However, these methods differ from the method presented in this work and have several disadvantages, like the dependency on tracer substances and slow measurement speed. The dynamics of glycerol-water mixtures have also been separately analyzed with numerical methods and with broadband dielectric spectroscopy (BDS) and differential scanning calorimetry (DSC). The performance of mixing of viscoelastic fluids in a microchannel and convective mixing were analyzed with fluorescence imaging, and complex concentration profiles were also examined with a fluorescence microscope. Raman spectroscopy was also used for interdiffusion analysis with liquids, such as a water and glycerol-water mixture, with different viscosities or for monitoring the hydrolysis of acetal in microreactors. Raman is widely used in studies for diffusion and interdiffusion processes in microchannels. A Y-shaped mini-channel was selected to verify the measurement using a basic geometry with a distinct observation of the fluids in the inlet of the channel.Ĭurrently, there are various inline measurement methods for microreactor analysis, including spectroscopic methods. In this study, concentration profiles and an indirect calculation of viscosity were investigated by using a new approach of near-infrared imaging with an optical measurement method to evaluate the mixing process of fluids with very different properties, such as water and glycerol, in a cell with a Y shape and by using the Lambert–Beer law for comprehensive absorbance analyses. The analysis of mixing efficiency in microchannels consists of determining crucial parameters, in this case, the local concentration and viscosities.

Additionally, fluids in channels of micro-scale dimensions behave differently as compared to macroscopic geometries. It results in more efficiency for chemical reactions and mass and heat transfer. Due to this property, they gain most of their advantages over conventional-sized chemical process equipment. An extremely high surface-to-volume ratio characterizes microchannel-based devices because of their small linear dimensions. These devices can be reactors, heat exchangers, and static mixers, among other process components. These components vary in size, but all devices can be fabricated in configurations scaled in millimeters and embedded with micrometer-sized channels. By variating the fluid parameters, the influences of the highly different original viscosities in the mixing procedure were investigated and visualized.ĭuring the last few years, the application of micro-structured components for process engineering has gained increasing importance in chemical, pharmaceutical, and life sciences. The result of local concentration in mass fraction was used to determine the local viscosity and illustrated as distribution images. A linear behavior between the concentration and the absorption coefficient is demonstrated. The resulting measurement images were converted in a concentration profile by using absorbance calculated with Lambert–Beer law. Absorption differences of glycerol and water and their mixtures with a mass fraction of glycerol from 0 to 0.95 g G l y c g t o t a l − 1 were analyzed in the NIR spectral area.

The proof-of-concept setup consists of a near-infrared (NIR) camera and cost-effective dome lighting with NIR light-emitting diodes (LED) covering the wavelength range of 1050 to 1650 nm.

Trending Questions Which landforms are most affected by ice wedging? What is the term used to describe when warm air touches something cool? How are rocks affected by weathering? Many people get their water from groundwater through wells that have been drilled into the? Water vapor does not need a solid object on which to condense.The work presents an efficient and non-invasive method to visualize the local concentration and viscosity distribution of two miscible and non-reacting substances with a significant viscosity difference in a microchannel with a Y-shape cell.

Viscosity of glycerol in pa s