How it works
Gas enters a cyclone tangentially and forms a downward outer vortex and an inner upward vortex that leaves through the vortex finder. In the swirling flow each particle feels a strong centrifugal force flinging it outward against the gas drag pulling it inward to the exit. Coarse, dense particles win, migrate to the wall, slide down the cone, and leave at the bottom as separated solids; fine particles stay entrained and exit with the cleaned gas.
The cut size — where capture probability is 50% — falls as the swirl velocity rises, so smaller cyclones and higher inlet velocities catch finer particles. But two effects complicate the simple picture: a solids-loading limit, where the gas can only carry so much before excess solids drop out en masse at the wall, and a secondary flow near the top that re-separates material around the vortex finder. Together these make real performance depend strongly on loading, geometry, and wall friction, not just particle size.
The model
Dyssol Pro computes the gas–solid separation at the population level: from the cyclone geometry and the operating gas flow it resolves the internal swirl field into a size-resolved separation efficiency, splitting the feed solids between the captured-solids outlet and the cleaned-gas outlet — together with the pressure drop across the cyclone, at every time point of the dynamic flowsheet.
The separation follows the swirl physics of the machine: the tangential velocities built up from the inlet down through the cylinder and cone set the centrifugal force on each particle, and its balance against gas drag defines a cut size that shifts finer as the swirl rises. Gas density and viscosity and every solid density are taken from the materials database, so the capture responds to particle size, density, and gas conditions together.
Crucially, the two loading effects that dominate real cyclones are resolved rather than idealised away: a solids-loading limit, above which the gas sheds its excess solids straight to the wall, and a secondary flow that re-separates material around the vortex finder. On this basis Dyssol Pro covers cyclone duties from coarse pre-separators to fine high-efficiency units, and even machine-specific behavior beyond the standard description can be brought into the flowsheet.
Equipment this model can represent
Any centrifugal gas–solid separation duty that spins solids out of a gas stream.
Reverse-flow cyclones
The classic tangential-inlet dust separator; gas reverses and exits the top.
Axial-inlet cyclones
Guide vanes impart swirl; compact, used in multicyclone arrays.
Multicyclones
Many small-diameter cyclones in parallel for a finer cut at high throughput.
Cyclone pre-separators
Coarse-duty cyclones ahead of bag or cartridge filters to offload them.
Typical engineering studies
What teams investigate with the cyclone model.
Capture & exhaust dust
Predict solids capture and exhaust dust load for a given cyclone geometry and gas flow.
Geometry sensitivity
Study how diameter, vortex-finder size, and inlet shape move the cut.
Gas-cleaning trains
Connect upstream (pneumatic transport, fluid bed) and a downstream gas filter, and optimize the cyclone as a pre-separator.
Efficiency calibration
Calibrate the efficiency adjustment factor to measured performance, then use predictively.
Loading & temperature effects
Study solids-loading and gas-temperature effects on capture across operating points.
Technical FAQ
How does a Muschelknautz cyclone differ from a standard cyclone?
It’s not a different cyclone but a more complete way to model one: a loading-based method adds the solids-loading limit, wall friction, and the secondary vortex-finder flow that simpler cut-size formulas ignore. Dyssol Pro works at exactly this level of description, so predicted efficiency reflects geometry and loading rather than particle size alone.
How do I calculate cyclone separation efficiency?
Efficiency comes from the swirl velocity, geometry, solids loading, and particle size and density. Dyssol Pro computes the size-resolved grade efficiency and the overall capture directly from the cyclone geometry and gas flow you specify.
Why is my cyclone not removing enough fine particles?
Fines below the cut size simply follow the gas out; capturing them needs a higher swirl velocity or a smaller cyclone. In Dyssol Pro you vary the inlet flow and geometry (outer and vortex-finder diameters) and watch the fine-end capture on the grade curve to see what it would take.
How can I reduce pressure drop in a cyclone?
