Effect of Wall Heat Transfer on the Fluidization Process

The fluidized bed and the fluidization process and characteristics were studied in this paper numerically using Computational Fluid Dynamics (CFD) Ansys Fluent 15.0. Constant temperature was applied to both sides of the two-dimensional fluidized bed geometry. The superficial velocity of the working fluid ranged amid (0.08 – 0.5 m/s) and the initial height of the solid particles changed amid (0.05, 0.1, 0.2 m). Aluminum particles and water was used as working materials within the fluidized bed. The model used for the investigations was validated using Ngoh and Lim research results. The results showed that the fluidization head increases as the water inlet superficial velocity increases. As well as when the water inlet superficial velocity increases, the average solid phase temperature increases.

Study on “cold” Model of the Fluidization Process of Various Types of Biomass and Its Mixture With Coal

The analysis of experimental method for the evaluation of Umf in gas fluidized beds was carried out. It was based on pressure fluctuation measurements in which Umf is determined by the relationship between the standard deviation of pressure measurements and fluid velocity. Unlike previous works, this method was used to determine the minimum fluidization velocity of polydisperse beds of biomass (milled litter), and for beds of mixture of coal ash or sand particles and straw pellets. The experiments were carried out at room temperature in a transparent apparatus with a diameter of 172 mm. It was found that for some mixtures it is impossible to determine Umf from the curve of the pressure drop in the bed on fluid velocity. On the other hand, the method of determining Umf from the relationship between standard deviation of pressure measurements and fluid velocity allows this to be done for all studied beds.

Impinging Fluid in Immersed Granular Material to Obtain Local Fluidization for Breaking Sedimentation

Granular material is the most abundant material type in industry. Efforts to improve the efficiency of handling of granular material are continually ongoing. Sedimentation is one of the problems in transporting this material; when sedimentation occurs, the flow of material is obstructed and requires significant energy to clean the pipelines. The problem of sedimentation in pipes is thus an issue that merits serious attention. To solve the sedimentation problem, it is proposed to use the impinging method, which is a shock flow that is inserted into the granular sediment. This experiment to impinge immersed granular material is proposed to solve this depositional problem. Shooting high-speed fluid in a short time is expected to be one of the methods of preventing sedimentation that occurs in handling granular material. The material used in this experiment varies in granule size: very fine, fine, and medium-sized granules. These experiments provide an overview of post-impinging granular behavior with fluidization movement. For very fine granular size, post-impinging fluid cavity expansion occurs, followed by slow fluidization. This fluidization movement occurs for a long time. For fine granules, fluid cavity formation happens much faster, and fluidization occurs immediately. For medium-sized granules, post-impinging fluidization occurs immediately. To measure the impinging process to produce fluidization, the Reynold Number of Impinging (Re*) is used. The fluidization process occurs at Re* < 4000. The internal fluidization movements occur mainly at Re* values 2000-4000 (i.e. transition regions).