Phase Doppler Anemometer - PDA. We measure spray properties with high resolution in 3-D!
The Phase Doppler Anemometer, also called PDA for short, is used where the specific spray properties at a nozzle no longer permit the use of the laser diffraction spectrometer. For example, if the spray density is high due to large volume flows to be atomised. Or if the spray angle is very large. And, of course, whenever, in addition to the droplet sizes, the respective droplet speeds are of interest.
Unlike the laser diffraction spectrometer, measurements with the Phase Doppler Anemometer are so-called local measurement methods. Thus, not an entire measuring volume is evaluated quasi integrally in one measuring process wutrary to the case with laser diffraction spectrometers. Rather, certain and defined points can be examined in a spray in detail. This makes it possible to analyze the entire spray in detail and selectively.
In combination with the speed vectors of the drops, undesirable recirculations in the spray can be determined. As well as dead water areas. This is especially important in the pharmaceutical and food industry!
The Phase Doppler Anemometer, PDA, in the test rig.
By using existing and PC-controlled traversing devices in our spray laboratory, the spray of a nozzle or any atomizer can be measured selectively and completely in 3-D and therefore in high resolution! This is an enormous advantage, especially for combustion processes, material and heat transfer processes as well as flow optimization!
More detailed information on the properties of sprays and multiphase flows can hardly be obtained. Therefore, the Phase Doppler Anomemeter can certainly be described as the "silver bullet" in spray measurement technology.
In combination with the existing and flexible test benches for nozzles and atomizers, even complex atomization processes can be determined and optimized reproducibly with this special spray measurement technology.
If the required information on the drop sizes is already available or does not play a role, the speeds of drops can be measured cost-effectively with the available Laser-Doppler-Anemometer, LDA. This measuring method is also suitable for investigating flows in pipelines or vessels.
The Phase-Doppler-Anemometer PDA as a complementary tool to CFD calculations!
Due to the fact that the required measuring data can be determined with the phase-doppler anemometer in highest resolution and in 3-D, naturally without contact and influence, this measuring method is also an excellent supplement to numerical flow calculations, CFD.
Results from CFD calculations should definitely be verified. The PDA can of course be used for this purpose. PDA measurements are of course particularly interesting when reliable input variables are required for CFD calculations. This is often the case with optimizations in the area of mass and heat transfer. Typical examples are the cooling of gases or surfaces as well as mass transfer processes in chemical industry.
Effort and costs for measurements with the Phase Doppler Anemometer
Naturally, the use of a 3-D Phase Doppler Anemometer requires a certain amount of technical effort. This is significantly higher than, for example, in laser diffraction spectrometry. Simply evaluating the raw data from the measurements and checking the plausibility of the measurement results is relatively time-consuming. This requires highly qualified engineers or physicists, who are of course available.
Nevertheless, the use of this technology is expressly worthwhile for certain applications, since the higher investment costs for the application of this method quickly pay off compared to laser diffraction spectrometry.
Advice on the use of the Phase Doppler Anemometer
The choice of the appropriate measurement method depends on a number of aspects that must be taken into account. Because not all available measuring techniques are always suitable for every task. In addition, the different costs for the measuring methods must of course be taken into account!
Therefore, our specialists will advise you regarding the possibilities and limitations of different spray measurement methods and will also suggest further alternative methods if they make sense and are more cost-effective. For particular applications, alternative methods such as particle image velocimetry (PIV for short) may be considered.
Even if you not only want to determine particle or drop sizes and their velocities in a flow field, but also temperature fields play an important role, we can help you!
We have special know-how in the "Temperature field analysis using liquid crystals".
Do you have questions about measuring spray properties with the PDA or the laser diffraction spectrometer? Then discuss your individual task in spray measurement technology with our engineers under the hotline
+49 251 2 87 99 53-0
or fill in the contact form outside our office hours. We will contact you as soon as possible!
