基于声吸收谱峰值点的天然气燃烧特性检测理论

A theory for monitoring combustion of natural gas based on the maximum point in sound absorption spectrum

天然气的成分构成会随产地来源变化而不同,使其具有不同的燃烧特性和经济价值.本文利用声吸收谱峰值点随气体成分变化而改变的声分子弛豫现象,提出一种天然气燃烧特性检测理论.它基于两频点上声测量值可合成声吸收谱峰值点,且依赖于频率的声吸收谱可由峰值点重建的物理原理;可利用峰值点对应的特征量——弛豫频率和弛豫吸收最大值与气体成分的关系,从两个维度同时定量检测天然气成分.该理论避免了传统上测量声吸收谱峰值点方法需要不断改变气体腔体压强的问题,还具有无需测量气体密度的优点.

Compositions of natural gases are different between each other because of different sources, resulting in the fact that natural gases have different energy contents and monetary value. This paper presents a theory to monitor the combustion properties of natural gas by using the acoustic relaxation phenomenon in which the maximum point of acoustic spectrum varies with gas composition. The theory is developed from the frequency-dependent sound absorption spectrum which can be reconstructed from its maximum point synthesized in the acoustic measurements at two frequencies. The theory uses the relation between the two values of the maximum point （i.e. the relaxation frequency and the maximum relaxational absorption） and gas composition to quantitatively monitor the gas. Moreover, the theory has the advantages of avoiding the detection of the gas density and the variation of the ambient pressure, which is necessary in the traditional way of measuring the maximum point of sound absorption spectrum.