Thursday, May 20, 2010

Tutorial : GAMBIT - MODELING A COMBUSTION CHAMBER (3-D)


In this tutorial, you will create the geometry for a burner using a top-down geometry construction method in GAMBIT (creating a volume using solids). You will then mesh the burner geometry with an unstructured hexahedral mesh.

In this tutorial you will learn how to:
• Move a volume
• Subtract one volume from another
• Shade a volume
• Intersect two volumes
• Blend the edges of a volume
• Create a volume using the sweep face option
• Prepare the mesh to be read into FLUENT 5/6 

In this tutorial, you will create a combustion chamber geometry using the “top-down” construction method. You will create volumes (in this case, bricks and cylinders) and use Boolean operations to unite, intersect, and subtract these volumes to obtain the basic geometry. Finally, using the “blend” command, you will round off some edges to complete the geometry creation.

For this model, it is not possible to simply pick the geometry and mesh the entire domain with hexahedral elements, because the Cooper tool (which you will be using in this tutorial) requires two groups of faces, one group topologically parallel to a sweep path, and the other group topologically perpendicular. However, the rounded (blended) edges fit in neither group. See the GAMBIT Modeling Guide for a more detailed description of the Cooper tool. You need to decompose the geometry into portions that can be meshed using the Cooper tool. There are several ways to decompose geometry in GAMBIT. In this example, you will use a method whereby portions of the volume around the blend are split off from the main volume.

The problem to be considered is shown schematically in Figure above. The geometry consists of a simplified fuel injection nozzle that feeds into a combustion chamber. You will only model one quarter of the burner geometry in this tutorial, because of the symmetry of the geometry. The nozzle consists of two concentric pipes with radii of 4 units and 10 units respectively. The edges of the combustion chamber are blended on the wall next to the nozzle.

DOWNLOAD TUTORIAL
TUTORIAL GAMBIT 04


- Experimental studies of incineration in a cylindrical combustion chamber
- Design Engineering Challenges and Solutions of Kistler Automotive Combustion Pressure Sensors, Water-cooled Sensors, Piezoelectric Sensors, the Crank Angle ... System, and the Sensor Calibrarion Process
- Fuels of Opportunity: Characteristics and Uses in Combustion Systems

Combustion Science and Engineering (Computational Mechanics and Applied Analysis)Combustion, Fourth Edition

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