scholarly journals Simultaneous formaldehyde PLIF and high-speed schlieren imaging for ignition visualization in high-pressure spray flames

2015 ◽  
Vol 35 (3) ◽  
pp. 3167-3174 ◽  
Author(s):  
Scott A. Skeen ◽  
Julien Manin ◽  
Lyle M. Pickett
Keyword(s):  
High Pressure ◽  
High Speed ◽  
Schlieren Imaging ◽  
Spray Flames

Cyclone Bomb hits Southern Brazil in 2020

2020 ◽  
Vol 3 (3) ◽  
Author(s):  
Ricardo Gobato ◽  
Alireza Heidari
Keyword(s):  
High Pressure ◽  
Atmospheric Pressure ◽  
High Speed ◽  
Satellite Images ◽  
The State ◽  
Southern Brazil ◽  
Santa Catarina ◽  
High Area ◽  
South Of Brazil ◽  
Rapid Drop

An “explosive extratropical cyclone” is an atmospheric phenomenon that occurs when there is a very rapid drop in central atmospheric pressure. This phenomenon, with its characteristic of rapidly lowering the pressure in its interior, generates very intense winds and for this reason it is called explosive cyclone, bomb cyclone. With gusts recorded of 116 km/h, atmospheric phenomenon – “cyclone bomb” (CB) hit southern Brazil on June 30, the beginning of winter 2020, causing destruction in its influence over. One of the cities most affected was Chapecó, west of the state of Santa Catarina. The satellite images show that the CB generated a low pressure (976 mbar) inside it, generating two atmospheric currents that moved at high speed. In a northwest-southeast direction, Bolivia and Paraguay, crossing the states of Parana and Santa Catarina, and this draft that hit the south of Brazil, which caused the destruction of the affected states.  Another moving to Argentina, southwest-northeast direction, due to high area of high pressure (1022 mbar). Both enhanced the phenomenon.

YSS YXM4

Alloy Digest ◽  
2019 ◽  
Vol 68 (11) ◽  
Keyword(s):  
High Pressure ◽  
High Temperature ◽  
Physical Properties ◽  
Tool Steel ◽  
High Speed ◽  
Temperature Performance

Abstract YSS YXM4 is a cobalt-alloyed molybdenum high-speed tool steel with resistance to abrasion, seizure, and deformation under high pressure. This datasheet provides information on composition, physical properties, and hardness. It also includes information on high temperature performance. Filing Code: TS-780. Producer or source: Hitachi Metals America, Ltd.

Experimental investigation of wall heat transfer due to spray combustion in a high-pressure/high-temperature vessel

2021 ◽  
pp. 146808742110072
Author(s):  
Karri Keskinen ◽  
Walter Vera-Tudela ◽  
Yuri M Wright ◽  
Konstantinos Boulouchos
Keyword(s):  
Heat Transfer ◽  
Heat Flux ◽  
High Pressure ◽  
High Temperature ◽  
High Speed ◽  
Transfer Problem ◽  
Wall Heat Transfer ◽  
Gas Temperature ◽  
Reference Case ◽  
High Pressure High Temperature

Combustion chamber wall heat transfer is a major contributor to efficiency losses in diesel engines. In this context, thermal swing materials (adapting to the surrounding gas temperature) have been pinpointed as a promising mitigative solution. In this study, experiments are carried out in a high-pressure/high-temperature vessel to (a) characterise the wall heat transfer process ensuing from wall impingement of a combusting fuel spray, and (b) evaluate insulative improvements provided by a coating that promotes thermal swing. The baseline experimental condition resembles that of Spray A from the Engine Combustion Network, while additional variations are generated by modifying the ambient temperature as well as the injection pressure and duration. Wall heat transfer and wall temperature measurements are time-resolved and accompanied by concurrent high-speed imaging of natural luminosity. An investigation with an uncoated wall is carried out with several sensor locations around the stagnation point, elucidating sensor-to-sensor variability and setup symmetry. Surface heat flux follows three phases: (i) an initial peak, (ii) a slightly lower plateau dependent on the injection duration, and (iii) a slow decline. In addition to the uncoated reference case, the investigation involves a coating made of porous zirconia, an established thermal swing material. With a coated setup, the projection of surface quantities (heat flux and temperature) from the immersed measurement location requires additional numerical analysis of conjugate heat transfer. Starting from the traces measured beneath the coating, the surface quantities are obtained by solving a one-dimensional inverse heat transfer problem. The present measurements are complemented by CFD simulations supplemented with recent rough-wall models. The surface roughness of the coated specimen is indicated to have a significant impact on the wall heat flux, offsetting the expected benefit from the thermal swing material.

