Numerical simulation and experimental investigation of heat transfer coefficient and pressure drop in a fluidized bed

نوع: Type: thesis

مقطع: Segment: Masters

عنوان: Title: Numerical simulation and experimental investigation of heat transfer coefficient and pressure drop in a fluidized bed

ارائه دهنده: Provider: Muhammad Georjie Azandaryani

اساتید راهنما: Supervisors: Habib Allah sayehvand

اساتید مشاور: Advisory Professors:

اساتید ممتحن یا داور: Examining professors or referees: Fazl Allah Eskandari Manjili, Mohsen Goodarzi

زمان و تاریخ ارائه: Time and date of presentation: 2022/03/13 , 14:00

مکان ارائه: Place of presentation: online

چکیده: Abstract: Fluidization is a kind of a unit operation through which a bed of solid particles placed on a fluid dispensing plate behaves similarly to a fluid at a velocity above a certain critical velocity. Its industrial applications include drying, washing, direct reduction, and centrifugal fluidized beds. In this dissertation, a fluidized bed has been studied using numerical simulation and performing experimental works. Important hydrodynamic parameters such as pressure drop in the bed, minimum velocity required for fluidity, heat transfer coefficient and the effect of bed height on these parameters have been studied numerically and experimentally. In addition, the effect of particle density on the pressure drop, the ratio of the dimensions of the cylindrical chamber and the condition of the bed in terms of bubble formation and flow regime have been investigated only numerically. In numerical solution, the Eulerian two-fluid model, the theory of kinetic energy of granular flows and the Gidaspow drag model are used to analyze the pressure drop. The Nusselt model is used for thermal analysis. The experimental setup was simulated in two dimensions using Ansys Fluent 18 software. The results showed that the numerical graphs of density, pressure drop and pressure in terms of inlet gas velocity are very well matched with the graphs obtained from the experimental method. There is also a slight difference between the experimental and numerical graphs of the heat transfer coefficient. According to the results, with increasing the density of particles in the bed, the pressure drop also increases. In addition, as the inlet gas velocity increases, the bed heat transfer coefficient increases. On the other hand, according to the experimental results, the bed pressure increases up to the onset speed of fluidity. Then in a certain range, the pressure drop fluctuates. The results also show that with increasing the immersion depth of the heater in the bed, the heat transfer coefficient increases and after a depth of 30 mm from the solid bed surface, the depth changes have no effect on reducing or increasing the heat transfer coefficient. Taking into account all the obtained results, the optimal velocity of the gas entering the substrate is 0.07 m / s and the appropriate depth of the heater for heat transfer is 10 mm from the surface of the particles.

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