Input data

Cyclone diameter

Particle density

Air flow

Air density

Air viscosity

Blower efficiency

Output data

Cut diameter

Head loss

Power

L1

L2

W

Dd

H

De

L3

Description

The Lapple cyclone is a widely used device for separating solid particles from gases through centrifugal force. It provides a simplified yet effective model to estimate separation efficiency, pressure drop, and power requirements in ventilation and exhaust systems.

Lapple Cyclone Lapple Cyclone

Available calculation methods:

Dimensions – computes main geometric parameters, cut diameter, pressure drop, and power.
Granulometric curve – generates the grade efficiency curve as a function of particle size.
Granulometry from the cyclone diameter – calculates the outlet granulometric distribution based on the cyclone diameter.
Granulometry from the diameter cut – estimates outlet granulometric distribution using a predefined cut diameter.

Inputs and outputs of the dimension calculation

Inputs

Parameter	Default units	Description
Cyclone diameter ( $dc$ )	m	Main dimension of the cyclone
Particle density ( $\rho_p$ )	kg/m³	Solid particle density
Air flow ( $Q$ )	m³/s	Volumetric airflow
Air density ( $\rho$ )	kg/m³	Carrier fluid density
Air viscosity ( $\mu$ )	Pa·s	Dynamic viscosity of air
Blower efficiency ( $\eta$ )	%	Efficiency of the fan

Outputs

Parameter	Default units	Description
Cut diameter ( $d_p$ )	m	Particle diameter at 50% collection efficiency
Head loss ( $\Delta P$ )	Pa	Pressure drop across the cyclone
Power ( $P$ )	W	Power required for operation
L1, L2, L3	m	Characteristic heights of the cyclone
W	m	Inlet width
Dd	m	Discharge duct diameter
H	m	Cylindrical body height
De	m	Exit diameter

Description

Lapple Cyclone Lapple Cyclone

Available calculation methods:

Dimensions – computes main geometric parameters, cut diameter, pressure drop, and power.
Granulometric curve – generates the grade efficiency curve as a function of particle size.
Granulometry from the cyclone diameter – calculates the outlet granulometric distribution based on the cyclone diameter.
Granulometry from the diameter cut – estimates outlet granulometric distribution using a predefined cut diameter.

Inputs and outputs of the dimension calculation

Inputs

Parameter	Default units	Description
Cyclone diameter ( $dc$ )	m	Main dimension of the cyclone
Particle density ( $\rho_p$ )	kg/m³	Solid particle density
Air flow ( $Q$ )	m³/s	Volumetric airflow
Air density ( $\rho$ )	kg/m³	Carrier fluid density
Air viscosity ( $\mu$ )	Pa·s	Dynamic viscosity of air
Blower efficiency ( $\eta$ )	%	Efficiency of the fan

Outputs

Parameter	Default units	Description
Cut diameter ( $d_p$ )	m	Particle diameter at 50% collection efficiency
Head loss ( $\Delta P$ )	Pa	Pressure drop across the cyclone
Power ( $P$ )	W	Power required for operation
L1, L2, L3	m	Characteristic heights of the cyclone
W	m	Inlet width
Dd	m	Discharge duct diameter
H	m	Cylindrical body height
De	m	Exit diameter

References

CIMBALA, J. M. Lesson 12B: Lapple Cyclone. A Practical Application of Inertial Separation.

Calculations

Lapple cyclone

Input data

Cyclone diameter

Particle density

Air flow

Air density

Air viscosity

Blower efficiency

Output data

Cut diameter

Head loss

Power

L1

L2

W

Dd

H

De

L3

Input data

Output data

Input data

Cyclone's diameter

Particle density

Air density

Air flow

Air viscosity

Output data

Input data

Diameter cut

Output data

Description

Inputs and outputs of the dimension calculation

Description

Inputs and outputs of the dimension calculation

References