scholarly journals Cavitation patterns in high-pressure homogenization nozzles with cylindrical orifices: Influence of mixing stream in Simultaneous Homogenization and Mixing

2021 ◽  
Author(s):  
V. Gall ◽  
E. Rütten ◽  
H. P. Karbstein
Keyword(s):  
High Pressure ◽  
Process Design ◽  
High Speed ◽  
State Of The Art ◽  
Back Pressure ◽  
High Pressure Homogenization ◽  
Unit Operation ◽  
Mixing Chamber ◽  
Cavitation Intensity ◽  
Droplet Sizes

AbstractHigh-pressure homogenization is the state of the art to produce high-quality emulsions with droplet sizes in the submicron range. In simultaneous homogenization and mixing (SHM), an additional mixing stream is inserted into a modified homogenization nozzle in order to create synergies between the unit operation homogenization and mixing. In this work, the influence of the mixing stream on cavitation patterns after a cylindrical orifice is investigated. Shadow-graphic images of the cavitation patterns were taken using a high-speed camera and an optically accessible mixing chamber. Results show that adding the mixing stream can contribute to coalescence of cavitation bubbles. Choked cavitation was observed at higher cavitation numbers σ with increasing mixing stream. The influence of the mixing stream became more significant at a higher orifice to outlet ratio, where a hydraulic flip was also observed at higher σ. The decrease of cavitation intensity with increasing back-pressure was found to be identical with conventional high-pressure homogenization. In the future, the results can be taken into account in the SHM process design to improve the efficiency of droplet break-up by preventing cavitation or at least hydraulic flip.

scholarly journals Cycloaddition of Thiourea- and Guanidine-Substituted Furans to Dienophiles: A Comparison of the Environmentally-Friendly Methods

2020 ◽  
Vol 3 (1) ◽  
pp. 57
Author(s):  
Luka Barešić ◽  
Davor Margetić ◽  
Zoran Glasovac
Keyword(s):  
High Pressure ◽  
Functional Groups ◽  
Organic Synthesis ◽  
High Speed ◽  
Environmentally Friendly ◽  
Microwave Assisted ◽  
Pressure Synthesis ◽  
Ultrasound Assisted ◽  
Substituted Furans ◽  
Guanidine Moiety

The cycloaddition strategy was employed in order to obtain a 7-oxanorbornene framework substituted with a guanidine moiety or its precursor functional groups: protected amine or thiourea. In order to optimize the conditions for the cycloaddition, several environmentally-friendly methods—microwave assisted organic synthesis, high pressure synthesis, high speed vibrational milling, and ultrasound assisted synthesis—were employed. The outcomes of the cycloaddition reactions were interpreted in terms of endo/exo selectivity, the conversion of the reactants to the product, and the isolated yields. In general, our results indicated the HP and HSVM approaches as the methods of choice to give good yields and conversions.

