| 摘要 |
The invention concerns a method and device for determining the aerodynamic diameter of particles carried in a flow. To that end, the velocity of the flow is altered in an area and the particle velocity measured at at least one point before said area and at at least one point in or after said area. Owing to the alteration of the flow velocity, the particles carried in the flow are with increasing aerodynamic diameter retarded or accelerated increasingly more slowly than the carrier fluid, depending on whether an area of flow retardation or flow acceleration is concerned. Knowing the constraints makes it possible, therefore, by measuring the particle velocity in or shortly after this area of altered flow velocity, to infer the aerodynamic diameter. Correlating the particle velocity data thus obtained with the as well performed particle velocity measurement before the area of flow velocity alteration, where all of the particles of different size still have approximately the same velocity, allows determining the aerodynamic diameter independently of the inflow velocity of the particle-laden flow. Hence, a device basing on the method can be installed directly in a technical circulation, which enables "in-situ" measurements of the aerodynamic diameter of particles.
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