Solid fuel combustion in a chamber does not necessarily occur at a constant rate and may show fluctuations due to variables such as varying burning rates, chamber pressure, and residual combustion. These variables can cause the fuel to burn disproportionately. The acoustic environment of obstacle vortex-driven flow due to transient combustion with pressure oscillations in a solid fuel chamber is numerically investigated in the present study. Solid fuel combustion is considered transient, and flow characteristics of the present problem are governed by large eddies shed from an obstacle. Since unsteady Reynolds-averaged Navier-Stokes (URANS) simulations are not appropriate to compute the present flow phenomenon, therefore, a detached eddy simulation (DES) is performed to precisely predict the flow behavior. Simulation of steady-state combustion is carried out to validate the numerical results with available experimental data from the literature. The simulation of transient combustion shows that if the combustion frequency is close to the chamber’s modal frequency of the chamber, its amplitude increases greatly and creates an acute acoustic environment. This will result in fuel savings. The amplitude of pressure oscillation up to 18% and 5% of mean pressure are evident at the first and second mode of forced oscillation frequencies respectively. Interestingly, it is also found that pressure oscillation always occurs at inlet mass flux disturbance frequency and not between the disturbance and natural frequency of the chamber. As a result, it is evident that the combustion process or chamber configuration could be modified to ensure that both frequencies are far away enough to interact and create both a harsh acoustic environment and sufficient fuel to burn disproportionately.

Combustion instability inside a chamber may lead to catastrophic failure. It is due to inappropriate combustion or flow physics. Flow-driven instability is mostly governed by surface, corner, or obstacle vortex shedding. Inhibitorsare placed inside a solid fuel combustion chamber to control the burning of the solid fuel grain. They burn slowly as compared to solid fuel and create protrusions inside the combustion chamber. These protrusions work as flow obstacles. An obstacle vortex is shed from the inhibitor and produces pressure oscillations. The effects of inhibitor position on pressure oscillation inside a solid fuel combustion chamber is investigated in the present study. Large eddies must be resolved to compute vortex-driven flow. Therefore, the Detached Eddy Simulation is applied to cylindrical combustion chambers having inhibitor and nozzle. Five different configurations are simulated. All parameters of different configurations are similar except inhibitor position. The inhibitor is moved upstream and downstream from the reference position to examine its effect on pressure oscillations. Pressure time histories at eight distinct places of the combustion chamber are recorded. Fast Fourier Transform (FFT) has been utilized to get pressure oscillation frequency and amplitude. It is interesting to reveal that the maximum amplitude of pressure oscillation occurs when the inhibitor to stagnation point distanceis close to the combustion chamber diameter. It is up to 70% higher as compare to reference inhibitor position results. Computed results are also compared with available experimental data for validation purpose.

In this research, we explore the equations of motion governing the behaviour of a finitely conducting incompressible fluid with variable viscosity, heat transfer, and the presence of a transverse magnetic field. By solving these equations, we obtain exact solutions that describe flows in which the vorticity distribution is varying indirect proportion to the stream function perturbed by both uniform and exponent streams. To obtain these exact solutions, we introduce a transformation variable that allows us ttransforming a non-linear system into a linear form the governing equations. From there, we are able to derive several exact solutions that provide insight into the behaviour of the fluid in these conditions.

This study investigates the behavior of Newtonian fluids in pipes filled with and without porous media under combing and separating flow configurations. Numerical simulations are conducted to analyze the effects of changing flow rates, inertia, and porous media on flow patterns, vortex development, and pressure difference. The aim of this study is to examine the impact of inertia on flow behavior by analyzing the streamline patterns, vortex growth, and intensity at different Reynolds numbers, ranging from Re=1 to Re=5000.

Traditional methods for oil spill cleanup, such as chemical dispersants and mechanical recovery, are often expensive and can harm marine ecosystems. If orange peels (OP) prove to be a cost-effective alternative, it could save money for companies and governments involved in oil spill response efforts. Response surface methodology (RSM) optimisation conducted in this study, with dosage ranging from 0.2 – 0.4 g and time from 41 – 50 min, identified OP particles of BSS 100 sieve size as an effective adsorbent for oil spill mop up. Using the basic SigmaXL features in Excel, a design of experiments (DOE) based on central composite design (CCD) indicates that the maximum adsorption capacity of OP is 34.17 g/g. This capacity is characterised by its limonene content, which enhances its sorption ability under optimal conditions of 0.2 g and 50 min. As such, a quadratic model, whose reliability is described by F, p-value, T and mean square (MS) model significance parameters, illustratively satisfy the predicted response variable at R2 = 0.8988. As a result, the residual plots show a uniform distribution of residuals, while the 3D surface and contour plots indicate connection between the input and output variables. SigmaXL not only gives the optimal combinations but allows for further optimum variable predictions outside the boundaries chosen at 95% confidence and prediction intervals. This study also shed light on resource and time management with respect to OP utilisation for oil sorption, which is the sole aim of selecting the two factors analysed to minimise cost.

Fluid flows in channel systems are prevalent in many industrial and engineering applications. Flow rates, Reynolds numbers, and inertia significantly impact the dynamics of fluid flows in channel systems. However, analyzing these factors' effects on fluid flows is challenging. This study investigates the impact of flow rates, Reynolds numbers, and inertia on fluid flows within a channel system filled with non-porous media using Taylor-Galerkin/Pressure-Correction Scheme. Various flow conditions, including equal and unequal flow rates, reversed flow, and unidirectional flow, are analyzed to determine the effects on pressure differences and streamline patterns by numerical simulation. The results demonstrate the crucial role of inertia on vortex development, pressure differences, and the formation of eddies in different regions of the channel. The study reveals that pressure differences increase linearly with increasing Reynolds number in unidirectional flow scenarios and that unequal flow rates can significantly alter flow behavior. The study's findings provide insight into the complex interplay between flow rates, inertia, and pressure variations in fluid flows within a channel system.