In the previous article we have seen an introduction to pneumatic conveying and the two categorizations. In a pneumatic transport line quite often a cyclone is needed in order to seperate the particles from the air, conveyed with the help of an fan .

The dust particles move along a spiral path inside the cyclone. The acting centrifugal force results in the deposition of the dust. The computation of the cyclone is performed according to the theory of Barth, Muschelknautz and Brunner. This computation method makes the following assumptions:

The largest peripheral velocity u 1...

In order to define the negative pressure at the fan , we can use the following tables:

Equivalent straight length of pipe elbows (bends) Chart for determining the air velocities

The assumed standard diameters, elbow radiuses, and equivalent straight pipe lengths of 90 o elbows (bends) are given in the table below.

Based on the values of the 90 o elbows, it is possible to estimate the equivalent straight pipe length of other angles using the following factors.

Finally, from the Moody chart, see below, we can get the Darcy-Weisbach friction factor f D as...


An important feature for classifying conveying systems is the air velocity. It allows the following categorization:

Dilute-phase conveying: with air velocities of approx. 15 – 25 m/s Dense-phase conveying: with air velocities of approx. 2 – 15 m/s

Dilute-phase conveyors are the most widely applied conveying systems in the grain milling industry. The application of dense-phase conveyors is rather rare. Dilute-phase conveyors include the conveying systems shown in the chart below.

Dilute-phase conveying offers various advantages over dense-phase conveying:...


The 10th international conference of numerical analysis and applied mathematics, ICNAAM 2012 , started yesterday, honoring Gerhard Wanner on the occasion of his 70th birthday. Today, on his talk Gerhard Wanner talked about the work and influence on modern mathematics of Pappus , one of the last great greek mathematicians of antiquity. Pappus is known for his theorem on projective geometry.

The topics of the conference include numerical methods of fluid dynamics, numerical optimization, stochastic differential equations, methods of nanotechnology and nanomaterials,...


Στο βιβλίο The Computer and the Brain ο von Neumann παρουσιάζει τις απόψεις του σχετικά με τις αναλογίες μεταξύ των υπολογιστών και του ανθρώπινου εγκεφάλου. Στο πρώτο μέρος του βιβλίου, ο von Neumann περιγράφει τη δομή και τη λειτουργία του ηλεκτρονικού υπολογιστή, τόσο τις αναλογικές διεργασίες όσο και τις ψηφιακές, καθώς και το λογικό έλεγχο. Στο δεύτερο μέρος συνεχίζει με μια απλουστευμένη περιγραφή της λειτουργίας των νευρώνων, τη φύση του νευρικού ερεθίσματος και με το πρόβλημα της μνήμης μέσα στο νευρικό σύστημα.

Ο von Neumann καταλήγει ότι ο εγκέφαλος λειτουργεί εν μέρει...


Today was the presentation of Delta Pi Systems at the 10th international conference of numerical analysis and applied mathematics, ICNAAM 2012 , with title "Optimal control of coupled PDE networks with automated code generation".

The purpose of this work is to present a framework for the optimal control of coupled PDE networks. A coupled PDE network is a system of partial differential equations coupled together. Such systems can be represented as a directed graph. A domain specific language (DSL)--an extension of the DOT language--is used for the description of such a coupled PDE...