INFLUENCE OF THE FIRE-TECHNICAL FACILITY LOAD ON THE HEAT STATE OF MICROJET BURNER DEVICES WITH MULTILAYER COATINGS

2017 ◽  
Author(s):  
Nataliia Fialko ◽  
◽  
Viktor Prokopov ◽  
Julii Sherenkovskiy ◽  
Nataliia Meranova ◽  
...  
Keyword(s):  
Cfd Simulation ◽  
Multilayer Coatings ◽  
Technical Facility ◽  
Temperature Regimes ◽  
Wide Range ◽  
Heat State

The results of CFD simulation of temperature regimes of microjet burners with protective multilayer coatings are presented, when the load of fire-technical facilities equipped with these burners varies over a wide range.

scholarly journals CFD SIMULATION OF TEMPERATURE REGIMES OF THE COMBUSTION ZONE OF STABILIZER-TYPE BURNERS WITH ASYMMETRIC FUEL SUPPLY

2019 ◽  
Vol 41 (4) ◽  
pp. 13-18
Author(s):  
N.М. Fialko ◽  
V.G. Prokopov ◽  
Ju.V. Sherenkovskyi ◽  
S.O. Alioshko ◽  
N.O. Meranova ◽  
...  
Keyword(s):  
Computer Simulation ◽  
Combustion Zone ◽  
Cfd Simulation ◽  
Temperature Fields ◽  
Fuel Gas ◽  
Fuel Distribution ◽  
Temperature Regimes ◽  
Stage Combustion ◽  
Heat State ◽  
Stabilizer Type

The results of computer simulation of the heat state of the combustion zone and the burnup rate of fuel for stabilizer burners with asymmetric fuel distribution are presented. The features of temperature fields in this zone that are characteristic of the conditions under study are revealed. The analysis of these features in the aspect of their conditionality by the two-stage combustion of fuel gas is carried out.

scholarly journals CFD SIMULATION OF TEMPERATURE REGIMES OF THE COMBUSTION ZONE OF STABILIZER-TYPE BURNERS WITH ASYMMETRIC FUEL SUPPLY

2020 ◽  
Vol 42 (1) ◽  
pp. 19-26
Author(s):  
N.М. Fialko ◽  
V.G. Prokopov ◽  
Ju.V. Sherenkovskyi ◽  
S.O. Alioshko ◽  
N.O. Meranova ◽  
...  
Keyword(s):  
Computer Simulation ◽  
Combustion Zone ◽  
Cfd Simulation ◽  
Temperature Fields ◽  
Fuel Gas ◽  
Fuel Distribution ◽  
Temperature Regimes ◽  
Stage Combustion ◽  
Heat State ◽  
Stabilizer Type

The results of computer simulation of the heat state of the combustion zone and the burnup rate of fuel for stabilizer burners with asymmetric fuel distribution are presented. The features of temperature fields in this zone that are characteristic of the conditions under study are revealed. The analysis of these features in the aspect of their conditionality by the two-stage combustion of fuel gas is carried out.

CFD SIMULATION OF TEMPERATURE REGIMES OF BURNER DEVICES USING COATINGS WITH DIFFERENT HEAT-CONDUCTING PROPERTIES

2017 ◽  
Author(s):  
Nataliia Fialko ◽  
◽  
Viktor Prokopov ◽  
Julii Sherenkovskiy ◽  
Nataliia Meranova ◽  
...  
Keyword(s):  
Heat Conductivity ◽  
Cfd Simulation ◽  
Multilayer Coatings ◽  
Heat Conducting ◽  
Temperature Regimes

The results of studies of the influence of the heat conductivity coefficients of multilayer coatings on the temperature regimes of microjet burners with these coatings are presented.

CFD Simulation of Fluid Flow Through Porous Media: Application to Decomposed Gases Flow Through Foam Pattern in Lost Foam Casting

Materials ◽  
2003 ◽  
Author(s):  
Sayavur I. Bakhtiyarov ◽  
Ruel A. Overfelt
Keyword(s):  
Cfd Simulation ◽  
Reynolds Numbers ◽  
Phase Flow ◽  
Flow Through Porous Media ◽  
Foam Material ◽  
Element Analysis ◽  
Wide Range ◽  
Flow Through ◽  
Foam Pattern ◽  
Lost Foam

Numerical simulation of decomposed gases through foam pattern was conducted using finite element analysis. A new kinetic model is proposed for gaseos phase flow between molten metal and foam material. The computations were performed for a wide range of Reynolds numbers. The results of the simulations are compared with the experiemental data obtained in this study.

scholarly journals Influence of inlet air distributor geometry on the fluid dynamics of conical spouted beds: A CFD study

2018 ◽  
Vol 24 (4) ◽  
pp. 369-378 ◽  
Author(s):  
J.N.M. Batista ◽  
R.C. Brito ◽  
R. Béttega
Keyword(s):  
Fluid Dynamics ◽  
Cfd Simulation ◽  
Low Cost ◽  
Scale Up ◽  
Straight Tube ◽  
Spouted Bed ◽  
Bed Height ◽  
Spouted Beds ◽  
Wide Range ◽  
Solid Dynamics

