Search Results (28)

As aviation operations extend into complex natural environments, dust particles present significant challenges to flight stability and safety, particularly in dust-prone regions like southern Xinjiang. This study employs high-fidelity computational fluid dynamics (CFD) simulations, combined with the SST turbulence model and the Lagrangian discrete phase model, to analyze the aerodynamic response of the NACA 0012 airfoil at varying wind speeds (5, 15, and 30 m/s) and angles of attack (3°, 8°, and 12°). The results indicate that, at low speeds and moderate to high angles of attack, dust particles reduce lift by over 70%, primarily due to boundary layer instability, weakened suction-side pressure, and premature flow separation. Higher wind speeds slightly delay flow separation, but cannot counteract the disturbances caused by the particles. At higher angles of attack, drag increases by more than 60%, driven by wake expansion, shear dissipation, and delayed pressure recovery. Pitching moment frequently reverses from negative to positive, reflecting a forward shift in the aerodynamic center and a loss of pitching stability. An increase in dust concentration amplifies these effects, leading to earlier moment reversal and more abrupt stall behavior. These findings underscore the urgent need to improve aircraft design, control, and safety strategies for operations in dusty environments. Full article

The temperature of the water wall in the furnace chamber is extremely important for the daily operation of a boiler. Considering the high temperature and dusty environment in the furnace, a temperature measurement device mainly composed of four parts (armored temperature sensor, in-furnace heat-collecting block, out-furnace fixing base, and protective cannula) was designed in this study, which could be used to directly obtain the temperature of the in-furnace water-wall. Numerical simulations of temperature measurement devices with different heat-collecting block structures were carried out using the computer fluid dynamics method. After comparing the measurement accuracy and considering the practical application scenarios, the optimized heat-collecting block structure with a specific expansion gap (0.5 mm wide and 4 mm deep) was selected for practical application. Such a temperature measurement device was then applied to a 1000 MW ultra-supercritical coal-fired boiler in China, and the tested in-furnace water-wall temperature data were in good agreement with relevant research. Compared with the conventional temperature measurement device arranged outside the furnace, the in-furnace water-wall temperature-measurement device adopted in this study has a more sensitive response characteristic and can directly reflect the temperature of the water wall inside the furnace. In addition, it can also reflect the local slag formation state of the water wall and has a long service life. Full article

In the present study with a novel two-chamber setup (TCS) for dustiness investigations, the relationship between pressure differences as well as air velocities and the resulting dust emissions is investigated. The dust emissions of six particle size fractions of acetaminophen at pressure differences between 0 and 12 Pa are examined. The results show that both simulated and measured air velocities increase with increasing pressure difference. Dust emissions decrease significantly with increasing pressure difference and air velocity. Fine particles cause higher dust emissions than coarse particles. A high goodness of fit is obtained with exponential and quadratic functions to describe the relationship between pressure difference and dust emission, indicating that even moderate increases in pressure may lead to a reduction in the emission. Average air velocities within the TCS simulated with Computational Fluid Dynamics are between 0.09 and 0.37 m/s, whereas those measured experimentally are between 0.09 and 0.41 m/s, both ranges corresponding to the recommended values for effective particle separation in containment systems. These results underline the ability of the novel TCS to control pressure and airflow, which is essential for reliable dust emission measurements and thus provide support for further scientific and industrial applications. Full article

Understanding of dusty fluids for different Brinkman numbers in porous media is limited. This study examines the Darcy–Brinkman model for two-dimensional magneto-hydrodynamic fluid flow across permeable stretching/shrinking surfaces with heat transfer. Water was considered as a conventional base fluid in which the copper (Cu), silver (Ag), and titanium dioxide ($Ti{O}_2$) nanoparticles were submerged in a preparation of a ternary dusty nanofluid. The governing nonlinear partial differential equations are converted to ordinary differential equations through suitable similarity conversions. Under radiation and mass transpiration, analytical solutions for stretching sheets/shrinking sheets are obtained. Several parameters are investigated, including the magnetic field, Darcy–Brinkman model, solution domain, and inverse Darcy number. The outcomes of the present article reveal that increasing the Brinkman number and inverse Darcy number decreases the velocity of the fluid and dusty phase. Increasing the magnetic field decreases the momentum of the boundary layer. Ternary dusty nanofluids have significantly improved the heat transmission process for manufacturing with applications in engineering, and biological and physical sciences. The findings of this study demonstrate that the ternary nanofluid phase’s heat and mass transpiration performance is better than the dusty phase’s performance. Full article

