Ventilation system for reduction of particle concentration in automotive painting line environment

Abstract

In the painting production process, repairing of paint work defects by running the part through the process again, together with the requisite quality control routines, account for a very large proportion of the operating costs. At current defective rate of 37 per cent rejection due to dust, not only it deteriorates the quality and the performance o f productivity, but it also brings negative impact to the operation cost and company revenue. Hence, this research focuses on identifying the air flow patterns for existing painting booth utilising Computational Fluid Dynamic (CFD) to understand the concentration and movement o f dust particles. The data gathered from the CFD simulation is used to remodel the mechanical design o f air ventilation system for the painting booth by focusing on the size and location of the exhaust system. Based on this, the optimum value for air flow velocity which is also an important variable in the movement and concentration o f particles can be defined. However, the range for the tested air flow supply is subjected to the capability o f current painting booth Air Supply Unit (ASU) which is from 0.1 m/s ~ 0.5 m/s. During CFD simulation process, Renormalization Group (RNG) k-e turbulence model has been used to predict the particles movement and concentration. Eight new designs based on current painting booth have been proposed and validated. Painting booth o f model I found to be the best solution to minimize and reduce the dust particle concentration with 98.13 per cent of average particles escaped with air flow rate of 16103 m3/min. An experimental data has been collected using the air flow meter in a small-scale model of painting booth together with smoke visualization to validate findings from numerical simulation, CFD. It is found that the average relative error for model A, was recorded at range o f 1.04 to 3.08 per cent. In summary, the relative error between numerical and experimental data is less than 10 per cent which is acceptable and in a good agreement. So far, this is the first study that has been conducted to understand the dust particles movement with the impact of the ventilation system and multiple air velocity setting in context o f M alaysia automotive painting industry.