Similar to fine dust, liquid aerosols represent a risk to human health since small droplets may enter the respiratory system and cause health problems or severe diseases, such as COVID-19. Oil mist emissions from production processes and from air brakes are reduced by filters and by air dryer cartridges, respectively, while virus-like aerosols are removed by face-masks. Since the two-phase flow processes

ABSTRACT A pooled fishway is an artificial structure to improve the river flow connectivity and facilitate fish migration. Its conventional layout is characterized by straight weirs and suffers from limited passage rate. To improve its flow behaviors, an alternative design, featuring a V-shaped weir arrangement, is devised. CFD simulations are performed to examine its effects on the flow conditions

ABSTRACT In this study, a new vortex-based fluidic oscillator was designed whose performance was numerically evaluated by solving the URANS equations. The oscillator consists of a primary chamber and secondary chamber, separated by a mid-throat and connected by two feedback channels. The jet passing through these chambers forms two pairs of vortices inside the primary and secondary chambers. These

To speed up the calculation of dynamic analysis for elastic ring squeeze film dampers (ERSFDs) and investigate the dynamic characteristics of ERSFD-rotor systems, a semi-analytic method (SAM) is proposed for analyzing oil film pressure and force. This method is subsequently verified by comparison with numerical simulation and experimental results. Based on this SAM, an improved dynamic model of an

High-pressure water jets under nozzle moving conditions are widely utilized for rock breakage in geotechnical engineering. The nozzle motion state significantly influences the jet flow field and flow characteristics, thus changing its rock-breaking performance. In this paper, a single-jet nozzle model with different traverse speeds was established to investigate the jet flow field features and deflection

The scientific and effective control of steam wetness in steam turbines is of great significance for improving power generation efficiency. Based on the research status of wet steam, the influence of different surface heating intensity in a stator cascade was studied. The distribution of condensation flow parameters in White cascade under 0–700 kW/m2 surface heating intensity is calculated. On this

Accurate predictions of decaying swirling flow behavior in the multi-lobed swirl generator (MLSG) are essential for certain engineering applications. In this study, decaying swirling flow characteristics in an MLSG are examined using the Computational Fluid Dynamics (CFD) technique with a Reynolds stress turbulence model (RSM). The effects of different lobe numbers (n) and pitch length ratios (P/D)

The aerodynamic performance and dynamic response of two cars in overtaking maneuver under crosswind were investigated using a multi-car two-way coupling method. The coupling was achieved by exchanging aerodynamic forces obtained by computational fluid dynamic and vehicle dynamic responses acquired by multi-body dynamics in real time. The change rules of the aerodynamic force, moment, yaw angle, and

Significant nonlinearity of electronic hydraulic brake (EHB) systems often leads to complex hydraulic force control responses. This paper designs a motor-driven EHB system and analyzes nonlinear friction induced by the deceleration mechanism. To compensate this friction, a flutter signal is added to the controller input. In addition, this paper designs a fuzzy-PI (Proportional and Integral) controller

Jet in cross flow is an important issue in engineering practice, for example, it is used to improve turbine efficiency in film cooling. In this study, the large eddy simulation and the spectrum analysis are employed to analyze the vortices in a jet in cross flow. The results show that the Rortex method more accurately identifies the vortex structures than other methods. In the analysis of the evolution

The study aimed to enhance the heat transport by improving the hydrodynamic structure of the system by changing and restructuring the duct's internal geometry. Modern fins, of the shape ‘V’, have been proposed with different dimensions, and they are periodically arranged over the duct surfaces. The most important steps of this research are the change in the V-fin attack-angle (40°–80°), length (H b/2

Slipstream severely affects the safety of trackside workers and equipment. With use of profile superimposition method and vehicle modeling method, parametrization of the whole train is carried out. Then, a slipstream optimization study has been performed, taking components of slipstream in different directions at the standard heights, the drag coefficient of the whole train and the volume of the driving

