A design programme for dilute phase pneumatic conveyors

[摘要] A computer programme for the simulation of dilute phase pneumatic conveying of solids ispresented. This includes positive pressure and vacuum pneumatic conveying. The characteristicconveying parameters such as the conveying absolute pressure, conveying air density,interstitial and average air velocity, particle velocity and voidage are calculated by integratingfive differential equations that govern two-phase flow. The two-phase flow is approximated asone-dimensional along the pipe axis. Density and acceleration effects are accounted for. Theintegration is carried out by means of the Runge-Kutta-Fehlberg method yielding conveyingparameter traces along the length ofthe pipeline.A new method is presented for the determination of the solids friction coefficient from thesolids motion equation. This allows for a more accurate determination of the solids velocity inthe pipeline when compared to currently used methods. The computer model results arecompared to experimental results for cement and ice conveying yielding good correlation forthe main output parameters.The theory for the scaling and calculation of Roots blower performance characteristics ispresented. This is implemented in a Roots blower selection programme as an integral part ofdetermining the prime air mover for the design of a pneumatic conveyor.The aim of providing a fast, user-friendly interface in terms of pipeline geometry input,simulation and data visualisation has been achieved by using the advantages of objectorientated programming and the visual user interface of the DELPHI programming language.

[发布机构] Stellenbosch University