The Experts below are selected from a list of 25047 Experts worldwide ranked by ideXlab platform
M F Cerqueira - One of the best experts on this subject based on the ideXlab platform.
-
on line monitoring of the residence time distribution along a kneading block of a twin Screw Extruder
Polymer Testing, 2004Co-Authors: O S Carneiro, José A. Covas, J A Ferreira, M F CerqueiraAbstract:An on-line Residence Time Distribution (RTD) measuring set-up that enables the characterisation of twin Screw Extruders at short axial increments is presented. It uses the light emission of a fluorescent tracer (perylene) to generate concentration versus time curves, which are then used to determine the usual RTD parameters, delay time, mean residence time and variance. The system is initially mounted on a rectangular die coupled to a single Screw Extruder, on-line and off-line measurements being directly contrasted. Then, the optical probe is positioned at several points along the axis of a modular co-rotating twin Screw Extruder, on-line and off-line data being again compared. Having gained confidence in the measuring technique, an experimental unit utilizing a transparent barrel is used to characterize the evolution of RTD along a kneading block of a twin Screw Extruder.
Auder Ainser - One of the best experts on this subject based on the ideXlab platform.
-
Residence time distribution in a corotating twin-Screw Extruder
Chemical Engineering Science, 2000Co-Authors: J. P. Puaux, G Bozga, Auder AinserAbstract:A modeling study for the polymer flow and mixing in a corotating twin-Screw Extruder is presented. The residence time distribution (RTD) in a fully intermeshing corotating twin-Screw Extruder was measured, using iron powder as tracer, and an LDPE as flow material. Pulse-type input signal experiments were performed in different working conditions. To fit the experimental data obtained on two different Screw profiles, the one- and two-parameter flow models described in literature were tested. The best fitting of the experimental RTD curves was obtained by using a delayed tanks in series model with internal recirculation, or a delayed axial dispersion model. This is consistent with the physical characteristics of the flow in a fully intermeshing corotating twin-Screw Extruder.
Li Zhou - One of the best experts on this subject based on the ideXlab platform.
-
Research on Screw Extruder Die Pressure and Speed Relationship
Applied Mechanics and Materials, 2014Co-Authors: Lei Wang, Li ZhouAbstract:This paper studies the variation of speed and pressure to achieve accurate control of the die pressure for Screw Extruder based on high viscosity PVC production. SolidWorks was used to establish the model of Screw Extruder, and then imported SolidWorks models into the ANSYS to analysis the relationship of speed and die pressure at the speed of 2rpm to 7rpm.It laid the foundation of establishing Extruder pressure control system.
-
Modeling and Simulation of Single Screw Extruder Control System
Applied Mechanics and Materials, 2014Co-Authors: Lei Wang, Li ZhouAbstract:This article is mainly talking about a pressure control system designed for single Screw Extruder. In order to achieve constant pressure control of the head, we used fuzzy PID self-tuning techniques and Smith Predictor to control extrusion system and then we used Matlab Simulink toolbox to simulated control result. Simulation results show that the method achieve good control effect and meet the design requirements.
-
The Effect of Screw Speed on Extrusion Quality of the Single-Screw Extruder
Advanced Materials Research, 2014Co-Authors: Yuan Lou Gao, Xin Wang, Li ZhouAbstract:This paper adopts the method of multi-phase flow to simulate the extrusion process of single-Screw Extruder based on different Screw speed by using the finite element analysis software, and get the conclusion that the Screw speed has a significant effect on the extrusion quality and outlet pressure of the single-Screw Extruder. With the increase of the Screw speed, the extrusion quality of the single-Screw Extruder gets worse and the outlet pressure of the single-Screw Extruder increases.
-
The Impact of Different Screw Edge Width on Extrusion Quality of the Single-Screw Extruder
Advanced Materials Research, 2014Co-Authors: Xin Wang, Li ZhouAbstract:The Screw edge width is usually selected based on experience when designing Screw Extruders, and it is difficult to get the best extrusion quality. The extrusion process of Screw Extruder is a process of multi-phase flow, which includes gas, liquid and solid. Making it simplified to single-phase flow process can cause relatively large error. This paper adopts the method of multi-phase flow to simulate the extrusion process of single-Screw Extruder based on different Screw edge width by using the finite element analysis software, and get the conclusion that increasing the Screw edge width appropriately under the condition that the production efficiency is acceptable is helpful to improve the extrusion quality of single-Screw Extruders.
James L. White - One of the best experts on this subject based on the ideXlab platform.
