PARTICLE CONTAMINATION BELOW A ROBOT ARM IN A CLEANROOM

Experimental velocity and particle concentration data have been obtain ed near a circular cylinder robot arm in a chamber that simulates a ve rtical unidirectional flow Class 10 cleanroom. The airflow field aroun d the robot arm has been characterized using a hot wire anemometer. Bo th mean velocities and turbulence spectral data were obtained. Sodium chloride particles were injected through small holes below the arm to simulate particles generated by moving joints. Results indicate that t he turbulent wake near the arm causes an unsymmetrical widespread disp ersion of the particles from a single point source on the arm. Particl es disperse much stronger along the cylinder axis than normal to the c ylinder near the injection point.