This paper investigates the hydrodynamic characteristic of a single-stage centrifugal pump with inlet inducer and outlet Radial Guided Vanes (RGVs) influenced by the clocking effect for the first time. Different from general ones, the outlet RGVs in this paper have specificities. The hydraulic performance and dynamic characteristics of the centrifugal pump are numerically studied and validated by experiments

ABSTRACT Installing a turbine in a duct generally increases the flow through the rotor. If there is flow confinement due to limited water depth, the presence of lateral boundaries, or the presence of adjacent turbines, a further flow enhancement through the rotor will be achieved. Extensive studies of ducted turbines in uni-directional flow have shown that rotor-based power coefficient C p can exceed

This paper mainly proposed a dynamic control method of particle distribution uniformity in a rolling circulating fluidized bed (RCFB) by using an air distribution plate. An Euler–Euler numerical simulation approach which is called two-fluid flow model is used to simulate the behaviors multiphase flow within the RCFB. Six different tilt angles θ which are θ = 2°, 5°, 8°, 10°, 12° and 15° are used for

ABSTRACT Deviant geometry of nasal channels results in significant changes to nasal aerodynamics that alter flow resistance, sensation, and the ability to filter aerosols. The invasive, operative modification of nasal geometry might alter the intranasal flow patterns, and this must be considered in advance at the stage of surgical planning. The present work describes flow patterns, reproduced numerically

Pre-swirl system is installed to minimize energy loss between the stationary and rotating parts of turbine secondary air system. Although various optimization studies were conducted to increase the pre-swirl efficiency, most of the studies were focused on a hole type pre-swirl nozzles. In this study, a vane type pre-swirl nozzle was optimized to increase mass flow rate and temperature drop for given

Enhancing the efficiency of gear systems is of significance to reduce fuel consumption and overall weight. Windage power losses become prevailing in high-speed gear systems, such as aero-engine applications. To avoid the shortages and limitations of commonly used methods (e.g. negative volume in dynamic mesh method and one moving object in sliding meshing method), this paper describes an unstructured

Compressor design is always a prevalent research issue as nowadays the compressor demands higher performance. Designing afresh a new compressor of higher aerodynamic performance will cost a tremendous amount of time and expense. Consequently, the wiser method of acquiring a higher performance compressor is to optimize a current compressor, discussed in this paper. First, a detailed numerical simulation

In this study, we numerically investigated the effects of CO2 gas in geothermal water and the scale deposition formed in the wellbore on the flow characteristics. Geothermal water that contains CO2 gas has the potential to produce calcite scale deposits in the wellbore. To prevent scale formation, scale inhibitor is injected below the flash point in the wellbore, which is a challenging job. Therefore

Due to industrial development, the volume of carbon dioxide (CO2) is rapidly increasing.. Several techniques have been used to eliminate CO2 from the output gas mixtures. One of these methods is CO2 capturing by ionic liquids (ILs). Computational models for estimating the CO2 solubility in ILS is of utmost importance. In this research, a white box model in the form of a mathematical correlation using

The precise calculation of drag forces in the technical application of automatic balancing of rotating machinery provides important information about efficiency and stability. With increasing geometric complexity of the design, this poses a challenge that can be solved with computer-aided fluid dynamic approaches. In rolling element bearings, the influence of drag induced by the lubricant is predominantly

A new numerical methodology to solve the 3D Navier-Stokes equations for incompressible fluids within complex boundaries and unstructured body-fitted tetrahedral mesh is presented and validated with three literature and one real-case tests. We apply a fractional time step procedure where a predictor and a corrector problem are sequentially solved. The predictor step is solved applying the MAST (Marching

Manning’s roughness coefficient(n) is considered a key parameter in a one-dimensional (1D) hydrodynamic model. However, it is highly variable and time- and site- dependent. Further, identifying proper n values is not easy, especially in plain looped river network areas. Therefore, a more systematic approach is needed. This study proposes a coupled optimization-simulation model to systematically estimate

Numerical modeling of turbulent impinging swirling jets involve complex flow physics that make their computation still very challenging. Thus, the literature on computational modeling of these nanofluid jets is really scarce, with most works on laminar impinging nanofluid jets or turbulent swirling/non-swirling air or water-only jets. In this paper a computational analysis of different configurations