In this paper, we investigate the behavior of dust ion acoustic solitary waves (DIASWs) with arbitrary amplitudes in a magnetized anisotropic dusty plasma that includes inertial hot ion fluid, electrons following a Kappa distribution, and negatively charged dust particles in the background. An ambient magnetic field aligns with the x-direction, while the wave propagation occurs obliquely to the ambient magnetic field. In the linear regime, two distinct modes, namely fast and slow modes, are observed. We employ the Sagdeev pseudo-potential method to analyze the fundamental properties of arbitrary amplitude DIASWs. Additionally, we examine how various physical parameters influence the existence and characteristics of symmetric planar dust ion acoustic solitary structures (DIASs). The characteristics of the solitary structures are greatly influenced by the dust concentration, the electrons superthermality (spectral) index, the obliquity parameter, the magnetic field, the parallel ion pressure and the perpendicular ion pressure. The results show that the amplitude and width of both compressive and rarefactive DIASWs are sensitive to the degree of electron superthermality and dust concentration. Additionally, it is shown that the propagation features of DIASWs are highly affected by the parallel component of ion pressure as compared to perpendicular component of ion pressure. Full article

The intensive of this study is to examine the melting heat and second-order slip (SoS) effect at the boundary in nanofluid and hybrid nanofluid (HN) ethylene–glycol (EG) based fluid through a curved surface using the Modified Fourier Law (MFL) and dust particles. Considering similarity transformation, the PDEs are converted to ODEs and then solved numerically by using the finite element method (FEM). The effects of solid volume fraction (SVF), melting heat factor, curvature factor, first and second-order slip factor, fluid particle concentration factor, and mass concentration factor on the velocity field, dust phase velocity (DPV), temperature field, dust phase temperature (DPT), and the Ski Friction (SF) are investigated through graphs and tables. The thermophysical properties of nanofluid and HN are depicted in tables. The novelty of the present work is to investigate the dusty- and dusty-hybrid nanoliquids over the curved surface with a melting heat effect and MFL which has not yet been studied. In the limiting case, the present work is compared with the published work and a good correlation is found. The confirmation of the mathematical model error estimations has been computed. Full article

This work examined the thermodynamics of the MHD rotating dusty Maxwell water-based nanofluid with suspended dust particles. This study examines the importance of increasing the volume fraction of tiny particles of TiO₂ and dust on fluid dynamics. With appropriate similarity transformations, the governing PDEs for both fluid and dusty-phase models are transformed into non-linear linked non-dimensional ODEs. To acquire graphical consequences, the bvp4c technique is implemented in MATLAB scripts. The primary and secondary velocities’ magnitude in both phases decreases with an increase in the dust particle volume concentration, Lorentz force, rotating, and Maxwell fluid parameters. The growing strength of tiny particles of dust and TiO₂ is responsible for the upshot of temperature in both dust and nanofluid phases. A visual representation of the Nusselt number and skin friction coefficients are is provided. Full article

A model of two-phase flow involving non-Newtonian fluid is described to be more reliable to present the fluid that involves industrial applications due to the special characteristics in its behavior. Many models of non-Newtonian fluid were discovered in the last few decades but the model that captured the most attention is the Williamson model. The consideration of the existing particles in the Williamson flow (two-phase Williamson fluid) will make the model more interesting to investigate. Hence, this paper is aimed to explore the flow of two-phase Williamson fluid model in the presence of MHD and thermal radiation circumstances. The obtained ordinary differential equations after the transformations are solved using the Runge-Kutta Fehlberg (RKF45) method. The flow is considered asymmetric since it moves over a vertical stretching sheet with external stimuli. The result displays variation in dust phases compared to the fluid phase under distribution of velocity and temperature. It can be concluded that the fluid–particle interaction (FPI) parameter lessening the motion of fluid and heating characteristics. In addition, the upsurges on skin friction and heat transfer are resulting from the rising FPI. Furthermore, the presence of Williamson parameter increases the skin friction while causing degenerations on heat transfer of flow. Full article

The main purpose of this study is to develop an understanding of the aerodynamic performance of a horizontal axis wind turbine (HAWT) operating in a dusty environment, with various concentration of dust in the flow domain. The computational analysis was accomplished by the commercial computational fluid dynamics (CFD) code ANSYS Fluent 16.0. Initially, a user-friendly developed application was utilized for the optimum blade geometry special characteristics calculation. The design of the HAWT rotor and meshing of the computational domain follows. The moving reference frame (MRF) model was applied for the rotary motion of the blades, the dust was added in the computational domain by the discrete phase model (DPM) and SST k–ω turbulence model was enabled. The power output of the studied HAWT, operating in several dusty environments, was estimated and compared with the power output of a particular HAWT in clean air. The flow field around the HAWT rotor, including the contours of pressure, particles dissipation rate and erosion rate on both blade sides, are shown. In general, it is concluded that the operation of a HAWT in a dusty environment results in degraded performance, due to the particles deposition on the blades. Full article

In the present study, it was shown that a newly developed two-chamber setup (TCS) for containment investigations consisting of an emission and a detection chamber may serve to predict the dustiness of HPAPIs in a sealed system at different flow conditions. These flow conditions include the plain diffusive transport and the diffusive transport with the oppositely directed convective flow of airborne particles of the safe surrogate substance acetaminophen (ACAM). A linear correlation was found between an atomized amount of up to 400 mg of ACAM and the resulting dust emissions. The dust emission was reduced significantly by an oppositely directed convective flow. The results from the examinations, using either atomized ACAM or smoke for the determination of the evacuation time of the detection chamber, indicated that both methods are comparable. Furthermore, computational fluid dynamics (CFD) simulations were performed to determine the evacuation time. A time period of 9 min was sufficient for a reproducible evacuation and a reliable detection of most airborne ACAM particles within the detection chamber. CFD simulations were also carried out to simulate the air velocity resulting from various pressure differences and to visualize the flow of the airborne particles within the detection chamber. Full article

