Dynamics of Flow Structures and Transport Phenomena, 2. Relationship with Design Objectives and Design Optimization

Abstract

There have been several approaches in the literature to identify and characterize flow structures qualitatively as well as quantitatively. In the first part of this review, the methodologies and applications of various experimental fluid dynamics and computational fluid dynamics techniques, as well as mathematical techniques, have been discussed. Their chronological developments, and relative merits and demerits, have been presented to allow readers to make a judgment as to which techniques to adopt. In the present part of the review series, a stepwise procedure is suggested for the design of equipment using flow structure knowledge. An attempt has been made to relate the structure properties (such as age, penetration depth, size, shape, and energy content distribution) to the design parameters (such as mixing time, heat- and mass-transfer coefficient, drag coefficient, dissipation rate, etc.). This understanding of flow structures has brought improvements in the formulations of heuristic models of mass and heat transfer. This review makes an effort in developing insights into the views of earlier established analytic and heuristic theories of heat and mass transfer. The recently revealed dynamics of flow structures (as uncovered through the use of various techniques) has helped in furthering the efforts of developing new theories of heat, mass, and momentum transfer. Such an understanding between the structure dynamics and the transport phenomena has helped in the optimization of flow pattern (for instance, maximization of ratios of heat and mass transfer, as well as mixing, with respect to energy input). In this direction, some success stories have been described that have already been implemented in industry and have good potential for implementation.

Comparison of specific energy dissipation rate calculation methodologies utilising 2D PIV velocity measurement

“…In the recent past, local flow structures have been experimentally studied by using particle image velocimetry and have been reviewed by Joshi et al (2009) and Mathpati et al (2009). Further, a few published literature describe estimation of turbulent specific energy dissipation rate and its distribution in geometries like stirred tanks (Gabriele et al, 2009) and submerged jet ); however, scanty information is available in the published literature for OGT.…”

Study on effect of process parameters and mixing on morphology of ammonium diuranate

“…Various investigators [16][17][18][19][20][21][22][23][24][25][26][27][28][29][30][31][32][33][34][35] have reported that the fluid dynamics or mixing plays an important role in controlling supersaturation profile, hence determining particle sizes and the morphology. Both mixing between fluid and particles, and particles and particles affect the crystallization process.…”

Large Eddy Simulation for Dispersed Bubbly Flows: A Review

“…If only mixing is the important design criterion, then the knowledge about the mean flow pattern (large-scale structures) would generally suffice the purpose (Ekambara and Joshi [81]). However, for the prediction of the gas holdup, bubble size distribution, true mass transfer coefficient, and heat transfer coefficient, the knowledge about all the scales is important [82,83]. Hence, it is imperative to identify the scales and dynamics of turbulent flow structures and their relationship with the rates of different transport process.…”

“…The subject of quantification of local turbulent flow structures and reliable estimation of transport properties has been reviewed by Joshi et al [84] and [82,83]. The velocity and pressure data from LES were analyzed using the mathematical techniques such as multiresolution analysis [85], wavelet transforms (discrete and continuous), proper orthogonal decomposition (POD), and hybrid POD-wavelet techniques (Tabib and Joshi [86], Tabib et al [87], Sathe et al [88], and Mathpati et al [89]).…”