ASME PTC4中锅炉效率不确定度传递公式的探讨

Discussion of Propagation Formula for Boiler Efficiency Uncertainty in ASME PTC4

锅炉热效率试验不但需要给出热效率结果,还需要对测量结果进行质量评估,以满足目标要求。然而,不确定度评定涉及大量数学概念,在标准中仅给出了评定程序和基本公式,没有对公式来源进行说明,导致在不确定度评定时容易出现错误。以ASME PTC4-2013中的核心公式锅炉热效率不确定度传递公式为基础,基于泰勒级数法和高斯分布法,给出了不确定度传递公式的严格证明过程,推导了不确定度正交加法计算公式,分析了不确定度一般加法和正交加法的区别,提出了各参数随机不确定度的正交合成方法,获得了随机不确定度和系统不确定度合成为标准不确定度的基本条件。

Boiler thermal efficiency testing requires not only thermal efficiency results,but also quality evaluation of measurement results to meet target requirements.However,uncertainty assessment involves a large number of mathematical concepts,and only the assessment procedure and basic formula are given in the standard,and the source of the formula is not explained,resulting in errors in uncertainty assessment.Based on the core formula boiler thermal efficiency uncertainty propagation formula in ASME PTC4-2013,a strict proof process of uncertainty propagation formula based on the Taylor series method and Gaussian distribution method is given,derives the uncertainty orthogonal addition calculation formula,analyzes the diference between general addition and orthogonal addition of uncertainty,proposes an orthogonal synthesis method of random uncertainty of each parameter,and obtains the basic conditions for the synthesis of random uncertainty and system uncertainty into standard uncertainty.