scholarly journals A study and comparison of the modes of diffusion combustion of hydrogen and methane at their outflow from the annular nozzle together with the flow of supplied air from the coaxially located circular nozzle

2021 ◽  
Vol 2119 (1) ◽  
pp. 012035
Author(s):  
A S Tambovtsev ◽  
V V Kozlov ◽  
M V Litvinenko ◽  
Yu A Litvinenko ◽  
A G Shmakov
Keyword(s):  
Nozzle Exit ◽  
Qualitative Data ◽  
Diffusion Combustion ◽  
Qualitative Comparison ◽  
Annular Slot ◽  
Combustion Stabilization ◽  
Micro Nozzle ◽  
Combustible Gas ◽  
Initial Stage ◽  
Combustion Of Hydrogen

Abstract The article presents qualitative data on the study of the process of diffusion combustion during the outflow of a gas jet from a nozzle apparatus with a certain arrangement of nozzles. The nozzle apparatus is a round nozzle with a straight channel and a coaxially located annular slot. In the experiments, hydrogen or methane was supplied through an annular slot, and the air was supplied through a central circular micro nozzle. The main features of the diffusion combustion of hydrogen and methane during the outflow from the nozzle apparatus are revealed and a qualitative comparison of the processes is carried out. In both cases, at the initial stage, laminar combustion is observed near the nozzle exit and a breakthrough of the flame front occurs with the release of an incombustible mixture of combustible gas and air. At a high flow rate, the flame separates from the nozzle exit. The fundamental difference is that hydrogen exhibits significantly better combustion stabilization characteristics at the nozzle exit.

Features Of The Diffusion Combustion Of Hydrogen Microjet At Various Spatial Orientation Of The Nozzle Exit

2015 ◽  
Vol 10 (4) ◽  
pp. 60-76
Author(s):  
Genrich Grek ◽  
Viktor Kozlov ◽  
Oleg Korobeinichev ◽  
Yuriy Litvinenko ◽  
Andrey Shmakov
Keyword(s):  
Nozzle Exit ◽  
Spatial Orientation ◽  
Velocity Vector ◽  
Experimental Studies ◽  
Diffusion Combustion ◽  
Jet Velocity ◽  
Basic Characteristics ◽  
Vector Orientation ◽  
The Given ◽  
Combustion Of Hydrogen

The purpose of the given work will consist in the experimental studies of features diffusion combustion of a hydrogen round microjet depending on spatial orientation of the nozzle exit. It is revealed, that a hydrogen round microjet at diffusion combustion in conditions of a jet velocity vector orientation towards terrestrial gravitation vector «g» (opposite or perpendicular) the basic characteristics of the flame evolution depending on a jet velocity are practically coincided. To these characteristics concern such as ranges of the «bottleneck» flame area presence, flame detachment at presence of the «bottleneck» flame area, presence of the «bottleneck» flame area, but absence of a turbulent jet combustion and finally ending of the microjet combustion. On the contrary, in situation of the hydrogen round microjet diffusion combustion in conditions of a jet velocity vector orientation towards terrestrial gravitation vector «g» (orientability – like) the basic characteristics of the flame evolution depending on a jet velocity are sharply differed from two previous cases. The range of existence of the «bottleneck» flame area is reduced, flame detachment occurs in absence of the «bottleneck» flame area and finally ending of the microjet combustion occurs at the much greater jet velocity.

Influence Of Initial Conditions At The Micro Nozzle Exit On Hydrogen Diffusion Combustion

2016 ◽  
Vol 11 (3) ◽  
pp. 34-45
Author(s):  
Viktor Kozlov ◽  
Genrich Grek ◽  
Oleg Korobeinichev ◽  
Yuriy Litvinenko ◽  
Andrey Shmakov
Keyword(s):  
Velocity Profile ◽  
Nozzle Exit ◽  
Hydrogen Diffusion ◽  
Initial Conditions ◽  
Diffusion Combustion ◽  
Mean Velocity ◽  
Micro Nozzle ◽  
Flame Region ◽  
Region Size ◽  
Efflux Velocity