The spouted bed presents limitations in terms of scale-up. Furthermore, its stability depends on its geometry as well as the properties of the fluid and solid phases. CFD provides an important tool to improve understanding of these aspects, enabling a wide range of information to be obtained rapidly and at low cost. In this work, CFD simulation was used to evaluate the effects of different inlet air distributors (Venturi and straight tube) and the effects of static bed height on the fluid and solid dynamics of a conical spouted bed. Simulations were performed using the two-dimensional Euler-Euler approach. In order to evaluate the fluid dynamics model, static pressure data obtained by simulation were compared with experimental data obtained with the Venturi distributor. The fluid and solid dynamics of the conical spouted bed were obtained by CFD simulation. The results showed that the pressure drop was lower for the straight tube air distributor, while the Venturi air distributor provided higher stability and a more homogenous air distribution at the bed entrance.

Quenching rates and critical densities of c-C3H2

2019 ◽  
Vol 15 (S350) ◽  
pp. 148-151
Author(s):  
Malek Ben Khalifa ◽  
Emna Sahnoun ◽  
Silvia Spezzano ◽  
Laurent Wiesenfeld ◽  
Kamel Hammami ◽  
...  
Keyword(s):  
Potential Energy Surfaces ◽  
Full Potential ◽  
Thermodynamical Equilibrium ◽  
Medium Temperature ◽  
Permanent Electric Dipole Moment ◽  
Temperature Regimes ◽  
Wide Range ◽  
History Of ◽  
Energy Surfaces ◽  
Local Thermodynamical Equilibrium

AbstractCyclopropenylidene,, is a simple hydrocarbon, ubiquitous in astrophysical gases, and possessing a permanent electric dipole moment. Its readily observed multifrequency rotational transitions make it an excellent probe for the physics and history of interstellar matter. The collisional properties of with He are presented here. We computed the full Potential Energy Surfaces, and we perform quantum scattering in order to provide rates of quenching and excitation for low to medium temperature regimes. We discuss issues with the validity of the usual Local Thermodynamical Equilibrium assumption, and also the intricacies of the spectroscopy of an asymmetric top. We present the wide range of actual critical densities, as recently observed.

Contrasting Responses of Morphologically Similar Wheat Cultivars to Temperatures Appropriate to Warm Temperature Climates With Hot Summers: a Study in Controlled Environment

1977 ◽  
Vol 4 (6) ◽  
pp. 877 ◽  
Author(s):  
AK Bagga ◽  
HM Rawson
Keyword(s):  
Temperature Stability ◽  
Kernel Weight ◽  
Controlled Environment ◽  
Wheat Cultivars ◽  
Warm Temperature ◽  
Temperature Regimes ◽  
Wide Range ◽  
Phase Temperature ◽  
Warm Temperate ◽  
Plant Basis

This study attempted to determine if and why there are differences among three cultivars of wheat in their responses to temperature. The three semidwarf cultivars examined, Kalyansona, Condor and Janak, are currently used commercially. Temperature regimes chosen matched the range to which plants in warm temperate climates with hot summers would be exposed at different stages of development. Plants were grown in a phytotron in sunlit cabinets. Responses to temperature were different among the cultivars. Kalyansona was relatively un- responsive to temperatures during the floret phase, being little affected in the sizes of upper leaves, in floret production and grain set, in overall plant growth or in grain yield. The sole character to respond to temperature in this cultivar was kernel weight, which declined with increasing grain phase temperature. In contrast, Condor demonstrated marked plasticity during the floret phase in all plant characters measured. Its plasticity was such that, at the lower temperatures, it outyielded Kalyansona by a substantial margin while at the higher temperatures its yield was relatively poor. On a plant basis, Janak performed similarly to Condor. Rates of photosynthesis were relatively unaffected by temperature in any cultivar. This wide range of response among three superficially similar cultivars has promising implications for the tailoring of cultivars for different temperature zones. The importance of different plant characters to temperature stability is considered in the discussion.

CFD Simulation of PWR Subchannel Void Distribution Benchmark

2010 ◽  
Author(s):  
Wang-Kee In ◽  
Chang-Hwan Shin ◽  
Tae-Hyun Chun
Keyword(s):  
Void Fraction ◽  
Cfd Simulation ◽  
Fluid Model ◽  
Small Diameter ◽  
Operating Conditions ◽  
Heated Wall ◽  
Bubble Generation ◽  
Void Distribution ◽  
Wide Range ◽  
Two Fluid Model

A CFD study was performed to simulate the steady-state void distribution benchmark based on the NUPEC PWR Subchannel and Bundle Tests (PSBT). The void distribution benchmark provides measured void fraction data over a wide range of geometrical and operating conditions in a single subchannel and fuel bundle. This CFD study simulated the boiling flow in a single subchannel. A CFD code was used to predict the void distribution inside the single subchannel. The multiphase flow model used in this CFD analysis was a two-fluid model in which liquid (water) and vapor (steam) were considered as continuous and dispersed fluids, respectively. A wall boiling model was also employed to simulate bubble generation on a heated wall surface. The CFD prediction with a small diameter of vapor bubble shows a higher void fraction near the heated wall and a migration of void in the subchannel gap region. A measured CT image of void distribution indicated a locally higher void fraction near the heated wall for the test conditions of a subchannel averaged void fraction of less than about 20%. The CFD simulation predicted a subchannel averaged void fraction and fluid density which agree well with the measured ones for a low void condition.

