Liquid Velocity Distributions

Kelsall, in 1952, performed a classic series of experiments measuring axial and tangential fluid velocity profiles in a hydrocyclone using an ingenious experimental system with rotating objectives. The radial velocity was calculated by continuity. The velocity profiles are shown in Figure 2. More recently, velocity profiles measured using laser Doppler velocimetry (LDV) were found to correspond closely to those of Kelsall.

The fluid velocity in the cyclone has tangential, axial and radial components. The axial velocity is negative (downward) close to the walls in the cone and positive (upward) near the air core, increasing towards the spigot. This results in a locus of zero vertical velocity between the two vortices, which roughly follows the profile of the cyclone. Toroidal rotation in the inlet flow and interaction between the vortices result in multiple flow reversals.

The tangential velocity increases toward the axis, reaching a maximum near the air core, thereafter decreasing in a forced vortex region. It is the tangential velocity component that generates the centrifugal force, which separates coarser particles from finer ones. The radial velocity, which is two orders of magnitude smaller than the axial or tangential velocities, is directed toward the centre of the cyclone and increases toward the apex.

Solar Panel Basics

Solar Panel Basics

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