scholarly journals Flow visualisation in real-size optical injectors of conventional, additised, and renewable gasoline blends

2022 ◽  
Vol 252 ◽  
pp. 115109
Author(s):  
Milad Heidari-Koochi ◽  
Ioannis K. Karathanassis ◽  
Phoevos Koukouvinis ◽  
Joonsik Hwang ◽  
Lyle M. Pickett ◽  
...  
Keyword(s):  
Flow Visualisation ◽  
Real Size

scholarly journals Combined visualisation of cavitation and vortical structures in a real-size optical diesel injector

2020 ◽  
Vol 62 (1) ◽  
Author(s):  
I. K. Karathanassis ◽  
J. Hwang ◽  
P. Koukouvinis ◽  
L. Pickett ◽  
M. Gavaises
Keyword(s):  
High Speed ◽  
Cone Angle ◽  
Frame Rate ◽  
Flow Visualisation ◽  
Fuel Injector ◽  
Two Phase ◽  
Vortical Structures ◽  
Flow Motion ◽  
Real Size ◽  
Set Up

Abstract A high-speed flow visualisation set-up comprising of combined diffuse backlight illumination (DBI) and schlieren imaging has been developed to illustrate the highly transient, two-phase flow arising in a real-size optical fuel injector. The different illumination nature of the two techniques, diffuse and parallel light respectively, allows for the capturing of refractive-index gradients due to the presence of both interfaces and density gradients within the orifice. Hence, the onset of cavitation and secondary-flow motion within the sac and injector hole can be concurrently visualised. Experiments were conducted utilising a diesel injector fitted with a single-hole transparent tip (ECN spray D) at injection pressures of 700–900 bar and ambient pressures in the range of 1–20 bar. High-speed DBI images obtained at 100,000 fps revealed that the orifice, due to its tapered layout, is mildly cavitating with relatively constant cavity sheets arising mainly in regions of manufacturing imperfections. Nevertheless, schlieren images obtained at the same frame rate demonstrated that a multitude of vortices with short lifetimes arise at different scales in the sac and nozzle regions during the entire duration of the injection cycle but the vortices do not necessarily result in phase change. The magnitude and exact location of coherent vortical structures have a measurable influence on the dynamics of the spray emerging downstream the injector outlet, leading to distinct differences in the variation of its cone angle depending on the injection and ambient pressures examined. Graphic abstract

APPLYING THE ISF TECHNOLOGY TO PRODUCE THE CAR PART MODELS

2010 ◽  
Vol 13 (4) ◽  
pp. 91-98
Author(s):  
Tuan Dinh Phan ◽  
Binh Thien Nguyen ◽  
Dien Khanh Le ◽  
Phuong Hoang Pham
Keyword(s):  
Rapid Prototyping ◽  
Incremental Sheet Forming ◽  
Cad Model ◽  
Post Processing ◽  
Technological Parameters ◽  
Batch Production ◽  
Complex Products ◽  
3D Cad ◽  
Real Size ◽  
Single Batch

The paper presents an application the research results previously done by group on the influence of technological parameters to the deformation angle and finish surface quality in order to choose technology parameters for the incremental sheet forming (ISF) process to produce products for the purpose of rapid prototyping or single-batch production, including all steps from design and process 3D CAD model, calculate and select the technological parameters, setting up manufacturing and the stage of post-processing. The samples formed successfully showed high applicability of this technology to practical work, the complex products with the real size can be produced in industries: automotive, motorcycle, civil...

China: "A Bee Has a Stripy Back, but No One Can Call It a Tiger"

2003 ◽  
pp. 61-75
Author(s):  
V. Guelbras
Keyword(s):  
Energy Consumption ◽  
Gdp Growth ◽  
International Demand ◽  
Real Size ◽  
Rates Of Growth

The article is devoted to verification of the Chinese GDP data. The author compares the rates of GDP growth with the rates of growth of energy consumption, transport turnover of goods, and numbers of projected and constructed objects in 1980-2000. The former was significantly lower during that period. He also analyses the level of using productive capacities and the quality of production. About 25-30% of industrial productive capacities are not used because there is neither national nor international demand for their low quality goods. The main conclusion of the article is that the Chinese GDP real size is about 20-30% less than official releases.

