A review of heat transfer and flow friction data for staggered arrays of pin fins in turbine cooling applications is presented. This review presents discussions on local-and array-averaged heat transfer, the effects of different geometric parameters such as pin height and pin spacing on heat transfer and flow friction, and the effect of the accelerating flow in converging pin fin channels. A review of current heat transfer correlations is also presented with recommendations for correlating parameter limits and correlation accuracy. The correlations currently available for friction factor are reviewed, with an attempt to account for the effects of the converging channels.

The objective of the Innovative High-Temperature Fuel Nozzle Program was to design, fabricate, and test propulsion engine fuel nozzles capable of performance despite extreme fuel and air inlet temperatures. Although a variety of both passive and active methods for reducing fuel wetted-surface temperatures were studied, simple thermal barriers were found to offer the best combination of operability, cycle flexibility, and performance. A separate nozzle material study examined several nonmetallics and coating schemes for evidence of passivating or catalytic tendencies. Two pilotless airblast nozzles were developed by employing finite-element modeling to optimize thermal barriers in the stem and tip. Operability of these prototypes was compared to a current state-of-the-art piloted, prefilming airblast nozzle, both on the spray bench and through testing in a can-type combustor. The three nozzles were then equipped with internal thermocouples and operated at 1600F air inlet temperature while injecting marine diesel fuel heated to 350F. Measured and predicted internal temperatures as a function of fuel flow rate were compared. Results show that the thermal barrier systems dramatically reduced wetted-surface temperatures and the potential for coke fouling, even in an extreme environment.

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.

The objective of the innovative high-temperature fuel nozzle program was to design, fabricate, and test propulsion engine fuel nozzles capable of performance despite extreme fuel and air inlet temperatures. Although a variety of both passive and active methods for reducing fuel wetted-surface temperatures were studied, simple thermal barriers were found to offer the best combination of operability, cycle flexibility, and performance. A separate nozzle material study examined several nonmetallics and coating schemes for evidence of passivating or catalytic tendencies. Two pilotless airblast nozzles were developed by employing finite-element modeling to optimize thermal barriers in the stem and tip. Operability of these prototypes was compared to a current state-of-the art piloted, prefliming airblast nozzle, both on the spray bench and through testing in a can-type combustor. The three nozzles were then equipped with internal thermocouples and operated at 1600°F air inlet temperature while injecting marine diesel fuel heated to 350°F. Measured and predicted internal temperatures as a function of fuel flow rate were compared. Results show that the thermal barrier systems dramatically reduced wetted-surface temperatures and the potential for coke fouling, even in an extreme environment.

Ingersoll-Rand Energy Systems commissioned the construction of a fuel mixing facility to test its commercial microturbines fueled with alternative fuels like those produced by landfills, agricultural digesters, wastewater treatment plants, and petroleum gas well heads. This paper provides an overview of the fuel mixing facility and its capabilities, a discussion of diluted fuel compositions that are typically found in field applications, and a summary of the combustion performance of the IR 250 kW and 70 kW microturbines while operating on diluted fuels (LHV < 34 MJ/m3). The pollutant emission measurements taken with the microturbine burning diluted fuel supplied by the fuel mixing facility are compared with the measured emissions taken from a microturbine operating at a landfill to provide validation of the measurements gathered from the fuel mixing facility. Pollutant emissions are closely tied to not only the magnitude of diluents, but the composition of the diluents as well.