Improving dust capture efficiency with local exhaust hoods in manicure shops

As a prerequisite for our goal of studying the entrainment of dust particles released by nail filing in nail salons we have identified their physical and mechanical properties that were previously unknown: density, particle-size distribution, dynamic shape coefficient and dust concentration in the manicurist's working zone. It was proven using a computational experiment a lateral exhaust would capture dust particles effectively. Using the discrete vortex method and numerical integration of the dust particle motion equation, a mathematical simulation was developed for the flow of dust-laden air around a flanged lateral hood. Relationships behind the dust particle capture range for an exhaust hood mounted on a horizontal table were identified in connection to the terminal velocity of dust particles, quantity and inclination angle of the initial escape velocity vector, velocity inside the duct, flange length, and duct inlet edge shaping along the identified vortex zone boundaries. Dust released by nail treatment can be trapped effectively with a tabletop-mounted lateral exhaust duct with a semicircular flange having a length of 2–4 times gauge (pipe radius). As a means of reducing drag, it is proposed to shape duct inlet edges along the identified boundaries of vortex zones occurring at duct inlet. For a local exhaust hood, such shaping will render the added benefit of reducing noise generated in vortex zones along with preventing contaminant release from these zones. Patterns in dust particle capture range identified by us can be used to determine the required performance of local exhaust ventilation. •Motion of dust particles near lateral exhaust hood considered.•The concept of a dust particle capture range and an algorithm for its determination are introduced.•The extrema to function of the capture range from the dust particles velocities was found.•Graphical dependencies for determination of required exhaust rate are built.•The properties of dust generated in a manicure cabinet are studied.