The Role of Porous Media in Homogenization of High Pressure Diesel Fuel Spray Combustion

2013 ◽  
Vol 136 (1) ◽  
Author(s):  
Navid Shahangian ◽  
Damon Honnery ◽  
Jamil Ghojel
Keyword(s):  
High Pressure ◽  
Porous Media ◽  
High Speed ◽  
Fuel Spray ◽  
Compression Ignition Engines ◽  
System Pressure ◽  
Novel Approach ◽  
Air Mixing ◽  
The Media

Interest is growing in the benefits of homogeneous charge compression ignition engines. In this paper, we investigate a novel approach to the development of a homogenous charge-like environment through the use of porous media. The primary purpose of the media is to enhance the spread as well as the evaporation process of the high pressure fuel spray to achieve charge homogenization. In this paper, we show through high speed visualizations of both cold and hot spray events, how porous media interactions can give rise to greater fuel air mixing and what role system pressure and temperature plays in further enhancing this process.

Experimental Study of Spray Penetration under High Pressure Common Rail Condition

2011 ◽  
Vol 347-353 ◽  
pp. 66-69
Author(s):  
Jian Xin Liu ◽  
Song Liu ◽  
Hui Yong Du ◽  
Zhan Cheng Wang ◽  
Bin Xu
Keyword(s):  
High Pressure ◽  
High Speed ◽  
Injection Pressure ◽  
Electronic System ◽  
Common Rail ◽  
Spray Penetration ◽  
Jet Breakup ◽  
Secondary Breakup ◽  
Breakup Time ◽  
High Pressure Common Rail

The fuel spray images were taken with an equipment (camera-flash-injection) which has been synchronized with a purpose made electronic system under the condition of the high pressure common rail in two injection pressure has been expressed in this paper. It is discovered when fitting spray tip penetration that after jet breakup for a period of time, the spray tip begin to slow down rapidly, and the speed of spray tip running becomes smooth. Hiroyasu and other traditional tip penetration fitting formula are fitting larger to this phase. This is because that after jet breakup, the secondary breakup of striker particles will occur under the influence of the aerodynamic, surface tension and viscosity force. Therefore, a spray penetration fitting formula containing secondary breakup time to fit penetration in three sections was proposed in this paper. Results show that when pressure difference increase, both first and second breakup time become earlier. The former is because of gas-liquid relative velocity increasing, while the latter is due to high speed interface movement acceleration increasing.

scholarly journals The Effect of the In-Situ Heat Treatment on the Martensitic Transformation and Specific Properties of the Fe-Mn-Si-Cr Shape Memory Alloys Processed by HSHPT Severe Plastic Deformation

Materials ◽  
2021 ◽  
Vol 14 (16) ◽  
pp. 4621
Author(s):  
Carmela Gurau ◽  
Gheorghe Gurau ◽  
Felicia Tolea ◽  
Bogdan Popescu ◽  
Mihaela Banu ◽  
...  
Keyword(s):  
Plastic Deformation ◽  
High Pressure ◽  
Severe Plastic Deformation ◽  
High Speed ◽  
High Pressure Torsion ◽  
Electron Interaction ◽  
Sudden Increase ◽  
Neel Temperature ◽  
Néel Temperature

This work focuses on the temperature evolution of the martensitic phase ε (hexagonal close packed) induced by the severe plastic deformation via High Speed High Pressure Torsion method in Fe57Mn27Si11Cr5 (at %) alloy. The iron rich alloy crystalline structure, magnetic and transport properties were investigated on samples subjected to room temperature High Speed High Pressure Torsion incorporating 1.86 degree of deformation and also hot-compression. Thermo-resistivity as well as thermomagnetic measurements indicate an antiferromagnetic behavior with the Néel temperature (TN) around 244 K, directly related to the austenitic γ-phase. The sudden increase of the resistivity on cooling below the Néel temperature can be explained by an increased phonon-electron interaction. In-situ magnetic and electric transport measurements up to 900 K are equivalent to thermal treatments and lead to the appearance of the bcc-ferrite-like type phase, to the detriment of the ε(hcp) martensite and the γ (fcc) austenite phases.

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