Seeding particles are essential to all LDA and PIV measurements and in most applications, liquid or solid particles must be added to obtain high quality measurements.
Dantec Dynamics offers liquid and powder seeding generators for LDA and PIV, and fog generators for LDA and flow visualization.
Selecting the right type of seeding
Selecting a seeding generator requires finding a compromise between signal amplitude and the particles ability to follow the flow. Larger particles will increase signal quality and data rate or reduce demand for illumination, but will have a slip in accelerating flows, e.g. a high frequency turbulence.
Smaller particles will reduce signal amplitude and data rate or increase demand for illumination, but will follow the flow to higher frequencies.
Rough guidelines:
- 3 µm oil droplets in air will follow flow fluctuations up to 1 kHz.
- 1 µm oil droplets in air will follow flow fluctuations up to 10 kHz.
- 1 µm powder particles in air will follow flow fluctuations up to 1 kHz.
- 0.4 µm powder particles in air will follow flow fluctuations up to 10 kHz.
- For supersonic flows particles should not exceed 1 µm.
Liquid and Powder Seeding Generators
| Model | Type | Particle type | Characteristics |
| 10F02 | Liquid seeding Generator |
Oil droplets ~3 µm |
PIV and LDA, high signal amplitude, remote control |
| 10F03 | High volume Liquid seeding Generator |
Oil droplets ~3 µm |
PIV and LDA where large volumes must be seeded, high signal amplitude |
| 10F01 | Powder seeding Generator | Aluminum oxide or titanium dioxide particles ~0.3 µm | PIV and LDA, high signal amplitude, remote control, high temperature e.g. combustion |
Liquid Seeding generator (10F02)
This seeding generator produces droplets ideal for PIV and LDA measurements. It is the preferred solution for medium to large size facilities.
High volume liquid seeding generator (10F03)
This seeding generator produces droplets ideal for PIV and LDA measurements. It is the preferred solution for medium to large size facilities.
Powder seeding generator (10F01)
This seeding generator produces powder particles for PIV and LDA measurements. As it is able to operate in pressurised facilities and is equipped with remote control it is recommended for difficult applications including combustion studies.
Fog Generators
Flow visualization with the fog probe system
The fog probe system is especially developed and optimized for flow field visualization in wind tunnels. The flexible connection between the probe and the supply unit makes it very easy to use. Multiple fog probes can be combined on a common mount to form a fog rake. Different probe nozzles allows adaptation to various flow speeds.
Fog Probe NS4
This is a fog-injection system for aerodynamic flow visualization in large wind tunnels. The fog quantity can be adjusted and adapted to the air-flow velocity. The fog probe NS4 is available for 220V 50 Hz line power only.
Accessories
A range of accessories are available for the Fog Probe System.
Fog generators (10D15-60)
SAFEX fog generators are small, powerful devices that generate a dense white fog by evaporation and condensation of a water-based fog liquid. The fog is non-irritant and non-flammable.
The mean droplet size is around 1 µm and the fog’s durability can be controlled through the choice of different fog liquids (Blitz, Standard, Super). The fog fluid type Extra Clean consists of ingredients with extremely high purity and is designed for applications in clean-room environments.
Fog generator: FOG 2010
This standard device satisfies the majority of applications. The fog quantity can be varied directly at the fog generator or by using an electronic remote control unit.
Fog generator: 195 SG-D
The system for applications requiring fog in very large quantities.
Fog fluids
The durability of the fog can be varied through the choice of different fog fluids, but also depends on the ambient temperature and relative humidity.
