Mathematical Modeling and Simulation of Wind Mill Blade Manufacturing (VARIM) Process

This paper presents the manufacturing of wind turbine rotor blades using VARIM (Vacuum Assisted Resin Injection Moulding). Vacuum assisted resin infusion techniques have become popular in manufacturing of these composites. In this process, resin is drawn into a preform through use of a vacuum, rather than pumped in under pressure. It has become todays technology due to its low cost tooling also it has a wide application in large structures. It also reduces volatile organic compounds (VOCs) emissions. The resin is infused into the preform. The basic concept of infusion is to suck a resin into the reinforcing fibres and fabrics by a vacuum. The vacuum decreases the pressure at one end of the fabric stack allowing atmospheric pressure to force the resin over the fibres. The main process defects are caused by the possible in homogeneities in the fibre mat, or its improper installation. This will lead to the race tracking, which represents the main for all resin molding processes. In race tracking the movement of the fluid at both mold sides, or at one side only, with higher permeability regions, is more than the bulk of the fluid. Race tracking can start to the formation of macro-voids (dry spots) in the molded composite part during manufacturing. To solve it we first prepare a mathematical model (based on fluid flow properties and material properties) and then we use COMSOL multiphysics software in which the Navier-Stokes equation has been discretized by the finite element method as well as the level set equation.