Effect of tunnel cross section on gas temperatures and heat fluxes in case of large heat release rate

The flammability of nine polypropylene fabrics or sheets has been tested using cone calorimeter at various heat fluxes (25, 35, 50, and 75 kW/m2) in order to assess the relevance of this fire test for thermally thin materials. The chosen procedure uses a grid and allows maintaining a constant exposed surface during the test, except for the lightest fabric. The structure of the knitted fabrics has a relatively small influence on the main flammability parameters. On the contrary, the area density of the sample (from 218 to 5729 g/m2) impacts strongly the time to ignition, the peak of heat release rate, and the increase in heat release rate after ignition (fire growth rate). At a fixed heat flux, thicker is the sample, higher are the time to ignition and the peak of heat release rate and lower is the fire growth rate. Moreover, thick samples exhibit the highest sensitivity of peak of heat release rate and the lowest sensitivity of fire growth rate to heat flux. This study emphasizes the fact that a moderate change in weight may have a significant influence on cone calorimeter results, without any significance on real flammability.

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Influence of fiberglass mesh on flammability of EPS used as insulation of buildings

Thermal Science ◽

10.2298/tsci160405173x ◽

2018 ◽

Vol 22 (2) ◽

pp. 1025-1036

Author(s):

Qiang Xu ◽

Cong Jin ◽

Gregory Griffin ◽

Jordan Hristov ◽

Dejan Cvetinovic ◽

...

Keyword(s):

Heat Release ◽

Heat Release Rate ◽

Release Rate ◽

Fire Behavior ◽

Fire Spread ◽

Expanded Polystyrene ◽

Heat Fluxes ◽

Release Capacity ◽

Heat Release Capacity ◽

Combustion Calorimeter

Different scale tests to explore the influence of fiberglass mesh on the fire behavior of expanded polystyrene (EPS) have been conducted. Micro scale combustion calorimeter to measure the heat release rate per unit mass, heat release capacity, and the total heat release of EPS and as well as the fiberglass for milligram specimen mass has been used. Cone colorimeter bench scale burning tests with the EPS specimens and EPS-fiberglass compound specimens have been carried out. The heat release rate per unit area, ignition times, and the derived minimum igniting heat fluxes were determined. Comparative burning tests on the fire spread tendency of EPS and EPS-fiberglass compound specimens have been carried out. It was established that the fiberglass mesh stabilizes the EPS fire as a wick fire due to the adherence of the melting polystyrene adheres to the fiberglass mesh and this causes an upwards fire spread.

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Inversion for Fire Heat Release Rate Using Transient Heat Flux Data

Volume 1: Aerospace Heat Transfer; Computational Heat Transfer; Education; Environmental Heat Transfer; Fire and Combustion Systems; Gas Turbine Heat Transfer; Heat Transfer in Electronic Equipment; Heat Transfer in Energy Systems ◽

10.1115/ht2017-5107 ◽

2017 ◽

Author(s):

Andrew Kurzawski ◽

Ofodike A. Ezekoye

Keyword(s):

Cost Function ◽

Heat Release ◽

Heat Release Rate ◽

Release Rate ◽

Important Variable ◽

Heat Fluxes ◽

Data Sets ◽

Inversion Algorithm ◽

Gas Measurement ◽

The Cost

The heat-release rate (HRR) of a burning item is key to understanding the thermal effects of a fire on its surroundings. It is, perhaps, the most important variable used to characterize a burning fuel packet and is defined as the rate of energy released by the fire. HRR is typically determined using a gas measurement calorimetry method. In this study, an inversion algorithm is presented for conducting calorimeter on fires with unknown HRRs located in a compartment. The algorithm compares predictions of a forward model with observed heat fluxes from synthetically generated data sets to determine the HRR that minimizes a cost function. The effects of tuning a weighting parameter in the cost function and the issues associated with two different forward models of a compartment fire are examined.

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Research on combustion performance of PVC foam in fire propagation apparatus

E3S Web of Conferences ◽

10.1051/e3sconf/201911801034 ◽

2019 ◽

Vol 118 ◽

pp. 01034

Author(s):

Guoan Zhang ◽

Lingling Wei ◽

Junhao Gao ◽

Tingting Qiu ◽

Rongnan Yuan ◽

...

Keyword(s):

Heat Flux ◽

Heat Release ◽

Heat Release Rate ◽

Release Rate ◽

High Speed ◽

Mass Loss Rate ◽

Ignition Time ◽

Combustion Characteristics ◽

Heat Fluxes ◽

Fire Propagation

Polyvinyl chloride foam (PVC) is widely used as the wall materials of the high-speed train. The combustion characteristics of PVC foam under the heat fluxes of 20-60 kW/m2 are investigated by fire Propagation Apparatus (FPA). The results show that the ignition time of PVC foam decreases with the increase of heat flux. The peak of heat release rate, mass loss rate and smoke production rate increase with the increase of heat flux. Under the condition of 60 kW/m2, the heat release rate has the peak value of 109.10 kW/m2. The research on the combustion characteristics of the PVC can be used to analyse the fire risk of the train and guide the formulation of safety measures.

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