Advanced Powder Technol., Vol. 18, No. 1, pp. 23–38 (2007)  VSP and Society of Powder Technology, Japan 2007. Also available online - www.brill.nl/apt Invited paper Application of magnetic resonance imaging techniques to particulate systems A. J. SEDERMAN ∗ , L. F. GLADDEN and M. D. MANTLE Department of Chemical Engineering, University of Cambridge, Pembroke Street, Cambridge CB2 3RA, UK Received 15 September 2006; accepted 16 October 2006 Abstract—Magnetic resonance imaging (MRI) is a well-established technique in the medical field, typically for imaging liquid water in the human body, but it is increasingly being used in the field of engineering and materials science. A particular section of this is in the area of particulate systems and granular material flows. MRI is being used to provide a unique insight into particle distribution and motion with in situ measurements. In this paper we discuss how judicious choice and development of imaging technique applied to various different granular systems can provide us with valuable new data on the processes occurring in granular flows. Experimental results focus on rotating bed segregation, velocity imaging in vertical fluidized beds and phase-resolved velocity distributions within vertical vibro-fluidized beds. A discussion of the various imaging techniques used to acquire these data is also given. Keywords: Magnetic resonance imaging (MRI); flow imaging; rotating kilns; fluidized beds; vibro- fluidized beds. 1. INTRODUCTION Granular materials and granular flows play an important role in a wide variety of industrial processes, including rotary kilns, mixing, fluidization and flows of particles. These processes are industrially important in many areas, including reaction engineering, pharmaceuticals, food processing and materials processing. There is therefore much research and interest in advancing the understanding of granular flows. Despite their importance, the understanding of granular flows is relatively undeveloped compared with fluid flows for several reasons; in particular, the complex and numerous particle interactions, and the difficulty of making measurements inside these opaque systems. Magnetic resonance imaging (MRI) has long been utilized in medicine for non-invasively imaging structure and transport ∗ To whom correspondence should be addressed. E-mail: ajs40@cam.ac.uk