Challenges in Gas Turbine Combustor Design
The pressurized and heated air is injected with fuel inside the Combustor of a Gas Turbine. The flame temperature can go as high as 3000 F during the process. Considering that the typical material strength for common metals used in the Combustor starts decaying rapidly for temperatures higher than 1550 F, prediction of the flame shape and thermal field inside the Combustor is critical. Once the heat loads (and/or temperatures) on the components are predicted (and/or measured) different cooling strategies are applied during the design of Combustor parts.
Fig. 1 Gas temperature contours in a combustor
Engineering Solution
Thermal paint tests are a commonly used experimental approach to get an understanding of temperature variation on Combustor parts such as liner or cap at a single operating point. However, such tests are extremely costly and usually, temperature magnitude is hard to discern. These tests provide great insight to temperature variations and hot spots. Adding thermocouples on these parts provide locally measured temperatures. The flame temperature is hard to measure, and may only be visually detected for shape and location information.
Therefore, computational methods become key to properly quantify the heat load from combustion and the temperature of the parts. Computational Fluid Dynamics (CFD) methods are the most common physics based approaches to model the highly complex, reacting turbulent flow field present in the Combustors. Manufacturers use the simulations to do heat shield designs to protect components and extend life of high-temperature parts.
Ansys Solution Benefits
Ansys CFD software such as Fluent, offers high fidelity combustion and turbulence models. Besides, accurate heat transfer calculation, including radiation is a must for Combustor applications. Fluent also contains explicit conjugate heat transfer (CHT) for transient heat transfer and perforate wall model to handle tiny effusion holes for cooling.
Fig. 2 Wall temperature prediction by perforated wall model vs fully resolved effusion model
Further more, thermal boundary conditions from Fluent can easily be transferred to Ansys Mechanical for thermal, life and fatigue analyses. This enables better designs with increased life for hot components under dynamic load cycles. Another benefit of using Fluent is improved efficiency of cooling concepts.
In summary, Ansys provides best-in-class tools and industry-validated workflow for lifing of components!
Fig. 3 Ansys workflow for product lifing
Ozen Engineering Expertise
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Ozen Engineering Inc. leverages its extensive consulting expertise in CFD, FEA, optics, photonics, and electromagnetic simulations to achieve exceptional results across various engineering projects, addressing complex challenges like multiphase flows, erosion modeling, and channel flows using Ansys software.
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