A method for the redesign of pneumatic dryers

A method for the design and redesign of pneumatic dryers is proposed. As an example, this pragmatic and fast method is applied to the redesign of a pneumatic dryer for potato particles that suffered from ignition of resident particles. In the method, a duct, geometrically qua flow dynamics equivalent to the industrial installation, as well as analysis-based modifications of it, are studied using velocity fluctuation measurements. For most practical flows of gas-particles, one-way coupling usually suffices to assess the influence of the flow on particle migration and deposition. Redesign proposals are based on measured fluctuation levels. The typical example given concerns optimization of the inclination of a ramp, air inlet and a grid. Some of these recommendations have successfully been applied in practice.

[1]  H. Fernholz.  Boundary Layer Theory , 2001 .

[2]  J. G. Brennan,et al.  A Mathematical Model of Simultaneous Heat and Moisture Transfer during Drying of Potato , 1995 .

[3]  A. H. Pelegrina,et al.  Modelling the pneumatic drying of food particles , 2001 .

[4]  G. Karniadakis.  Simulating turbulence in complex geometries , 1999 .

[5]  Jgm Hans Kuerten,et al.  Subgrid modeling in particle-laden channel flow , 2006 .

[6]  B. Roux,et al.  Modeling of the HESCO nozzle diffuser used in IEA Annex-20 experiment test room , 2004 .

[7]  A. Periz,et al.  Drying model for α-amylase in a horizontal spray dryer , 1997 .

[8]  Drop size distribution evolution after continuous or intermittent injection of butane or propane in a confined air flow , 2001 .

[9]  F. Ampofo,et al.  Turbulent natural convection in an air filled partitioned square cavity , 2004 .

[10]  Joon Sang Lee,et al.  Large eddy simulation of heated vertical annular pipe flow in fully developed turbulent mixed convection , 2004 .

[11]  Avi Levy,et al.  Steady state one dimensional flow model for a pneumatic dryer , 1999 .

[12]  John S. Young,et al.  A theory of particle deposition in turbulent pipe flow , 1997, Journal of Fluid Mechanics.

[13]  C. W. M. van der Geld,et al.  Experiments on the effect of acceleration on the drag of tapwater bubbles , 2001 .

[14]  Heinz A. Preisig,et al.  Modelling of a pneumatic dryer for potato starch , 1998 .

[15]  M. L. Laucks,et al.  Aerosol Technology Properties, Behavior, and Measurement of Airborne Particles , 2000 .