Optical Feedback Interferometry for Velocity Measurement of Parallel Liquid-Liquid Flows in a Microchannel

Abstract

Optical feedback interferometry (OFI) is a compact sensing technique with recent implementation for flow measurements in microchannels. We propose implementing OFI for the analysis at the microscale of multiphase flows starting with the case of parallel flows of two immiscible fluids. The velocity profiles in each phase were measured and the interface location estimated for several operating conditions. To the authors knowledge, this sensing technique is applied here for the first time to multiphase flows. Theoretical profiles issued from a model based on the Couette viscous flow approximation reproduce fairly well the experimental results. The sensing system and the analysis presented here provide a new tool for studying more complex interactions between immiscible fluids (such as liquid droplets flowing in a microchannel).

Overview of self-mixing interferometer applications to mechanical engineering

“…29 The four basic measurements outlined above can be considered as the building blocks of many additional applications, in mechanical engineering as well as in other field of physical measurements and of biology or medicine. 21 For example, the basic displacement scheme can be finalized to: (i) the real-time measurement of ablation depth 30 and (ii) become a velocimeter 31 when we look at the frequency content of the interferometric phase measured by the SMI, ϕ ¼ 2 ks, (k ¼ 2π∕λ being the wavenumber) whose time derivative dϕ∕dt ¼ 2 kds∕dt is just proportional to velocity, and also (iii) a flow meter [32][33][34][35] when we aim to a fluid in flow in front of the SMI, and (iv) a thickness meter. 36,37 Further applications have been successfully demonstrated and, for sake of saving space, we address the reader to a review paper 38 on SMI for a more exhaustive overview.…”

Laser feedback interferometry and applications: a review

“…In this work, the measurement of local velocity in fluids with spatial resolution in the micrometer range is achieved by minimizing the laser spot size with the diameter being 32.26 μm. Ramírez-Miquet et al 83 utilized a blue-violet laser diode with a wavelength of 405 nm, which is capable of measuring very slow velocities. The system is found to be a good representation of the liquid-liquid two-phase system's hydrodynamics.…”

Self-Mixing Interferometry-Based Micro Flow Cytometry System for Label-Free Cells Classification

“…One major SMI-based micro particle characterization research aspect is particle size distribution estimation by analyzing the signal frequency power spectrum subjected to the dynamic scattering light from the particle population [20][21][22][23]. Another perspective is developing the device or data processing algorithm for particle flowing velocity spatial distribution profile via Doppler frequency spectrometer [24][25][26][27][28]. Neither focus on the individual particle properties, and to date only a few works have reported the characteristics of a single object.…”