EFFECT OF GAS FLOW DIRECTION ON PASSIVE SUBSEA COOLER EFFECTIVENESS

2019 ◽  
Vol 11 (1-2) ◽  
pp. 1-16 ◽  
Author(s):  
Nikolay Ivanov ◽  
Vladimir V. Ris ◽  
Nikolay A. Tschur ◽  
Marina Zasimova
Keyword(s):  
Gas Flow ◽  
Flow Direction

scholarly journals Elongated Wire-Like Zinc Oxide Nanostructures Synthesized from Metallic Zinc

2012 ◽  
Vol 15 (1) ◽  
pp. 19 ◽  
Author(s):  
El-Shazly M. Duraia ◽  
G.W. Beall ◽  
Zulkhair A. Mansurov ◽  
Tatyana A. Shabanova ◽  
Ahmed E. Hannora
Keyword(s):  
Electron Microscopy ◽  
Zinc Oxide ◽  
Silicon Substrate ◽  
Gas Flow ◽  
Flow Direction ◽  
Crystal Defects ◽  
Near Band Edge ◽  
Band Edge Emission ◽  
Metallic Zinc ◽  
Zinc Oxide Nanostructures

Elongated wire-like Zinc oxide, nanocombs and nanocrystals have been successfully synthesized on the silicon substrate from the metallic zinc as a starting material. The annealing temperature was as low as 450 ºC in argon atmosphere mixed with about 3% oxygen. Structural analysis using the X-ray Diffraction (XRD) and Transmission Electron Microscopy (TEM) showed that the existence of two phases; nanowires and crystalline form. Moreover some nanoparticles aggregates were noticed to be attached in the bulk to the sides of the ZnO nanocrystals and sometimes these aggregate attached to the Zinc oxide hexagonal crystal and grow to form nanowire at different angles. Scanning electron microscopy (SEM) investigations for the zinc oxide nanostructure on the silicon substrate showed the formation of the nanocrystals in the gas flow direction and at the low energy sites over the silicon substrate. Photoluminescence (PL) measurements, performed at the room temperature, showed the existence of two basic emissions: narrow ultraviolet (UV) emission at 398 nm which attributed to the near band edge emission of the wide band gap and a very wide, more intensive, green emission at 471 nm corresponds to the crystal defects such as vacancies, interstitial sites in ZnO.

scholarly journals Numerical Simulation on Double-nozzle Spray Evaporation of Desulfurization Wastewater

2021 ◽  
Author(s):  
Hong Xu ◽  
Shuqin Feng ◽  
Liehui Xiao ◽  
Yazhen Hao ◽  
Xiaoze Du
Keyword(s):  
Flue Gas ◽  
Gas Flow ◽  
Evaporation Rate ◽  
Flow Direction ◽  
Droplet Diameter ◽  
Numerical Results ◽  
Least Square ◽  
Lagrangian Model ◽  
Support Vector ◽  
Exhaust Heat

To achieve the near zero emission of wastewater in the flue gas desulfurization (FGD) system in coal-fired power plant and better utilize the exhaust heat from flue gas, a feasible technology of spraying FGD wastewater in the flue duct for evaporation is discussed in the present study. A full-scale influencing factor investigation on the wastewater droplet evaporation performance is established under the Eulerian-Lagrangian model numerically. The dominant factors, including the characters of wastewater droplets, flue gas and the spray nozzles were analyzed under different conditions, respectively. Considering the multiple factors and conditions in the process, a Least-Square support vector machine (LSSVM) model is introduced to predict the evaporation rate based on the numerical results. Conclusions are made that the flue gas temperature and droplet diameter are of great importance in the evaporation process. The spray direction of droplet parallel with the flue gas flow direction is profitable for the dispersion of droplet, resulting the maximal evaporation rate. A double-nozzle arrangement optimized with relatively small flow rate is recommended. The LSSVM model can accurately predict the evaporation rate using the numerical results with different conditions.

Improved and Large Area Single-Walled Carbon Nanotube Forest Growth by Controlling the Gas Flow Direction

ACS Nano ◽  
2009 ◽  
Vol 3 (12) ◽  
pp. 4164-4170 ◽  
Author(s):  
Satoshi Yasuda ◽  
Don N. Futaba ◽  
Takeo Yamada ◽  
Junichi Satou ◽  
Akiyoshi Shibuya ◽  
...  
Keyword(s):  
Carbon Nanotube ◽  
Gas Flow ◽  
Flow Direction ◽  
Forest Growth ◽  
Large Area ◽  
Single Walled Carbon Nanotube ◽  
Single Walled Carbon

scholarly journals Any which way but loose? - the significance of gas flow direction through a vaporiser

