Numerical Simulation on Refrigerator Mold Filling Processes with Rigid Polyurethane Foams
|School||University of Science and Technology of China|
|Course||Mechanical and Electronic Engineering|
|Keywords||A rigid polyurethane foam Foam Numerical simulation of VOF Deformation of the Refrigerator Door Finite Element|
The rigid polyurethane foam due to its excellent thermal insulation, the unique resistance to water penetration and chemical stability, coupled with light weight, convenient shape and become the essential materials of the refrigerator insulation layer. For Refrigerator Door scrap rework problems easy to produce rigid polyurethane foam filling after the release of the deformation, the paper to be adopted based on the numerical simulation solution ideas. Chemical reaction kinetics from polyurethane foam gel foaming process, the understanding of the mechanism of polyurethane generated by numerical simulation to extract key parameters that affect the foam properties. The use of the rheology theory polyurethane foam flow filling. Select the FLUENT software, the SIMPLE algorithms and VOF model and establish the mathematical model of the polyurethane material in the foaming process, the establishment of scalar equations calculate the extent of the chemical reaction of the polyurethane foam during the foaming process, taking into account the exothermic chemical reaction physical blowing agent evaporation suction thermal effects, and the definition of material parameters and control Fangcheng Yuan parameters defined by secondary development program. Simplify the process of expansion of the bubble flow process, the degree of chemical reaction with the flow of non-steady laminar flow separately. The mixture of two-dimensional rectangular region into the 2.16kg polyurethane foam foaming process temperature, density, temperature field distribution law the polyurethane mixture inflated 40s. Its density reduced to approximately 30kg/m3, the mixture within the maximum temperature rose to 137.8014 ° C, the temperature rises when the post-crosslinking reaction 100s to 153.5989 ° C highly exothermic chemical reaction. Measure the deformation of the door and the physical properties of the polyurethane samples parameters. Using height vernier caliper and optical precision platform with three vertices of the refrigerator door pad level, measuring the amount of deformation of the door pillar, to get the maximum deformation of the two door body were 2.56mm and 2.42mm. Measurement door body polyurethane sample density approximately 42.6037kg/m3, thermal conductivity is about 0.02626W / (m · K), the specific heat capacity of approximately 2380.455J/kg · K. Finally ABAQUS software-door body filling with polyurethane foam layer and door components door combination structure temperature field to demold cooling process, heat distortion analysis. The temperature field analysis showed little effect door body shell components-door body stripping cooling temperature field. The releasability of the polyurethane material of the piece and the cooling heat distortion trend is convex to the inside of the door in the middle, while the deformation of the door body is rendered intermediate convex to the outside, in line with the actual measurement of the deformation trend, indicating serious door body shell structure affect the deformation of the door. The difference of simulation results and measurement results of the simplified simulation model, material parameters factors. When the polyurethane foam from the housing to limit the contraction deformation is very obvious. 5mm tempered glass of the door panel near the polyurethane shrinkage deformation effectively resist white HIPS board of the door liner can not be good boycott of the inside of the contraction trend deformation was the middle of the trend of contraction. The polyurethane is extremely difficult to decompose, environmental pollution, the results of this study will improve refrigerator quality at the same time, to reduce environmental pollution in the production process. Of rigid polyurethane industrial product development and can provide a cleaner, a scientific way more low-cost and more environmentally friendly.