Geometrical investigation of microchannel with two trapezoidal blocks subjected to laminar convective flows with and without boiling

Abstract

Microchannels are important devices to improve the heat exchange in several engineering applications as heat, ventilation and air conditioning, microelectronic cooling, power generation systems and others. The present work performs a numerical study of a microchannel with two trapezoidal blocks subjected to laminar flows, aiming to analyze the influence of the boiling process on the geometric configuration of the microchannel. Constructal Design and Exhaustive Search are used for the geometrical evaluation of the blocks. The Mixture multi-phase model and the Lee phase change model were both employed for the numerical simulation of the boiling process. In this study, the influence of the height and higher width of the first block (H11/L11) over the heat transfer rate and pressure drop for different magnitudes of the ratio between the lower width and higher width (L12/L11) was investigated. It is considered water in monophase cases and water/vapor mixture for multiphase flow. Two different Reynolds numbers (ReH = 0.1 and 10.0) were investigated. Results indicated that, for the present thermal conditions, the consideration of boiling flows were not significant for prediction of optimal configurations. Results also showed that in the cases where the boiling process was enabled, the multi-objective performance was higher than in the cases without boiling, especially for ReH = 0.1.

Short-Term Electrical Load Demand Forecasting Based on LSTM and RNN Deep Neural Networks

“…[26] researched the impact of activation function on classification accuracy using DNN. However, choosing an appropriate activation feature is a difficult task [27][28][29]. Some of the commonly employed activation functions are given in the subsequent sections.…”

High-Order Compact Difference Method for Solving Two- and Three-Dimensional Unsteady Convection Diffusion Reaction Equations

“…For example, the CDR equation has been used to describe the following: the conduction of heat in the fluid [1], thermo-hygro transfer in porous media [2], predatorprey interactions in population densities [3], the transport of adsorbing contaminants and microbe-nutrient systems in groundwater [4], heat transfer in a draining film [5], etc. However, in most cases, similar to some other widely used mathematical models [6,7], the CDR equation cannot obtain exact solutions. So, how to get effective and accurate numerical solutions of this kind of equation is always a problem that researchers pay attention to.…”

Inertia Theory Frequency Dynamic Analysis and Control of Power System with High Proportion of Renewable Source

“…e National Grid recently negotiated 201 MW of EFR facilities from ESS from a variety of providers. By the end of 2021, the majority of these providers should be able to offer their services [56,57]. Timescale of the frequency response in accordance with load response in the system can be seen in Figure 2.…”

“…Large-sized synchronous generators, such as those used in the United Kingdom's power system, account for roughly 70% of the system's inertia. Small-sized synchronous generators deliver regulated power in the moderate power grids [56]. Challenges of inertia reduction due to their power electronics, some RES, such as wind and solar, do not have through connection between the machine and the system, preventing their spinning mass from backing to system inertia [57,58].…”