Vol.:(0123456789) 1 3 Journal of the Brazilian Society of Mechanical Sciences and Engineering (2020) 42:46 https://doi.org/10.1007/s40430-019-2140-x TECHNICAL PAPER Study of the fow distribution in parallel micro‑channels with a triangular manifold Mohammad Ali Zoljalali 1  · Elham Omidbakhsh Amiri 1 Received: 21 February 2019 / Accepted: 6 December 2019 © The Brazilian Society of Mechanical Sciences and Engineering 2019 Abstract Flow distribution and pressure drop in parallel micro-channels are two efective parameters on the performance of diferent devices. These two parameters are afected by diferent factors, such as the manifold geometry, channels geometry, fow rate and fuid direction of inlet fow. In the present work, the structure of the inlet manifold (the triangular geometry, with straight and curved walls) has been studied as the main subject. However, the efect of the fow rate (as the Reynolds number) and fuid direction of inlet fow has been studied on the fow distribution and pressure drop with these manifold geometries. The results show that in the low-Reynolds number range, with increasing the Reynolds number, the fow distribution does not change, but the pressure drop increases. Also, the vertical direction of the inlet fow in comparison with the horizontal direction is preferable. Flow distribution with triangular manifolds with curved walls is more uniform than with straight walls, while, in straight walls, equilateral triangle is a better choice. At the end of this consideration, the efect of geometry parameters (such as the channel number, channel width and depth of curvature) on the non-uniformity parameter was studied with concave manifolds. Keywords Curvature · Triangular manifold · Flow distribution · Uniformity 1 Introduction The transition of fuid through micro-channels due to large surface-to-volume ratio improves transport phenomena in these channels in comparison with conventional channels. Nowadays, micro-channels are used in many industrial devices such as microelectronic devices, fuel cells, micro- reactors and micro-heat exchanger. Usually, a collection of parallel micro-channels are used for this application. Flow distribution in these parallel micro-channels is one of chal- lenges in this subject. Non-uniformity in the fow distribu- tion in parallel micro-channels has a negative efect on their performance in diferent applications [1]. As an example, in micro-heat exchangers (such as microelectronic device), non-uniformity in the fow distribution of the parallel micro- channels leads to non-uniform heat transfer which provides hot spots on the electronic chip and decreases its durability. Furthermore, non-uniformity decreases the energy produc- tion potential in fuel cells (as a negative efect). Also, non- uniformity of the fow distribution in micro-reactors leads to diferent fow rates of reactants fed to each micro-channel, so, diferent product distribution will be achieved as not desirable for reactor designer [1]. Moreover, pressure drop in these channels is related to some of parameters such as fow distribution. Therefore, it should be considered as a signifcant parameter. Some factors such as fow rate (as Reynolds number), manifold geometry, inlet direction of fuid fow, which are impressive on pressure drop and fow distribution, can be studied. Numerous investigations have been done to improve and fnd the best combination of these factors. Considering the manifold geometry, the studied structure of the manifolds can be divided into two general categories called as U-type and Z-type. In U-type structure, inlet fow and outlet fow are located at the same direction, while in Z-type, the inlet fow and outlet fow are located at two diagonal corners. One of the studies with U-type structure is Huang and Zhu’s work [2]. They studied the fow distribution in U-type layers of fuel cells, analytically. They formulated uniform Technical Editor: Daniel Onofre de Almeida Cruz, D.Sc. * Elham Omidbakhsh Amiri e.omidbakhsh@umz.ac.ir 1 Department of Chemical Engineering, Faculty of Engineering, University of Mazandaran, Babolsar, Iran