CFD Study for the Particle Transport and Deposition in Secondary Air Systems

2019 ◽  
Author(s):  
Nomesh P. Kandaswamy ◽  
Kali Charan Nayak ◽  
Guy D. Snowsill ◽  
John Irving ◽  
Ben Littley
Keyword(s):  
Parametric Study ◽  
Particle Transport ◽  
Particle Deposition ◽  
Three Dimensional ◽  
Velocity Model ◽  
Civil Aviation ◽  
Aviation Industry ◽  
Salt Particle ◽  
Wide Range ◽  
Secondary Air

Abstract The recent expansion of civil aviation industry into the new market demands modern aero-engines to operate in hot, harsh and polluted environments. Moreover there is a significant increase in the flight paths across the sea leading to large amount of micro salt particle ingestion into the engines. These contaminants can cause severe damage to the turbine parts through hot corrosion fatigue. The mechanism of the very small particle transport in the secondary air system and their deposition on turbine parts is less reported and not well understood. This study explores the physics of the particle transport (< 0.5–10 micron) and their deposition characteristics in the secondary air paths. Specifically, a three-dimensional computational fluid dynamics (CFD) model is developed for an engine representative turbine cavity with blade shank utilizing commercial finite volume-based software incorporating the SST k-ω turbulence model. The particle transport is captured using discrete random walk model and their wall interaction (bounce and stick) is simulated using the critical velocity model. A comprehensive parametric study is conducted using 2 and 6 micron CaSO4 particles covering a wide range of operating and design variables. From the parametric study it has been observed that rotor speed, swirl and the radial location of the feed holes strongly influence the flow structure in the shank cavity and particle deposition.

scholarly journals Parametric based study for design of liquid-filled elevated tanks

2016 ◽  
Vol 43 (7) ◽  
pp. 619-630 ◽  
Author(s):  
Mehdi Moslemi ◽  
Amir Reza Ghaemmaghami ◽  
M. Reza Kianoush
Keyword(s):  
Finite Element ◽  
Parametric Study ◽  
Three Dimensional ◽  
Time History ◽  
History Analysis ◽  
Wide Range ◽  
Elevated Tanks ◽  
Elevated Water ◽  
Element Technique ◽  
Water Tanks

In this study, the dynamic behavior of elevated water tanks is investigated by performing a comprehensive parametric study on conical elevated tanks using the finite element technique. Through this study, a wide range of tank parameters and geometries typically found in practice is considered. To perform this parametric study, a parametric model capable of building any finite element models of a three-dimensional conical elevated tank with varying parameters is developed. As a result of this parametric study, pressure distribution graphs corresponding to both impulsive and convective hydrodynamic pressures can be generated by carrying out spectral analysis. These pressure graphs can be utilized simply in design applications for liquid-filled conical elevated tanks. The accuracy of the proposed pressure graphs is verified by comparing these results with those calculated using the previously verified finite element time-history analysis and also the “current practice”.

scholarly journals Offshore anchor piles under mooring forces: numerical modeling

2013 ◽  
Vol 50 (2) ◽  
pp. 189-199 ◽  
Author(s):  
Mohamed I. Ramadan ◽  
Stephen D. Butt ◽  
R. Popescu
Keyword(s):  
Parametric Study ◽  
Three Dimensional ◽  
Element Model ◽  
Model Parameters ◽  
Test Results ◽  
Dense Sand ◽  
Centrifuge Tests ◽  
Wide Range ◽  
Inclination Angles ◽  
Mooring Forces

A parametric study was carried out to study the behavior of offshore anchor piles under mooring forces in dense sand using a three dimensional (3-D) finite element model (FEM). The Mohr–Coulomb plastic model has been used to model the soil, and has been calibrated based on the centrifuge tests discussed in a Ph.D. thesis (published by Ramadan in 2011). The selection of model parameters and comparison of calibrated results with the centrifuge test results are discussed. In the parametric study, different pile lengths and diameters were considered to have different pile–soil rigidities. The pile was loaded at different load inclination angles to examine a wide range of loading conditions. From the current parametric study, design methods and design recommendations are given to help in improving the design of offshore anchor piles under monotonic mooring forces.