-
Continuous polymerization of ω‐lauryl lactam in an intermeshing corotating twin‐Screw Extruder
Journal of Applied Polymer Science, 2005Co-Authors: In Kim, James L. WhiteAbstract:This article describes the synthesis of poly(ω-lauryl lactam) by a reactive extrusion process. Anionic ring-opening polymerization was performed in an intermeshing corotating twin-Screw Extruder. We investigated the evolution of conversion of ω-lauryl lactam as a function of reaction time, Screw speeds, different feed rates, and different Screw configurations along the Screw axis in a twin-Screw Extruder. For comparison with continuous polymerization in a twin-Screw Extruder, we studied polymerization in an internal mixer, which was considered a batch reactor. We found the final conversion of ω-lauryl lactam made in a twin-Screw Extruder was higher than in an internal mixer. Higher molecular weights are found at lower Screw speeds and feed rates. Melt viscosities and mechanical properties of the polymers were measured. Residence time, molecular weights, and shear mixing have the main effect on the mechanical properties of products. The twin-Screw Extruder performance was interpreted in terms of commercial software. It was found that twin-Screw Extruder reaction rate was higher than those in the batch reactor and increased locally with Screw speed and feed rate. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 97: 1605–1620, 2005
-
Experimental study of maleation of polypropylene in various twin-Screw Extruder systems
Journal of Applied Polymer Science, 2003Co-Authors: Dohoon Chang, James L. WhiteAbstract:A range of continuous mixing machines were used as continuous reactors for grafting maleic anhydride onto polypropylene. The machines used were (1) a nonintermeshing modular counterrotating twin-Screw Extruder, (2) an intermeshing modular corotating twin-Screw Extruder, (3) intermeshing modular counterrotating twin-Screw Extruder, and (4) a Kobelco Nex-T continuous mixer. The grafting reaction of maleic anhydride onto polypropylene and degradation of polypropylene during the grafting reaction were investigated as means for comparing these different machines for reactive extrusion. The influence of processing variables such as Screw speed and processing temperature on polymer characteristics also was investigated. Generally, in a comparison of the different machines, the intermeshing counterrotating twin-Screw Extruder had the lowest levels of grafted maleic anhydride, whereas the Kobelco Nex-T continuous mixer under the conditions used had the highest levels of grafted maleic anhydride. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 1755–1764, 2003
-
Experimental study of maleation of polypropylene in various twin‐Screw Extruder systems
Journal of Applied Polymer Science, 2003Co-Authors: Dohoon Chang, James L. WhiteAbstract:A range of continuous mixing machines were used as continuous reactors for grafting maleic anhydride onto polypropylene. The machines used were (1) a nonintermeshing modular counterrotating twin-Screw Extruder, (2) an intermeshing modular corotating twin-Screw Extruder, (3) intermeshing modular counterrotating twin-Screw Extruder, and (4) a Kobelco Nex-T continuous mixer. The grafting reaction of maleic anhydride onto polypropylene and degradation of polypropylene during the grafting reaction were investigated as means for comparing these different machines for reactive extrusion. The influence of processing variables such as Screw speed and processing temperature on polymer characteristics also was investigated. Generally, in a comparison of the different machines, the intermeshing counterrotating twin-Screw Extruder had the lowest levels of grafted maleic anhydride, whereas the Kobelco Nex-T continuous mixer under the conditions used had the highest levels of grafted maleic anhydride. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 1755–1764, 2003
-
maleic anhydride modification of polyolefin in an internal mixer and a twin Screw Extruder experiment and kinetic model
Polymer Engineering and Science, 2001Co-Authors: James L. WhiteAbstract:There has been little effort. to quantitatively understand graft copolymerization in batch and continuous mixers. Little information exists on the evolution of grafting reactions with respect to residence time in an internal mixer or along the Screw axis in a twin-Screw Extruder. In this study, maleic anhydride was grafted onto polypropylene in both an internal mixer and a twin Screw Extruder. The influence of residence time on degree of grafting in an internal mixer and a twin Screw Extruder was studied through measuring reaction yields with respect to reaction time in the internal mixer as well as along the Screw axis in the Extruder. The dependence of the degree of grafting with monomer and peroxide concentration was determined. A free radical kinetic model of the process was developed and compared to experiment. Kinetic parameters were determined.
-
Maleic anhydride modification of polyolefin in an internal mixer and a twin‐Screw Extruder: Experiment and kinetic model
Polymer Engineering and Science, 2001Co-Authors: James L. WhiteAbstract:There has been little effort. to quantitatively understand graft copolymerization in batch and continuous mixers. Little information exists on the evolution of grafting reactions with respect to residence time in an internal mixer or along the Screw axis in a twin-Screw Extruder. In this study, maleic anhydride was grafted onto polypropylene in both an internal mixer and a twin Screw Extruder. The influence of residence time on degree of grafting in an internal mixer and a twin Screw Extruder was studied through measuring reaction yields with respect to reaction time in the internal mixer as well as along the Screw axis in the Extruder. The dependence of the degree of grafting with monomer and peroxide concentration was determined. A free radical kinetic model of the process was developed and compared to experiment. Kinetic parameters were determined.
