Uncertainty analysis of steady state incident heat flux measurements in hydrocarbon fuel fires.
Uncertainty analysis of steady state incident heat flux measurements in hydrocarbon fuel fires.
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碳氢化合物燃料火灾中稳态事件热通量测量的不确定性分析。
DOI：
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发表时间：
2005
期刊：
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通讯作者：
J. Nakos
中科院分区：
文献类型：
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作者：
J. Nakos
本报告的目的是开发三个热通量测量技术的不确定性估计，用于测量在辐射和对流环境相结合的入射热通量。这涉及到对放置在烃燃料（柴油、JP-8喷气燃料）火灾内的物体的热通量的测量，这是非常难以准确地进行的（例如，不到10%）。三种方法将被讨论：施密特-波尔特热通量计;量热计和逆热传导方法;和薄板和能量平衡方法。稳态不确定性估计为两种类型的火灾（即，在三个时间（火灾早期、火灾后期和中间时间），结果表明，所有三种方法都存在较大的不确定性。施密特-伯尔特计的典型不确定度范围从大风火灾的{+-}23%到大风火灾的{+-}39%。对于量热计/逆方法，不确定度为{+-}25%至{+-} 40%。薄板/能量平衡法的不确定度范围为{+-}21%~{+-} 42%。Schmidt-Boelter规范的23-39%的不确定度比引用的仅辐射环境的不确定度大得多（即，{+-}3%）。这种大的差异是由于对流的贡献，因为辐射和对流环境的应变计灵敏度是不相等的。所有这些值都大于期望值，这表明需要改进火灾中的热通量测量。
The objective of this report is to develop uncertainty estimates for three heat flux measurement techniques used for the measurement of incident heat flux in a combined radiative and convective environment. This is related to the measurement of heat flux to objects placed inside hydrocarbon fuel (diesel, JP-8 jet fuel) fires, which is very difficult to make accurately (e.g., less than 10%). Three methods will be discussed: a Schmidt-Boelter heat flux gage; a calorimeter and inverse heat conduction method; and a thin plate and energy balance method. Steady state uncertainties were estimated for two types of fires (i.e., calm wind and high winds) at three times (early in the fire, late in the fire, and at an intermediate time). Results showed a large uncertainty for all three methods. Typical uncertainties for a Schmidt-Boelter gage ranged from {+-}23% for high wind fires to {+-}39% for low wind fires. For the calorimeter/inverse method the uncertainties were {+-}25% to {+-}40%. The thin plate/energy balance method the uncertainties ranged from {+-}21% to {+-}42%. The 23-39% uncertainties for the Schmidt-Boelter gage are much larger than the quoted uncertainty for a radiative only environment (i.e ., {+-}3%). This large difference is due to the convective contribution and because the gage sensitivities to radiative and convective environments are not equal. All these values are larger than desired, which suggests the need for improvements in heat flux measurements in fires.