ASTM E3057-2019 pdf free download

ASTM E3057-2019 pdf free download.Standard Test Method for Measuring Heat Flux Using Directional Flame Thermometers with Advanced Data Analysis Techniques
1. Scope
1.1 This test method describes the continuous measurement of the hemispherical heat flux to one or both surfaces of an uncooled sensor called a “Directional Flame Thermometer” (DFT). 1.2 DFTs consist of two heavily oxidized, Inconel 600 plates with mineral insulated, metal-sheathed (MIMS) thermo- couples (TCs, type K) attached to the unexposed faces and a layer of ceramic fiber insulation placed between the plates. 1.3 Post-test calculations of the net heat flux can be made using several methods. The most accurate method uses an inverse heat conduction code. Nonlinear inverse heat conduc- tion analysis uses a thermal model ofthe DFT with temperature dependent thermal properties along with the two plate tempera- ture measurement histories. The code provides transient heat flux on both exposed faces, temperature histories within the DFT as well as statistical information on the quality of the analysis. 1.4 A second method uses a transient energy balance on the DFT sensing surface and insulation, which uses the same temperature measurements as in the inverse calculations to estimate the net heat flux. 1.5 A third method uses Inverse Filter Functions (IFFs) to provide a near real time estimate of the net flux. The heat flux history for the “front face” (either surface exposed to the heat source) of a DFT can be calculated in real-time using a convolution type of digital filter algorithm. 1.7 The transient response of the DFTs is limited by the response of the MIMS TCs. The larger the thermocouple the slower the transient response. Response times of approxi- mately 1 to 2 s are typical for 1.6 mm diameter MIMS TCs attached to 1.6 mm thick plates. The response time can be improved by using a differential compensator. 1.8 The values stated in SI units are to be regarded as standard. The values given in parentheses after SI units are provided for information only and are not considered standard. 1.9 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appro- priate safety, health, and environmental practices and deter- mine the applicability ofregulatory limitations prior to use. 1.10 This international standard was developed in accor- dance with internationally recognized principles on standard- ization established in the Decision on Principles for the Development of International Standards, Guides and Recom- mendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
4. Summary of Test Method
4.1 This test method provides techniques for measurement of the net heat flux to a surface. Because Directional Flame Thermometers are un-cooled devices, they are minimally affected by soot deposition or condensation. Calibration factors or sensitivity coefficients are not required because alternate methods of data reduction are used. DFTs are simple to fabricate and use, but are more complicated when reducing the data. Gardon and Schmidt-Boelter gauges have relatively linear outputs with heat flux and only require a single sensi- tivity coefficient (for example, xx mv/unit of flux) to convert the output to an incident heat flux. DFTs have two thermo- couple outputs as a function of time. Those outputs along with temperature dependent thermal properties and advanced analy- sis techniques are used with a thermal model to calculate the net heat flux. The net heat flux (with an energy balance) can be used to estimate the total cold wall heat flux, which is same as the measurement made by Gardon or S-B gauges [Janssens, 2007 (18)].