Multicomponent plasmas are ubiquitous in astrophysics and space plasma environments. In the present manuscript, we assumed a dusty plasma system consisting of negative and positive dust species and kappa-distributed electrons and ions. The analysis is based on the fluid model of plasmas, and the reductive perturbation method was used to study the behavior of propagating waves. New arbitrary parameters were obtained to measure the strength of nonlinearity, dispersion, and dissipation in the plasma system. We investigated the effects of the arbitrary parameters on the appearance of the different nonlinear waves as soliton, shock, and solitary waves. Furthermore, we studied the effects of the kappa parameter, the viscosity of dust species, and the ratio between the temperature of positive and negative dust species in the type of wave, i.e., compressive or rarefactive. Full article

The primary objective of the study is to explore the phenomena of dusty fluid flow through an inclined irregular channel under the impact of the transversely applied magnetic field of fixed strength. The density and viscosity of the working fluid are assumed to vary along with the height of the channel as it behaves as a replica of many real world mechanisms. Hence, a stratified dusty fluid through a channel that tilts to an angle $\theta$ is the main objective of the present study. The prescribed flow is mathematically modeled and it is approached numerically under two distinct boundary conditions. The finite difference technique is employed to discretize the system of equations and solved using the Thomas algorithm. The velocity and temperature fields are discussed for different pertinent parameters which influence the flow. The friction factor and heat transfer rate are discussed as it has been a subject of interest in recent decades. The results show that the stratification decay parameter leads to enhancement in the momentum of the fluid flow. The temperature field is found to be higher in the convective boundary than the Navier slip boundary. Full article

In this work, the mixed convection flow of non-Newtonian Eyring–Powell fluid with the effects of temperature dependent viscosity (TDV) were studied together with the interaction of dust particles under the influence of Newtonian Heating (NH) boundary condition, which assume to move over a vertical stretching sheet. Alternatively, the dusty fluid model was categorized as a two-phase flow that consists of phases of fluid and dust. Through the use of similarity transformations, governing equations of fluid and dust phases are reduced into ordinary differential equations (ODE), then solved by efficient numerical Keller–box method. Numerical solution and asymptotic results for limiting cases will be presented to investigate how the flow develops at the leading edge and its end behaviour. Comparison with the published outputs in literature evidence verified the precision of the present results. Graphical diagrams presenting velocity and temperature profiles (fluid and dust) were conversed for different influential parameters. The effects of skin friction and heat transfer rate were also evaluated. The discovery indicates that the presence of the dust particles have an effect on the fluid motion, which led to a deceleration in the fluid transference. The present flow model can match to the single phase fluid cases if the fluid particle interaction parameter is ignored. The fluid velocity and temperature distributions are always higher than dust particles, besides, the opposite trend between both phases is noticed with $\beta$. Meanwhile, both phases share the similar trend in conjunction with the rest factors. Almost all of the temperature profiles are not showing a significant change, since the viscosity of fluid is high, which can be perceived in the figures. Furthermore, the present study extends some theoretical knowledge of two-phase flow. Full article

Although water is the second most important fluid, after air, found on the Earth, there is a vital problem in the availability of water for many organisms, and this problem faces the whole world. As a result, scientists have developed many methods of purifying the saline/brackish water to be suitable for different uses in addition to the purpose of drinking. Fortunately, solar distillation is very rewarding in terms of operating costs and costs for a liter of freshwater distillated with using clean and environmentally friendly energy. Solar distiller is one of the solar distillation systems devices, which is simple in construction, cheap, and easy to use but it has the drawback of low productivity. This article aims to provide a summary of the different ideas and works on solar stills through different variables that affect the performance of distillers. In contrast to the review papers dealing with this topic, this paper contains comprehensive and complete details and careful reviews of all the variables that affect the performance of distillers. Therefore, it is like a ladder in front of the authors until they reach the recent of what has been studied on the distillers in a simplified way to save time and effort, which will help them to come up with different ideas that were not easily studied. Thus, this paper introduces an overview on the detailed parameters affecting the performance of solar stills. These parameters are climatic, design, and operating factors. Climatic factors consist of solar radiation, ambient temperature, air speed, and dusty and cloudy weather. While the design factors include the evaporative and exposure surface areas, glazing cover material, inclination, and thickness, distiller material, and of insulating material and thickness. Whist, the operating parameters consist of the water temperature, feed water temperature, applying vacuum, temperature difference between water and glass cover, and hybrid systems. From the extensive literature, it is concluded that the climatic, design, and operating factors significantly affect the performance of the solar still. Finally, some points are proposed for further investigation. Full article