Numerical study on the improvement of flow distribution uniformity among parallel minichannels

Parallel micro or mini-channels are widely used in various devices of process and energy engineering including micro-reactors, compact heat exchangers and fuel cells. Nevertheless, the flow maldistribution due to the improper design of distributor/collector is usually observed, leading to globally poor performances of these devices. The objective of this study is to optimize the shape of the distributor/collector pipes so as to achieve a uniform flow distribution among an array of parallel mini-channels. A Z-type ladder fluid network with 10 mini-channels in parallel having square section is introduced and investigated. Two methods are used to optimize the shape of distributor/collector pipes: a discrete stairway shape optimized according to the scaling relations proposed by Tondeur et al. (2011) and a continuous tapered shape with the inclined angle varying from 0° to 30°. 3D-CFD simulations are carried out using the ANSYS FLUENT code. Numerical results obtained show that a relatively uniform flow distribution may be reached by the discrete stairway shape or by the linear tapered shape under very low flow-rate conditions. Larger inclined angle or fewer channels in parallel are favorable for more uniform flow distribution under higher flow-rate conditions. Nevertheless this implies that the distributor and the collector pipes occupy a large volume so that the entire device is less compact.Papers presented to the 12th International Conference on Heat Transfer, Fluid Mechanics and Thermodynamics, Costa de Sol, Spain on 11-13 July 2016

Heuristic optimality criterion algorithm for shape design of fluid flow

International audienceThis paper presents a heuristic optimality criterion algorithm for shape design of fluid flow. In this algorithm, the lattice Boltzmann method (LBM) is utilized to calculate the flow field of a fluid domain which is divided into elemental cells. A heuristic optimality criterion is applied for cells at the solid–fluid interface, i.e. the dynamic pressure for fluid cells and the viscous stress on their neighboring solid cells. An automatic program is processed step by step to exchange the positions of solid and fluid cells identified by the optimality criterion, with the objective of decreasing the flow resistance at the constraint of constant fluid volume. To illustrate the procedure of this algorithm for shape design of fluid flow, two simple examples are presented: one with fluid flowing through a right angle elbow and the other through a converging T-junction. Numerical results show that this algorithm can successfully reduce the total pressure drop of the system, demonstrating its potential applications in engineering optimal design

Heuristic optimality criterion algorithm for shape design of fluid flow

This paper presents a heuristic optimality criterion algorithm for shape design of fluid flow. In this algorithm, the lattice Boltzmann method (LBM) is utilized to calculate the flow field of a fluid domain which is divided into elemental cells. A heuristic optimality criterion is applied for cells at the solid-fluid interface, i.e. the dynamic pressure for fluid cells and the viscous stress on their neighboring solid cells. An automatic program is processed step by step to exchange the positions of solid and fluid cells identified by the optimality criterion, with the objective of decreasing the flow resistance at the constraint of constant fluid volume. To illustrate the procedure of this algorithm for shape design of fluid flow, two simple examples are presented: one with fluid flowing through a right angle elbow and the other through a converging T-junction. Numerical results show that this algorithm can successfully reduce the total pressure drop of the system, demonstrating its potential applications in engineering optimal design. (C) 2010 Elsevier Inc. All rights reserved