On the Effectiveness of National Resources Utilization

2003 ◽  
pp. 31-40
Author(s):  
N. Fedorenko ◽  
V. Simchera
Keyword(s):  
Resource Potential ◽  
Low Level ◽  
Real Size

The authors are of the opinion that in order to answer the question of Russia's resource potential utilization it is necessary to measure national resources, estimate their real size, the degree of their assimilation and effectiveness. Coefficients of resource potential assimilation are considered, which suggest not only its low level but also the absence of corresponding demand. For making specific decisions aimed at increasing the level of resources utilization the authors propose a number of measures.

scholarly journals Limitations of Nanoparticles Size Characterization by Asymmetric Flow Field‑Fractionation Coupled with Online Dynamic Light Scattering

2021 ◽  
Author(s):  
Francesco Giorgi ◽  
Judith M. Curran ◽  
Douglas Gilliland ◽  
Rita La Spina ◽  
Maurice Whelan ◽  
...  
Keyword(s):  
Light Scattering ◽  
Dynamic Light Scattering ◽  
Flow Field ◽  
Field Flow Fractionation ◽  
Asymmetric Flow ◽  
Uv Detector ◽  
Elution Time ◽  
On Line ◽  
Real Size ◽  
Flow Fractionation

AbstractThe development of reliable protocols suitable for the characterisation of the physical properties of nanoparticles in suspension is becoming crucial to assess the potential biological as well as toxicological impact of nanoparticles. Amongst sizing techniques, asymmetric flow field flow fractionation (AF4) coupled to online size detectors represents one of the most robust and flexible options to quantify the particle size distribution in suspension. However, size measurement uncertainties have been reported for on-line dynamic light scattering (DLS) detectors when coupled to AF4 systems. In this work we investigated the influence of the initial concentration of nanoparticles in suspension on the sizing capability of the asymmetric flow field-flow fractionation technique coupled with an on-line dynamic light scattering detector and a UV–Visible spectrophotometer (UV) detector. Experiments were performed with suspensions of gold nanoparticles with a nominal diameter of 40 nm and 60 nm at a range of particle concentrations. The results obtained demonstrate that at low concentration of nanoparticles, the AF4-DLS combined technique fails to evaluate the real size of nanoparticles in suspension, detecting an apparent and progressive size increase as a function of the elution time and of the concentration of nanoparticles in suspension.

scholarly journals Preliminary Results on the Dynamics of a Pile-Moored Fish Cage with Elastic Net in Currents and Waves

2020 ◽  
Vol 9 (1) ◽  
pp. 14
Author(s):  
Gianluca Zitti ◽  
Nico Novelli ◽  
Maurizio Brocchini
Keyword(s):  
Numerical Model ◽  
Laboratory Experiments ◽  
Numerical Models ◽  
Offshore Structures ◽  
Fish Farm ◽  
Maximum Displacement ◽  
Drag Forces ◽  
Real Size ◽  
Lift And Drag ◽  
Mesh Grid

Over the last decades, the aquaculture sector increased significantly and constantly, moving fish-farm plants further from the coast, and exposing them to increasingly high forces due to currents and waves. The performances of cages in currents and waves have been widely studied in literature, by means of laboratory experiments and numerical models, but virtually all the research is focused on the global performances of the system, i.e., on the maximum displacement, the volume reduction or the mooring tension. In this work we propose a numerical model, derived from the net-truss model of Kristiansen and Faltinsen (2012), to study the dynamics of fish farm cages in current and waves. In this model the net is modeled with straight trusses connecting nodes, where the mass of the net is concentrated at the nodes. The deformation of the net is evaluated solving the equation of motion of the nodes, subjected to gravity, buoyancy, lift, and drag forces. With respect to the original model, the elasticity of the net is included. In this work the real size of the net is used for the computation mesh grid, this allowing the numerical model to reproduce the exact dynamics of the cage. The numerical model is used to simulate a cage with fixed rings, based on the concept of mooring the cage to the foundation of no longer functioning offshore structures. The deformations of the system subjected to currents and waves are studied.

