The 17th edition of Computing+ Seminar was held on 19 Oct, 2023. Professor Clinton Groth, from Institute for Aerospace Studies, University of Toronto gave a lecture on New Interpolative-Based Maximum-Entropy Moment Closures for Predicting Real-Gas Radiative Heat Transfer with Application to Sooting Laminar Flames. The seminar was chaired by Dr. Kai Liu from Zhejiang University, and researchers from Zhejiang University participated in the seminar both on site and online.
Maximum-entropy-inspired interpolative-based moment closure methods are considered for the prediction of nonequilibrium radiative transfer in non-gray participating media, including application to sooting laminar flames. Professor Groth and his team studied interpolative-based versions of both the first- and second-order maximum entropy closures, M1 and M2. The interpolative-based closures were constructed so as to duplicate many of the desirable mathematical properties of maximum-entropy closure techniques, including positivity and moment realizablility of the distribution of radiative energy and hyperbolicity of the resulting moment equations while offering significant computational savings compared to approaches that involve the direct numerical solution of the optimization problem for entropy maximization.
In this talk, Professor Groth presented theoretical details of the proposed interpolative-based moment closures, along with a description of an efficient Godunov-type finite-volume scheme that had been developed for the numerical solution of the moment equations on multi-block body-fitted quadrilateral meshes with anisotropic adaptive mesh refinement (AMR). He assessed the predictive capabilities of the proposed non-gray interpolative-based M1 and M2 closures by considering their application to canonical radiative transfer problems involving transport through real gases with a strong spectral dependence of the absorption coefficient as well as to gaseous, methane-air, sooting, laminar, co-flow, diffusion flames at elevated pressures. Further, absorption properties of the gases for these applications were evaluated using a statistical narrow-band correlated-k model. The assessment also included comparisons to the predictions of more commonly adopted first-order, P1, and third-order, P3, spherical harmonic moment closures, as well as the popular discrete ordinates method (DOM). The numerical results demonstrated the potential of the maximum-entropy-inspired closures. In particular, the non-gray interpolative-based M1 and M2 closures were shown to provide improved predictions compared to the P1 closure and were of comparable or even of improved accuracy compared to the P3 closure, while providing additional computational robustness relative to the spherical harmonic closures. For the higher-pressure laminar flames, the M1 and M2 closures both yielded improved predictions compared to the P3 closure. For situations involving crossing photon beams emanating from different directions, the M2 closure provided better results compared to the M1 closure, which failed to capture such phenomena properly and instead might yield un-physical solutions.
The audiences echoed with Professor Groth’s work, and interacted with him during Q&A session. Professor Groth patiently answered all questions and engaged in an intense discussion with audiences onsite and online. The seminar was a success and continues the tradition of the Computing+ series.
About “Computing+” Seminar
The revolution characterized by intelligent computing has continued to drive the pervasive application of algorithms and computing power to information, life, and physical sciences, accelerating the construction of a joint world of human, physical world, intelligent machine and digital information science.
In this light, Shanghai Institute for Advanced Study, Zhejiang University launched 'Computing+' seminar series, inviting academics to share latest developments and exchange ideas and thoughts to further explore the intersections of computing with life sciences, engineering and social sciences.