The speed of an excavation and suction rescue vehicle (ESRV) can be adjusted by adjusting the opening position/diameter of the vertical suction component in the gas-liquid flow field within the pipe. In this study, changes in gas-liquid flow in a vertical suction pipe were observed using computational fluid dynamics (CFD) in ANSYS Fluent software. A total of 95 geometric models were established for

This paper presents a study to investigate the effects of the shape of rollers in high precision enveloping speed reducer on the reducer’s lubrication performance. Theoretical models for the precision speed reducer with cylindrical and conical rollers as its transmission components were constructed at first based on the meshing theory. Next, numerical analysis was conducted investigate the lubrication

Perforated plates are prevalently used in various integrated energy systems for flow restriction, vibration, and noise reduction. The characteristics of flow energy transfer and loss in perforated plates have a significant impact on its piping systems. The existing design and previous studies largely paid little attention to the characteristics of flow energy variation, resulting in severe performance

In this study, two kernel-based models were used which include Support Vector Regression (SVR) and Gaussian Process Regression (GPR) and were compared with two tree-based models that are M5 and Random Forest (RF) for estimating missing monthly precipitation data in Antakya, Dortyol, Iskenderun and Samandag stations, which are the important precipitation stations in the Eastern Mediterranean region

When the canard-controlled missile is conducting roll control, the asymmetric downwash induced by the canard impacts on the fins and produces a reverse rolling moment, resulting in the aerodynamic coupling between the canards and the fins. The rolling coupling can cause the reduction and even failure of the missile roll control. However, the current rolling decoupling methods always have adverse effects

In this work, a computational simulation of the pollutants spread generated during fuel combustion at Ekibastuz SDPP-1 and their chemical reaction in the atmosphere have been presented. Using the example of a real thermal power plant (Ekibastuz SDPP -1), the dispersion NO, NO2, CO and products NO2, HNO3, CO2 during a chemical reaction with oxygen was modeled. The numerical method was verified by solving

In this paper, a comprehensive computational modeling study of the unsteady aerodynamic environment around a warship with a helicopter is performed. An experimental validation exercise is also conducted, comparing computational fluid dynamics (CFD) results of the airwake calculated for a reduced-scale model of the isolated Landing Helicopter Assault (LHA) model with high-quality particle image velocimetry

With the gradual orderly opening of low-altitude areas and the increasing number of private aircraft, the general aviation industry has ushered in new opportunities for development. Ventilation and cooling optimization of the piston aeroengine has become a very important field in general aviation enterprises. The traditional aircraft engine design method and control system do not consider the coupling

This study aims to provide valuable insight into the irrigation in curved root canals with CFD method. Numerical simulation of the flow originated from a side-vented or an open-ended flat needle located in the prepared root canal with two different insertion depths was performed. The distribution of velocity, wall shear stress, apical pressure, and the detailed flow structures were all evaluated. The

In a boundary layer ingestion (BLI) propulsion system, the compressor rotor operates under the condition of a severe inflow distortion because the boundary layers on the surface of aircraft have been ingested. In this situation, the low-momentum fluid would inevitably raise the blade load and aggravate the local aerodynamic losses, thus severely deteriorating the compressor overall aerodynamic performance

Tumbling Multi-Chamber (TMC) gear pump is a generally unknown type of hydraulic device, which features a unique three-dimensional shape of the gears. The main benefits of such design over the conventional gear pumps are self-adapting tightness of the pump parts, the possibility to mold the parts from a polymer material and high volumetric efficiency, considering the simplicity of the design. The specific

This research aims to model soil temperature (ST) using machine learning models of multilayer perceptron (MLP) algorithm and support vector machine (SVM) in hybrid form with the Firefly optimization algorithm, i.e. MLP-FFA and SVM-FFA. In the current study, measured ST and meteorological parameters of Tabriz and Ahar weather stations in a period of 2013–2015 are used for training and testing of the

