High Fidelity Modeling and Simulation of Turbulent Flame Spread Over Charring Materials

1033328 DesJardin The objective of this proposal is to develop an advanced modeling and simulation framework for predicting fire spread. The modeling is based on Large Eddy Simulation (LES) techniques using a newly developed embedded fame spread modeling (EFSM) approach that will result in unprecedented accuracy in the prediction of turbulent fame spread. Validation and verification of this new modeling approach and dissemination of knowledge to the public will be facilitated by a strong collaboration with U.S. government and industry laboratories specializing in fire science. Specifically, the agencies involved are the Fire Science and Technology department at Sandia National Laboratories (SNL), and Factory Mutual Global Research (FM Global). These collaborations will result in: (1) a web-portal will be created for the downloading and using the EFSM library and (2) a fame spread workshop will be hosted by the University at Buffalo during the second year of the effort. All of the tools and modeling methods developed in this research endeavor will be incorporated into the classroom through a class the P.I. currently teaches on Fire Science and Safety Engineering. Intellectual Merit: The intellectual merit of this research is in a unified predictive computational capability to predict turbulent fame spread over charring materials. The modeling advancements for this effort are focused on: (1) a new modeling approach for predicting turbulent wall fires based on the use of EFSM, (2) a thermal model to account for charring of construction materials, (3) a new near-wall boundary model and scaling theory for computing buoyancy driven turbulent reacting boundary layers. The implementation of these models will be incorporated into an existing high-order accurate fluid-structure computational framework for simulating coupled conjugate heat and mass transfer using both direct numerical simulation (DNS) and LES. The inclusion of the models will require numerical algorithm advances for use on massively parallel computers that will result in unprecedented levels of time and spatial resolution for the prediction of turbulent flame spread. These advances include: (1) an adaptive mesh refinement procedure for computation of conjugate heat and mass transfer processes across solid-gas interfaces and (2) a new embedded cut-cell approach for computing participating radiation heat transfer in complex geometries. Broader Impact: The impact of this research on society is to offer scientific insight on the growth of large scale structural fires. The longer term impact of this research is to provide a high fidelity, broad-based computational tool, to predict the performance of structures from fire and a trained workforce who are able to use these tools for high performance computing. The expectation is that these efforts will provide suggestions for new performance based design approaches for insuring fire safety of critical infrastructures. In addition, the broad-based mathematical, modeling and simulation framework developed as part of this research is not unique to flame spread modeling and could also be used to analyze a wide range of energy-conversion problems which involve fluid-solid conjugate heat and mass transfer processes for reacting flows.