1.1 本试验方法包括通过系统能量平衡测量到给定水冷表面的稳定净热流。 1.2 单位- 以国际单位制表示的数值应视为标准值。本标准不包括其他计量单位。 1.3 本标准并非旨在解决与其使用相关的所有安全问题（如有）。本标准的用户有责任在使用前制定适当的安全、健康和环境实践，并确定监管限制的适用性。 1.4 本国际标准是根据世界贸易组织技术性贸易壁垒（TBT）委员会发布的《关于制定国际标准、指南和建议的原则的决定》中确立的国际公认标准化原则制定的。 ====意义和用途====== 5.1 本试验方法的目的是测量水冷表面的净热流，以校准放置试样进行评估的热环境。 实测净热流是关联材料行为的重要参数之一。如果量热计和支架的尺寸、形状和表面光洁度与试样相同，则认为量热计测得的净热流与样品受热表面的净热流相同。如果热量计配置（支架尺寸、形状、光洁度等）与试样不同，则可能需要修改测量结果以考虑这些差异。看见 附录X1 . 5.2 水- 冷却式热量计是用于测量净热流的几种热量计概念之一。主要缺点是其响应时间长，即实现稳态运行所需的时间。为了计算添加到冷却水中的能量，需要准确测量冷却液温度的升高，应将所有能量损失降至最低，并且热量计的热环境和流体流动中必须存在稳态条件。 5.3 无论输入到水冷式热量计表面的能量来源如何（辐射、对流或其组合），测量均在表面上进行平均- 量热计的有效面积。如果水冷式热量计仅用于测量辐射通量或组合对流辐射净热通量率，则应在相关波长区域测量热量计的表面反射率（取决于辐射能的来源）。如果气流中存在不均匀性，则大表面积水冷式热量计将趋于平滑或平均任何变化。因此，建议将热量计的尺寸限制在相对较小的表面积内，并应用于净热流均匀的地方。 在测试大样本的情况下，建议使用一些直径较小的水冷式热量计（而不是一个大装置）。这些应位于受热面上，以便能够描述净热流分布。这样，可以将更详细的净热流测量应用于样本测试，并从测试中推断出更多信息。

1.1 This test method covers the measurement of a steady net heat flux to a given water-cooled surface by means of a system energy balance. 1.2 Units— The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard. 1.3 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, health, and environmental practices and determine the applicability of regulatory limitations prior to use. 1.4 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee. ====== Significance And Use ====== 5.1 The purpose of this test method is to measure the net heat flux to a water-cooled surface for purposes of calibration of the thermal environment into which test specimens are placed for evaluation. The measured net heat flux is one of the important parameters for correlating the behavior of materials. If the calorimeter and holder size, shape, and surface finish are identical to that of the test specimen, the measured net heat flux to the calorimeter is presumed to be the same as that to the sample's heated surface. If the calorimeter configuration (holder size, shape, finish, etc.) is not identical to that of the test specimen, then the measurement results may need to be modified to account for those differences. See Appendix X1 . 5.2 The water-cooled calorimeter is one of several calorimeter concepts used to measure net heat flux. The prime drawback is its long response time, that is, the time required to achieve steady-state operation. To calculate energy added to the coolant water, accurate measurements of the rise in coolant temperature are needed, all energy losses should be minimized, and steady-state conditions must exist both in the thermal environment and fluid flow of the calorimeter. 5.3 Regardless of the source of energy input to the water-cooled calorimeter surface (radiative, convective, or combinations thereof) the measurement is averaged over the surface-active area of the calorimeter. If the water-cooled calorimeter is used to measure only radiative flux or combined convective-radiative net heat flux rates, then the surface reflectivity of the calorimeter shall be measured over the wavelength region of interest (depending on the source of radiant energy). If nonuniformities exist in the gas stream, a large surface area water-cooled calorimeter would tend to smooth or average any variations. Consequently, it is advisable that the size of the calorimeter be limited to relatively small surface areas and applied to where the net heat flux is uniform. Where large samples are tested, it is recommended that a number of smaller diameter water-cooled calorimeters be used (rather than one large unit). These shall be located across the heated surface such that a net heat flux distribution can be described. With this, a more detailed net heat flux measurement can be applied to the specimen test and more information can be deduced from the test.