The purpose of the given work will consist in an experimental study of influence of initial conditions at the micro nozzle exit on hydrogen diffusion combustion. It is shown, that the mean velocity profile and presence/absence of a heatcapacious material at the nozzle exit play an essential role on a flame structure and process of a round hydrogen microjet combustion. Velocity ranges of existence of a round hydrogen microjet diffusion combustion, flame separation and «bottleneck flame» region for a case of a top – hat mean velocity profile at the nozzle and two cases of a parabolic mean velocity profile with presence/absence of a heatcapacious material at the nozzle exit are found. Dependences of the «bottleneck flame» region size from a hydrogen microjet efflux velocity for case of a top – hat mean velocity profile at the nozzle and two cases of a parabolic mean velocity profile with presence/absence of a heatcapacious material at the nozzle exit are shown. Decrements of reduction of the «bottleneck flame» region size with growth of the hydrogen microjet efflux velocity for three situations of changes of initial conditions at the nozzle exit are determined.

scholarly journals Effect of Employee Performance Factors on Corporate Performance: Evidance in Information Technology Firm

2020 ◽  
Vol 3 (2) ◽  
pp. 306
Author(s):  
Lina Suciati
Keyword(s):  
Quantitative Research ◽  
Qualitative Data ◽  
Corporate Performance ◽  
Employee Performance ◽  
Performance Variables ◽  
Independent Variables ◽  
Performance Factors ◽  
Initial Stage ◽  
The Relationship ◽  
A Company

The MNC (Multinational) company based in California is a computer storage and data management (storage) company. PT. NetApp is very concerned about the welfare of its employees. All NetApp achievements are inseparable from good management of its human resources, in this context the performance of its employees. Although NetApp is one of the best companies at work, the percentage of employee turnover has increased from year to year. This type of research is quantitative research. Sugiyono (2007) Quantitative data is data in the form of numbers, or qualitative data that is called up (scoring). This study is intended to determine the relationship between the seven variables, namely Recruitment of Independent Variables (X1) and Career Path (X2), namely Corporate Performance Dependent variable (Y) and Employee Performance (Z) as a variable intervening. After a statistical test, the results are obtained: first the recruitment variable has a significant effect on corporate performance variables. This means that recruitment is the initial stage of the employee to enter into a company. not significant to corporate performance variables

scholarly journals THE MODIFIED MODEL OF DIFFUSION FLOW OF MULTICOMPONENT COMBUSTIBLE GAS

2015 ◽  
pp. 93-97
Author(s):  
R. A. Shtykov
Keyword(s):  
Gas Diffusion ◽  
Diffusion Combustion ◽  
Gas Temperature ◽  
Active Components ◽  
Simple Modification ◽  
Modified Model ◽  
Total Enthalpy ◽  
Combustible Gas ◽  
Excess Concentration

The model of gas diffusion combustion developed by Zeldovich Ya.B., despite of the fairly satisfactory agree-ment of the obtained data with the experiment shows a non-universality and a large volume of the algorithm for de-termining the concentrations of the components when a number of active components and their composition change. In this regard, it became necessary to develop a different, simple modification of Zeldovich’s model, which would lead to the least number of operations for determination of the gas temperature and density at known values of rela-tively excess concentration and total enthalpy.

Features of diffusion combustion of hydrogen in the round and plane high-speed microjets (part II)

2016 ◽  
Vol 41 (44) ◽  
pp. 20240-20249 ◽  
Author(s):  
V.V. Kozlov ◽  
G.R. Grek ◽  
O.P. Korobeinichev ◽  
Yu.A. Litvinenko ◽  
A.G. Shmakov
Keyword(s):  
High Speed ◽  
Diffusion Combustion ◽  
Combustion Of Hydrogen

scholarly journals Air Round Microjet Interaction with Coaxial Hydrogen Jet at It Combustion for Supersonic Speed Jets Efflux

2019 ◽  
Vol 14 (3) ◽  
pp. 53-63
Author(s):  
V. V. Kozlov ◽  
G. R. Grek ◽  
M. V. Litvinenko ◽  
Yu. A. Litvinenko ◽  
A. S. Tambovzev ◽  
...  
Keyword(s):  
Nozzle Exit ◽  
Acoustic Noise ◽  
Turbulent Flame ◽  
Experimental Studies ◽  
Supersonic Combustion ◽  
Small Scale ◽  
Diffusion Combustion ◽  
Supersonic Speed ◽  
Combustion Region ◽  
Flame Region

