Eventos Anais de eventos
COBEM 2021
26th International Congress of Mechanical Engineering
Constructal Design Applied to a Microchannel with Two Mounted Trapezoidal Blocks Subjected to Laminar Boiling Flows
Submission Author:
Bruno Feijó , RS , Brazil
Co-Authors:
Bruno Feijó, Grégory Muniz, Liércio Isoldi, Luiz Alberto Oliveira Rocha, Sylvie Lorente, Elizaldo dos Santos
Presenter: Bruno Feijó
doi://10.26678/ABCM.COBEM2021.COB2021-0145
Abstract
The present work aims to study the geometric configuration of a microchannel with two trapezoidal blocks mounted in its surfaces subjected to laminar boiling flows. Constructal Design method is used to geometrically evaluate the blocks mounted in the microchannel. These microchannel heat exchangers are used in several areas such as refrigeration and air conditioning, electronics and microelectronics, power generation industry, process industry, bioengineering, among others. Here, a computational fluid dynamics (CFD) based on the Finite Volume Method (FVM) is used for the simulation of the boiling flow. The multi-phase Mixture model and the phase change model of Lee are employed. A microchannel with a length of 1.0 mm and height of 0.1 mm is simulated. The walls of this microchannel have a temperature of 573 K and a fluid, water in its liquid phase, enters the microchannel with a temperature of 372 K at atmospheric pressure with a mass flow equal to 1.0 kg/(m².s). Along the microchannel, the water is heated and boiled. At the outlet of the microchannel, the working fluid is composed of a liquid/gaseous mixture. The microchannel has two trapezoidal blocks, one mounted on the lower surface and another on the upper surface and downstream to the first block. The problem is subjected to four degrees of freedom: ratio between the height and higher width of both blocks and ratio between the lower and higher widths of the trapezoidal blocks. Here, it is investigated the influence of the height and higher width of the first block (H11/L11) over the heat transfer rate and quality of generated vapor for different magnitudes of the ratio between the lower width and higher width (L12/L11). The problem is subjected to two constraints (areas of blocks 1 and 2). Results indicated that the design of the first block have significant influence over the heat transfer rate between the heated surface and the fresh water, as well as, over the amount of vapor generated in the domain.
Keywords
Heat transfer, Boiling, flow, Microchannel, Constructal Design
