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Heat Transfer Mathematical Modelling Numerical Methods and Information Technology Part 10

Tham khảo tài liệu 'heat transfer mathematical modelling numerical methods and information technology part 10', kỹ thuật - công nghệ, cơ khí - chế tạo máy phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | Study of Hydrodynamics and Heat Transfer in the Fluidized Bed Reactors 349 classification. Spherical particles with different diameter and a density of 1830 kg m3 were fluidized with air at ambient conditions. Typically the static bed height was 30 and 40cm with a solid volume fraction of 0.6. A roots-type blower supplied the fluidizing gas. A pressure-reducing valve was installed to avoid pressure oscillations and achieve a steady gas flow. The airflow rate was measured using a gas flow meter rotameter placed between the blower and the inlet pipe to an electrical heater. Initial solid particle temperature was 300K. An electrical heater was used to increase the inlet gas temperature from ambient temperature to 473K. A cooling system was used to decrease the gas temperature that exited from the reactor in order to form a closed cycle. Fig. 4 A shows a schematic of experimental set-up and its equipments. Pressure fluctuations in the bed were measured by three pressure transducers. The pressure transducers were installed in the fluidized bed column at different heights. Seven thermocouples Type J were installed in the center of the reactor to measure the variation of gas temperature at different locations. Also three thermocouples were used in different positions in the set-up to control the gas temperature in the heat exchanger and cooling system. Fig. 4. B shows the locations of the pressure transducers and thermocouples. The pressure probes were used to convert fluctuation pressure signals to out-put voltage values proportional to the pressure. The output signal was amplified digitized and further processed on-line using a Dynamic Signal Analyzer. Analog signals from the pressure transducers were band pass filtered 0-25 Hz to remove dc bias prevent aliasing and to remove 50 Hz noise associated with nearby ac equipment. The ratio of the distributor pressure drop to the bed pressure drop exceeded 11 for all operating conditions investigated. The overall pressure drop