Insight Into Supersonic Combustion Using High-order Simulations

High-order simulations of supersonic combustion are presented to advance understanding of the complex chemically-reacting flow processes and identify unknown mechanisms of the high-speed combustion process. We have employed 11th-order accurate implicit large-eddy simulations in conjunction with thermochemistry models comprising 20 chemical reactions. We compare the computations with available experiments and discuss the accuracy and uncertainties in both. Jets emanating from above and below the hydrogen plumes influence the combustion process and accuracy of the predictions. The simulations reveal that high temperatures are sustained for a long-distance downstream of the combustion onset. A barycentric map for the Reynolds stresses is employed to analyse the turbulent anisotropy. We correlate the axisymmetric contraction and expansion of turbulence with the interaction of reflected-shock waves with the supersonic combustion hydroxyl production regions. The physics insights presented in this study could potentially lead to more efficient supersonic combustion and scramjet technologies.

Thermophoresis and Brownian Effect for Chemically Reacting Magneto-Hydrodynamic Nanofluid Flow across an Exponentially Stretching Sheet

This comparative research investigates the influence of a flexible magnetic flux and a chemical change on the freely fluid motion of a (MHD) magneto hydrodynamic boundary layer incompressible nanofluid across an exponentially expanding sheet. Water and ethanol are used for this analysis. The temperature transmission improvement of fluids is described using the Buongiorno model, which includes Brownian movement and thermophoretic distribution. The nonlinear partial differential equalities governing the boundary layer were changed to a set of standard nonlinear differential equalities utilizing certain appropriate similarity transformations. The bvp4c algorithm is then used to tackle the transformed equations numerically. Fluid motion is slowed by the magnetic field, but it is sped up by thermal and mass buoyancy forces and thermophoretic distribution increases non-dimensional fluid temperature resulting in higher temperature and thicker boundary layers. Temperature and concentration, on the other hand, have the same trend in terms of the concentration exponent, Brownian motion constraint, and chemical reaction constraint. Furthermore, The occurrence of a magnetic field, which is aided by thermal and mass buoyancies, assists in the enhancement of heat transmission and wall shear stress, whereas a smaller concentration boundary layer is produced by a first-order chemical reaction and a lower Schmidt number.

Experimental and Numerical Study of Volt-Ampere Characteristics of a Packed Tube Heated by Joule Heating

This work is devoted to experimental and numerical studies of volt-ampere characteristics of a fixed bed heated by the Joule heating. The main feature of this type of fixed bed is internal heat generation using the Joule heat. The application is to provide the heat to chemically reacting gases flowing through the bed reactor. To validate our model a cylindrical packed bed is considered with a height of 11 cm and an internal diameter of 4.8 cm. This bed is filled with 86 balls made of carbon steel with a diameter of 1/2 inches (1.27 cm). For numerical simulation, open-source DEM software is used to generate the cylindrical packed bed. Electric field distribution is calculated using a new particle-unresolved DEM-based model coupled with a discrete heat transfer model to account for the temperature dependency of the electrical conductivity of steel particles. The results of the simulation were found to be in good agreement with experimental data.

Solid Soap Formulation with Ethanol Extract of Ginger Rhizome (Zingiber officinale Rosc.) Combination of Virgin Coconut Oil (Vco) and Palm Oil

Soap is a type of cleaning product that is used to clean dust, oil, dirt, germs, and bacteria that stick to the skin. Ginger is a plant that contains a wide range of antibacterial compounds including E. Coli, Staphylococcus aureus, B. Cereus, L monocytogenes and Candida albicans bacteria. Soap is made by chemically reacting sodium or potassium compounds with fatty acids derived from vegetable oil or animal oil. This study aims to determine the physical characteristics of solid soap with ginger rhizome extract with a combination of coconut oil and palm oil and analyze the panelist’s response to the soap produced. In the third week of observation, it is known that the water content ranges from 0,07%-0,1% with foam stability 71,11%-88,23% and pH 8,96-9,08. The most preferred solid soap based on the response of the panelist is soap from a mixture of coconut oil and palm oil with a ratio of 15:5.