Elasto-Plastic Contact Behaviors of Nominally Flat Surfaces: Modeling and Parametric Study

2007 ◽  
Author(s):  
W. Wayne Chen ◽  
Yuchuan Liu ◽  
Wei Chen ◽  
Jiao Cao ◽  
Cedric Xia ◽  
...  
Keyword(s):  
Fourier Transform ◽  
Material Properties ◽  
Parametric Study ◽  
Three Dimensional ◽  
Digital Filtration ◽  
Flat Surfaces ◽  
Geometrical Characteristics ◽  
Wide Range ◽  
Filtration Technology ◽  
Skewness And Kurtosis

Interactions of nominally flat surfaces can be modeled based on the periodic similarity of surface topography and a numerical three-dimensional elasto-plastic contact model with the assistance of the continuous convolution and Fourier transform (CC-FT) algorithm. The rough surfaces were generated by a digital filtration technology with a wide range of topographical parameters. A group of contact simulations were conducted to investigate the effects of surface geometrical characteristics (including RMS roughness, correlation length ratio, skewness and kurtosis), material properties, and load on the elasto-plastic contact performance of materials.

Fabrication of Pliable Biodegradable Polymer foams to Engineer Soft Tissues

1996 ◽  
Vol 5 (4) ◽  
pp. 465-473 ◽  
Author(s):  
M. Conley Wake ◽  
Puneet K. Gupta ◽  
Antonios G. Mikos
Keyword(s):  
Soft Tissues ◽  
Three Dimensional ◽  
Weight Fraction ◽  
Processing Parameters ◽  
Great Promise ◽  
Blend Ratio ◽  
Salt Particle ◽  
Biodegradable Scaffolds ◽  
Wide Range ◽  
Initial Salt

We have fabricated pliable, porous, biodegradable scaffolds with poly(lactic-co-glycolic acid) (PLGA) and poly(ethylene glycol) (PEG) blends using a solvent-casting and particulate-leaching technique. Our study investigated the effects of four different processing parameters on pliability and pore morphology of the biodegradable scaffolds. The parameters investigated were the PLGA copolymer ratio, the PLGA/PEG blend ratio, the initial salt weight fraction, and the salt particle size. A wide range of shear moduli (0.59 to 9.55 MPa), porosities (0.798 to 0.942), and median pore diameters (71 to 154 μm) was able to be achieved by varying the combination of these parameters. Our study indicates that initial salt weight fraction and PLGA/PEG blend ratio have the most significant effects on the physico-mechanical properties of the scaffolds. Enhanced pliability of the three dimensional foams made with blends of PLGA and PEG is evidenced by the ability to roll them into a tube without macroscopic damage to the scaffold. Pliable polymer substrates hold great promise for regeneration of soft tissues such as skin, or those requiring a tubular conformation such as intestine or vascular grafts.

scholarly journals Influence of Thermophoretic Particle Deposition on the 3D Flow of Sodium Alginate-Based Casson Nanofluid over a Stretching Sheet

Micromachines ◽  
2021 ◽  
Vol 12 (12) ◽  
pp. 1474
Author(s):  
Bheemasandra M. Shankaralingappa ◽  
Javali K. Madhukesh ◽  
Ioannis E. Sarris ◽  
Bijjanal J. Gireesha ◽  
Ballajja C. Prasannakumara
Keyword(s):  
Differential Equations ◽  
Particle Deposition ◽  
Three Dimensional ◽  
Industrial Applications ◽  
Vital Role ◽  
Exact Estimate ◽  
Surface Drag ◽  
Similarity Transformations ◽  
Wide Range ◽  
Non Linear

The wide range of industrial applications of flow across moving or static solid surfaces has aroused the curiosity of researchers. In order to generate a more exact estimate of flow and heat transfer properties, three-dimensional modelling must be addressed. This plays a vital role in metalworking operations, producing plastic and rubber films, and the continuous cooling of fibre. In view of the above scope, an incompressible, laminar three-dimensional flow of a Casson nanoliquid in the occurrence of thermophoretic particle deposition over a non-linearly extending sheet is examined. To convert the collection of partial differential equations into ordinary differential equations, the governing equations are framed with sufficient assumptions, and appropriate similarity transformations are employed. The reduced equations are solved by implementing Runge Kutta Fehlberg 4th 5th order technique with the aid of a shooting scheme. The numerical results are obtained for linear and non-linear cases, and graphs are drawn for various dimensionless constraints. The present study shows that improvement in the Casson parameter values will diminish the axial velocities, but improvement is seen in thermal distribution. The escalation in the thermophoretic parameter will decline the concentration profiles. The rate of mass transfer, surface drag force will reduce with the improved values of the power law index. The non-linear stretching case shows greater impact in all of the profiles compared to the linear stretching case.

