Investigations of flow instabilities within the dense pneumatic conveying system

Abstract The gas–solids flows in the dense pneumatic conveying exhibit many interesting features related to their three-dimensional and unsteady nature. The dominant characteristic in this type of flows is the appearance of discrete flow instabilities commonly known as ‘slugs’ and ‘plugs’. These are investigated by two techniques: a high-speed video camera and a twin-plane electrical capacitance tomography (ECT), and the results obtained are discussed. Data extracted from tomographic measurements can be processed and presented in several different ways to enable a better understanding of the flow behaviour. Several examples are given, including body shape type information, internal structure of the flow instabilities, their propagation velocity and frequency characteristics. A short case study, focused on measurements of bidirectional flow in a vertical channel, is presented.

[1]  Tomasz Dyakowski,et al.  A behaviour of a catalyst powder flowing down in a dipleg , 2000 .

[2]  Avi Levy,et al.  Two-fluid approach for plug flow simulations in horizontal pneumatic conveying , 2000 .

[3]  K. Konrad.  Boundary element prediction of the free surface shape between two particle plugs in a horizontal pneumatic transport pipeline , 1988 .

[4]  K. Konrad,et al.  Dense-phase pneumatic conveying through long pipelines: effect of significantly compressible air flow on pressure drop , 1986 .

[5]  Tomasz Dyakowski,et al.  Process tomography applied to multi-phase flow measurement , 1996 .

[6]  K. Konrad,et al.  Dense-phase pneumatic conveying: A review , 1986 .

[7]  K. Konrad,et al.  Vertical pneumatic conveying of particle plugs , 1989 .

[8]  Artur J. Jaworski,et al.  The design of an electrical capacitance tomography sensor for use with media of high dielectric permittivity , 2000 .

[9]  Tomasz Dyakowski,et al.  On-line monitoring of dense phase flow using real time dielectric imaging 1 The authors are members , 1999 .

[10]  Tomasz Dyakowski,et al.  Tomographic measurements of solids mass flow in dense pneumatic conveying: What do we need to know about the flow physics? , 2001 .

[11]  Richard A Williams,et al.  Process tomography : principles, techniques and applications , 1995 .

[12]  Wuqiang Yang,et al.  Hardware design of electrical capacitance tomography systems , 1996 .

[13]  K. Konrad,et al.  The gas—liquid analogy in horizontal dense-phase pneumatic conveying , 1984 .

[14]  Richard A Williams,et al.  Process tomography for identification, design and measurement in industrial systems , 1992 .

[15]  Tomasz Dyakowski,et al.  Applications of electrical tomography for gas-solids and liquid-solids flows : a review , 2000 .

[16]  Richard A Williams,et al.  Solids Flow Imaging and Attrition Studies in a Pneumatic Conveyor , 1995 .

[17]  Richard A Williams,et al.  Simulation of the performance of electrical capacitance tomography for measurement of dense phase pneumatic conveying , 1997 .

[18]  M. S Beck,et al.  Imaging Industrial Flows: Applications of Electrical Process Tomography , 1995 .

[19]  David J. Mason,et al.  A novel experimental technique for the investigation of gas–solids flow in pipes , 2000 .

[20]  Ø. Isaksen,et al.  A review of reconstruction techniques for capacitance tomography , 1996 .

[21]  Jpk Seville,et al.  Experimental validation of granular dynamics simulations of gas-fluidised beds with homogeneous inflow conditions using Positron Emission Particle Tracking , 2001 .

[22]  O. Molerus,et al.  Overview: Pneumatic transport of solids , 1996 .