Mukund V. Karwe - One of the best experts on this subject based on the ideXlab platform.
-
Measuring of Velocity Distributions in the Nip Region of a Co-Rotating Twin-Screw Extruder
Food and Bioproducts Processing, 1999Co-Authors: Serafim Bakalis, Mukund V. KarweAbstract:Self wiping co-rotating twin-Screw Extruders are used widely in food, polymer and pharmaceutical industries. Some of their advantages over single-Screw Extruders are their flexibility, efficient mixing and pumping capabilities. These attributes of twin-Screw Extruders are ascribed to the intermeshing region between the two Screws (nip region). Measurement of velocity profiles in the nip region of a twin-Screw Extruder offers a method to elucidate the transport phenomena. Velocity field in the nip region of a co-rotating twin Screw Extruder was measured using laser Doppler anemometry for a Newtonian model fluid. The effect of Screw speed was investigated. Two velocity components, namely transverse and axial were measured. Whilst the axial velocity component varied significantly with respect to the angular rotation of the Screw shaft, the transverse velocity component was almost uniform. Contour plots revealed that the velocity distributions were asymmetrical with respect to the middle of the channel.
-
Velocity field in a twin‐Screw Extruder
International Journal of Food Science and Technology, 1997Co-Authors: Serafim Bakalis, Mukund V. KarweAbstract:Velocity measurements inside the Screw channels of a co-rotating, self-wiping, twin-Screw Extruder were carried out. A laser Doppler anemometer (LDA) system was used to measure tangential and axial velocity components in the translational region of one of the Screws of a twin-Screw Extruder. The velocity measurements were carried out using heavy corn syrup at different Screw speeds and for two forwards conveying elements differing in their pitch. It was found that velocity profiles in the translational region were substantially affected by the pitch of the Screw element, however, Screw speed (30-90 r.p.m.) did not have a significant effect on the shape of the velocity profiles. The range of velocity values in a 14 mm pitch Screw element was wider than that in a 28 mm pitch Screw element. Experimentally measured velocity profiles were compared with predictions of a one-dimensional model, which showed that the model underpredicted the velocity values, for the 14 mm pitch element.
-
Velocity field in a twin-Screw Extruder
International Journal of Food Science and Technology, 1997Co-Authors: Serafim Bakalis, Mukund V. KarweAbstract:Velocity measurements inside the Screw channels of a co-rotating, self-wiping, twin-Screw Extruder were carried out. A laser Doppler anemometer (LDA) system was used to measure tangential and axial velocity components in the translational region of one of the Screws of a twin-Screw Extruder. The velocity measurements were carried out using heavy corn syrup at different Screw speeds and for two forwards conveying elements differing in their pitch. It was found that velocity profiles in the translational region were substantially affected by the pitch of the Screw element, however, Screw speed (30-90 r.p.m.) did not have a significant effect on the shape of the velocity profiles. The range of velocity values in a 14 mm pitch Screw element was wider than that in a 28 mm pitch Screw element. Experimentally measured velocity profiles were compared with predictions of a one-dimensional model, which showed that the model underpredicted the velocity values, for the 14 mm pitch element.
-
Transport in a twin‐Screw Extruder for the processing of polymers
Polymer Engineering and Science, 1996Co-Authors: Raman V. Chiruvella, Mukund V. Karwe, Yogesh Jaluria, V. SernasAbstract:The fluid flow and heat transfer in polymer extrusion in a twin-Screw Extruder was studied numerically by using the finite volume method. In the mathematical model, the coordinate system is fixed to the Screw so that it is held stationary and the barrel is moved to simplify the complicated geometry. The Screw channel of a twin-Screw Extruder is approximated as two regions : translation and intermeshing. The flow in the translation region is similar to that in a shallow single Screw Extruder and is treated by the numerical methods given in the literature. In the nip or intermeshing region, strong mixing effects are expected, along with the diffusion of energy and momentum. The full governing equations are solved in this region to determine the velocity components in all the three coordinate directions. The energy equation is coupled with the equations of motion through viscosity, since the viscosity of the polymeric, non-Newtonian, fluids considered here is dependent upon the shear rate and temperature. There is no clear physical demarcation between the nip region and the translation region. Therefore, a domain matching was employed at an arbitrary location that was varied numerically to ensure that the results were independent of this location. The variation of pressure and bulk temperature along the helical channel of the twin-Screw Extruder is obtained, along with the shear rate. An experimental investigation of the velocity profiles in the translation region of a self-wiping twin-Screw Extruder, which is often used in practical applications, was carried out using a Laser Doppler Anemometer. The numerically predicted velocity profiles are compared with those from the experiments, yielding fairly close agreement.
