One Way Based On Rayleigh-Brillouin Scattering To Measure Gas Viscosity

With the changes in the environment, the entire Earth’s climate also changed, the little change in the atmospheric environment to people’s living environment will bring a very big impact. With more and more attention of people on the atmospheric environment, many countries have begun to research institutions invested heavily in environmental monitoring of atmospheric science and technology in the field of in-depth study. Lidar technology is one of several major detection technology being developed. Lidar technology as a new atmospheric sounding techniques are increasingly being applied to various fields, defense industry, atmospheric environmental monitoring, aerospace and other areas are beginning more and more to use this new technology, and showing a very prominent advantages, especially in the field of atmospheric environmental monitoring. Atmospheric environmental monitoring of atmospheric temperature and can be divided into two aspects make strenuous efforts to monitor the field, and in the strenuous efforts field, bulk viscosity of gas is a pivotal important role in many areas are required to make strenuous efforts a more accurate calculation of field, such as: satellite recovery, ballistic flight path of the aircraft shape layout, high-rise and high-rise buildings and atmospheric environmental monitoring and other fields. So gas bulk viscosity measurements for development in many fields have a very important significance.This article describes the Rayleigh- Brillouin scattering basic theory, design a kind of nitrogen Rayleigh- Brillouin scattering spectrum of experimental apparatus for the actual measurement. The experimental device is used for nitrogen in Rayleigh90 ° direction- Brillouin scattering data acquisition, and installation of a gas pressure control scattering cell added temperature control system, making the scattering cell gas temperature can be realized Control. Experiments gas at a temperature between environmental parameters 273K-313 K, pressure in 0atm-8atm between. After a series of experiments using experimental data collected for nitrogen Rayleigh- Brillouin scattering spectrum characteristics were analyzed and compared with the theoretical analysis results. In the process of comparing them, found several reasons of bias: First,because there is impurity scattering in the pool, so had Mie, has a big influence on the experimental data; the second is the impact FP scanning interferometer; Third there isno laser frequency stabilization device, making it a certain frequency drift occurs.According to the experience accumulated during the experiment, several issues are raised to improve the program. Finally, the use of experimental data and S6 models,through theoretical analysis and data calculation, successfully obtained bulk viscosity values of nitrogen, and the measurement results of the foreign teams are in good agreement, which proves the feasibility of the method. Compared with traditional methods of the measurement of bulk viscosity, the new method is more simple and efficient, broader scope, but the results of the new calculation method, there are still relatively large errors in the measurement accuracy need to be further improved.