Analysis of endurance of the material in the nozzle throat in high-pressure gas-dynamic facilities

2012 ◽  
Vol 53 (6) ◽  
pp. 954-960
Author(s):  
M. E. Topchiyan ◽  
V. I. Pinakov ◽  
A. A. Meshcheryakov ◽  
V. N. Rychkov
Author(s):  
G. O. Voropaiev ◽  
Ia. V. Zagumennyi ◽  
N. V. Rozumnyuk

The paper presents the numerical results on gas-dynamic processes in various elements of the impulse ejector, including pre-chamber, supersonic nozzle and mixing chamber, to determine optimal geometric parameters providing the given flow rate characteristics. At an extra-high pressure of the ejecting gas (>100 bar) it is impossible to create a nozzle design with continuously changing cross-sectional area and limited nozzle length. So, it is necessary to place a pre-chamber between the gas generator and the ejector nozzle for throttling full gas pressure. In order to optimize the pre-chamber parameters in the ejector with discrete holes of the gas generator and the operating pressure in the range of 400÷1000 bar, a series of calculations were performed to determine the pre-chamber parameters, ensuring stable operation of the supersonic annular nozzle at the high pressure of 35÷45 bar and the flow rate of 0.5÷0.6 kg/s. 3D numerical simulation of the gas flow into the pre-chamber through the gas generator holes shows the degree of the flow pattern non-uniformity in the pre-chamber at the ejector nozzle inlet is quite low. This justifies the numerical simulation of gas flow in the ejector in axisymmetric formulation and allows restricting the number of the gas generator holes without inducing significant non-uniformity in the azimuthal direction.


2021 ◽  
Vol 47 ◽  
pp. 102243
Author(s):  
Davoud M. Jafarlou ◽  
Bryer C. Sousa ◽  
Matthew A. Gleason ◽  
Gehn Ferguson ◽  
Aaron T. Nardi ◽  
...  

1996 ◽  
Vol 113 (1) ◽  
pp. 137-166 ◽  
Author(s):  
R. BLUMENTHAL ◽  
K. FIEWEGER ◽  
K. H. KOMP ◽  
G. ADOMEIT

Author(s):  
М.Г. Бергер

Определить причину того или иного явления значит указать фактор, действие которого позволяет объяснить все особенности этого явления. При всей несомненной доказанности взрывоподобного газодинамического характера катастрофического выброса ледника Колка 20 сентября 2002г., некоторые важнейшие вопросы, касающиеся причин и механизма этого выброса, требуют прояснения. Их рассмотрению посвящена данная статья. При этом автор во многом опирается на результаты, полученные в области изучения взрывоподобных внезапных газодинамических выбросов в подземных горных выработках, история исследования которых начинается с 1834 года. В газодинамическом выбросе (вынос, отбросе, инерциальном разлете, направленном метании) материала, независимо от его состава, во всех случаях первостепенная (решающая) роль принадлежит находящимся в свободной фазе высоконапорным природным газам различного состава, физико-химических свойств и происхождения. Соответственно, причиной, вызывающей внезапные взрывоподобные газодинамические выбросы, главным действующим фактором, определяющим и объясняющим их основные характерные особенности, являются расширяющиеся сжатые высоконапорные (обладающие высоким или даже сверхвысоким пластовым давлением) природные газы. Основной источник высоконапорных природных газов, вызвавших взрывоподобный направленный газодинамический выброс ледника Колка 20 сентября 2002 года, очевиден им были глубинные поствулканические газы, постоянно генерирующиеся в глубинных зонах Казбекско-Джимарайского района и всей Казбекской неовулканической области. Таким образом, взрывоподобный внезапный газодинамический (газоледокаменный) выброс ледника Колка имел эндогенный поствулканический характер. Взрывоподобный внезапный газодинамический выброс ледника Колка со всей очевидностью показал, что именно аномально высокое (сверхвысокое) пластовое давление свободных газов, скопившихся в подледниковом пространстве, является основной причиной этого выброса его подготовки, запуска, проявления и постпароксизмального завершения. Основным источником этих газов были глубинные процессы постоянно протекающей в данном районе поствулканической деятельности, сопровождающиеся генерацией, выделением в свободную фазу, концентрацией и восходящей миграцией высоконапорных глубинных природных газов To determine the cause of a phenomenon means to indicate a factor whose action allows to explain all the features of this phenomenon. With all the undeniable evidence of the explosion-like gas-dynamic nature of the catastrophic outburst of the Kolka glacier on September 20, 2002, some of the most important questions regarding the causes and mechanism of this outburst require clarification. This article is devoted to consideration of these causes. Moreover, the author relies heavily on the results obtained in the field of studying explosion-like sudden gas-dynamic outburst in underground mine workings, the research history of which begins in 1834. In the gas-dynamic outburst (removal, rejection, inertial expansion, directional throwing) of the material, regardless of its composition, in all cases the primary (critical) role belongs to the high-pressure natural gases of different composition, physicochemical properties and origin that are in the free phase. Accordingly, the cause of sudden explosion-like gas-dynamic emissions, the main acting factor determining and explaining their main characteristic features are expanding compressed high-pressure (having high or even ultra-high reservoir pressure) natural gases. The main source of high-pressure natural gases that caused the explosion-like directional gas-dynamic outburst of the Kolka glacier on September 20, 2002, is obvious - they were deep post-volcanic gases, which are constantly generated in the deep zones of the Kazbek-Dzhimara region and the whole Kazbek neovolcanic region. Thus, the explosion-like sudden gas-dynamic (gas-ice-stone) outburst of the Kolka glacier had an endogenous post-volcanic character. The explosion-like sudden gas-dynamic outburst of the Kolka glacier has clearly shown that it is the abnormally high (ultrahigh) layer pressure of the free gases accumulated in the subglacial space that is the main cause of this outburst - its preparation, launch, development and post-paroxysmal completion. The main source of these gases were the deep processes of ongoing post-volcanic activity in the area, accompanied by the generation, release into the free phase, concentration and upward migration of high-pressure deep natural gases


