Statistical modeling of turbulent diffusion combustion
Statistical modeling of turbulent diffusion combustion under the intermittency conditions. Mathematical model for calculation of carbon dioxide concentration
Tech Area / Field
- PHY-NGD/Fluid Mechanics and Gas Dynamics/Physics
3 Approved without Funding
Kazakh National University / Combustion Problems Institute, Kazakstan, Almaty
- Thermophysics Technologies INC, USA, TX, Sugar Land
Project summaryThe basic idea of the proposed Project is to develop the ASMTurbC method under intermittency conditions that will provide a researcher with the construction of high-performance physical-mathematical models for turbulent diffusion combustion.
The Project objectives are:
•To develop the ASMTurbC method for construction of high-performance physical-mathematical models for statistical characteristics of turbulent diffusion combustion.
•To develop a new ASMTurbC model for calculation of statistical characteristics of turbulent diffusion combustion of carbon-containing fuels, including carbon dioxide concentration.
•To validate the ASMTurbC model by the example of the submerged reacting jet of propane through the use of the ASMTurbC-MathCad and ASMTurbC-LES numerical models.
•To make computer codes with their further implementation in applied CFD software in effort to simulate submerged reacting axisymmetric jets of propane, including the carbon dioxide formation, and to calculate the self-similar statistical characteristics of such jets.
Our proposed ASMTurbC method based on a new principle of statistical modeling of turbulent diffusion combustion will be proposed on physics and mathematics grounds. The distinctive feature of the method proposed is that the effects of intermittency of dynamic and scalar fields will be taken into account with the implication of the known method of PDF for ‘reduced fuel concentration’. The ASMTurbC method will be validated by constructing and verifying a physical-mathematical model for turbulent diffusion combustion of the submerged reacting axisymmetric jet of propane. The results will be presented in the form of calculations of the main statistical characteristics of dynamic and scalar fields in the self-similar region of a turbulent diffusion flame, including carbon dioxide concentration distributions, and will be compared with the experimental reference data.
The ASMTurbC-based physical-mathematical model for turbulent diffusion combustion of the submerged reacting jet of propane will allow the statistical characteristics up to second central moments to be calculated. A special role here is played the potentialities of this model to predict more precisely carbon dioxide emissions. To verify the ASMTurbC-based model, the statistical characteristics of the submerged reacting propane jet in its self-similar region will be calculated.
The Project studies (in particular, ASMTurbC method development) are dealing with fundamental research in the field of the statistical theory of turbulent diffusion combustion and are aimed at taking into account the intermittency phenomenon. Fundamentally, our approach will different from the well-known RANS-PDF and LES-PDF methods that do not provide good accuracy of turbulent flow modeling.
The Project practical importance is that turbulent diffusion combustion is realized in combustion chambers of various engineering devices.
Technical Approach and Methodology.To achieve the Project objectives, the new approaches of statistical fluid mechanics considering intermittency events will be used, namely: the ASMTurb method for constructing physical-mathematical models for description of the energy-containing structure of a turbulent flow; the statistical theory of turbulent transfer of a passive scalar (admixture, pollution) with regard to the intermittency effects of a scalar field in an inhomogeneous turbulent flow; new principles of the LES theory under the intermittency conditions and the ASMTurb-based LES model for simulation of turbulent transfer of passive scalar.
The Project is a fundamental research of the statistical theory of turbulent diffusion combustion taking into account the intermittency phenomenon. Fundamentally, this theory is different from the well-known RANS-PDF and LES-PDF theories that do not provide good accuracy of turbulent flow modeling.
The ASMTurbC-MathCad and ASMTurbC-LES numerical models will be developed in the Project for simulation of the submerged axisymmetric reacting jet as a special type of turbulent diffusion combustion. In this case, the differential equations of statistical fluid dynamics can be reduced to a system of self-similar ordinary differential equations. However, for the more complicated turbulent flows (e.g., complex geometrical configuration, temperature stratification impact, etc.) such a procedure is hardly feasible and not always successful. That is why in the Project the ASMTurbC-LES method will be developed. This method will be capable of solving the turbulent diffusion combustion problems regarding to the more complicated structure of turbulent flows.