Simultaneous Multiphase Flow Characterization and Component Fingerprinting
Volume Title: 1
2Vienna University of Technology, Institute of Chemical Engineering
In this paper, a new method for simultaneous measurement of velocity, velocity fluctuations, composition and concentration in process streams is presented. It combines two well-known measurement techniques, Raman spectroscopy and Laser Doppler Velocimetry (LDV), where the LDV laser source was used as the single light source for LDV and Raman for simultaneous measurements from the same point. This is essential e.g. for multiphase flows or for blending/mixing applications. The scattered light from measurement volume is collected and analyzed – the characteristic LDV bursts are analyzed for the velocity information, the frequency shift of the light is investigated for Raman shifts, which identify the chemical components in the fluid mixture and can be calibrated for concentration detection. Spatial synchronization is achieved by rigid mounting of the LDV and Raman probes on defined geometrical arrangement; temporal synchronization is taken care of by using trigger signals for starting the data acquisition. The suggested technology has been tested with performing measurements inside a mixing T-channel for different types of fluids (miscible and immiscible). The new method can deliver combined information from selected positions in a flowing fluid with time resolution. This overcomes the limitations of other methods, which deliver flow velocity and concentration information from different, independent devices.