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A practical computational fluid dynamics (CFD) approach to modeling effusion orifices in gas turbine combustor liners is proposed specifically when liner metal geometry is not included and conjugate heat transfer is not invoked. The focus is on eliminating effusion orifices from the model while maintaining the imprint of the orifices on the cold and hot sides of the liner wall. The imprinted boundaries serve as embedded mass flow inlets and outlets on both sides of the wall and maintain the integrity of the wall geometry. An empirical model is then used to extract and inject mass from the cold and hot sides of the liner, respectively. The mass extraction and injection process is performed for each orifice based on local conditions such as pressure, temperature and discharge coefficient. The discharge coefficient is, in turn, dynamically computed for each orifice based on approach angle, approach Mach number, discharge Mach number and orifice length to diameter ratio. With this approach, the fidelity of the liner wall is preserved for better heat transfer predictions and easier near wall meshing. In addition, the discharge coefficient is not assumed but calculated allowing the redeployment of inherently inadequate effusion orifice mesh cells to other critical areas of the combustor. Presented are results of two combustor cases to demonstrate the practicality and accuracy of the proposed method as compared to standard effusion modeling and their comparison with rig data.

This report describes an effort undertaken to improve small gas turbine combustor design I techniques. This analytical procedure is viewed as a significant step toward reducing the design and development time and the cost associated with future Army gas turbine combustors while simultaneously achieving a more durable and fuel-efficient design. The reader is referred to the report documentation page for a description of each of the three volumes of this report. It Is considered worthy of widespread application with the turbine Industry. Any critique or other response regarding its use should be addressed to this agency. Mr. Kent Smith of the Propulsion Technical Area, Aeronautical Technology Division, served as Project Engineer for this effort. '3 DISCLAIMERS The findings In this report are not to be construed as en official Department of the Army position unless so designated by other authorized documents. Mhen Government drawings, specifications, or other date are used for any purpose other then In connection with a definitely related Government procuremnent operation, the United $tate Government thereby Incurs no responsibility nor eny obligation whatsoever; and the fact that the Government may have formulated, furnished, or in any way supplied the sald drawings. specifications, or other date is not to be regarded by Implication or otherwise as in any manner licensing the holder or any other person or corporation, or conveylng any rights or permission, to rmanufacture, use, or sell any patented invention that may in any way be related thereto. Trade names cited in this report do not constitute en officiil endorsement or approval of the use of such h commercial hardware or softwsre, ,,POel 1" ION TRUCTIONS Destroy this report whon no longer needeld, D0 not return it to the originito,. Unclassi~fied SECWRIT'I CLASSIFICATION OF THIS PAO&E (fton, Data Sniet.d)

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Since 1998, the Honeywell Engines & Systems, Combustion & Emissions Group has been developing an advanced, CFD-based, parametric, detailed design-by-analysis tool for gas turbine combustors called Advanced Combustion Tools (ACT). ACT solves the entire flow regime from the compressor deswirl exit to the turbine stator inlet, and can be used for combustor diagnostics, design, and development. ACT is applicable to can, through-flow, and reverse-flow combustors, and accommodates features unique to different combustor designs. The main features of ACT are: 1. Reduction of Analysis Cycle Time: Geometry modeling and grid generation are fully parametric and modular, using an inhouse feature-based technology. Each geometrical feature can be deleted, replaced, added, and modified easily, quickly, and efficiently. 2. Elimination of Inter-Feature Boundary Assumptions: All the complex combustor features, such as wall cooling configuration, details of the air swirler assemblies and fuel atomizer systems, dome-shroud/cowl wall, and splash cooling plate, are considered and fully coupled into the CFD calculations. This allows the plenum and annulus aerodynamics to interact directly with the combustor internal flow. 3. Ease of Use: To reduce setup time and errors and to facilitate parametric studies, ACT is highly customized for engineers. 4. Accurate and Efficient CFD Solutions: Advanced physical submodels of combustion and spray have been implemented. This paper provides an overview and development experiences of ACT. Application of ACT to a through-flow combustor system is presented to illustrate the approach as applied to real-world combustors. Validation of the ACT system, by comparison to test cell data, is in-progress and will be the subject of a future paper.