Ricardo J. Santos

Operational and Design Study of RIM Machines

Abstract Particle Image Velocimetry (PIV) and Laser Doppler Anemometry (LDA) data is presented and used to characterize the dynamic behaviour of the flow field in a RIM machine, and the main flow patterns and mixing mechanisms are examined and established. A two-dimensional CFD model is used for the simulation of mass transfer and chemical reaction in the mixing chamber of a RIM machine. Some design and operational parameters are considered and its influence on the mixing behaviour of a RIM machine is analysed.

Validation of a 2D CFD Model for Hydrodynamics' Studies in CIJ Mixers

A 2D model of a confined impinging jets mixer having the same geometry of the mixing chamber of a Reaction Injection Moulding, RIM, machine is introduced for the flow field simulation in a Computational Fluid Dynamics, CFD, code. From the CFD simulations the flow field structures and dynamics are clearly established. In addition, the numerical parameters affecting the 2D model simulations are studied, setting for each parameter a validity range. The 2D model is validated and used in the study of some operational parameters: the Reynolds number, the Froude number and the momentum ratio between the opposed jets. The validation of the CFD simulations is also made by comparison with experimental results. The limitations of the 2D model, for simulating the actual 3D flow field, are assessed; from the 2D/3D comparison, it is clearly shown that the introduced model can predict the main flow field features.

Anaerobic biodegradability of category 2 animal by-products : methane potential and inoculum source

Category 2 animal by-products that need to be sterilized with steam pressure according Regulation (EC) 1774/2002 are studied. In this work, 2 sets of experiments were performed in mesophilic conditions: (i) biomethane potential determination testing 0.5%, 2.0% and 5.0% total solids (TS), using sludge from the anaerobic digester of a wastewater treatment plant as inoculum; (ii) biodegradability tests at a constant TS concentration of 2.0% and different inoculum sources (digested sludge from a wastewater treatment plant; granular sludge from an upflow anaerobic sludge blanket reactor; leachate from a municipal solid waste landfill; and sludge from the slaughterhouse wastewater treatment anaerobic lagoon) to select the more adapted inoculum to the substrate in study. The higher specific methane production was of 317 mL CH(4)g(-1) VS(substrate) for 2.0% TS. The digested sludge from the wastewater treatment plant led to the lowest lag-phase period and higher methane potential rate.

Quantification of mixing in RIM using a non-diffusive two-phase flow numerical model

Mixing in RIM is made mainly by advective mechanisms, rather than diffusion. In this paper, the advective mechanisms that enable reducing the mixing scales down to the values required for the complete chemical reaction of the two monomers inside the RIM mixing chamber are identified and studied. From Computational Fluid Dynamics (CFD) simulations of non-diffusive two-phase flow using the Volume-of-Fluid (VOF) model, a linear scale of segregation is determined as a measure of the degree of mixing and the effect of the Reynolds number is studied.

Concurrent Development of RIM Parts

The aim of this paper is to present a research project which intends to identify and organize the knowledge required in the development process of Reaction Injection Molding (RIM) parts in the conceptual design phase, particularly as to material selection, mold design and the process planning for mold making and molding operations. The overall objective of the research is to verify if an Expert System, a computer program that uses knowledge and inference procedures to model the RIM development process, provides the required insight into metrics such as development lead time and manufacturing costs to deal with the decision makings required early on in order to reduce the subsequent redesigns and reworks. Based on the characterization of the industrial practice of RIM, it is our belief that the concurrent concept development is the appropriate approach to achieve this goal. This paper will focus on the structurization of the downstream processes and procedures of developing product design concepts for RIM parts; and on the dimensions of knowledge required in the concurrent concept development of RIM parts, aspects which are the basis of the knowledge base and production rules of an Expert System currently being developed.