Investigation on the laser transmission properties of nanofluids

摘要

Our recent work revealed that, when nanofluids containing a modest volume fraction of nanoparticles are illuminated by a parallel monochromatic laser beam, speckles would be formed. Therefore, it is realized that Laser Speckle Velocimetry can be used to measure the velocities of nanoparticles in nanofluids. This paper aims to investigate the laser transmission properties of nanofluids via experiments and numerical simulations, so as to determine the proper conditions for the formation of speckles. First, experiments are performed to measure the light transmittance of nanofluids at different laser power and different particle volume fraction. Then, Monte Carlo simulations are carried out based on a physical model considering random collisions between photons and nanoparticles to simulate light propagation in nanofluids. The numerical results are in good agreement with the experimental results, and a final conclusion is drawn that the particle volume fraction and particle size are the prime factors that influence the light transmittance.