Prof. Dr.-Ing. Dr. h. c. Uwe Hampel

Experimental Thermal Fluid Dynamics
Phone: +49 351 260 2772

Autonomous Sensor Concepts


In most industrial processes the acquisition of spatially distributed parameters in large vessels is problematic, as sensor mounting or cable connections are not feasible or desired. Therefore, state of the art instrumentation of e.g. reactors is commonly limited to few spatial positions and as a consequence the measured parameters are often not representative for the whole vessel. We developed the concept of instrumented flow followers (sensor particles) for the long-term measurement of spatially distributed process parameters in chemically and mechanically harsh environments of agitated industrial vessels. Each sensor particle comprises of an onboard measurement electronics that logs the signals of different sensors, namely temperature, absolute pressure (immersion depth, axial position), 3D acceleration, rotational rate and magnetic field. The whole electronics is enclosed in a robust neutrally buoyant capsule, to allow free movement with the flow. Applications are in stirred fermentation biogas reactors and activated sludge basins and others.


Validation of the prototype sensor particles was carried out in a stirred vessel, a stirred fermentation reactor model, a draft-tube reactor and a bubble column. Also, tests in large scale process vessels, namely an activated sludge basin and a pilot biogas fermenter, were carried out. The analyzed data reveal the internal process conditions and particularly the flow conditions in the vessels. Furthermore, axial parameter profiles can be extracted from the captured data of the sensor particles. Conclusions can be drawn on the mixing homogeneity, the axial distribution of solid fraction, the degree of suspension, the axial flow profile and the structure of large eddy flows. Moreover, model parameters of stirred vessels, such as the circulation number and the velocity head, and also parameters of dispersed flow models, such as the PECLÉT-number, can be estimated from the measured circulation time distributions.


  • Christian-Albrechts-Universität zu Kiel, Institute of Electrical Engineering and Information Technology
  • Münster University of Applied Sciences, Institute of Energy and Process Technology
  • Fraunhofer Institute for Ceramic Technologies and Systems, Biomass Technologies and Membrane Process Technology
  • SOWAG Süd-Oberlausitzer Wasserversorgungs- und Abwasserentsorgungsgesellschaft mbH
  • Stadtentwässerung Dresden GmbH

Funded by (2008 – 2011)



  • S. Thiele, M. J. Da Silva, U. Hampel
    Autonomous sensor particle for parameter tracking in large vessels
    Meas. Sci. Technol., vol. 21 (8) 085201 (2010)
  • S. Reinecke, U. Hampel
    Autonome Sensorpartikel zur Prozessdiagnose in Großbehältern
    Tech. Mess., vol. 79 (10) 464 - 471 (2010)
  • S. Reinecke, et al.
    Flow following sensor particles - Validation and macro-mixing analysis in a stirred fermentation vessel with a highly viscous substrate
    Biochem. Eng. J. 69, 159–171 (2012)
  • S.F. Reinecke
    Instrumentierte Strömungsfolger zur Prozessdiagnose in gerührten Fermentern, Dissertation
    Dresdner Beiträge zur Sensorik, Band 52, TUDpress (2014)
  • S. Reinecke, U. Hampel
    Instrumented flow-following sensor particles with magnetic position detection and buoyancy control
    J. Sens. Sens. Syst., 5, 213-220 (2016)
  • S. Reinecke, et al.
    Macro-mixing characterisation of a stirred model fermenter of non-Newtonian liquid by flow following sensor particles and ERT
    Chem. Eng. Res. Des. 118, 1–11 (2017)