TY - JOUR
T1 - Prediction of hydrodynamic and optical properties of TiO2/water suspension considering particle size distribution
AU - Song, Dongxing
AU - Hatami, Mohammad
AU - Wang, Yechun
AU - Jing, Dengwei
AU - Yang, Yang
N1 - Publisher Copyright:
© 2015 Elsevier Ltd. All rights reserved.
PY - 2016/1/1
Y1 - 2016/1/1
N2 - In this study, evolution and final state of particle size distribution (PSD) of TiO2/water suspension were described by a modified population balance equation considering both natural convection and Brownian motion. The calculation was verified by experimental measurement of scanning electron microscope and Laser particle analyzer. Based on the predicted PSD, Rayleigh scattering theory (for d < 4λ) and Fraunhofer diffraction theory (for d > 4λ) were then employed to determine the scattering and absorption coefficients of TiO2/water suspensions with various particle concentrations and at various light wavelengths. UV-Vis investigation showed that the predicted optical properties of TiO2/water suspension considering PSD are in much better agreement with the experimental results than that without considering PSD, at all particle concentrations investigated. It is traditionally accepted that for colloid suspension the scattering coefficient can be neglected compared to the absorption coefficient and therefore the extinction, which is the combination of the absorption and scattering coefficients, can be approximately replaced by the absorption coefficient. However, our finding indicates that, when particle aggregation is considered, the scattering coefficient of TiO2/water suspension could be much higher than the absorption coefficient. Consequently, using the absorption coefficient alone to replace the extinction coefficient even at long wavelengths could result in significant calculation errors and is not recommended.
AB - In this study, evolution and final state of particle size distribution (PSD) of TiO2/water suspension were described by a modified population balance equation considering both natural convection and Brownian motion. The calculation was verified by experimental measurement of scanning electron microscope and Laser particle analyzer. Based on the predicted PSD, Rayleigh scattering theory (for d < 4λ) and Fraunhofer diffraction theory (for d > 4λ) were then employed to determine the scattering and absorption coefficients of TiO2/water suspensions with various particle concentrations and at various light wavelengths. UV-Vis investigation showed that the predicted optical properties of TiO2/water suspension considering PSD are in much better agreement with the experimental results than that without considering PSD, at all particle concentrations investigated. It is traditionally accepted that for colloid suspension the scattering coefficient can be neglected compared to the absorption coefficient and therefore the extinction, which is the combination of the absorption and scattering coefficients, can be approximately replaced by the absorption coefficient. However, our finding indicates that, when particle aggregation is considered, the scattering coefficient of TiO2/water suspension could be much higher than the absorption coefficient. Consequently, using the absorption coefficient alone to replace the extinction coefficient even at long wavelengths could result in significant calculation errors and is not recommended.
KW - Hydrodynamic and optical properties
KW - Particle size distribution
KW - TiO/water suspension
UR - https://www.scopus.com/pages/publications/84943405848
U2 - 10.1016/j.ijheatmasstransfer.2015.08.101
DO - 10.1016/j.ijheatmasstransfer.2015.08.101
M3 - 文章
AN - SCOPUS:84943405848
SN - 0017-9310
VL - 92
SP - 864
EP - 876
JO - International Journal of Heat and Mass Transfer
JF - International Journal of Heat and Mass Transfer
ER -