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The present work deals with the thermal degradation, the physical characterization, and kinetic mechanisms of green epoxy resin‐based biocomposites (BC) reinforced by banana leaf fiber (BLF). The two main samples have been manufactured using the vacuum bag resin transfer molding method. The first, BLF‐based BC, is used as a control sample, while the second sample is coated with 6% wt. of intumescent fire retardant (IFR), which contains APP and boric acid. The effect of IFR coating has been investigated using thermogravimetric analysis (TGA) under inert and oxidative atmospheres and kinetic studies of model‐free and model‐based approaches have been applied for predicting the kinetic parameters of thermal degradation reactions. The TGA results show that the IFR coating delays the thermal degradation around 13–20 K of BLF‐based BC materials, which leads to an increase of 8% in the char residue under inert atmosphere. In addition, the sample has been characterized by SEM, EDS, and FTIR analysis (before and after the TGA test). The effectiveness of the IFR protective role is displayed on the SEM micrographs by showing the hole of the char enclosed and built the foam layer. The kinetic parameters from model‐free and model‐based curve fitting of BLF‐based BC and BLF‐based BC‐coated IFR are obtained, while the effect of IFR on the kinetic parameter increased the activation energy (model‐free and model‐based) under inert atmosphere. The fitting methods and optimization procedure gave excellent results for kinetic parameters, showing a particularly good correspondence with the TGA experimental data. [ABSTRACT FROM AUTHOR]

In this work, a thermal behaviour comparison of a new bamboo-based and banana-based Green Bio-Composites (GBC) is conducted using thermogravimetric analysis (TGA) and cone-calorimeter experiments. An Intumescent Fire-Retardant (IFR) coating (a mixture of Exolit IFR36 and boric acid) has been applied on the investigated GBC materials in order to explore the flammability resistance of such GBCs. Vacuum Bag Resin Transfer Moulding (VBRTM) technique has been used to manufacture the samples. TGA test have been conducted under oxidative atmosphere with three different heating rates while cone calorimeter tests have been performed with a horizontally exposure on the top surface of the sample. The outcomes of TGA revealed that Bamboo-based (BM-GBC) and Banana-based (Bn-GBC) materials exhibited similar thermal degradation patterns. However, BM-GBC outperformed Bn-based in the cone calorimetry analysis, this is proven by the fire reaction parameters as well as the higher char residue. In addition, IFR coating improved the flame retardancy of both GBCs, reduced the Peak Heat Release Rate (PHRR) by approximately 40–50% and smoke production (SEA) by 26%. SEM and EDS analysis of char residue were performed to deeply investigate the effectiveness of the IFR as a protecting layer. [ABSTRACT FROM AUTHOR]

Two‐phase flow in pipes finds application in many industrial activities, mostly in the energy sector, necessitating model systems that correctly predict flow behaviors like flow pattern, pressure drop, and liquid holdup during the design and planning of a fluid transport system. This study aims to analyze three‐dimensional two‐phase liquid‐gas flows in a horizontal flowline. InterFoam, a transient two‐phase solver, was first modified to implement the low‐Reynolds number (LRN) k‐ε model in the OpenFOAM source code. This LRN k‐ε turbulence model is utilized to resolve the turbulence phenomena within the two‐phase mixtures. The two‐phase flow is calculated by using the developed solver based on the volume‐of‐fluid approach. Flow pattern results at different superficial gas and liquid velocities are validated by experimental data from the literature. Then, three Reynolds‐averaged Navier‐Stokes models were used for computations: LRN k‐ε, standard k‐ε, and the shear stress transport k‐ω model. [ABSTRACT FROM AUTHOR]

Compact heat exchangers for heat removal has become one of the most effective cooling techniques. In this paper, numerical scheme to simulate conjugated heat transfer using additively manufactured heat exchanger is presented. A lattice structure as porous medium is used as effective cooling techniques for heat removal. The objective of these lattices is to transmit heat from the hot part to the cold part while letting the system benefit from two phenomena, heat conduction and convection. An optimization procedure using response surface method is proposed for the presented compact heat exchanger to improve the efficiency. This method was introduced in order to reach the global optimum with a limited number of computer experiments. Two optimization variables are identified: edge thickness for the lattices and the inlet velocity. A constraint optimization problem is formulated to maximize the heat flux through the heat exchanger. Hence at the same time, limiting the increase of the pressure drop and the decrease of the exit temperature. [ABSTRACT FROM AUTHOR]

Due to the endothermic nature of the steam methane reforming reaction, the process is often limited by the heat transfer behavior in the reactors. Poor thermal behavior sometimes leads to slow reaction kinetics, which is characterized by the presence of cold spots in the catalytic zones. Within this framework, the present work consists on a numerical investigation, in conjunction with an experimental one, on the one-dimensional heat transfer phenomenon during the heat supply of a catalytic-wall reactor, which is designed for hydrogen production. The studied reactor is inserted in an electric furnace where the heat requirement of the endothermic reaction is supplied by electric heating system. During the heat supply, an unknown heat flux density, received by the reactive flow, is estimated using inverse methods. In the basis of the catalytic-wall reactor model, an experimental setup is engineered in situ to measure the temperature distribution. Then after, the measurements are injected in the numerical heat flux estimation procedure, which is based on the Function Specification Method (FSM). The measured and estimated temperatures are confronted and the heat flux density which crosses the reactor wall is determined. [ABSTRACT FROM AUTHOR]