Study On The Simulation Of Flame Manikin Test Based On The Theories Of Computational Fluid Dynamics

In recent years,with the development of computer technology,computational fluid dynamics(CFD)has a wide range of application to many fields especially the research of fabric thermal protective performance.Currently,numerical simulations for TPP and fire manikin experiments are carried out by scholars abroad as part of a study of the performance of thermal protective garments during an exposure to fire,while few domestic scholars do the research in this area.On the basis of reviewing the research at home and abroad,this paper developed an creative and integrated numerical simulator for the fire manikin experiment with CFD software.Though the establishment of the numerical simulation laboratory can't replace the real experiment,but it can provide reference data and improve work efficiency in the preparation and exploration of experiment.First,the fabric properties were tested,which provided the basic data to the boundary conditions of numerical dressed manikin experiment.Then,nude manikin experiment and dressed manikin experiment were conducted.The analysis of the heat transfer between the flame,air and manikin under flash fire exposure conditions provided a theoretical basis for the model selection of numerical simulation.At the same time,the infrared camera recorded the surface temperature distribution of manikin during and after combustion for testing the accuracy of the numerical simulation.With the analysis of air flow and heat transfer characteristics of combustion laboratory,the physical models in numerical simulation were determined.Then,the data cloud of nude and dressed manikin was scanned by non-contact 3D body scanner.After fixing the cloud data,wrapping the model,the manikin model was established with reverse engineering software Geomagic Studio.The manikin model was imported into Gambit to establish the laboratory and burner model.The computational domain was got through the split function,and discretized with unstructured grid technology.Based on the studies above and the theory of flame manikin test,the solver and physical models were defined in FLUENT.The numerical model reproduced the air flow indoor,the transient temperature and heat flux of the simulated manikin surface during and after the flash fire exposure.The numerical simulation of flame manikin test was established successfully.The verification of numerical model showed that the simulation of air flow indoor was feasible.The heat flux distribution of numerical manikin test and the cumulative frequency trend was basically reasonable.Because the proportion of the radiation heat flux in total heat flux is reasonable,the selection of radiation model is correct.The temperature trend of numerical manikin was the same with the temperature data which was measured by the infrared camera after the flame was extinguished,and the variations in data can be explained by the properties of sensor and manikin material.At last,the contour of clothing is too complex to be described by a single geometry and the air layer is too thin to be divided by grid,therefore the clothing was simplified to the cylinder.After the set of fabric boundary condition,the numerical simulation of dressed manikin was explored.In addition based on the establishment of the 3D manikin model,the distribution of air gap layer was reproduced with Geomagic Qualify,while the thickness of the air gap layer in different parts was calculated accurately.It's a new way to measure the thickness of air gap in any part of the manikin which is easy to be operated with less error and time.In summary,the numerical model of nude flame manikin test reproduced the temperature distribution and heat flux distribution of body surface,as well as the air flow in laboratory.It's a valid basis for the numerical simulation of dressed flame manikin test in future.Future research should consider more detailed chemical reaction mechanism and makes a more accurate and reliable numerical simulation of propane burner,with the establishment of the combustion box and clothing model closer to the true state.