Anaesthesia ◽  
2001 ◽  
Vol 56 (6) ◽  
pp. 598-600 ◽  
Author(s):  
S. Yee ◽  
S. Old
Keyword(s):  
Gas Flow ◽  
Flow Direction

scholarly journals Pressure and Gas Flow Distribution Inside the Filter of a Non-Filter Ventilated Lit Cigarette During Puffing

2017 ◽  
Vol 27 (6) ◽  
pp. 113-124
Author(s):  
Bin Li ◽  
Xiaomeng Cui ◽  
Lucan Zhao ◽  
Le Wang ◽  
Guoyong Xie ◽  
...  
Keyword(s):  
Flow Velocity ◽  
Gas Flow ◽  
Flow Direction ◽  
Flow Distribution ◽  
Mainstream Smoke ◽  
Cigarette Filter ◽  
Spatially Resolved ◽  
Dynamic Filtration ◽  
Temperature And Pressure ◽  
Burning Coal

SummaryEstablishing a realistic gas flow velocity distribution inside a cigarette filter during smoking is important to understand filtration mechanisms of different mainstream smoke species and the overall effect of filter designs on mainstream smoke composition. In this paper, an experimental method is described which directly measures the gas pressure field inside a cellulose acetate filter during cigarette smoking. This was demonstrated by using 3R4F research reference cigarettes smoked under a 35 mL puff of 6 s duration. In addition, filter temperature measurements were also carried out at multiple locations within the filter. Both the temperature and pressure sensing locations were selected to match the radial and longitudinal directions of the cigarette filter. The temperature and pressure measurements were then used to calculate the velocity according to Darcy’s Law along the mainstream flow direction in the cigarette filter at each puff. The spatially resolved maps of temperature, pressure and flow velocity on a puff-by-puff basis provide useful insights into the dynamic filtration of smoke aerosol under the influence of the approaching burning coal and progressive accumulation of smoke particulate matter.

Effect of the angle between gas flow direction and electrode on single-chamber SOFC stacks

2019 ◽  
Vol 23 (6) ◽  
pp. 1651-1657 ◽  
Author(s):  
Yanting Tian ◽  
Zhe Lü ◽  
Zhihong Wang ◽  
Bo Wei ◽  
Xiang Guo ◽  
...  
Keyword(s):  
Gas Flow ◽  
Flow Direction ◽  
Single Chamber ◽  
Sofc Stacks

Growth and properties of GaxIn1−xAs–GaAs strained layer superlattices grown by low-pressure metal-organic vapour-phase epitaxy

1987 ◽  
Vol 65 (8) ◽  
pp. 909-912 ◽  
Author(s):  
A. P. Roth ◽  
R. A. Masut ◽  
M. Sacilotti ◽  
P. J. D'Arcy ◽  
G. I. Sproule ◽  
...  
Keyword(s):  
Gas Flow ◽  
Flow Direction ◽  
Low Pressure ◽  
Vapour Phase ◽  
Vapour Phase Epitaxy ◽  
Strained Layer ◽  
Additional Strain ◽  
Metal Organic ◽  
Organic Vapour ◽  
Strained Layer Superlattices

We have analyzed the structural and optical properties of GaxIn1−xAs–GaAs strained-layer superlattices (SLS) grown by low-pressure metal-organic vapour-phase epitaxy. Sample uniformity over 2.5 cm × 2.5 cm has been studied by X-ray diffraction and low-temperature photoluminescence. The sample composition and period are uniform in the longitudinal direction (gas-flow direction in the reactor) and in the central portion (1.5 cm) in the transverse direction. On each side, the In composition decreases slightly towards the edges, as shown by an energy shift of the photoluminescence excitonic recombinations. Comparison of experimental and calculated transition energies in a series of samples, taking into account strain and quantization, shows clearly that SLS grown on mismatched buffer layers arc under additional strain. This additional strain is not present when the layer or whole SLS thicknesses exceed a critical value beyond which the mismatch is partially accommodated by misfit dislocations.

Effect of Internal Coolant Crossflow on the Effectiveness of Shaped Film-Cooling Holes

2003 ◽  
Vol 125 (3) ◽  
pp. 547-554 ◽  
Author(s):  
Michael Gritsch ◽  
Achmed Schulz ◽  
Sigmar Wittig
Keyword(s):  
Film Cooling ◽  
Gas Flow ◽  
Flow Direction ◽  
Turbine Blades ◽  
Density Ratio ◽  
Cooling Effectiveness ◽  
Cooling Performance ◽  
Film Cooling Effectiveness ◽  
Hot Gas ◽  
Wide Range

