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Abstract Although most of the parameters affecting spiral jet milling have already been studied, there are no investigations of several parameters and their effects on the flow conditions over the entire cross-section inside the spiral jet mill via non-invasive methods. In order to vary several geometrical and operative parameters and to determine the flow conditions inside the jet mill, a new type of experimental spiral jet mill apparatus was designed and constructed. It has an almost entire optical accessibility and its highly modular construction enables a very convenient variation of the geometric parameters. This paper describes the new type of mill apparatus and preliminary experimental results concerning the flow conditions inside the spiral jet mill as well as grinding effects under different conditions on particle size distributions of barium sulphate micro particles.

The impact of the length of axially segmented lifters, as used in industrial rotary drums, on their process behavior and in particular the axial solids transport is analyzed in this study. Experime...

Abstract The impact of sectional internals, as often used in industrial rotary drums, on the axial solid transport in rotary drums is investigated experimentally under variation of the operation parameters solid feed rate, drum inclination and rotational speed. Different section numbers and internal-lengths have been analyzed, applying the axial dispersion model, in a fully optically accessible lab scale rotary drum apparatus. The mean residence times are increasing with the section numbers and their length up to 4 times compared to bare drum results. Capacity limits have been detected, resulting in higher back-spillage ratios dependent on the set of operational parameters. The impacts of parameter changes on the axial dispersion are decreasing with section number and length, resulting in a more constant axial dispersion coefficient of about 1 × 10−6 m2/s. A qualitative similarity of the axial solid bed profile proposed by the Saeman-model for bare drums has been found for sectional internals.

Abstract The effect of sectional internals on the solid bed cross section in rotary drums is investigated with a novel, fully optical accessible rotary drum apparatus for different internal configurations. The impact on mixing behavior is analyzed for different section numbers and filling degrees as well as material configurations. The mixing kinetics is affected positively by the sections, particularly for lower rotational speeds and filling degrees. The goodness of mixing in segregating particulate systems can be improved by sectional internals. Additionally to mixing effects, the impact of sectional internals on phase interfaces of the cross section is analyzed. A mathematical model description of the solid bed cross section is created and validated with the experimental data. The gas/solid interface is increasing logarithmically compared to the bare drum. The solid/inner wall interface is increasing linearly with the number of sections and the solid/outer wall interface is not affected significantly by sectional internals.

Abstract In this paper, a model-based scheme is presented for the detection and isolation of sensor faults in the vehicle lateral dynamics control systems. Core of the scheme is the handling of model uncertainties. This scheme has been successfully tested using real driving data.

AbstractThe influence of different internal geometries on the solid flow in rotary drums under variation of the operational parameters feed rate, slope, and rotational speed is investigated. Four different configurations of a fully optically accessible lab‐scale rotary drum are analyzed. The internals are built as sectional compartments of the cross section, referring to industrial applications. The axial dispersion model is used to calculate the mean residence times and axial dispersion coefficients. It can clearly be shown that the sectional internal geometries significantly increase mean residence times and holdups in dependence on the set of operational variables. The axial dispersion coefficients were in a comparable range with literature data.

Abstract Due to economical and safety advantages in comparison to existing technologies, gas hydrates show a vast potential with regard to several technical applications, like gas separation and storage. Therefore, an increased interest in applied gas hydrate research can be recognized. This paper describes the development of an absorption process which allows the immediate storage of gas in form of hydrates by the example of simulated natural gas comprising methane, ethane and propane. Methane is removed and stored in gas hydrates while natural gas liquids remain in the gas phase. The experiments were conducted under moderate conditions, using the thermodynamic promoter tetrahydrofuran in a stoichiometric concentration of 5.56 mole%. High storage capacities, formation rates and separation efficiencies were achieved, showing the feasibility of this concept. An adapted McCabe-Thiele-diagram was created to determine necessary stage numbers for high purity requirements.

Abstract Plenty of operational and geometric parameters have effects on spiral jet milling. Changes in the parameters cause distinctions in the flow conditions inside the mill and thereby also lead to consequences regarding the milled product. A new type of experimental spiral jet mill apparatus with almost entire optical accessibility enables a very convenient variation of the operational and geometric parameters as well as the determination of the flow conditions inside the spiral jet mill via non-invasive optical methods. Particle Image Velocimetry (PIV) measurements with diethylhexyl sebacat (DEHS) tracer droplets as well as solid barium sulphate micro particles were carried out to investigate the flow conditions inside the spiral jet mill. The differences between the net milling gas velocity fields and the velocity fields of loaded spiral jet mills were exposed. With the mill being loaded, the comminution zone decreases in the horizontal direction as well as decreases and deflects in the vertical direction. Besides, the analysis of the velocity fields inside the mill apparatus showed that decreasing milling nozzle numbers lead to increasing velocities inside the spiral jet mill, even if the mass flow rate of the gas supply is kept constant and the nozzle jet velocity is limited to sonic velocity at choked flow. With decreasing milling nozzle numbers, broader comminution zones and increasing lengths of the milling jets were investigated. As a consequence, a better grinding efficiency was expected and also confirmed with decreasing milling nozzle number by grinding experiments, as the new type of experimental apparatus was constructed in a fully operative way concerning the grinding ability.