Importance of Personal Data Protection Law for Commercial Air Transport

2017 ◽  
Vol 2017 (1) ◽  
pp. 35-44
Author(s):  
Dawid Zadura
Keyword(s):  
Data Protection ◽  
Public Information ◽  
Personal Data ◽  
Air Transport ◽  
Civil Aviation ◽  
Aviation Industry ◽  
Personal Data Protection ◽  
It Systems ◽  
Data Protection Law ◽  
The Law

Abstract In the review below the author presents a general overview of the selected contemporary legal issues related to the present growth of the aviation industry and the development of aviation technologies. The review is focused on the questions at the intersection of aviation law and personal data protection law. Massive processing of passenger data (Passenger Name Record, PNR) in IT systems is a daily activity for the contemporary aviation industry. Simultaneously, since the mid- 1990s we can observe the rapid growth of personal data protection law as a very new branch of the law. The importance of this new branch of the law for the aviation industry is however still questionable and unclear. This article includes the summary of the author’s own research conducted between 2011 and 2017, in particular his audits in LOT Polish Airlines (June 2011-April 2013) and Lublin Airport (July - September 2013) and the author’s analyses of public information shared by International Civil Aviation Organization (ICAO), International Air Transport Association (IATA), Association of European Airlines (AEA), Civil Aviation Authority (ULC) and (GIODO). The purpose of the author’s research was to determine the applicability of the implementation of technical and organizational measures established by personal data protection law in aviation industry entities.

Business Aviation in Russia: Specific Features and Prospects of Development

2020 ◽  
Vol 26 (1) ◽  
pp. 86-93
Author(s):  
D. V. Slivinsky ◽  
I. A. Fomina ◽  
D. G. Menshikh
Keyword(s):  
Systems Approach ◽  
National Policy ◽  
Civil Aviation ◽  
Economic Growth Rate ◽  
Factors Affecting ◽  
Organization And Management ◽  
Transport Services ◽  
Business Aviation ◽  
Wide Range

The presented study determines the role of business aviation in the modern economy and examines the specific features of its development in Russia.Aim. The study aims to analyze the development of business aviation in Russia and its correlation with economic development in general.Tasks. The authors determine the benefits of business aviation as a business tool, examine the specific features of the Russian business aviation market and problems of its development, and identify factors that affect the development of business aviation in Russia.Methods. This study uses the methods of comparative and retrospective analysis, cross-country comparison, systems approach, and expert analytics.Results. Business aviation is a new segment of civil aviation for Russia. Therefore, it is advisable to rely on foreign practices in the management of its development. In many countries, business aviation is a separate industry that specializes in providing transport services to a wide range of corporate clients and/or individuals. The development of this industry is associated with the economic growth rate and the development level of the national economy, and also depends on the national institutional specifics. This study describes the specific features of development of business aviation in Russia and problems arising in the organization and management of this type of business.Conclusions. The authors develop a system of factors affecting the development of business aviation in Russia, describe the major problems of this industry, and propose solutions. The results of this study can be used in the development (adjustment) of business aviation development strategies in Russia both at the industrial and corporate level, and in the implementation of the national policy in this field.

Turbulent three-dimensional dielectric electrohydrodynamic convection between two plates

2012 ◽  
Vol 696 ◽  
pp. 228-262 ◽  
Author(s):  
A. Kourmatzis ◽  
J. S. Shrimpton
Keyword(s):  
Spatial Data ◽  
Three Dimensional ◽  
Reynolds Numbers ◽  
Two Dimensions ◽  
Three Dimensions ◽  
Energy Budgets ◽  
Turbulent Regime ◽  
Scalar Flux ◽  
Wide Range ◽  
Scalar Variance

