• Journal of the Korean Society of Safety
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• v.22 no.6
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• pp.46-54
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• 2007

The purpose of this study was to examines the burning rate of fire retardant treated wood in the cone heater with a one-dimensional integral model. The wood samples used in this study were four species. The species of woods are Redwood, White oak, Douglas fir and Maple. Each sample was nominally 50mm thick and 100mm square. Samples were exposed to a range of incident heat fluxes 10 to $35kW/m^2$ using the cone heater. A one-dimension integral model has been used to predict burning rate, heat of gasification, flame heat fluxes, charring rate and char depth of samples. As a result measurement of mass loss rate, softwoods(Redwood and Douglas fir) has relatively low value than those for hardwoods(White oak and Maple). Average charring rate of woods in case of fire retardant treatment showed reduction effect of 41.29%, 50.00%, 48.18% and 60.82% for Redwood, Douglas fir, White fir and Maple, respectively. Almost all the predictions from integral model showed faster charring than those measured. Average difference between predictions and experimental data was 16%, 9.5% and 11.8% for N, F1 and F2 respectively. Water-soluble fire retardant used in this study find out more effect in hardwood than softwood from the result of measurement of mass loss rate and average charring rate.

• Journal of the Korea Institute of Building Construction
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• v.23 no.1
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• pp.23-33
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• 2023

It is widely known that the level of fire resistance of wooden structure is determined by a charring rate or charring depth, and these are adopted for fire design. In this study, specimens of domestic larch column with a lamination wooden type were prepared and the fire resistance properties such as the charring depth, load ratio and the specific charring rate suggested by EN Code investigated. Test results showed that as expected, the weakest part was the corner of the column, so that the charring depth of the corner was deeper than the other parts of the column. For the load ratio less than 0.9, it had little effect on the charring depth.

• The KSFM Journal of Fluid Machinery
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• v.14 no.1
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• pp.34-41
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• 2011

Fire characteristics can be analyzed more realistically by using more accurate properties related to the fire dynamics and one way to acquire these fire properties is to use one of the inverse property estimation techniques. In this study two optimization algorithms which are frequently applied for the inverse heat transfer problems are selected to demonstrate the procedure of obtaining pyrolysis properties of charring material with relatively simple thermal decomposition. Thermal decomposition is occurred at the surface of the charring material heated by receiving the radiative energy from external heat sources and in this process the heat transfer through the charring material is simplified by an unsteady 1-dimensional problem. The basic genetic algorithm(GA) and repulsive particle swarm optimization(RPSO) algorithm are used to find the eight properties of a charring material; thermal conductivity(virgin, char), specific heat(virgin, char), char density, heat of pyrolysis, pre-exponential factor and activation energy by using the surface temperature and mass loss rate history data which are obtained from the calculated experiments. Results show that the RPSO algorithm has better performance in estimating the eight pyrolysis properties than the basic GA for problems considered in this study.

• Fire Science and Engineering
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• v.25 no.3
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• pp.78-84
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• 2011

In this study, we have measured the charring rate of solid sawn timber as a preceding step for develop performance based fire safety design method of wood framed building structures. The follows are the summary of fire test results carried out with $400{\times}400$ mm cross-section Douglas-fir in varied of thickness and grain directions. I) When the timber thickness increase under same dimension, the charring rate decreases gradually. It is seemed the charring layer up on a thickness roles as a insulation, gives combustion delaying time to specimen. 2) The charring rates measured at different depths (10, 20, 30, 40 mm) in timber which varying thickness (20, 40, 80, 120 mm) when exposed maximum 1 hour standard fire increase by 30 mm depth, but decrease at 40 mm. It is seemed the minimum charr layer should be 30 mm for having role of insulation. 3) The charring rate of cross section surface (direction of perpendicular to grain) was more high than that of grain direction. It can be explained by the cracks and gaps from greater charr contraction made more heat flux incident into timber.