Discretizing and synthesizing random flow generation (DSRFG) is applied to generate inflow turbulence satisfying large eddy simulation (LES) requirements for bridge wind engineering. The variation of the turbulent wind along the computational domain is investigated considering multiple grid sizes and time steps. The aerodynamic admittance functions (AAFs) of a thin plate and two bridge sections are

ABSTRACT The impact of presence of nano-scale particles inside a flow between two flat plates which known as Poiseuille flow is numerically analyzed. Nanofluids have been investigated in the past few years mainly by considering the heat transfer aspect in a fully developed section of internal flows, rather than detailing the hydrodynamic and thermal developing viewpoint of nanofluid. In other words

The turbulence–chemistry interaction model with finite-rate chemistry is a common model for solving supersonic turbulent combustion and takes into consideration the interaction between turbulent mixing and chemical reactions as well as finite chemistry reaction instead of the fast chemistry assumption. However, not only the density and viscosity but also the chemical reactions are affected by the compressibility

This paper has established an evaluation system for the sensitivity analysis of cascade/compressor aerodynamic performance to geometric deviations. The system includes blade profile parameterization with non-uniform rational B-spline (NURBS), uniform Latin hypercube sampling in association with Monte Carlo algorithm and statistical investigation methods. The sensitivity of a subsonic cascade performance

With the increase of the running speed of the high-speed train (HST), aerodynamic interference between the HST and surrounding structures becomes more and more important. Traditional wind tunnel experiments using the stationary model can not fully reveal the pulsing behavior of the aerodynamic forces on both the HST and surrounding structures. This paper numerically investigates the aerodynamic characteristics

Many important technical systems operate according to the principles of momentum transfer, heat transfer and mass transfer near the surface of a cylinder rotating in a confined space. Numerical study of the Taylor–Couette flow with an imposed inward radial throughflow in the rotating inner cylinder demonstrates the possibility of flow stabilization to prevent large-scale vortices up to high rotation

Fluid seepage into rock pores not only generates poroelastic stress but also exerts seepage force on the rock skeleton. However, since the mechanism of the effect of seepage force on the stress field around the wellbore is not clear, conventional methods calculate the stress field only taking into account the poroelastic stress without the coupled effects of seepage force and rock deformation. Based

Ploughbreast is the crucial soil-engaging component of horizontally reversible plough (HRP). Its biggest merit, compared to conventional ploughs, is to enable the ploughbody to perform alternative and shifting tillage operations with high speeds. A major technical challenge in the aforementioned operation is violent flowing interaction between soil and ploughbreast. This flowing interaction may result

To find the influence of the suction chamber and throat inlet profiles on the cavitation performance of an annular jet pump (AJP), a numerical method using a combination of the realizable k–ϵ turbulence model and the Schnerr–Sauer cavitation model was applied. This paper comprehensively studied the cavitation performance of AJPs with a polygonal line profile (POL) and a streamlined profile (STR). The

The failure of tube heat exchangers is an acute problem in industry and, in most cases, is due to the solid particle erosion of a few tubes. Identifying the critical erosion surfaces and thereafter changing the particle impingement pattern on the surfaces is one of the solutions to increase the lifetime of heat exchangers. In this work the fluid flow, solid particle motion and metal erosion of different

The fast and accurate simulation of aircraft wake vortices evolution and safety assessment of wake encounters are important in identifying the hazard zone of wake vortices, reducing wake separation, and increasing the capacity of airports. However, numerical simulation of wake vortices often takes a lot of time due to a large number of grids. In order to reduce the computation time, Solution-Based

Accurate streamflow prediction is essential in reservoir management, flood control, and operation of irrigation networks. In this study, the deterministic and stochastic components of modeling are considered simultaneously. Two nonlinear time series models are developed based on autoregressive conditional heteroscedasticity and self-exciting threshold autoregressive methods integrated with the gene

This study consists of proposing a new mathematical method to develop a new model for evaluating thermal distributions throughout convergent-divergent channels between non-parallel plane walls in Jeffery Hamel flow. Subsequently, dimensionless equations that govern temperature fields and velocity are numerically tackled via the Runge–Kutta-Fehlberg approach based on the shooting method. Additionally

To reduce the impact of a mountain ridge on the crosswind flow field of a specific section of the Lanzhou-Xinjiang high-speed railway, a portion of the mountain ridge was removed to increase the distance from the windbreak. To verify the effects of this flow optimization measure, the wind speed and wind angle were tested in this mountain ridge region. In this paper, under the actual conditions of this

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