ABSTRACT The flow of barrier fluid through an industrial pressurized dual mechanical seal cartridge is investigated and evaluated experimentally and numerically. The cartridge is of the bi-directional type wherein it is radial-flow designed and fitted with a bi-directional integral pumping ring. The standard k–ϵ turbulence model is applied and the multiple frame of reference method is utilized to simulate

ABSTRACT Double unit trains running at high speeds may create additional aerodynamic challenges due to two streamlined structures with close proximity, exploring the aerodynamic performance of double unit trains is now critical. In this study, detached eddy simulation (DES) approach was employed to study the aerodynamic performance and the nearby flow patterns of a double unit train, whose results

The corrosion properties of AISI 316L stainless steel in upward slug flow were initially investigated using the electrochemical measurements and computational fluid dynamics (CFD) simulations. The results demonstrate that the slug flow may destroy the passivation film on the specimen surface due to its intermittency and volatility, accelerating the pitting corrosion process on the electrode surface

The airflow cylinder sieve directly affects the harvesting effect as one of the main components of the rice combine harvester. The process of grain separated from threshed rice mixture is a multi-physical random pattern. This paper constructed accurately the components particle models, and reproduced the screening process of mixture via CFD-DEM (Computational Fluid Dynamics and Discrete Element Method)

Vaned mixed-flow pump is widely used for liquid transportation in industry and agriculture. The structural-asymmetricity induces large axial force which causes axial vibration and shaft system damage. In this study, impeller forces are analyzed and optimized based on numerical simulation and experiment. Balance holes and a balance plate are used in cooperation. Orthogonal experiment is conducted to

One of the important parameters illustrating the mass transfer process is the diffusion coefficient of carbon dioxide which has a great impact on carbon dioxide storage in marine ecosystems, saline aquifers, and depleted reservoirs. Due to the complex interpretation approaches and special laboratory equipment for measurement of carbon dioxide-brine system diffusivity, the computational and mathematical

A certain gap spacing between adjacent vehicles is usually inevitable in wind tunnel force tests of high-speed trains under no crosswind, which may affect the wind tunnel test results. Thus, to understand the influence of gap spacings on the train aerodynamics, the aerodynamic drag, pressure distributions and airflow structures of 1/8th-scale high-speed train models with gap spacings of 0, 5, 8, 10

This paper presents a numerical study on a sperm swimming in a viscous fluid by using an immersed boundary-lattice Boltzmann method (IB-LBM). The sperm is modeled simply by integrating a slender tail and an elliptical head. By applying a tail traveling wave vertical to the wall, a sperm swims near a surface is simulated. Based on which the corresponding swimming velocity, pressure, and shear stress

In this paper, modeling and analysis of a hybrid solar power plant are presented. Within a theoretical framework, thermodynamic modeling of several components of the cycles has been conducted through simultaneous consideration of energy, exergy, and emissions. The energy and exergy of the combined cycle of the solar-gas turbine and organic Rankine cycle (ORC) have been investigated. Heat loss from

Estimation of wave height is essential for several coastal engineering applications. This study advances a nested grid numerical model and compare its efficiency with three machine learning (ML) methods of artificial neural networks (ANN), extreme learning machines (ELM) and support vector regression (SVR) for wave height modeling. The models are trained by surface wind data. The results demonstrate

Water Quality Index (WQI) is the most common determinant of the quality of the stream-flow. According to the Department of Environment (DOE, Malaysia), WQI is chiefly affected by six factors, which are, chemical oxygen demand (COD), biochemical oxygen demand (BOD), dissolved oxygen (DO), suspended solids (SS), -potential for hydrogen (pH), and ammoniacal nitrogen (AN). In fact, understanding the inter-relationships

This paper first introduces the structure and working principle of a 2D piston pump invented by the research team that the authors are involved with. Afterward, the mechanism of the churning losses caused by the pump’s moving parts, which are rotating in oil, is carefully studied by building up mathematical models and using CFD simulations. A test rig is set up to estimate the churning losses of the