Pressure drop falls with lower inlet velocity and larger vortex finder — but so does efficiency, so it’s a trade-off. Dyssol Pro calculates the cyclone pressure drop, so you can study it directly against velocity and geometry alongside the separation efficiency and pick the operating point that balances both.
How does inlet velocity affect cyclone performance?
Higher inlet velocity raises centrifugal force and captures finer particles, at the cost of more pressure drop, erosion, and re-entrainment. In Dyssol Pro the inlet velocity follows from gas flow and entry geometry and sets the internal tangential velocities, so you can map capture against flow.
How do particle size and density influence cyclone efficiency?
Capture rises strongly with particle size and with the solid-to-gas density difference. Dyssol Pro uses both — size from the PSD and densities from the materials database — in the cut-size calculation, so multi-size, multi-density feeds are handled per class.
How can I prevent solids buildup in a cyclone?
Build-up comes from sticky or moist solids and low wall velocity, so it is limited by keeping the solids dry and the wall velocity high enough to scour deposits. Dyssol Pro tracks the upstream moisture and temperature feeding the cyclone, so you can favor conditions that keep the solids in the free-flowing regime.
What causes re-entrainment of particles in a cyclone separator?
Already-separated solids get picked back up when loading limits and the secondary flow near the vortex finder are exceeded. Dyssol Pro explicitly resolves the loading limit and a secondary stream, so you can study how loading drives re-entrainment and capture.
How do I improve cyclone efficiency for submicron particles?
Cyclones are intrinsically poor below ~1 µm; you need extreme swirl or, realistically, a downstream filter. Dyssol Pro shows the weak submicron capture on the grade curve and lets you add a gas filter downstream to handle what the cyclone cannot.
Why is my cyclone outlet dust concentration too high?
Either fines are below the cut or the cyclone is overloaded, so solids leave with the gas. In Dyssol Pro you quantify the solids mass flow at the gas outlet, optimize geometry and flow to lower it, and couple a filter if the target is below what a cyclone can reach.
How does cyclone geometry affect cut size?
The outer and vortex-finder diameters, heights, and inlet shape all set the swirl field and therefore the cut. In Dyssol Pro these are model parameters, so you run a geometry sensitivity study and see the cut size respond directly.
How can I reduce product loss through the cyclone exhaust?
This is the same as improving fine capture: raise swirl, tighten geometry, or add a filter. Dyssol Pro lets you study the gas-outlet solids against geometry and flow and design a cyclone-plus-filter train that recovers the product.
How do I choose between single cyclone and multicyclone systems?
Many small cyclones in parallel give a finer cut at the same throughput, at higher pressure drop. In Dyssol Pro you model a smaller-diameter unit to see the finer cut it achieves and read its pressure drop, so you can weigh the parallel arrangement against the pressure-drop budget.
How does gas temperature affect cyclone separation?
Temperature changes gas density and viscosity, which shift settling and the cut. Dyssol Pro takes gas properties from the materials database at the operating condition, so you can study temperature by running at the corresponding gas properties.
How can I detect plugging in a cyclone?
Plugging comes from moist or sticky solids bridging at the cone apex or dust outlet, so it is limited by keeping the feed dry and the solids loading within the range the outlet can clear. Dyssol Pro tracks the upstream moisture and solids loading feeding the cyclone, so you can see when conditions drift toward the sticky, plugging-prone regime and adjust before it happens.
What is the influence of solids loading on cyclone pressure drop?
Higher solids loading actually lowers pressure drop (the solids damp the swirl) while changing the capture through the loading limit. Dyssol Pro calculates the pressure drop and models the loading effect on separation efficiency, so you can study both responses to solids loading together.
How can I optimize a cyclone before a bag filter?
The cyclone should strip the coarse bulk so the filter handles only fines, extending filter life. In Dyssol Pro you connect the cyclone to the gas filter and optimize the cyclone cut so it removes as much load as possible before the filter — sizing the whole gas-cleaning train together.