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Radiative heat transfer modeling in numerical simulation of a heavy duty steam generator

Darbandi, M ; Sharif Universty of Technology

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  1. Type of Document: Article
  2. Publisher: American Institute of Aeronautics and Astronautics Inc, AIAA
  3. Abstract:
  4. The proper modeling of radiation is of great importance in numerical simulation of combustion processes. A simple gray weighted-sum-of-gray-gases (WSGG) model has been intensively used in CFD simulations of industrial combustion applications, mainly because of its low computational costs. However, the gray assumption is far from the real behavior of non-gray combustion gases. This could consequently affect the accuracy of temperature field and heat flux distribution predictions. On the other hand, modern non-gray global radiation models such as the standard spectral line-based weighted-sum-od-gray-gases (SLW) model are still computationally expensive for many engineering purposes. To overcome this shortcoming, we recently introduced the SLW3-opt model, which could efficiently calculate radiative heat transfer in combustion processes. Here, we implement the SLW3-opt model and further a gray WSGG model to simulate a utility boiler numerically. We first validate the accuracy of these models in the radiation calculations of an enclosure as a representative of a flame in a furnace. Investigation of the results demonstrates that the SLW3-opt model could provide the same accuracy of the standard SLW model in this test problem; however, with much lower computational costs. This is while the results of the gray WSGG model suffer from poor accuracy. Next, we simulate the case of a heavy duty steam generator using a comprehensive mathematical model for turbulent reactive flow. We present the results of numerical simulation by applying both SLW3-opt and gray WSGG models. Comparisons in this case also display that the gray predictions of temperature field and heat flux distribution have noticeable differences with the predictions provided by the SLW3-opt model. Therefore, care should be taken in applying the gray WSGG model to industrial CFD simulations. We suggest the SLW3-opt model for use in such simulations
  5. Keywords:
  6. Aerospace engineering ; Atmospheric radiation ; Aviation ; Combustion ; Computational fluid dynamics ; Forecasting ; Heat flux ; Heat transfer ; Radiative transfer ; Steam generators ; Temperature ; Combustion pro-cess ; Computational costs ; Heat flux distributions ; Industrial combustion ; Radiation calculations ; Radiative heat transfer ; Radiative heat transfer modeling ; Weighted-sum-of-gray-gases ; Numerical models
  7. Source: 54th AIAA Aerospace Sciences Meeting, 2016, 4 January 2016 through 8 January 2016 ; 2016 ; 9781624103933 (ISBN)
  8. URL: https://arc.aiaa.org/doi/abs/10.2514/6.2016-2151