Author(s):  
Sergei V. Ryzhkov ◽  
Andrey V. Anikeev

Field-Reversed Configuration (FRC) [1] and Gas-Dynamic Trap (GDT) [2] represent compact system, which is a special magnetic geometry for plasma confinement. Theoretical and experimental study of gas-dynamic regimes with high energy content is carried out. The approach to a high beta (β is the ratio of plasma pressure to magnetic pressure) magnetic systems assumed different regimes of plasma with beta > 0.5 that is proper to compact devices such as tori and mirror traps. Both FRC and GDT traps are axial symmetric configurations, has open field lines and poloidal magnetic field only. Last experimental results on GDT have shown the possibility to build the stationary system with high beta. Analysis of the global energy and particle balance together with the Monte-Carlo equilibrium modelling allowed to conclude that two-component plasma confined in a steady-state regime. The characteristic plasma lifetimes are 4 to 5 times less then the experiment duration. A peripheral gas-puff near the mirror region enabled to maintain the radial profile of background plasma during the all neutral beam injection (NBI) pulse. This report is focused mainly on ambipolar effect and the possibility of further increasing the fast ion energy content and β. Improved gas-dynamic regimes in high pressure magnetic discharges and microinstabilities arising are described. Synthesized hot ion plasmoid (SHIP) experiment in the compact mirror section attached to the GDT central cell and the scheme of compact tori (FRC formation) for the compact mirror cell of GDT device are presented. Fusion prospects (reactor, neutron source, material studies) of such systems with high-energy (fast) particles [3, 4] and hybrid FRC + GDT scheme proposed by author from Bauman Moscow State Technical University (BMSTU) are discussed.


2013 ◽  
Vol 2013 ◽  
pp. 1-7
Author(s):  
Mykola Kalinkevych ◽  
Andriy Skoryk

The design method for channel diffusers of centrifugal compressors, which is based on the solving of the inverse problem of gas dynamics, is presented in the paper. The concept of the design is to provide high pressure recovery of the diffuser by assuming the preseparation condition of the boundary layer along one of the channel surfaces. The channel diffuser was designed with the use of developed method to replace the vaned diffuser of the centrifugal compressor model stage. The numerical simulation of the diffusers was implemented by means of CFD software. Obtained gas dynamic characteristics of the designed diffuser were compared to the base vaned diffuser of the compressor stage.


2018 ◽  
Vol 61 (4) ◽  
pp. 687-691
Author(s):  
B. Kh. Perel’shtein ◽  
B. M. Osipov ◽  
A. V. Titov

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