Various designs of inertial concentrators for cleaning dusty air are considered. The analyzed designs of devices for separating dust particles by fractions also have a number of disadvantages: low fractional efficiency and complexity of structures when divided into several fractions. The design of an inertial dust concentrator with adjustable parameters is proposed. This design of the concentrator provides an increase in fractional efficiency and a decrease in hydraulic resistance with the simplicity of the apparatus design. Three-dimensional modeling of the spatial motion of air in an inertial dust concentrator with adjustable parameters is performed. A system of equations describing gas-dynamic flows is given. The results of calculations of velocity and pressure in an inertial dust concentrator with adjustable parameters are presented. Reflecting vanes and a false wall inside an inertial concentrator act as deflectors, that is, deflect the flow, which leads to an increase in the time spent by suspended particles in the inertial concentrator and a decrease in their kinetic energy. In this case, the role of inertia forces on the motion of particles will increase. Numerical modeling of the three-dimensional air flow in the concentrator made it possible to obtain a flow pattern and the main flow characteristics (velocity and pressure) from the moment of air supply to the concentrator to the moment of establishing the flow.