Rheological materials in process industry: ReoMaT Final Report

'Rheological materials in process industry (ReoMaT)', was a three-year research project started 1.2.2003 and funded mainly by Tekes and industry. It was carried out as a joint effort of five research groups from VTT, University of Jyväskylä, Tampere University of Technology and Åbo Akademi University. The participating companies were Metso Paper Oy, Outokumpu Research Oy, M-real Oyj, Stora Enso Oyj, Kemira Chemicals Oy and Premix Oy. The project was devoted to the study of properties and dynamics of rheological and porous materials found in industrial processes. The general goal of the project part was to support the related industrial research by methods development, research networking and technology transfer. The research included three main topical areas: experimental rheology, development of experimental techniques and numerical analysis. In addition to conventional methods, the projected research utilized several novel techniques, both experimental and numerical, that have only recently become available in other disciplines of materials science and flow mechanics. The results of the first project year were reported separately in: M. Kataja (ed.), Rheological materials in process industry. ReoMaT Project Report 2003, VTT Project Report, 15.3.2004. This reports covers the results of ReoMaT consortium for its latter two-year funding period 1.1.2004-30.4.2006. The results of the project are prolific ranging from direct numerical simulation results on elementary dynamics of momentum transfer in particulate suspensions to new semiempirical pressure loss correlations in fibre suspension flows, rheological characterization of polymer-based and fibrous materials, and to new measurement methods for sedimenting suspensions. Results of general interest have been published in international conferences and journals. The main results of the project, readily applicable in industrial research and development are: A new measurement technique based on helical-flow modified rotational rheometer was developed. The measurement allows for characterization of strongly sedimenting suspensions, which has not been possible previously. The measurement will be offered to industry as a research service. The research has enabled to better identify and account for various factors related to the rheometry of polymer melts. The consequent improved accuracy of the rheological characterization of polymeric materials is of great practical importance for example when solving the processability problems in existing processes or when developing new materials. The research has led to several new innovations in experimental techniques for finding the relevant material properties of liquid-particle suspensions. In particular, methods based on ultrasound Doppler velocimetry are now being utilized in industrial research by the participating groups. Further development and possible commercialisation of some of the methods is projected. New improved semiempirical correlation model for estimating losses for fibre suspension flows was developed. The model and the related measurement techniques is adopted by the participating research groups as a new supplement in their research service potential, and is thereby available for the industry. New research method based on using x-ray tomography and numerical lattice-Boltzmann flow simulation has been employed and validated. The techniques is now available for the industry and has already been used in analysing e.g. structure and transport properties of paper-making fabrics. The in-plane mechanical properties of wet web were found to be strongly affected by furnish, chemicals and DCSs (dissolved and colloidal substances). This offers new possibilities for controlling rheology, stiffness and runnability of wet webs. The results have led to applications and applied research projects in the industry. The improved z-directional compression tester proved to be a valuable tool in studying the out-of-plane behaviour of paper under short compressive pulses. The instrument and the generated knowledge is applicable, and has been applied, in industrial cases for solving problems related to paper deformations and processability under z directional stresses. Many of these results now make an important contribution to the present capabilities of the participating groups and have already been successfully utilized in industrial research carried out parallel to the present project. Some of the results are expected to make similar contribution and benefit research and applications in the near future. Based on the results and their estimated impact, we conclude that the general goal of the ReoMaT project, namely "to support the related industrial research by methods development, research networking and technology transfer", has been met.