows (Duroc×Landrace×Yorkshire), with an average body weight 78.8±4.21 kg, fitted with T-cannulas at the distal ileum, were allotted to a double 3×3 Latin square design with 3 periods and 3 diets. Each period consisted of a 5-d adjustment period followed by a 2-d total collection of feces and then a 2-d collection of ileal digesta. The dietary treatments included a corn-soybean-wheat bran basal diet (CTR), mixed organic acid 1 diet (MOA1; CTR+3,000 mg/kg OA1), mixed organic acid 2 diet (MOA2; CTR+2,000 mg/kg OA2). Results: Pigs fed MOA (MOA1 or MOA2) showed improved (p<0.05) apparent total tract digestibility (ATTD) of gross energy, dry matter and organic matter, and pigs fed MOA2 had increased (p<0.05) ATTD of neutral detergent fiber compared to CTR. Dietary MOA supplementation decreased (p<0.05) pH value, and improved (p<0.01) concentrations of lactic acid and total volatile fatty acids (TVFA) in ileum compared to CTR. Pigs fed MOA showed higher (p<0.05) concentration of acetic acid, and lower (p<0.05) content of formic acid in feces compared to CTR. Pigs fed MOA1 had increased (p<0.05) concentration of TVFA and butyric acid in feces. Pigs fed MOA1 showed higher concentration of Lactobacillus and lower concentration of Escherichia in feces compared to CTR. Conclusion: Dietary supplementation of MOA 1 or 2 could improve nutrients digestibility, TVFA concentration and intestinal flora in growing-finishing pigs fed high fiber diet.

Core–shell structure g-MnO2-PANI carbon fiber paper-based flexible electrode material for high-performance supercapacitors

Xuxia Ling,Guoliang Zhang,Zhu Long,Xuefeng Lu,Zhibin He,Jie Li,Yuheng Wang,Dan Zhang 한국공업화학회 2021 Journal of Industrial and Engineering Chemistry Vol.99 No.-

Good conductivity is the key to ensuring high electrochemical performance, and the uniformity of theactive material directly affects the electrical conductivity. This paper proposes a novel modified stepwisein situ polymerization method to prepare composite materials, and then uses the K/S value method tocharacterize the uniformity of polyaniline distribution. Specifically, the study presents a papermakingwet-lay technique to prepare a carbonfiber paper substrate (CP) that is light-weight,flexible, andfoldable while also having low internal resistance and high porosity. The g-MnO2 is wrapped with PANI toform a core–shell structure, and a modified stepwise in situ polymerization method is adopted to depositthe core–shell structure uniformly on the CP substrate by physical adsorption. This process yields aflexible electrode material for supercapacitors, called g-MnO2-PANI-CP electrode. Results show thatthe g-MnO2-PANI-CP electrode has a high specific capacitance of 642.5 F g 1 at a current density of 1A g 1, and also has a high energy density of 114.2 Wh kg 1 at a power density of 798.6 W kg 1. In addition,the electrode retains 81.3% of the initial capacitance after 5000 cycles, demonstrating high cyclingperformance.

Numerical investigation of the mixing process in a Twin Cam Mixer: Influence of triangular cam height-base ratio and eccentricity

Yu He,Xiwen Li,Jiecai Long,Baojun Shen,Zhibin Sun,Yili Yang,Xiaobin Zhan 한국화학공학회 2021 Korean Journal of Chemical Engineering Vol.38 No.3

The twin cam mixer (TCM), as a general-purpose mixer, shares many attributes in common with 3D industrial mixers, like the internal mixer. We investigated the mixing process in a 2D TCM with two identical isosceles triangular cams rotating at 0.5 rpm. A 2D numerical model coupled with the species transport model was employed to study the influence of cam height-base ratio and eccentricity qualitatively and quantitatively, and both were found to have a significant effect on the mixing behavior of the mixer. Furthermore, a dimensionless parameter, named the modified pressurization coefficient, is put forward to quantify the geometry of the mixer. The logarithmic relationship between the modified pressurization coefficient and the mixing quality was discovered and expected to provide new ideas for establishing the relationship between the geometric parameters of a mixer and its mixing performance.

Research of Control Strategy on DC Side of Hybrid Energy Storage in Micro Grid

Tieyan Zhangi,Di Bai,Zheng Yang,Zhibin Long,Baiyu Gao 보안공학연구지원센터 2016 International Journal of Grid and Distributed Comp Vol.9 No.9

The uncertainty and fluctuation brought by distributed type of intermittent power generation in micro grid bring huge challenges to power quality of micro grid in isolating operation and power control in parallel operation. Nevertheless energy storage is able to well solve this problem. Hybrid energy storage integrates the respective advantages of storage battery and supercapacitor to have improved the performance of energy storage system. Service life of storage battery is tightly related to its charging/discharging times and problem of frequent charging/discharging storage battery still exists in current hybrid energy storage technology. In this paper, it respectively puts forward control strategies for storage battery and supercapacitor. As to control strategy for storage battery, it uses double-layered control strategy, namely, single loop control and power hysteresis control, to feedback low-frequency fluctuation of power and reduce charging/discharging frequency of storage battery. As to control strategy for supercapacitor, it uses inner loop current with power to control voltage in outer loop so as to feedback high-frequency fluctuation of power and it is able to well maintain stability of DC bus voltage. Simulation results suggest the validity of aforesaid control strategies.

Computational fluid dynamic analysis of mass transfer and hydrodynamics in a planetary centrifugal bioreactor

Baojun Shen,Xiaobin Zhan,Yu He,Zhibin Sun,Jiecai Long,Yili Yang,Xiwen Li 한국화학공학회 2021 Korean Journal of Chemical Engineering Vol.38 No.7

Planetary centrifugal bioreactors are promising candidates for cell culture platforms since there is no pollution caused by stirring blades. In this work, the fluid structure in a planetary centrifugal bioreactor was investigated using the computational fluid dynamics (CFD) method. The effects of operating conditions on the oxygen transfer rate (OTR), mixing efficiency and shear environment of the bioreactor were studied with the revolution speed (N) ranging from 60 to 160 rpm and the rotation-to-revolution speed ratio (i) from 2 to 1. The results show that the volumetric mass transfer coefficient (kLa), turbulence intensity, volumetric power consumption, and shear stress increase along with the increase of the revolution and rotation speeds. Furthermore, the rotation in the opposite direction to the revolution is beneficial to the performance of the bioreactor. The planetary centrifugal bioreactor has a higher kLa of 50- 200/h and a lower average shear stress of 0.01-0.05 Pa in comparison with conventional stirred tank bioreactors, which makes it suitable for biological culture of oxygen-consuming cells and shear-sensitive cells.