Use of Logistic Equation for Detection of the Initial Parasitism Phase of Egyptian Broomrape (Phelipanche aegyptiaca) in Tomato

Weed Science ◽  
2012 ◽  
Vol 60 (1) ◽  
pp. 57-63 ◽  
Author(s):  
Jhonathan E. Ephrath ◽  
Josseph Hershenhorn ◽  
Guy Achdari ◽  
Shalom Bringer ◽  
Hanan Eizenberg
Keyword(s):  
Temperature Regime ◽  
Thermal Time ◽  
Tomato Plants ◽  
Temperature Regimes ◽  
C 23 ◽  
Wide Range ◽  
Host Parasite Relationship ◽  
Parasite Relationship ◽  
Increasing Temperature ◽  
Host Parasite

The dynamics of the host–parasite relationship between tomato cv. Brigade and Egyptian broomrape is temperature-related. This relationship was utilized for the development of an equation on the basis of thermal time (as measured by growing degree days, GDD, C) to predict the parasitism dynamics of Egyptian broomrape in tomato. To obtain a reliable prediction from thermal time values, studies based on a wide range of temperatures are essential. Four temperature-regime treatments and five levels of infestation with Egyptian broomrape seeds were tested in a multiclimate greenhouse (phytotron) and a temperature-controlled greenhouse, respectively. The day/night temperature regimes were 20/12 C, 23/15 C, 26/18 C, and 29/21 C and the infestation levels were 0 (noninfested control), 1, 5, 10, and 25 mg of Egyptian broomrape seeds per liter of soil. As expected, increasing temperature or infestation levels resulted in faster appearance and higher rate of attachments, respectively. The relation between development of attachments and GDD was described as a three-parameter logistic curve. In both temperature-regime and infestation-level experiments, the development of attachments began 200 GDD after planting and the maximal number of attachments was recorded 800 GDD after planting. A significant reduction in the aboveground biomass of the tomato plants due to increased Egyptian broomrape biomass was recorded only for the 26/18 C and 29/21 C day/night treatments and the three highest infestation levels (5, 10, and 25 mg L−1 soil). The ability to predict the start of parasitism can be used to develop a climate-based system for Egyptian broomrape control with herbicides.

Physical dormancy in seeds of Dodonaea viscosa (Sapindales, Sapindaceae) from Hawaii

2004 ◽  
Vol 14 (1) ◽  
pp. 81-90 ◽  
Author(s):  
Jerry M. Baskin ◽  
Barbara H. Davis ◽  
Carol C. Baskin ◽  
Sean M. Gleason ◽  
Susan Cordell
Keyword(s):  
Seed Coat ◽  
White Light ◽  
Red Light ◽  
Dodonaea Viscosa ◽  
Physical Dormancy ◽  
Critical Moisture Content ◽  
Temperature Regimes ◽  
Wide Range ◽  
Critical Moisture ◽  
Impermeable Seed Coat

Dormancy in seeds ofDodonaea viscosais due to a water-impermeable seed coat (physical dormancy, PY). Thus, mechanically scarified seeds imbibed water (c.95% increase in mass) and germinated to high percentages over a wide range of temperature regimes in both white light and darkness, whereas non-scarified seeds did not take up water. Dry heat at 80–160°C and dipping in boiling water for 1–60 s also broke dormancy in a high percentage of the seeds, and continuous far-red light was not inhibitory to germination. However, dry storage in the laboratory for >1 year did not overcome dormancy. Seeds made water-permeable by boiling imbibed water, and thus germinated, at a much slower rate than those made water-permeable by mechanical scarification. We suggest that boiling opened the ‘water gap’ in the seed coat (not yet described inSapindaceaebut present in other taxa with PY) and that water entered the seed only through this small opening, thereby accounting for the slow rate of imbibition and subsequent germination. Physical dormancy has now been shown to occur in seeds of this polymorphic, worldwide species from Australia, Brazil, Hawaii, Mexico and New Zealand. The low level of dormancy reported for seed lots ofD. viscosain China, India and Pakistan is probably due to collection of seeds before they dried to the critical moisture content for development of water-impermeability of the seed coat. Germination of non-dormant seeds over a wide range of temperatures and in white light, far-red (leaf-canopy shade) light and darkness are part of the germination strategy ofD. viscosaand of other taxa whose seeds have PY at maturity.

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