Fidelity™ Flow Density-based Solver

Modeling combustion applications implies handling multiple species together with complex physical and chemical reactions. Conjugate heat transfer and radiation have a large impact on the control of the temperature distribution and on combustion efficiency.

To respond to these requirements, Fidelity™ Flow offers several modeling strategies including the classical flamelet, the hybrid BML/flamelet method, and the Flamelet Generated Manifolds method (FGM) to analyze the range of purely non-premixed gaseous to purely premixed combustion applications.

The combustion model can be coupled with pollutant prediction, radiation, and conjugate heat transfer analysis.

For  a case study on combustion and radiative heat transfer in a generic gas turbine (GGT)

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Cavitation inception: Left, no local refinement - Right, dynamic mesh adaptation

Multiphysics applications often involve two or more fluids of different nature or of different phases of the same fluid. These form mixtures and interactions occur between each.

The Open solver offers a wide range of multifluid modeling approaches whose domain of application depends on the physical properties, concentration and homogeneity of the mixture.

The thermo-tables fluid definition captures the phase change phenomena. The inert or reacting multispecies model describes the mixture of gases or liquid such as pollutant tracking. The Lagrangian particles model tracks the motion of dilute dispersed particles and their interaction with the main phase, for example sprays, particulate flows, cyclones. These models can be coupled with all other physical phenomena of the multiphysics environment.

With the purpose of meeting future aircraft engine requirements in terms of low emissions, high reliability and efficiency, a novel highly efficient fully-coupled RANS-based approach has been developed, enabling the simulation of a full aero-engine within a single code.

One of the advantages of a fully coupled approach over a component-by-component approach is that the boundary conditions at the interfaces do not need to be guessed.

A Smart Interface methodology ensures a direct coupling between the different engine components, compressor- combustor-turbine, and allows the CFD models to vary between each component within the same CFD code.

For the simulation of the combustion process, the Flamelet Generated Manifold (FGM) method is applied. While the approach is superior to classical tabulated chemistry approaches and reliably captures finite-rate effects, it is also computationally inexpensive.

The Nonlinear Harmonic method is used to model the unsteady interaction between the blade rows as well as the influence of the non-homogeneities at the combustor outlet on the downstream turbine blade rows. This method is 2 to 3 orders of magnitude faster than a classical URANS simulation.

Impeller volute - Image courtesy of Liebherr

Fluid-Structure Interaction (FSI) occurs when a fluid flow deforms a structure which in return influences the flow field.

The significance of aeroelastic instabilities has increased substantially in the last few decades, particularly in the industry of aviation and turbomachinery. A continuous trend towards lightweight and cost-efficient design forces engineers to push the boundaries in the design phase with the risk of leading to vibratory stresses and, in the worst case, to vibratory failure. Cadence offers several approaches to predict fluid-structure interactions depending on:

• the direct coupling between the flow and the structural solvers, 
• the use of the coupling server MpCCI, which manages the communication and the interpolation of coupling data between the fluid and structure solvers, 
• or the modal approach in the flow solver that takes advantage of the harmonic solution of the NLH method and solves the modal equations, to compute the global deformation of the structure written as a composition of mode shapes, removing the necessity of interpolation between fluid and solid domains. 

For an interesting case about wing flutter     Read more

"Masten Space Systems heavily utilized the FINE Suite at HPC scale to design our next-generation reusable satellite launch system." 

Allan Grosvenor, Aerodynamics Lead at Masten Space Systems

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