Results of experimental studies of the round air microjet interaction with a coaxial hydrogen jet at its combustion for supersonic speed jets efflux are presented in this work. It is revealed that combustion of the coaxial hydrogen jet with growth of its speed efflux is accompanied by all scenarios, observed at study of the round and plane hydrogen microjets diffusion combustion. However, “bottleneck flame region” undergoes considerable geometrical deformations because of specifics of a flame of a coaxial jet. It is shown that “bottleneck flame region” is transformed from Y-shaped to spherical shape in the activity of growth of a coaxial jet speed efflux. It is found that a round air microjet interaction with a coaxial hydrogen jet at its combustion is accompanied by several new phenomena: existence of cone-shaped area a coaxial jet combustion near a nozzle exit; existence of small-scale supersonic cells on a resultant flame; absence of the hydrogen combustion efflux from combustion region of a coaxial jet near nozzle exit; flame-out from combustion region of a coaxial jet near nozzle exit that leads to hydrogen ignition downstream, its intensive combustion and sharp acoustic noise occurrence; existence of a turbulent flame, to its separation from a nozzle exit and transition to supersonic combustion of a resultant jet.

scholarly journals Jalabi Practice: a Critical Appraisal of a Socio-Religious Phenomenon in Yorubaland, Nigeria

2015 ◽  
Vol 5 (1) ◽  
pp. 120
Author(s):  
Afiz Oladimeji Musa ◽  
Hassan Ahmad Ibrahim
Keyword(s):  
Qualitative Data ◽  
Critical Appraisal ◽  
Personal Observation ◽  
Initial Stage ◽  
Third Stage ◽  
Research Findings ◽  
Three Stages ◽  
Historical Phenomenon ◽  
The Many ◽  
Manuscript Collections

Jalabi is an extant historical phenomenon with strong socio-religious impacts in Yorubaland, south-western part of Nigeria. It is among the preparatory Dawah strategies devised by the Yoruba Ulama following the general mainstream Africa to condition the minds of the indigenous people for the acceptance of Islam. This strategy is reflected in certain socio-religious services rendered to the clients, which include, but not limited to, spiritual consultation and healing, such as petitionary Dua (prayer), divination through sand-cutting, rosary selection, charm-making, and an act of officiating at various religious functions. In view of its historicity, the framework of this research paper revolves around three stages identified to have been aligned with the evolution of Jalabi, viz. Dawah, which marked its initial stage, livelihood into which it had evolved over the course of time, and which, in turn, had predisposed it to the third stage, namely syncretism. Triangulation method will be adopted for qualitative data collection, such as interviews, personal observation, and classified manuscript collections, and will be interpretively and critically analyzed to enhance the veracity of the research findings. The orality of the Yoruba culture has greatly influenced the researcher’s decision to seek data beyond the written words in order to give this long-standing phenomenon its due of study and to help understand the many dimensions it has assumed over time, as well as its both positive and adverse effects on the socio-religious live of the Yoruba people of Nigeria.

Features Of The Diffusion Combustion Of Hydrogen Microjet At Various Spatial Orientation Of The Nozzle Exit With Top – Hat Mean Velocity Profile At The Nozzle Exit

2017 ◽  
Vol 12 (1) ◽  
pp. 66-78
Author(s):  
Genrich Grek ◽  
Maria Litvinenko ◽  
Grigory Kozlov ◽  
Valentin Vikhorev
Keyword(s):  
Velocity Profile ◽  
Nozzle Exit ◽  
Spatial Orientation ◽  
Velocity Vector ◽  
Turbulent Flame ◽  
Diffusion Combustion ◽  
Mean Velocity ◽  
Jet Velocity ◽  
Basic Characteristics ◽  
Vector Orientation

The purpose of the given work will consist in the experimental studies of features diffusion combustion of a hydrogen round microjet, effusing from micronozzle with top – hat mean velocity profile at the nozzle exit, depending on spatial orientation of the nozzle exit. It is revealed, that in conditions of a jet velocity vector orientation towards terrestrial gravitation vector «g» (opposite or perpendicular) the basic characteristics of the flame evolution depending on gas consumption (Q) (or jet velocity U) are rather close to each other. To these characteristics concern such as ranges of the «bottleneck flame area» presence, flame separation at presence of the «bottleneck flame area», presence of the «bottleneck flame area» but absence of a turbulent jet combustion and finally ending of the microjet combustion. On the contrary, in situation of the hydrogen round microjet diffusion combustion in conditions of a jet velocity vector orientation towards terrestrial gravitation vector «g» (orientability – like) the basic characteristics of the flame evolution depending on a jet velocity are sharply differed from two previous cases. The range of existence of the «bottleneck flame area» is reduced, flame separation occurs in absence of the «bottleneck flame area», there is no situation of the «bottleneck flame area» combustion at turbulent flame separation and there is no situation of the «bottleneck flame area» combustion at burn termination of the turbulent part of a microjet and finally ending of the microjet combustion occurs at the much greater jet velocity.

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