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A combination of the experimental and numerical methods was used to investigate the fluid flow behaviors in a proposed cyclone burner. Recirculation flow and pressure drop, two of the important fluid flow behaviors that affect the burner's performance, have been studied here. Experimentally, the recirculation flow phenomenon in the burner was observed through paper slices dynamic in a transparent burner, and pressure drop was measured using a tube manometer. Meanwhile numerically, the fluid flow behaviors were simulated using the standard k-e turbulence model, under Ansys-Fluent software. The simulation results showed that, at a certain value of inlet aspect ratio (R IA ) and initial tangential intensity (I IT ), especially for high I IT , the recirculation flow phenomenon was clearly observed in the center of the burner cylinder which closely resembles a tornado-tail. The indication of existence recirculation flow was also found from the experiment results. The study also exhibited that the results of simulated static pressure drop were closely approaching the experiment results, particularly for I IT values £ 4.3. The mean deviation of static pressure between the simulation and the experiment results, for a varied range of R IA and I IT ,was about 15%. From the results above, it was obvious that fluid flow behaviors (recirculation flow and static pressure) in the proposed cyclone burner are greatly influenced by the R IA and I IT values, where the I IT effect was more significant compared to the R IA . This study also suggests that, the standard k-e turbulence model could be relied upon to well predict the behaviors of fluid flow in the proposed cyclone burner, at low to moderate swirl intensities.

Flow structure inside a chamber greatly determines the process performances. Therefore, the flow structure inside a chamber are often constructed in such a way as an effort to obtain equipment performances in accordance with the expectations. This study explored flow structure inside several chamber geometries and operating conditions. Three types of chamber, namely; GTC, DTC and TJC were set as the investigated chambers. The Computational Fluid Dynamics technique, supported by some experimental data from the literature, is used as an investigation method. The RANS based models, under Ansys-Fluent software were used in this numerical investigation. Simulation results revealed that the flow structures of GTC and DTC are predominantly created by spiral and vortex patterns. The vortex stabilizer diameter in the GTC affects the vortex pattern, velocity profile and pressure drop. The flow structure of DTC presents the most complex behavior. The flow structure inside TJC, in the case of unconfined outlet boundary, is characterized by the helical and wavy jet pattern. This structure is determined by the initial tangential intensity (IIT) and the inlet aspect ratio (RIA). The structures of vortex, helical, and wavy axial flow are properly constructed and visualized in this paper. There is no a turbulence model which is always superior to the other models, consistently. The standard k-ε model exhibits the realistic and robust performances among all of investigatied cases.

Solid fuel combustion is always preceded by chemical decomposition. This process is largely determined by the flow structure and affected by the geometry and operating conditions of the combustion chamber. This study aimed to investigate the effect of relative axial inlet diameter (Dai//Dbc) on the flow structure in the proposed cyclone burner. The flow structure was determined with the standard k-e turbulent model using the Ansys-Fluent software. From the simulation results it was concluded that with all the axial inlet diameters used an integrated vortex formed in the center of the burner cylinder. The integrated vortex consisted of two vortices, namely a primary vortex and a secondary vortex. The primary vortex penetrated from the furnace box to the burner cylinder, while the secondary vortex was formed in the burner cylinder itself. There were two integration patterns from the primary vortex and the secondary vortex, namely a summation pattern and a multilayer pattern. The presence of a vortex in the center of the burner cylinder is allegedly responsible for an increase in the degree of mixing and pressure drop in that zone. The flow structure induced from the proposed burner had high symmetricity and was largely determined by the burner's axial inlet diameter.