Influence of ventilation arrangements on particle removal in industrial cleanrooms with various tool coverage

Abstract

This paper aims to investigate the influence of comparative ventilation arrangements (wall-return, locally balanced ceiling-return, and four-way ceiling-return) on the airflow distribution and particle fates within cleanrooms of ISO cleanliness class 7 with various tool coverage ratios (0%, 38%, and 60%). Computational fluid dynamics (CFD) was employed to analyze and compare the influence of the three ventilation arrangements on concentrations for particles of various sizes (diameters ranging from 0.01 to 100 μm) in the cleanrooms. The techniques of Eulerian and Lagrangian in CFD were employed for solving the continuous fluid and tracking the particle trajectory, respectively. The outcomes from this study suggested that particle removal rates for the given cleanrooms were significantly affected by the tool coverage ratios, the design of ventilation, and the particle sizes of concerns. In the cases of heavy tool coverage, the locally balanced ceiling-return ventilation arrangements can minimize the need for the relocation of the production lines and layouts of the production tools in cleanrooms, and may provide viable solutions to effective contamination without compromising contamination effectiveness or efficiency.

Surface Cleanliness Maintenance with Laminar Flow Based on the Characteristics of Laser-Induced Sputtering Particles in High-Power Laser Systems

“…However, the lateral dispersion of laminar flow intensified, leading to an increase in particle sedimentation percentage in neighboring zones. In reference to particle diameter (gravity), Tung et al [ 43 ] conducted numerical studies and determined that laminar flow protection (at an average velocity of 0.35 m/s in a 7.8 m × 7.8 m × 3.2 m clean room) is efficient for aerosol particles with diameters below 1 μm. Further experiments with varied layouts confirmed that the laminar flow at this velocity is ineffective in removing particles larger than 100 μm.…”

“…Take ref. [ 43 ] as an example. Although it has been suggested that maintaining cleanliness is related to particle gravity and terminal velocity, the decelerating mechanisms in the longitudinal direction remain largely unclear.…”

Numerical Investigation of using FDCU on Temperature Distribution in Non-Unidirectional Cleanrooms

“…Traditional cleanroom airflow pathways rely on installing fan filter units (FFUs) to introduce supply air from ceilings and extract return air through return air shafts (RASs) and wall-return air grilles. Tung et al, [6] studied the airflow characteristics and its effect on particle removal in a cleanroom equipped with tools arranged in different floor covering configurations and using different air return system opening arrangements. Even though the return air plenum drives up the cost of construction, the wall-return air system has various shortcomings.…”

Estimation of indoor contamination source location by using variational continuous assimilation method

“…The behavior of airborne particles depends on several variables such as their radius. Chen et al (2012) investigated the effect of near-wall heat source on particle deposition, and Tung et al (2010) investigated the behavior of particles in industrial clean rooms with various particle radius and tool coverage. To estimate concentration of indoor airborne particles, Zhang et al (2012) used the Lagrangianreversibility method, which employed a reversed flow field, and showed that the method performed a little better than the PR method.…”