Measurement of Rarefied Gas Flow by OPMS (Optical Pressure Measurement System)

研制了一种基于O_2猝灭发光原理的压敏漆光学压力测量系统。该压敏涂料是以铂-八乙基卟啉或酞菁为发光体，以透氧硅聚合物为基体。在760 ~ 10 μ Torr的气压范围内，在30 ~ 80 ℃的温度范围内，实验研究了发光强度随氧分压变化的规律<-3>。用波长为390 nm的紫外光照射油漆样品，用CCD摄像机检测荧光体发出的波长为650 nm的荧光，用PC机进行数据处理，得到如下结果：1.压力P下的荧光强度I与参考压力P下的荧光强度I之比<ref><ref>满足Stern-Volmer关系<numerical formula>，考虑油漆厚度的影响，对上述关系进行修正，得到了<numerical formula>：当P/P_小于0.1时，Stern-Volmer关系不满足<ref>。在此范围内，dI/dP较大，对压力的灵敏度较高。2.绝对荧光强度依赖于温度。在P/P_大于0.1的范围内，P/P_<ref>与P/P_<ref>之间的关系与温度无关<ref>。荧光强度随温度的升高而降低，这可能是由于基态荧光团的数量减少所致。3.在实验条件不变的情况下，荧光强度随时间的推移而降低。24小时后，荧光强度变为约80%PtOEP和约60%邻苯二甲酸酯。P/P_1<ref>与I/I_2<ref>的关系并不随时间的推移而改变。

An optical pressure measurement system utilizing pressure sensitive paint which is based on the O_2 quenching of luminescence has been developed. The pressure sensitive paint is consist of Pt-Octaethelporphyrin or phthalocyanine as luminophore and O_2-permeable silicon polymer as matrix. Variation of strength of luminescence with change of partial pressure of oxigen is studied experimentally in the pressure range from 760 to 10^<-3> Torr and temperature range from 30 to 80 degree Celsius. A painted sample is radiated by UV light of wave length 390nm and fluorescence of wave length of 650nm from luminophore is detected by a CCD camera and the data are processed by a PC.Following results have been obtained :1.Ratio of fluorescence intensity I at pressure P to fluorescence intensity I_<ref> at a reference pressure P_<ref> satisfies the Stern-Volmer relation,<<numerical formula>>Taking into account the effect of the paint thickness, the above relation is modified, giving<<numerical formula>>However, the coefficient of square term is very small compared with the one of the linear term. The Stern-Volmer relatiion is not satisfied for P/P_<ref> less than 0.1. In this range dI/dP is large, showing the high sensitivity to the pressure.2.Absolute fluorescence intensity depends on the temperature. The relation betweem P/P_<ref> and P/P_<ref> does not depend on the temperature in the range P/P_<ref> larger than 0.1. Decrease of fluorescence with increase of temperature may be attributable to the decrease of morecular populatiion in the ground state of the luminophore.3.Absolute strength of fluorescence decreases with lapse of time, keeping the experimental condition unaltered. After 24 hours, the strength of fluorescece becomes about 80% PtOEP and about 60% for phtalocyanine. However, relation between P/P_<ref> and I/I_<ref> does not change in spite of laspe of time.