A reduced chemical mechanism for modeling the combustion of n-butanol in air, including low temperature ignition phenomena, was obtained in the present work. To this end, only 14 chemical-kinetic reactions and six chemical species were included to a short base mechanism (the so-called San Diego mechanism). Two important features of the reaction of the hydroxybutyl radical C4H8OH-1 radical with molecular oxygen involve a path competition of low and high-temperature reactions, and low total available heat release not promoting NTC behavior. Validation of the chemical mechanism shows an excellent agreement against experimental data of laminar flame velocities, ignition delay times, and jet stirred reactors. These numerical results confirm that this reduced mechanism can be used instead of larger mechanisms, particularly when computing-time is an important fact to be considered for modeling practical combustion systems.

Heat exchangers play an important role in different industrial processes; therefore, it is important to characterize these devices to improve their efficiency by guaranteeing the efficient use of energy. In this study, we carry out a numerical analysis of flow dynamics, heat transfer, and entropy generation inside a heat exchanger; an aqueous medium used for oil extraction flows through the exchanger. Hot water flows on the shell side; nanoparticles have been added to the water in order to improve heat transfer toward the cold aqueous medium flowing on the tube side. The aqueous medium must reach a certain temperature in order to obtain its oil extraction properties. The analysis is performed for different Richardson numbers (Ri = 0.1–10), nanofluid volume fractions (φ = 0.00–0.06), and heat exchanger heights (H = 0.6–1.0). Results are presented in terms of Nusselt number, total entropy generation, Bejan number, and performance evaluation criterion. Results showed that heat exchanger performance increases with the increase in Ri when Ri > 1 and when reducing H.

The aim of this work is the simulation of volumetric strain of tuberous crop during drying. We propose a poroelastic model for predicting the drying kinetics and volume loss of potato cubes during convective drying. The Biot’s theory of poroelasticity was used, which considers the Lamé parameters, Young’s modulus and Poisson’s ratio. Drying kinetics and volumetric strain were modeled and compared versus experimental data. An X-ray microtomograph coupled with image analysis was used to visualize the shape and size of the samples during drying. Drying experiments were conducted at 50, 60 and 70 °C, 20% RH, with an air velocity of 1 and 2 m/s. The drying process was interrupted several times to perform tomographic acquisitions. We found a period of ideal shrinkage, nevertheless, the volumetric strain reveals a kinetic behavior over time. The model computes the volumetric strain, which describes correctly the experimental data obtained by microtomography.