• Fire Science and Engineering
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• v.18 no.4
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• pp.86-92
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• 2004

We tested five specimens of each species at each of five constant external heat flux levels (10, 15, 20, 25. and 35㎾/㎡). An Cone heater was used to expose the wood specimens to the heat flux. The 100-by 100-by 50-㎜ specimens were of four species: Redwood, White oak, Douglas fir, Maple. In result of test, charring of wood exposed to a constant external heat flux can be considered a linear with function of time. As compared with the charring rates Redwood is most rapidly, but on the other hand Douglas fir is most slowly. When the external heat flux is 35㎾/㎡, the charring rate is rapidly about twice then 10㎾/㎡. Using the Equation (2), the estimates for u were 1.02, 1.16, 1.23, 1.32, and 1.44 for the 10, 15, 20, 25, and 35 kw/m2 constant external exposure levels, respectively.

• Journal of computational fluids engineering
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• v.10 no.1
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• pp.16-23
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• 2005

The objective of this research is to estimate two dimensional ablating and charring of heat shield materials in severe aero-thermal heat transfer. This estimation requires an accurate and rapid technique for its serious heat transfer with a moving boundary. Aerodynamic heating is obtained by an explicit relation which is a function of Mach number and air condition, while a fully implicit method is used for heat transfer calculations. Moving boundary is captured by FLIAR method which is a subgroup of VOF. Thickness of ablating and charring of heat shield, temperature of the moving surface and rate of radiation heat are calculated and compared with references. The results are in good agreement with other calculations.

• Journal of the Korea Institute of Building Construction
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• v.23 no.6
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• pp.761-772
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• 2023

The fire resistance design of timber structures involves calculating the residual section based on charring depth, which is then utilized in structural design. Charring depth is determined from fire-resistance test results in Korea, which currently do not account for the charring properties of the adhesive used in Glued Laminated Timber(GLT) production. This study fabricated GLT using various adhesives employed in domestic GLT production, comparing the charring properties by adhesive type and the fire resistance performance relative to the directionality of the laminated surface. Melamine demonstrated the most advantageous fire resistance performance, followed by resorcinol and polyurethane. Furthermore, it was established that the laminated section exhibited a higher charring rate, influenced by the adhesive, compared to the laminated surface, which significantly impacts the fire resistance performance.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.23 no.9
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• pp.1201-1212
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• 1999

A numerical analysis is performed to predict the thermal response and ablation rate for charring or non-charring material which is designed to be used as thermal protection system (TPS). The numerical program composed of in-depth energy balance equation and the aerotherm chemical equilibrium (ACE) program. The ACE program calculates various thermochemical state from ablation products. The developed numerical program is verified by comparing the reported results from literature. The sensitivity tests for input parameters are performed. The thermal behavior of ablating material is mainly affected by density of ablating material, convective heat transfer coefficient and recovery enthalpy of flow field.

• Journal of the Korea Institute of Military Science and Technology
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• v.5 no.4
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• pp.88-96
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• 2002

The CSCM Upwind method and Material Transport Analysis(MTA) have been used to predict the thermal response and shape changes for charring/non-charring material which can be used as thermal protection material(TPM) on blunt-body nose tip. We performed intensive flight trajectory simulations to compare 1-D MTA results with those of 2-D/Axisymmetric MTA by using MTAs and Navier-Stokes code. Theheat-transfer rate and pressure distribution were predicted at selected altitudes and wall temperature along the flight trajectory and the shape changes of blunt-body nose tip were predicted subsequently by using current procedure.

• Proceedings of the KSME Conference
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• 2001.06e
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• pp.282-287
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• 2001

The CSCM Upwind method and Material Transport Analysis (MTA) have been used to predict the thermal response and ablation rate for non-charring material to be used as thermal protection material (TPM) in KSR-III test rocket nozzle. The thermal boundary conditions such as cold wall heat-transfer rate and recovery enthalpy for MTA code are obtained from the upwind Navier-Stokes solution procedure. The heat transfer rate and temperature variations at rocket nozzle wall were studied with shape change of the nozzle surface as time goes by. The surface recession was severely occurred at nozzle throat and this affected nozzle performance such as thrust coefficient substantially.