A system for measuring bubble voidage and frequency around tubes immersed in a fluidized bed of particles.
Gas-solid fluidized beds are common in chemical processing and energy production industries. These types of reactors frequently have banks of tubes immersed within the bed to provide heating or cooling, and it is important that the fluid dynamics within these bundles is efficient and uniform. This paper presents a simple, low-cost method for quantitatively analyzing the behavior of gas bubbles within banks of tubes in a fluidized bed cold flow model. Two probes, one containing an infrared emitter and one containing an infrared (IR) detector, are placed into adjacent glass tubes such that the emitter and detector face each other. As bubbles pass through the IR beam, the detector signal increases due to less solid material blocking the path between the emitter and detector. By calibrating the signal response to known voidage of the material, one can measure the bubble voidage at various locations within the tube bundle. The rate and size of bubbles passing through the beam can also be determined by high frequency data collection and subsequent analysis. This technique allows one to develop a map of bubble voidage within a fluidized bed, which can be useful for model validation and system optimization.
Hydrodynamics of multi-sized particles in stable regime of a swirling bed
Using particle imaging velocimetry (PIV), we observed particle motion within the stable operating regime of a swirling fluidized bed with an annular blade distributor. This paper presents velocity profiles of particle flow in an effort to determine effects from blade angle, particle size and shape and bed weight on characteristics of a swirling fluidized bed. Generally, particle velocity increased with airflow rate and shallow bed height, but decreased with bed weight. A 3° increase in blade angle reduced particle velocity by approximately 18%. In addition, particle shape, size and bed weight affected various characteristics of the swirling regime. Swirling began soon after incipience in the form of a supra-linear curve, which is the characteristic of a swirling regime. The relationship between particle and gas velocities enabled us to predict heat and mass transfer rates between gas and particles.
Looking for regional words in late seventeenth-century England: Bishop White Kennett and his glossary to Parochial Antiquities (1695) 1
The analysis of regional dialects in the Early Modern period has commonly been disregarded in favour of an ample scholarly interest in the ‘authorised’ version of English which came to be eventually established as a standard. The history of regional ‘Englishes’ at this time still remains to a very great extent in oblivion, owing mainly to an apparent dearth of direct textual evidence which might provide trustworthy data. Research in this field has been for the most part focused on phonological, orthographical and morphological traits by virtue of the rather more abundant information that dialect testimonies yield about them. Regional lexical diversity has, on the contrary, deserved no special attention as uncertainty arises with regard to what was provincially restricted and what was not. This paper endeavours to offer additional data to the gloomy lexical setting of Early Modern regional English. It is our aim to give a descriptive account of the dialect words collated by Bishop White Kennett’s glossary to Parochial Antiquities (1695). This underutilised specimen does actually widen the information furnished by other well known canonical word-lists and provides concrete geographical data that might contribute to bridging the gaps still existing in the history of lexical provincialisms at the time.