Optical fibres simulation

It is important to model a correlation spectroscopy system, firstly to predict performance, and also to aid the very important choice of optical filter (or choose the best LED or super-luminescent optical fibre source to give the optimal spectral output), in order to achieve the best detection performance or best selectivity possible. The length of the cells and the pressure of gas (or gas concentration) are also important parameters (although all simulated results described below are based on use of lm long cells). 

Environmental monitoring has also taken advantage of acoustic levitation for the investigation of physico-chemical processes relevant to the troposphere — mainly at temperatures below 0°C. Gas-liquid transfer of H2O2 from the gas phase to the levitated droplet was studied from in situ chemiluminescence measurements. Also, freezing of stably positioned droplets was observed by means of a microscope and a video camera, and the usefulness of this technique for simulation and investigation of cloud processes thus demonstrated. Ex situ microanalysis of sub-microlitre droplets by the use of an optical fibre luminometer also proved an effective means for investigating important physicochemical processes at the micro scale [100]. 

P Plaza, NQ Dao, M Jouan, H Fevrier, H Saisse. Simulation et optimisation des capteurs k fibres optiques adjacents. Appl Optics 25 3448-3454, 1986. 

ABSTRACT. Characteristics and fluid dynamics of gas phase recirculation in a novel Riser Simulator Reactor have been investigated using constant temperature hot wire anemometry. In situ concentration and velocity measurements enabled to evaluate the mixing time and the inner recirculation ratio of the gas phase. In addition, fibre optic techniques allowed to characterize the degree of fluidization of the catalyst particles and the effect of gas phase density changes. By combining the anemometry and the fibre optic techniques, mixing patterns in the Riser Simulator have been evaluated. The importance of the study can be realized in the context of the potential use of the Riser Simulator for gas-solid reaction kinetics. 

Figure 1. Schematics of the experimental system fibre optic system and hot wire anemometer are described as connected to the Riser Simulator Reactor.

To further evaluate the fluid-solid mixing characteristics taking place in the catalyst bed a fibre optic probe technique was used. The fibre optic probe was inserted from the side of the reactor through the basket where the probe contacts with catalyst particles. A schematic of the system is shown in Figure 1. It has to be noted that two models, cold and hot model, were constructed to apply the fibre optic technique (Kraemer, 1990). The cold model was made of plexiglass material and had the same internal dimensions as the hot model or the Riser Simulator Reactor made of inconel. 

LinkJM, Godlieb W, Tripp P, et al Comparison of fibre optical measurements and discrete element simulations for the study of granulation in a spout fluidised bed. Powder Technol 189 202-217, 2009. 

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