An induced gas flotation (IGF) machine is a type of water treatment equipment that separates oil droplets or particles from waste-water using the characteristics of floating air bubbles. In general, bubble movement inside an IGF is difficult to predict since the internal flow in an IGF is not linear due to vortex formation and recirculating flow. Furthermore, the actual bubbles are distributed in various

This article proposes a novel a magnetophoretic microfluidic device for separation of magnetic microparticles based on size and subsequently carries out simulation-based parametric analysis of the same. The microfluidic device is constructed with two inlets as well as two outlets and employs a soft magnetic element subjected to a uniform magnetic field to create the desired spatially varying magnetic

The thermal environment of four-engine liquid rocket exhaust plume impinging on the flame deflector with different impingement and uplift angles is analysed. The supersonic exhaust gas impinging model was established by using the compressible, multi-component, Reynolds-Averaged Navier-Stokes (RANS) equations with the finite volume method. A comparison between the numerical results and experimental

End of vehicle streamlined head was selected as the installation location, and aerodynamic behavior of trains with and without braking plates was compared to analyze the formation of the braking force and the evolution of the flow field. An IDDES method based on the SST κ–ω turbulence model was used to investigate the unsteady flow, and the numerical algorithm was validated. Results show that the train

In this study, computational fluid dynamics (CFD) was used to investigate the performance of the steam ejector used in refrigeration systems to increase operational flexibility and COP. A 2D-axisymetric model of a two-stage ejector (TSE) was developed and its performance was compared to that of the commonly used single-stage ejector. The SST k-omega (k-ω-sst) model was applied as a turbulence model

In the operation of a nuclear plant system, a distorted inflow of a reactor coolant pump appears owing to the steam generator channel head and multi-bend, leading to the deterioration of pump performance and stability. In the present study, three-dimensional numerical calculations of three model geometries are carried out using block grid technology, with RNG k-ε and DDES model applied in the stea

This paper considers a solution to the serious problem of hydraulic maladjustment in a dynamic flow balance valve for small diameter and low-pressure drop working conditions. The pressure drop compensation coefficient revising method was proposed to optimize the profile line of the valve core variable opening area. The flow rates of the valve before and after optimization under different displacements

High level of tropospheric ozone concentration, exceeding allowable level has been frequently reported in Malaysia. This study proposes accurate model based on Machine Learning algorithms to predict Tropospheric ozone concentration in major cities located in Kuala Lumpur and Selangor, Malaysia. The proposed models were developed using three-year of historical data for different parameters as input

ABSTRACT This paper reports the results of a numerical study on the dynamics of isothermal multiphase fluids using an energy-law-preserving method. A phase-field model is taken into account. Different to previous studies, a continuous finite element technique is used to simulate the Navier-Stokes-Cahn-Hilliard coupled model. A modified discrete energy law of the numerical simulation is derived in detail

ABSTRACT Colloidal particles removal from water is a challenge in surface water treatment. Previously, we suggested an original technique for colloidal particles separation from water based on physical flow manipulation by an oscillating device. Laboratory experiments and 2D numerical simulation indicated that this technology enhances colloidal particles grouping and enables their rapid, simultaneous

Instantaneous gas–liquid flow and distribution have an important influence on the performance of a multiphase pump, especially under the high gas content conditions. How to accurately simulate the complete working cycle of a multiphase pump and reflect the transient oil-gas flow inside the pump cavity are the main difficulties of the study. A three-dimensional whole-cycle numerical simulation has been

This paper aims to investigate the hydrodynamics of a flexible fishlike foil undulating near the vertical sidewall by using numerical simulation. To achieve the research target of this paper, an immersed boundary-lattice Boltzmann method (IB-LBM) was proposed for high Reynolds number fluid flow simulation. The influences of the clearance (0.2L ≤ d ≤ 0.8L, L is the chord length of the fishlike foil)

