温度和黏度对PLIF的影响

平面激光诱导荧光(PLIF)用于测量流体流动过程的浓度场,混合流体的浓度和温度及示踪物质的浓度都会对结果产生影响。为了把PLIF方法用于黏性流体的混合研究,设计实验用以探究混合流体的浓度和温度及示踪物质的浓度这些因素对PLIF结果的影响。在实验中罗丹明B(Rhodamine B)作为荧光染料,氩离子激光器作为激光光源。流体黏度、流体温度、罗丹明B的浓度在实验中可相应改变用以研究这些改变对荧光强度的影响,比如流体黏度从1 mPa·s增加至200 mPa·s。CCD照相机用以作数字图像采集,采得的图像作数字图像处理。混合液装于密封良好的3.5 mL的玻璃容器中,玻璃容器放置于可控温度的水浴中以控制混合流体温度。结果表明:溶液黏度增加使得荧光光强增加,温度增加使得荧光光强减弱,在溶液黏度从1~200 mPa·s范围内,荧光光强与染色剂浓度成正比,所以PLIF能用于测量黏度从1~200 mPa·s范围内的流体混合现象。

Influence of viscosity and temperature on pLIF

The tests of accuracy were carried out in order to adapt planar laser induced fluorescence （PLIF） to various viscous fluids and flows. The aim is to measure concentration field in case of mixing with viscous fluids. The influence of increasing viscosity parameter on fluorescence intensity was described in case of using Rhodamine B dye and Argon ion laser illumination. It concluded that the influences of the tested illumination laser was intensity, Rhodamine B dye concentration levels, temperature and viscosity on fluoresced intensity. These tests were developed with the objective of better describing the mixing flow in case of various viscous fluids. For this work an argon Ion laser was used as illumination and CCD camera used for digital image treatment and analysis. Rhodamine B dye was used and added to different solutions of increasing viscosities from 1 to 200 mPa· s. Temperature was controlled and modified with the help of a water bath whereas mixtures were enclosed in 3.5 ml glass cells which were perfectly sealed. Result shows fluorescence intensity is increased with the increase of viscosity of solution, while decreased with the increase of temperature. It is shown that the fluorescence intensity is linear with the concentration of Rhoda- mine B dye in the range of viscosities from 1 to 200 mPa · s. It is concluded that PLIF can be used in the measure- ment of mixing of viscous flows.