scholarly journals Designing an Artificial Intelligence Control Program Model to be Tested and Implemented in Virtual Reality for Automated Chevrolet Camaro

Proceedings ◽  
2020 ◽  
Vol 63 (1) ◽  
pp. 44
Author(s):  
Lavinia Andrei ◽  
Doru-Laurean Baldean ◽  
Adela-Ioana Borzan
Keyword(s):  
Artificial Intelligence ◽  
Virtual Reality ◽  
Control Program ◽  
Specific Model ◽  
Virtual Model ◽  
Program Model ◽  
Real Size ◽  
Virtual Modeling ◽  
And Robotics ◽  
Virtual Reality Application

A control program was designed with Unity 5 virtual reality application in the automotive and robotics field. Thus, a virtual model of a robotic car was tested in a virtual reality program. After optimization, the smart controller was implemented on a specific model of the automated Chevrolet Camaro. The main objective of the present paper is to design a control program model to be tested in virtual reality and in a real-size car. Results concerning the virtual modeling of an automated car and its artificial intelligence controls have been presented and discussed, outlining the forces, torques, and context awareness capabilities of the car.

Performance evaluation of metaheuristic search techniques in the optimum design of real size pin jointed structures

2009 ◽  
Vol 87 (5-6) ◽  
pp. 284-302 ◽  
Author(s):  
O. Hasançebi ◽  
S. Çarbaş ◽  
E. Doğan ◽  
F. Erdal ◽  
M.P. Saka
Keyword(s):  
Performance Evaluation ◽  
Optimum Design ◽  
Search Techniques ◽  
Metaheuristic Search ◽  
Real Size

Effect of back pressure and freestream dynamic pressure on a typical Ramjet engine duct under realistic supersonic inlet condition

2017 ◽  
Vol 122 (1247) ◽  
pp. 83-103 ◽  
Author(s):  
R. Saravanan ◽  
S.L.N. Desikan ◽  
T.M. Muruganandam
Keyword(s):  
Dynamic Pressure ◽  
Back Pressure ◽  
Flow Visualisation ◽  
Pressure Measurements ◽  
Shock Train ◽  
Unsteady Pressure ◽  
Expansion Waves ◽  
Ramjet Engine ◽  
Flap Deflection ◽  
Unsteady Pressure Measurements

ABSTRACTThe present study investigates the behaviour of the shock train in a typical Ramjet engine under the influence of shock and expansion waves at the entry of a low aspect ratio (1:0.75) rectangular duct/isolator at supersonic Mach number (M = 1.7). The start/unstart characteristics are investigated through steady/unsteady pressure measurements under different back and dynamic pressures while the shock train dynamics are captured through instantaneous Schlieren flow visualisation. Two parameters, namely pressure recovery and the pressure gradient, is derived to assess the duct/isolator performance. For a given back pressure, with maximum blockage (9% above nominal), the duct/isolator flow is established when the dynamic pressure is increased by 23.5%. The unsteady pressure measurements indicate different scales of eddies above 80 Hz (with and without flap deflection). Under the no flap deflection (no back pressure) condition, the maximum fluctuating pressure component is 0.01% and 0.1% of the stagnation pressure at X/L = 0.03 (close to the entry of the duct) and X/L = 0.53 (middle of the duct), respectively. Once the flap is deflected (δ = 8°), decay in eddies by one order is noticed. Further increase in back pressure (δ ≥ 11°) leads the flow to unstart where eddies are observed to be disappeared.

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