The accuracy of the exhaust flow measurement contributes significantly to the uncertainty of calorimetry measurements for large fire testing. Less than ideal flow characteristics such as skewed velocity distributions are typical of these large-scale flows and make it difficult to achieve the desired measurement accuracy. Consensus standards for fire testing recommend either bi-directional probes or orifice plates to determine exhaust flow. Both have limited accuracy in the presence of less than ideal flow conditions. Averaging pitot probes are an off-the-shelf technology widely used to monitor flows for industrial processes. They have been utilized in a system of large fire calorimeters to demonstrate differences of less than 5% between heat release rate measurements by oxygen consumption calorimetry and the theoretical heat output from a gas burner. Differences exceeded 5% for a small set of conditions but were still less than 10%. Both levels of agreement are within the confirmation requirements of the consensus standards and were achieved without a system calibration as recommended by the standards. Including this technology as an alternate method to measure exhaust flow would be an improvement to relevant fire testing standards and to the overall accuracy of calorimetry measurements for large fire testing.

中文翻译：

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改进大规模耗氧量热法流量测量的最新技术

废气流量测量的准确性对大型火灾测试的量热法测量的不确定性有很大影响。不理想的流动特性（例如倾斜的速度分布）是这些大规模流动的典型特征，并且难以达到所需的测量精度。防火测试的共识标准建议使用双向探头或孔板来确定排气流量。在不太理想的流动条件下，两者的准确性都有限。平均皮托管是一种现成的技术，广泛用于监测工业过程的流量。它们已被用于大型火量热计系统，以证明通过耗氧量热法测量的热释放率与燃气燃烧器的理论热输出之间的差异小于 5%。对于一小组条件，差异超过 5%，但仍低于 10%。这两个级别的协议都在共识标准的确认要求之内，并且在没有按照标准建议进行系统校准的情况下实现。将这项技术作为测量排气流量的替代方法，将改进相关的火灾测试标准，并提高大型火灾测试的量热法测量的整体准确性。这两个级别的协议都在共识标准的确认要求之内，并且在没有按照标准建议进行系统校准的情况下实现。将这项技术作为测量排气流量的替代方法，将改进相关的火灾测试标准，并提高大型火灾测试的量热法测量的整体准确性。这两个级别的协议都在共识标准的确认要求之内，并且在没有按照标准建议进行系统校准的情况下实现。将这项技术作为测量排气流量的替代方法，将改进相关的火灾测试标准，并提高大型火灾测试的量热法测量的整体准确性。