AbstractThe fundamental mechanisms responsible for the creation of electrohydrodynamically driven roll structures in free electroconvection between two plates are analysed with reference to traditional Rayleigh–Bénard convection (RBC). Previously available knowledge limited to two dimensions is extended to three-dimensions, and a wide range of electric Reynolds numbers is analysed, extending into a fully inherently three-dimensional turbulent regime. Results reveal that structures appearing in three-dimensional electrohydrodynamics (EHD) are similar to those observed for RBC, and while two-dimensional EHD results bear some similarities with the three-dimensional results there are distinct differences. Analysis of two-point correlations and integral length scales show that full three-dimensional electroconvection is more chaotic than in two dimensions and this is also noted by qualitatively observing the roll structures that arise for both low (${\mathit{Re}}_{E} = 1$) and high electric Reynolds numbers (up to ${\mathit{Re}}_{E} = 120$). Furthermore, calculations of mean profiles and second-order moments along with energy budgets and spectra have examined the validity of neglecting the fluctuating electric field ${ E}_{i}^{\ensuremath{\prime} } $ in the Reynolds-averaged EHD equations and provide insight into the generation and transport mechanisms of turbulent EHD. Spectral and spatial data clearly indicate how fluctuating energy is transferred from electrical to hydrodynamic forms, on moving through the domain away from the charging electrode. It is shown that ${ E}_{i}^{\ensuremath{\prime} } $ is not negligible close to the walls and terms acting as sources and sinks in the turbulent kinetic energy, turbulent scalar flux and turbulent scalar variance equations are examined. Profiles of hydrodynamic terms in the budgets resemble those in the literature for RBC; however there are terms specific to EHD that are significant, indicating that the transfer of energy in EHD is also attributed to further electrodynamic terms and a strong coupling exists between the charge flux and variance, due to the ionic drift term.

Unsteady simulations of migration and deposition of fly-ash particles in the first-stage turbine of an aero-engine

2021 ◽  
pp. 1-21
Author(s):  
Z. Hao ◽  
X. Yang ◽  
Z. Feng
Keyword(s):  
Fly Ash ◽  
Film Cooling ◽  
Particle Deposition ◽  
Flow Characteristics ◽  
Leading Edge ◽  
Velocity Model ◽  
Operating Conditions ◽  
Inlet Temperature ◽  
Internal Cooling ◽  
Aero Engine

Abstract Particulate deposits in aero-engine turbines change the profile of blades, increase the blade surface roughness and block internal cooling channels and film cooling holes, which generally leads to the degradation of aerodynamic and cooling performance. To reveal particle deposition effects in the turbine, unsteady simulations were performed by investigating the migration patterns and deposition characteristics of the particle contaminant in a one-stage, high-pressure turbine of an aero-engine. Two typical operating conditions of the aero-engine, i.e. high-temperature take-off and economic cruise, were discussed, and the effects of particle size on the migration and deposition of fly-ash particles were demonstrated. A critical velocity model was applied to predict particle deposition. Comparisons between the stator and rotor were made by presenting the concentration and trajectory of the particles and the resulting deposition patterns on the aerofoil surfaces. Results show that the migration and deposition of the particles in the stator passage is dominated by the flow characteristics of fluid and the property of particles. In the subsequential rotor passage, in addition to these factors, particles are also affected by the stator–rotor interaction and the interference between rotors. With higher inlet temperature and larger diameter of the particle, the quantity of deposits increases and the deposition is distributed mainly on the Pressure Side (PS) and the Leading Edge (LE) of the aerofoil.

scholarly journals Application of Dendrimers for Treating Parasitic Diseases

Pharmaceutics ◽  
2021 ◽  
Vol 13 (3) ◽  
pp. 343
Author(s):  
Veronica Folliero ◽  
Carla Zannella ◽  
Annalisa Chianese ◽  
Debora Stelitano ◽  
Annalisa Ambrosino ◽  
...  
Keyword(s):  
Drug Delivery ◽  
Water Solubility ◽  
Parasitic Infection ◽  
Three Dimensional ◽  
Medical Knowledge ◽  
High Ratio ◽  
Molecular Volume ◽  
Parasitic Infections ◽  
Parasitic Diseases ◽  
Wide Range

Despite advances in medical knowledge, parasitic diseases remain a significant global health burden and their pharmacological treatment is often hampered by drug toxicity. Therefore, drug delivery systems may provide useful advantages when used in combination with conventional therapeutic compounds. Dendrimers are three-dimensional polymeric structures, characterized by a central core, branches and terminal functional groups. These nanostructures are known for their defined structure, great water solubility, biocompatibility and high encapsulation ability against a wide range of molecules. Furthermore, the high ratio between terminal groups and molecular volume render them a hopeful vector for drug delivery. These nanostructures offer several advantages compared to conventional drugs for the treatment of parasitic infection. Dendrimers deliver drugs to target sites with reduced dosage, solving side effects that occur with accepted marketed drugs. In recent years, extensive progress has been made towards the use of dendrimers for therapeutic, prophylactic and diagnostic purposes for the management of parasitic infections. The present review highlights the potential of several dendrimers in the management of parasitic diseases.

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