Film-cooling was the subject of numerous studies during the past decades. However, the effect of flow conditions on the entry side of the film-cooling hole on film-cooling performance has surprisingly not received much attention. A stagnant plenum which is widely used in experimental and numerical studies to feed the holes is not necessarily a right means to re-present real engine conditions. For this reason, the present paper reports on an experimental study investigating the effect of a coolant crossflow feeding the holes that is oriented perpendicular to the hot gas flow direction to model a flow situation that is, for instance, of common use in modern turbine blades’ cooling schemes. A comprehensive set of experiments was performed to evaluate the effect of perpendicular coolant supply direction on film-cooling effectiveness over a wide range of blowing ratios (M=0.5…2.0) and coolant crossflow Mach numbers Mac=0…0.6. The coolant-to-hot gas density ratio, however, was kept constant at 1.85 which can be assumed to be representative for typical gas turbine applications. Three different hole geometries, including a cylindrical hole as well as two holes with expanded exits, were considered. Particularly, two-dimensional distributions of local film-cooling effectiveness acquired by means of an infrared camera system were used to give detailed insight into the governing flow phenomena. The results of the present investigation show that there is a profound effect of how the coolant is supplied to the hole on the film-cooling performance in the near hole region. Therefore, crossflow at the hole entry side has be taken into account when modeling film-cooling schemes of turbine bladings.

Three-Dimensional Simulation of Gas Flow in Microducts

2005 ◽  
Author(s):  
Abhishek Agrawal ◽  
Amit Agrawal
Keyword(s):  
Aspect Ratio ◽  
Knudsen Number ◽  
Gas Flow ◽  
Flow Direction ◽  
Pressure Ratio ◽  
Three Dimensional ◽  
Streamwise Velocity ◽  
Theoretical Development ◽  
Width Ratio ◽  
Two Dimensional

Three-dimensional lattice Boltzmann method based simulations of a microduct have been undertaken in this paper. The objective is to understand the different physical phenomena occurring at these small scales and to investigate when the flow can be treated as two-dimensional. Towards this end, the Knudsen number and aspect ratio (depth to width ratio) are varied for a fixed pressure ratio. The pressure in the microduct is non-linear with the non-linearity in pressure reducing with an increase in Knudsen number. The pressure and velocity behaves somewhat similar to two-dimensional microchannels even when the aspect ratio is unity. The slip velocity at the impenetrable wall has two components: along and perpendicular to the flow. Our results show that the streamwise velocity near the centerline is relatively invariant along the depth for aspect ratio more than three, suggesting that the microduct can be modeled as a two-dimensional microchannel. However, the velocity component along the depth is never identically zero, implying that the flow is not truly two-dimensional. A curious change in vector direction in a plane normal to the flow direction is observed around aspect ratio of four. These first set of three-dimensional results are significant because they will help in theoretical development and flow modeling at micro scales.

Research on the Gas Migration Regularity of Municipal Solid Waste Landfill in the Solid-Liquid-Gas-Heat Interaction

2011 ◽  
Vol 243-249 ◽  
pp. 2216-2219
Author(s):  
Xiao Li Liu ◽  
Wen Jing Si ◽  
Chun Ying Zhu
Keyword(s):  
Municipal Solid Waste ◽  
Solid Waste ◽  
Pore Pressure ◽  
Gas Flow ◽  
Flow Direction ◽  
Volumetric Strain ◽  
Horizontal Section ◽  
Municipal Solid Waste Landfill ◽  
Waste Landfill ◽  
Solid Liquid

With the establishment of large municipal solid waste landfills, the interaction of geological environment in landfill (seepage field, stress field and temperature field, etc.) has not to be ignored. The multi-field coupling problem of the municipal solid waste landfill is getting attention. But at present the study mainly concentrated on the solid-liquid-gas-heat coupling problem, the study of the waste gas of the municipal solid waste landfill is less. Gas diffusions, gas emissions, and gas collection are related to the secondary pollution problems of the municipal solid waste landfill. This paper established mathematical model which based on the solid-liquid-gas-heat interaction and researched the gas migration rule of the municipal solid waste landfills. The mainly work are as follows: (1) the definite conditions of dynamic model, (2) the solution of dynamic model, (3) results and analysis. The main conclusions are as follows: (1) Pore pressure along the gas flow direction is nonlinear distribution and shows decline trend. As time increases, the pore pressure of each horizontal section decreases. (2)The volumetric strain of the municipal solid waste landfill is nonlinear distribution along the gas flow direction and shows an increasing tendency. As time increases, volumetric strain of each horizontal section increases.(3)As the change of time, the pore pressure first increases, then decreases.(4) In the initial stage, as the change of time, gas output increases rapidly. When it achieves the maximum size, the production quantity of gas reduces and gradually tends to be a quantitative value.

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