Numerical simulation of mold filling in foam reaction injection molding

Seo, Dongjin; Youn, Jae Ryoun; Tucker, Charles L.

doi:10.1002/fld.582

Cited by 33 publications

(24 citation statements)

References 34 publications

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“…Within these categories, it is to be distinguished whether the simulations are used to illustrate the manufacturing process of a product made of a compact or foamed PUR material. For example, [5][6][7][8][9][10][11] shows approaches for the numerical simulation of the RIM manufacturing process for polyurethane foams. In addition, some authors such as Riviere et al [12] take up special methods of plastics processing such as the rotational moulding process for reactive moulding resins.…”

Section: Introductionmentioning

confidence: 99%

Kinetic Prediction of Fast Curing Polyurethane Resins by Model-Free Isoconversional Methods

Stanko

Stommel

2018

Polymers

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Abstract:In this work, the characterisation of reaction kinetics of a methylene diphenyl diisocyanate (MDI)-based fast curing polyurethane resin (PUR) and the mathematical description of its curing process are presented. For the modelling of the reaction process isoconversional methods, which are also called model-free approaches, are used instead of model-based approaches. One of the main challenges is the characterisation of a reactive system with a short pot life, which already starts to crosslink below room temperature. The main focus is the evaluation of the applicability of isoconversional methods for predicting the reaction kinetics of fast curing polyurethane resins. In order to realise this, a repeatable methodology for the determination of time-and temperature-dependent reaction curves using differential scanning calorimetry (DSC) is defined. The cure models defined by this method serve as the basis for process simulations of PUR processing technologies such as resin transfer moulding (RTM) or reactive injection moulding (RIM) and reactive extrusion (REX). The characterisation of the reaction kinetics using DSC measurements is carried out under isothermal and non-isothermal conditions. Within this work isoconversional methods have been applied successfully to experimentally determined DSC data sets. It is shown that the reaction kinetics of fast curing polyurethane resins can be predicted using this methods. Furthermore, it is demonstrated that the time-dependent change of conversion of the considered polyurethane under isothermal curing conditions can also be predicted using isoconversional methods based on non-isothermal DSC measurements. This results in a significant reduction in the experimental effort required to characterise and model the curing process of polyurethanes.

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Section: Introductionmentioning

confidence: 99%

Kinetic Prediction of Fast Curing Polyurethane Resins by Model-Free Isoconversional Methods

Stanko

Stommel

2018

Polymers

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“…The foam density was considered to be a function of temperature which varied due to the exothermic character of the reactions. Seo et al [5] worked on the numerical simulation of a self-expanding fluid and showed the differences to a flow field of a Newtonian fluid of constant viscosity. They described in detail their numerical method which is based on a finite volume method using a volume-of-fluid approach.…”

Section: Introductionmentioning

confidence: 99%

Numerical Simulation of Mold Filling Processes with Polyurethane Foams

2009

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Design and dimensioning of manufacturing processes based on filling molds with polyurethane foams still require the use of highly empirical approaches. This includes numerous experimental runs with expensive prototypes. Therefore, a method has to be found to analyze the molding process at an early stage of product development to shorten time-to-market cycles and cut costs by using fewer prototypes. With the computational power available today and growing computational power in the future, the tool of choice is the numerical simulation of mold filling processes with computational fluid dynamics software.

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“…Computational models have been developed to describe the foaming process of chemically blown polyurethane foams (e.g., ) and physically blown polyurethane and thermoplastics (e.g., ). However, despite recent progress, polymeric foams are still not well understood at a fundamental level .…”

Section: Introductionmentioning

confidence: 99%

A level set method to study foam processing: a validation study

Rao

Mondy²,

Noble³

et al. 2011

Numerical Methods in Fluids

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SUMMARY We have developed a production‐level foam processing computational model suitable for predicting the self‐expansion of foam in complex geometries. The model is based on a finite element representation of the equations of motion, with the movement of the free surface represented using the level set method. An empirically based time‐dependent and temperature‐dependent density model is used to encapsulate the complex physics of foam nucleation and growth in a numerically tractable manner. The evolving density drives the dynamics of foam self‐expansion. This continuum‐level model uses a homogenized description of foam, which does not include the gas explicitly, but allows varying local fields, such as temperature and gas volume fraction, and material models. In addition, material models vary with the location of the level set interface, taking properties of the displaced air phase in the negative level set region and the foam in the positive region. The level set zero describes the location of the interface, where surface forces are applied using the continuous surface force treatment. The variation from foam to gas properties is handled with a diffuse interface method using a smooth Heaviside function and equation averaging. Material model development was guided and populated by careful experiments. Results from the model are compared with temperature‐instrumented flow visualization experiments giving the location of the foam front as a function of time for a physically blown, epoxy foam. Good qualitative agreement is seen between simulations and experiments, although some of the subtleties of the filling process are lost to the model. Published 2011. This article is a US Government work and is in the public domain in the USA.

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Numerical simulation of mold filling in foam reaction injection molding

Cited by 33 publications

References 34 publications

Kinetic Prediction of Fast Curing Polyurethane Resins by Model-Free Isoconversional Methods

Kinetic Prediction of Fast Curing Polyurethane Resins by Model-Free Isoconversional Methods

Numerical Simulation of Mold Filling Processes with Polyurethane Foams

A level set method to study foam processing: a validation study

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