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ASTM E341-2008 用能量平衡法测量等离子体电弧气体焓的标准实施规程

ASTM E341-2008 用能量平衡法测量等离子体电弧气体焓的标准实施规程

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【英文标准名称】: Standard Practice for Measuring Plasma Arc Gas Enthalpy by Energy Balance
【原文标准名称】: 用能量平衡法测量等离子体电弧气体焓的标准实施规程
【标准号】: ASTM E341-2008
【标准状态】: 现行
【国别】: 美国
【发布日期】: 2008
【实施或试行日期】:
【发布单位】: 美国材料与试验协会(US-ASTM)
【起草单位】: E21.08
【标准类型】: (Practice)
【标准水平】: ()
【中文主题词】:
【英文主题词】: bulk enthalpy; energy balance; gas enthalpy; Bulk enthalpy; Electric-arc-heated gas stream; Energy analysis; Plasma arc gas enthalpy; Total gas enthalpy
【摘要】: The purpose of this practice is to measure the total or stagnation gas enthalpy of a plasma-arc gas stream in which nonreactive gases are heated by passage through an electrical discharge device during calibration tests of the system. The plasma arc represents one heat source for determining the performance of high temperature materials under simulated hyperthermal conditions. As such the total or stagnation enthalpy is one of the important parameters for correlating the behavior of ablation materials. The most direct method for obtaining a measure of total enthalpy, and one which can be performed simultaneously with each material test, if desired, is to perform an energy balance on the arc chamber. In addition, in making the energy balance, accurate measurements are needed since the efficiencies of some plasma generators are low (as low as 15 to 20 % or less in which case the enthalpy depends upon the difference of two quantities of nearly equal magnitude). Therefore, the accuracy of the measurements of the primary variables must be high, all energy losses must be correctly taken into account, and steady-state conditions must exist both in plasma performance and fluid flow. In particular it is noted that total enthalpy as determined by the energy balance technique is most useful if the plasma generator design minimizes coring effects. If nonuniformity exists the enthalpy determined by energy balance gives only the average for the entire plasma stream, whereas the local enthalpy experienced by a model in the core of the stream may be much higher. More precise methods are needed to measure local variations in total enthalpy.1.1 This practice covers the measurement of total gas enthalpy of an electric-arc-heated gas stream by means of an overall system energy balance. This is sometimes referred to as a bulk enthalpy and represents an average energy content of the test stream which may differ from local values in the test stream. 1.2 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 appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.
【中国标准分类号】: A54
【国际标准分类号】: 17_200_10
【页数】: 5P.;A4
【正文语种】: 英语

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