@article{8fd562980b8e4368a4c59e8a453418af,
title = "Shear rate coat-hanger die using casson viscosity model",
abstract = "Coat-hanger die design aims for optimization of the die geometry of the body and the flow distribution manifold, such that through the exit at the die lip homogeneous distribution of the polymer melt is achieved. This paper proposes a novel methodology for deriving the design equations of the coat-hanger die geometry for some specific extrusion materials and provides fluid–solid interaction simulations for validations. The basis for the calculations is the Casson rheological model, analytic velocity profiles for the pseudoplastic flow through circular pipe and slit, and the constant shear rate coat-hanger die design methodology developed by Winter and Fritz. The geometry obtained was then evaluated using the fluid-structure interaction numerical simulation approach. The sensitivity of the outlet velocity uniformity and die body deformation due to the material and mass flow rate change were investigated using the finite element software, Ansys. It was found that the homogeneity of the outlet velocity is very sensitive to the extrusion materials. The structural analysis of the solid die body also resulted in higher deformations when using some other extrusion materials different from the initial design. Mass flow rate increase only resulted in large zones of stagnation, which occurred around the melt as it passes from the manifold to the slit region. Therefore, it is recommended to define the required range of mass flow rate to prevent the formation of stagnation zones.",
keywords = "Casson model, Coat-hanger dies, Polymer extrusion, Power-law, Uniform wall shear rate",
author = "Dastan Igali and Asma Perveen and Dichuan Zhang and Dongming Wei",
note = "Funding Information: Acknowledgments: This research was funded under the target program No. AP05134166 “Development and Prototyping of Extrusion Dies for Advanced Plastic Sheets and Thin Film Production” from the Ministry of Education and Science of the Republic of Kazakhstan. The authors would like to acknowledge the support received from the Ministry of Education and Science of the Republic of Kazakhstan and School of Sciences and Humanities, Nazarbayev University. Funding Information: coat-hanger die depending on the product size, material being extruded, and operating mass flow rate required. The FSI study was conducted to assess the homogeneity of the outlet velocity and raterequirdeflection ed. Theof the solidFSI studydie body. Itwas conductedwas concludeto d assessthat the geometthe homogeneityry obtained caof then onloutlety be used velocityfor and deflection of the solid die body. It was concluded that the geometry obtained can only be used for the extIrnu asdiodnitioonf ,i dneitsipaltiem thaete fraciattlh(awt tihthe kho=mog0e.n02eti7y1 oPfath·sea onudltetn ve=ol cit0y.4 w12as7 )nofots rigwnhifiiccahntiltyw aaffescdteedsigned. In addition, despite the fact that the homogeneity of the outlet velocity was not significantly affected by the increasing mass flow rate, the specific range of the allowed mass flow rate should be calculated the solid die body is sensitive to the material change rather than the flow rate increase. to prevent the stagnation. The FSI study also determined that the deformation value of the solid die Overall, the methodology proposed for the mathematical modeling of the coat-hanger die is the body isaccepsensitivetable aptoprtheoach materialfor the inchangeitial derathersign. Howevthanether, fuflowrtherratemanincrualease.adjustments are required to Overall, the methodology proposed for the mathematical modeling of the coat-hanger die is the acceptathbele maanpipforoldaa cdhjufsotrmtehnet iwniitlila bled teimsige-nc.onHsouwmeinvge,r e,w ffuhorrilmthaetremriala #n3u tahlea odpjuesrtamtineng tfsloawartee r roefq tuheired to improve the flow uniformity at the manifold edge for material #1. For the extrusion of material #2, the manifold adjustment will be time-consuming, while for material #3 the operating flow rate of the machineframework of the paper; D.W. provideshould be reduced. d the key ideas for solving Equation (42), leading to the design Equations (47) and (53); D.I. developed the design equations and carried out numerical simulations; A.P. and D.Z. Author Contributions: D.W., A.P., and D.Z. conceived the idea of this research; D.I. and A.P. developed the framework of the paper; D.W. provided the key ideas for solving Equation (42), leading to the design Equations (47) and (53); D.I. developed the design equations and carried out numerical simulations; A.P. and D.Z. performed the detailed analysis of the structural part of the FSI study; D.I. prepared the manuscript under the supervision of Funding: This research and APC was funded by Ministry of Education and Science of the Republic of A.P., D.W., and D.Z. All authors have read and agreed to the published version of the manuscript. Kazakhstan under grant number. AP05134166. Funding: This research and APC was funded by Ministry of Education and Science of the Republic of Kazakhstan under grant number. AP05134166.",
year = "2020",
month = dec,
doi = "10.3390/pr8121524",
language = "English",
volume = "8",
pages = "1--17",
journal = "Processes",
issn = "2227-9717",
publisher = "MDPI AG",
number = "12",
}