CODES

Development of numerical solvers is a key effort within the CTF. The following software packages have been developed by members of CTF over the years:

A GPU-enabled Monte-Carlo ray tracing radiation solver

The modeling of thermal radiation in participating media is a challenge in computational heat transfer and combustion. In particular, systems with highly turbulent flows, multiple participating media, and spatial in-homogeneity, such as in gas turbine combustors and internal combustion engines, often require a spectrally-accurate and three dimensional model to obtain a satisfactory prediction of the radiative fluxes. The GPU-enabled MCRT radiation solver, combined with line-by-line spectral database, enables fast thermal radiation calculation in combustion environment. Compared to some of the state-of-art MCRT codes, this new solver features capability of ray-tracing through polyhedral mesh and flexibility of employing the most-efficient computer backend, be it CPU or GPU through the usage of Kokkos.

The code can be used as a stand-alone radiation solver or coupled to CFD software packages. It has been tested with OpenFOAM-5 and 7 as of Nov. 2024. A speedup of 400x has been observed with Nvidia’s A100 CPU card, compared to a single-core CPU calculation.

We welcome researchers for collaboration in further developing the code or simply utilizing the code.
Please contact Prof. Xinyu Zhao for access to the code.

Sponsors: Office of Naval Research, FM

A one-dimensional analytical model for solving radiative absorption within diffusion flames

The CylinderModel is a standalone Fortran code to compute the radiative absorption and net radiative loss according to the one-dimensional cylinder model. The code supports both gray and non-gray calculations. Please refer to the following two papers for more information:

Guilherme C. Fraga, B. Wu, M. Ihme, and X. Zhao (2023). Assessing requirements for modeling radiation in diffusion flames using an analytical, non-local model. Combustion and Flame 255, 112907.

Wu, B., M. Ihme, and Zhao, Xinyu (2021). Assessment of the flamelet assumptions for modeling a small-scale turbulent pool fire. Combustion and Flame 227, 346–358.

The code is publicly available through Github here.

Sponsors: FM

A ZND-type mini-solver for spray detonation

Similar to detonation toolbox, a ZND-type of solver is developed for understanding structures of spray detonation. The solver considers detonation through monodispersed spray droplets in the shock-stationary frame. Please refer to the following paper for more information. We are actively developing the code to include more modern droplet breakup models currently.

Nicolas N. Tricard and Zhao, Xinyu (Jan. 2022). One dimensional modeling of spray detonations considering loss effects. In: AIAA Scitech Forum. San Diego, CA.

The code is publicly available through Github here.

Sponsors: FM

OpenFOAM cases for conjugate heat transfer verification

A collection of validation cases used to validate the chtMultiRegionFoam (shipped with OpenFOAM-5.x), in-house versions (chtMultiRegionDecoupleFoam), and the reacting version developed by E. Daymo and M. Hettel (multiRegionReactingFoam) [2]. The cases include a infinitely fast flame (IFF) [1], flame-wall interaction (FWI) [1], and free convection. Refer to [3] for full details concerning the verification and validation of the OpenFOAM solvers mentioned above.

[1] Duchaine, F. et al., Conjugate heat transfer with large eddy simulation for gas turbine components, Colloque INCA, 2008.

[2] Daymo, E. and Hettel, M. Chemical Reaction Engineering with DUO and chtMultiRegionReactingFoam. In 4th OpenFOAM User Conference, pages 1–28, 2016.

[3] Toumey, J. Development of a Large Eddy Simulation Solver with Conjugate Convective and Radiative Heat Transfer. MS Thesis. University of Connecticut, 2021.

The cases can be found on GitHub here.