This is a new project (started at the end of 2010) in which a new particle tracking technique called Positron Emission Particle Tracking (PEPT) will be used for experimental study of particle flow.
How does it work?
We study a pneumatic flow of particles, e.g. in a bent pipe, such as shown in the figure below:
The pipe is located in a so-called PET-scanner (Positron Emission Tomography). PET is actually a medical imaging technique extensively used in fields such as: oncology, neurology, cardiology: this can also be used for studying two-phase flows!
This technique bases on the decay of a radioactive labeller, which leads to emission of a positron and a neutrino. One (or more) particles in the flow are labelled so that they are radioactive.
This positron travels then through the medium and is annihilated by an electron in the medium. This annihilation results in back-to-back emission of two gamma photons. These photons are detected by sensors in the PET-scanner.
To say it simple: the PET-scanner can "see" the labelled particle. This technique is non-invasive and also can be used for tracking the particles also in dense flows. No other technique can do it.
And there are only a few centres in the world that has access to PET-scanners. In our research we use the PET-scanner located in Haukeland University Hospital in Bergen.
Our first results have already been published. See [10] to find out more (note that you can download this paper).
Questions? Please contact: Pawel.Kosinski (_at_) ift.uib.no
If you want to read more, you can have a look at the following papers:
[1] Parker, D.J., Dijkstra, A.E., Martin, T.W., Seville, J.P.K., "Positron emission particle tracking studies of spherical particle motion in rotating drums", Chemical Engineering Science, vol. 52, pp. 2011-2022, 1997.
[2] Stellema, C.S., Gerritsen, A.W., Kolar, Z.I., de Goeij, J.J.M., van den Bleek, C.M., "Flow of solids in an interconnected fluidized beds system investigated using positron emission particle tracking", Canadian Journal of Chemical Engineering, vol. 79, pp. 314-321, 2001.
[3] Fangary, Y.S., Barigou, M., Seville, J.P.K., Parker, D.J., "A Langrangian study of solids suspension in a stirred vessel by Positron Emission Particle Tracking (PEPT)", Chemical Engineering & Technology, vol. 25, pp. 521-528, 2002.
[4] Seville, J.P.K., Ingram, A., Parker, D.J., "Probing processes using positrons", Chemical Engineering Research & Design, vol. 83, pp. 788-793, 2005.
[5] Dechsiri, C., Ghione, A., van de Wiel, F., Dehling, H.G., Paans, A.M.J., Hoffmann, A.C., "Positron emission tomography applied to fluidization engineering", Canadian Journal of Chemical Engineering, vol. 83, pp. 88-96, 2005.
[6] Hoffmann, A.C., Dechsiri, C., van de Wiel, F., Dehling, H.G., "PET investigation of a fluidized particle: spatial and temporal resolution and short term motion", Measurement Science and Technology, vol. 16, pp. 851-858, 2005.
[7] Stein, M., Ding, Y.L., Seville, J.P.K., Parker, D.J., "Solids motion in bubbling gas fluidized beds", Chemical Engineering Science, vol. 55, pp. 5291-5300, 2000.
[8] Snieders, F.F., Hoffmann, A.C., Cheesman, D., Yates, J.G., Stein, M., Seville, J.P.K., "The dynamics of large particles in a four-compartment interconnected fluidized bed", Powder Technology, vol. 101, pp. 229-239, 1999.
[9] Parker, D.J., Forster, R.N., Fowles, P., Takhar, P.S., "Positron emission particle tracking using the new Birmingham positron camera", Nuclear Instruments & Methods, vol. A477, pp. 540-545, 2002.
[10] Middha, P., Balakin, B.V., Leirvag, L., Hoffmann, A.C., Kosinski, P.: (2013) PEPT - a novel tool for investigation of pneumatic conveying, Powder Technology 237, pp. 87-96, 10.1016/j.powtec.2013.01.024 preprint