MetPro

Hydrocyclone Sizing Calculator - Plitt Model

Size hydrocyclones with the published Plitt (1976) model: corrected cut size d50c, pressure drop, flow split, sharpness of separation and number of cyclones for the duty.

Methodology & references

This calculator sizes hydrocyclones with the published Plitt (1976) model, using all four of Plitt’s equations: corrected cut size D50c, pressure drop, volumetric flow split S between underflow and overflow, and sharpness of separation m. The corrected efficiency curve is y(d) = 1 − exp(−0.693·(d/D50c)^m), so y(D50c) = 0.5 by construction. The Flintoff, Plitt & Turak (1987) viscosity term (µ^0.5) is included.

Two unit conventions trip up many implementations, and this one documents both: Plitt’s D50c constant is 50.5 with dimensions in cm and flow in L/min (the widely reprinted 14.8 pairs with flow in m³/h; they are the same equation in different units), and the free vortex height enters at the exponent 0.38 per the 1976 original, not 0.36. Inputs here are mm and m³/h and are converted internally.

Pressure enters the cut size only through the flow term Q^0.45, exactly as published. The number of cyclones for a duty comes from matching per-unit flow against a table of standard cyclone sizes. The implementation is a single authoritative transcription of the four equations, verified against an independent hand evaluation (15-inch cyclone: D50c = 99.75 µm, ΔP = 170.3 kPa, S = 0.177, m = 2.74).

References

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