Underwater vehicles are widely used in underwater detection, and bionic design, e.g. imitating fish, is an important way to improve their hydrodynamic performance. Most research is on the mechanical structure and kinematics of fish-like models, while evolvement rules and hydrodynamic effects of fluid field around fish have not been studied adequately. In this paper, a kinematic model to simulate the

The difference of the aerodynamic influence of two engine models – the Flow Through Nacelle (FTN) and With Powered Nacelle (WPN) – on BWB300 airframe is analyzed by using the 3-D unsteady compressible Reynolds-Averaged Navier-Stokes (RANS) computation. The results indicate that at cruise condition, the engine shape is a primary factor affecting the BWB airframe upper fuselage surface flow, the two

In this study, machine learning methods of artificial neural networks (ANNs), least squares support vector machines (LSSVM), and neuro-fuzzy are used for advancing prediction models for thermal performance of a photovoltaic-thermal solar collector (PV/T). In the proposed models, the inlet temperature, flow rate, heat, solar radiation, and the sun heat have been considered as the input variables. Data

A second order finite-difference numerical method is used to solve the Navier–Stokes equations of incompressible flow, in which the solid body with complex geometry is immersed into the fluid domain with orthogonal Cartesian meshes. To account for influences of the solid body, interactive forces are applied as boundary conditions at Cartesian grid nodes located in the exterior but in the immediate

The emissions of volatile organic compounds (VOCs) from petroleum product tankers potentially represent a significant source of VOCs in port cities. Emission factors are used to estimate the produced VOCs. VOC emissions from transit operations were simulated using a two part model of heat and mass transfer. Using local meteorological data of air temperatures, solar radiation and wind speed, the heat

The work simulates the transport pipeline movement of the marine dynamic environment based on the computational fluid dynamics research method. The present work also studies the influence of the marine dynamic environment on the solid–liquid two-phase flow field in the pipeline. An experimental study on the hydraulic transport flow law of natural gas hydrate pipeline is performed on the experimental

Climate change impacts and adaptations are ongoing issues that are attracting the attention of many researchers. Insight into the wind power potential in an area and its probable variation due to climate change impacts can provide useful information for energy policymakers and strategists for sustainable development and management of the energy. In this study, spatial variation of wind power density

ABSTRACT Distorted inflow caused by the complex structure of the steam generator channel head (SGCH) occurs at the entrance to the reactor coolant pump (RCP) in the AP1000 system, which may generate impeller cracks and result in deterioration of performance and stability. In this paper, to analyze the influence of distorted inflow on flow properties of the RCP, the inflow distortion characteristics

Fluid flows around a pointed object, e.g. the flow around a triangular prism, are often encountered. In this study, numerical simulation of the flow around a triangular prism was carried out using COMSOL Multiphysics® software. Two cases were considered: the entire area of the triangular prism is fixed; and only the center is fixed. The first case is divided into three different flow models according

Idling power loss suppression techniques of hydraulic retarders in non-braking operating conditions are of great significance to improve vehicle driving efficiency. Most proposed idling power loss suppression devices require auxiliary operating parts, take up a lot of space and increase the load on the vehicle. In this study, the plunger spoiler was optimized with a non-smooth bionic surface for improved

The air distribution system is an essential aircraft system, helping to create a safe, healthy and thermally comfortable cabin environment for large-scale aircraft. This complex pipe network system contains a large number of pipes, valves, elbows, joints and flow devices. The enormous number of components poses a severe challenge to the efficiency, accuracy and convergence of system thermal fluid analysis

Wind load of an external floating-roof tank is analyzed using large eddy simulation (LES). First, the governing equations and a LES solution procedure employing FLUENT software are presented. Subsequently, using two benchmark tank models, the accuracy of LES is examined and the advantages of LES over wind Reynolds-averaged Navier-Stokes (RANS) method in computing the unsteady wind loads and vortex