温度不均匀性对吸收池中气体吸收的影响

Effect of Nonuniform Temperature Distribution in Gas Cell on Gas Absorption Transmissivity

为研究温度不均匀性对低温控制吸收池中气体吸收的影响，建立了桌面不锈钢体低温控制吸收池体积分数标定装置，并使用自行编制的大气辐射传输软件ARHiRS进行模拟计算．实验结果和数值模拟计算结果表明，长1m，充满1．01×10^5Pa二氧化碳（CO2）气体的吸收池，由于吸收池内外温差导致内部温度不均匀分布（吸收池中轴向温度呈中心对称分布，且吸收池中间的气体温度较低，两端靠近窗片处的温度比中心温度高276～278K），温度不均匀分布对吸收池气体吸收透射比的影响不大于0．05％，对反演体积分数的影响不超过0．80％，能够满足体积分数定标的需要．

A low temperature controllable absorption cell was established, which can calibrate the concentration of gas. The atmosphere radiation transfer software ARHiRS was used to compute the absorption of the cell. The experimental result indicates that, due to the difference of the external and internal temperature of the cell, which was in the condition of 1 m in length and full filled with CO2 at 1.01 × 10^5 Pa, the internal temperature distribution is nonuniform. The simulation demonstrates that, the error caused by the effect of nonuniform temperature distribution on the absorption transmission of gas is no more than 0. 05%, and the error of the concentration inversion does not exceed 0.8 %. It is concluded that the established absorption cell can meet the needs of the concentration calibration.