Fin spacing interaction in fluidized bed heat exchangers

The work presented in this thesis is concerned with the heat transfer performance of a single horizontal bare tube and a variety of finned tubes immersed in a shallow air fluidized bed. Results of experimental investigations with the bare tube indicate that the tube position in the bed influences its performance narticularly where fine bed materials are used. In some cases the maximum heat transfer is obtained with the tube in the particle cloud just above the dense phase fluidized bed - a phenomenon that has not been previously observed. This was attributed to the unusual particle circulation in shallow beds. The data is also presented in dimensionless correlations which may be useful for design purposes. A close approximation to the bare tube data can be obtained by using thetransient heating of a spherical robe and this provides a valuable way of accumulating a lot of data very rapidly. The experimental data on finned tubes shows that a fin spacing less than twenty times the average particle diameter can cause a significant reduction in heat transfer due to the interaction which takes place between the particles and the surface of the fins. Furthermore, evidence is provided to show that particle shape plays an important part in the interaction with spherical particles being superior to angular particles at low fin spacing/particle diameter ratio. The finned tube data is less sensitive to tube position in the bed than bare tubes and the best performance is when the tube is positioned at the distributor.A reduction in bed depth decreases the thermal performance of the finned tube but in many practical installations the reduction in pressure drop might more than comnensate for the reduced heat flux. Information is also provided on the theoretical uerformance of fins and the effect of the root contact area between the fins and the tube was investigated.

Die Behandlung englischen Kulturgutes im Wiener fin de siècle:am Beispiel von Hugo von Hofmannsthal, Hermann Bahr und Peter Altenberg

This study explores the fascination which English culture represented in turn-of-the-century Vienna. The writers that are going to be discussed are the renowned Anglophile Hugo von Hofmannsthal, the more ambivalent Hermann Bahr and the idealizing, but Janus-faced Peter Altenberg. With the more widely known poet, prose writer and playwright, Hofmannsthal, individual aspects of his engagement with English culture have already been well researched; the same, however, cannot be said in the case of Hermann Bahr, whose extensive literary oeuvre has now largely been forgotten, and who has, instead, come to be valued as a prominent figure in the culture life of modernist Vienna, and Peter Altenberg, whose literary fame rests mainly on his prose poems and who, a legend in his life-time, has in recent years also increasingly attracted research interest as a phenomenon and ‘embodiment’ of the culture of his time: while their engagement with French literature, for example, has long received its due share of attention, their debt to English culture has, until now, been neglected. This thesis, therefore, sets out to explore Hofmannsthal’s, Bahr’s and Altenberg’s perception and portrayal of English civilization – ranging from English character and stereotypes, to what they saw as the principles of British society; it goes on to investigate the impulses they derive from Pre-Raphaelite art (Rossetti, Burne-Jones, Whistler) and the art and crafts-movement centred around William Morris, as well as their inspiration by the art criticism of John Ruskin and Walter Horatio Pater. In English literature one of the focal points will be their reading and evaluation of aestheticism as it was reflected in the life and writings of the Dubliner Oscar Wilde, who was perceived, by these Austrian authors, as a predominant figure of London’s cultural life. Similarly, they regarded his compatriot George Bernard Shaw as a key player in turn-of-the-century English (and European) culture. Hermann Bhar largely identified with him. Hofmannsthal, on the other hand, while having some reservations, acknowledged his importance and achievements, whereas Peter Altenberg saw in Shaw a model to reassure him, as his writings were becoming more openly didactic and even more miniaturistic than they had already been. He turned to Shaw, too, to explain and justify his new goal of making his texts more intelligent to a wider circle of readers.