LASER-DIAGNOSTIC MAPPING OF TEMPERATURE AND SOOT STATISTICS IN A 2-m DIAMETER TURBULENT POOL FIRE.
Abstract Not Provided
Kearney, Sean P↗
Engineering topics
Blanchat, Thomas K
Publications and source records attributed to Blanchat, Thomas K.
LASER-DIAGNOSTIC MAPPING OF TEMPERATURE AND SOOT STATISTICS IN A SOOTING TURBULENT POOL FIRE.
Abstract Not Provided
Kearney, Sean P↗
Hydrocarbon characterization experiments in fully turbulent fires : results and data analysis.
As the capabilities of numerical simulations increase, decision makers are increasingly relying upon simulations rather than experiments to assess risks across a wide variety of accident scenarios including fires. There are still, however, many aspects of fires that are either not well understood or are difficult to treat from first principles due to the computational expense. For a simulation to be truly predictive and to provide decision makers with information which can be reliably used for risk assessment the remaining physical processes must be studied and suitable models developed for the effects of the physics. The model for the fuel evaporation rate in a liquid fuel pool fire is significant because in well-ventilated fires the evaporation rate largely controls the total heat release rate from the fire. This report describes a set of fuel regression rates experiments to provide data for the development and validation of models. The experiments were performed with fires in the fully turbulent scale range (> 1 m diameter) and with a number of hydrocarbon fuels ranging from lightly sooting to heavily sooting. The importance of spectral absorption in the liquid fuels and the vapor dome above the pool was investigated and the total heat flux to the pool surface was measured. The importance of convection within the liquid fuel was assessed by restricting large scale liquid motion in some tests. These data sets provide a sound, experimentally proven basis for assessing how much of the liquid fuel needs to be modeled to enable a predictive simulation of a fuel fire given the couplings between evaporation of fuel from the pool and the heat release from the fire which drives the evaporation.
99 GENERAL AND MISCELLANEOUS↗
Metal fires and their implications for advanced reactors.
This report details the primary results of the Laboratory Directed Research and Development project (LDRD 08-0857) Metal Fires and Their Implications for Advance Reactors. Advanced reactors may employ liquid metal coolants, typically sodium, because of their many desirable qualities. This project addressed some of the significant challenges associated with the use of liquid metal coolants, primary among these being the extremely rapid oxidation (combustion) that occurs at the high operating temperatures in reactors. The project has identified a number of areas for which gaps existed in knowledge pertinent to reactor safety analyses. Experimental and analysis capabilities were developed in these areas to varying degrees. In conjunction with team participation in a DOE gap analysis panel, focus was on the oxidation of spilled sodium on thermally massive surfaces. These are spills onto surfaces that substantially cool the sodium during the oxidation process, and they are relevant because standard risk mitigation procedures seek to move spill environments into this regime through rapid draining of spilled sodium. While the spilled sodium is not quenched, the burning mode is different in that there is a transition to a smoldering mode that has not been comprehensively described previously. Prior work has described spilled sodium as a pool fire, but there is a crucial, experimentally-observed transition to a smoldering mode of oxidation. A series of experimental measurements have comprehensively described the thermal evolution of this type of sodium fire for the first time. A new physics-based model has been developed that also predicts the thermal evolution of this type of sodium fire for the first time. The model introduces smoldering oxidation through porous oxide layers to go beyond traditional pool fire analyses that have been carried out previously in order to predict experimentally observed trends. Combined, these developments add significantly to the safety analysis capabilities of the advanced-reactor community for directly relevant scenarios. Beyond the focus on the thermally-interacting and smoldering sodium pool fires, experimental and analysis capabilities for sodium spray fires have also been developed in this project.
22 GENERAL STUDIES OF NUCLEAR REACTORS↗
Temperature and heat flux datasets of a complex object in a fire plume for the validation of fire and thermal response codes.
It is necessary to improve understanding and develop temporally- and spatially-resolved integral scale validation data of the heat flux incident to a complex object in addition to measuring the thermal response of said object located within the fire plume for the validation of the SIERRA/FUEGO/SYRINX fire and SIERRA/CALORE codes. To meet this objective, a complex calorimeter with sufficient instrumentation to allow validation of the coupling between FUEGO/SYRINX/CALORE has been designed, fabricated, and tested in the Fire Laboratory for Accreditation of Models and Experiments (FLAME) facility. Validation experiments are specifically designed for direct comparison with the computational predictions. Making meaningful comparison between the computational and experimental results requires careful characterization and control of the experimental features or parameters used as inputs into the computational model. Validation experiments must be designed to capture the essential physical phenomena, including all relevant initial and boundary conditions. This report presents the data validation steps and processes, the results of the penlight radiant heat experiments (for the purpose of validating the CALORE heat transfer modeling of the complex calorimeter), and the results of the fire tests in FLAME.
99 GENERAL AND MISCELLANEOUS↗
Test plan for validation of the radiative transfer equation.
As the capabilities of numerical simulations increase, decision makers are increasingly relying upon simulations rather than experiments to assess risks across a wide variety of accident scenarios including fires. There are still, however, many aspects of fires that are either not well understood or are difficult to treat from first principles due to the computational expense. For a simulation to be truly predictive and to provide decision makers with information which can be reliably used for risk assessment the remaining physical processes must be studied and suitable models developed for the effects of the physics. A set of experiments are outlined in this report which will provide soot volume fraction/temperature data and heat flux (intensity) data for the validation of models for the radiative transfer equation. In addition, a complete set of boundary condition measurements will be taken to allow full fire predictions for validation of the entire fire model. The experiments will be performed with a lightly-sooting liquid hydrocarbon fuel fire in the fully turbulent scale range (2 m diameter).
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
Prescriptive vs. performance based cook-off fire testing.
In the fire safety community, the trend is toward implementing performance-based standards in place of existing prescriptive ones. Prescriptive standards can be difficult to adapt to changing design methods, materials, and application situations of systems that ultimately must perform well in unwanted fire situations. In general, this trend has produced positive results and is embraced by the fire protection community. The question arises as to whether this approach could be used to advantage in cook-off testing. Prescribed fuel fire cook-off tests have been instigated because of historical incidents that led to extensive damage to structures and loss of life. They are designed to evaluate the propensity for a violent response. The prescribed protocol has several advantages: it can be defined in terms of controllable parameters (wind speed, fuel type, pool size, etc.); and it may be conservative for a particular scenario. However, fires are inherently variable and prescribed tests are not necessarily representative of a particular accident scenario. Moreover, prescribed protocols are not necessarily adaptable and may not be conservative. We also consider performance-based testing. This requires more knowledge and thought regarding not only the fire environment, but the behavior of the munitions themselves. Sandia uses a performance based approach in assuring the safe behavior of systems of interest that contain energetic materials. Sandia also conducts prescriptive fire testing for the IAEA, NRC and the DOT. Here we comment on the strengths and weakness of both approaches and suggest a path forward should it be desirable to pursue a performance based cook-off standard.
45 MILITARY TECHNOLOGY, WEAPONRY, AND NATIONAL DEF↗