Structure-Properties Correlation of Lead Selenide-Lead Selenite Composite

The main areas of work are related to the synthesis of a two-phase composite (1-x)PbSe·xPbSeO3 in the form of a powder, faceted single crystal, film and compacted material with the possibility of changing the fraction (x) of the PbSeO3 phase from 0 to 1 by oxidation of PbSe in a dry atmosphere in the temperature range 20-550 °С and the study of its physicochemical properties. All initial samples are obtained by the original method from Pb1-ySey powder, in which the composition corresponds to the maximum melting temperature of the compound and is defined as ysmax=0.500025±0.000025 at. Se. The powder is crushed, after which homogenizing annealing is performed at a constant temperature (~750 °C) in a dynamic vacuum in order to achieve the minimum general pressure condition. The noted precursor-related technological procedures are necessary to achieve congruent evaporation conditions in all types of samples and help minimize the concentration of inherent defects and inclusions in phase two. Depending on application, it is possible to form crystalline powders with a given ratio of volumetric phases PbSe and PbSeO3 in a separate grain. For all cases, the "shell" for semiconductor particles PbSe is the dielectric phase PbSeO3. The principal possibility of forming the smallest (up to nanometer) grains of lead selenide in the dielectric matrix of lead selenite is shown. According to the proposed method, the synthesis of lead selenite by oxidation of lead selenide is possible.

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Experimental Study on Two-Phase Natural Circulation Flow Instability in Rod Bundle Channel Under Low Pressure Condition

Volume 6A: Thermal-Hydraulics and Safety Analyses ◽

10.1115/icone26-81225 ◽

2018 ◽

Author(s):

Kun Cheng ◽

Sichao Tan ◽

Zheng Liu ◽

Tao Meng

Keyword(s):

Flow Instability ◽

Natural Circulation ◽

Oscillation Amplitude ◽

Density Wave ◽

Low Pressure ◽

Heating Power ◽

Pressure Condition ◽

Two Phase ◽

Rod Bundle ◽

System Pressure

An experimental investigation was conducted in a natural circulation (NC) loop to study the characteristics of two-phase flow instability under low pressure condition. A 3 × 3 rod bundle channel was used as the test section. The effects of heating power, inlet subcooling degree and system pressure on the two-phase NC flow instability types and stable boundaries were studied. The experimental results show that three typical flow conditions can occur in rod bundle channel under NC condition, which are single-phase NC flow, subcooled boiling NC flow oscillation and density wave oscillations (DWO). The oscillation amplitude and period of DWO can be enlarged by increasing the heat flux. Increasing the inlet subcooling degree can increase the marginal heating power of flow instability in NC system. The occurrence of DWO can be suppressed by increasing the system pressure. The flow instability boundary presented by the subcooling number and phase change number was also obtained in present work.

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G0600404 Development of void fraction distribution measurement for boiling two-phase flow in heated rod bundle under high pressure condition

The Proceedings of Mechanical Engineering Congress Japan ◽

10.1299/jsmemecj.2015._g0600404- ◽

2015 ◽

Vol 2015 (0) ◽

pp. _G0600404--_G0600404-

Author(s):

Takahiro ARAI ◽

Masahiro FURUYA ◽

Kenetsu SHIRAKAWA ◽

Yoshihisa NISHI

Keyword(s):

High Pressure ◽

Void Fraction ◽

Two Phase Flow ◽

Phase Flow ◽

Pressure Condition ◽

Two Phase ◽

Distribution Measurement ◽

Rod Bundle ◽

Void Fraction Distribution ◽

Fraction Distribution

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Water Hammers in Transonic Modes of Steam-Liquid Flows in NPP Equipment

Nuclear and Radiation Safety ◽

10.32918/nrs.2019.2(82).08 ◽

2019 ◽

pp. 43-46

Author(s):

V. Skalozubov ◽

N. Bilous ◽

D. Pirkovskiy ◽

I. Kozlov ◽

Yu. Komarov ◽

...

Keyword(s):

Kinetic Energy ◽

Transonic Flow ◽

Computer Modelling ◽

Original Method ◽

Two Phase ◽

Acoustic Disturbances ◽

Flow Stagnation ◽

Speed Of Propagation ◽

Definition Of ◽

Liquid Flows

The analysis of well-known studies in modelling conditions for water hammers in equipment and components of pipeline systems has revealed that definition of conditions and parameters of water hammers in the transonic modes of single- and two-phase flows (at a speed of propagation of acoustic disturbances) is the least studied problem. The original method is proposed for determining the conditions and parameters of water hammers in transonic flow modes subject to the transition of the kinetic energy of the flow stagnation into the energy of the water hammer pulse. It was found that the simulated hydrodynamic loads in transonic modes can significantly exceed the corresponding known recommendations of N. Zhukovsky. The proposed method of equations computer modelling served to determine the criteria range for water hammers due to aperiodic thermohydrodynamic instability in transonic flow modes.

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Detailed Characterisation of a Swirled Air/Kerosene Spray in Reactive and Non-Reactive Conditions Downstream From an Actual Turbojet Injection System

Volume 2: Combustion, Fuels and Emissions, Parts A and B ◽

10.1115/gt2011-45173 ◽

2011 ◽

Cited By ~ 5

Author(s):

Renaud Lecourt ◽

Guillaume Linassier ◽

Ge´rard Lavergne

Keyword(s):

Data Base ◽

Gas Phase ◽

Two Phase Flow ◽

Flame Structure ◽

Original Method ◽

Injection System ◽

Spray Combustion ◽

Phase Flow ◽

Two Phase ◽

Axial Velocity Component

As part of the investigations of the ignition of jet-engines under altitude conditions, a detailed data base was built with the results of experiments on the two-phase flow produced by an actual swirl air/kerosene turbojet injection system. The injection system had a fairly simple geometry. It was used with liquid kerosene injected through a pressure-swirl fuel atomiser. In this case the measurements were carried out at atmospheric pressure in a windowed combustion chamber, with air at ambient temperature. The tested equivalence ratio was 0.95 which corresponds to an air mass flow rate of 0.035 kg/s. For this operating point, we obtained the velocity field of the gas phase under non-reactive conditions by LDA. The axial velocity component of the gas phase was also measured in the burning spray using an original method with a phase Doppler device. The data recorded with the PDA were also processed to obtain the kerosene droplet sizes and velocities under reactive conditions. The same phase Doppler device was used in non-reactive conditions to measure the size and velocity distributions of the kerosene droplets in a section close to the injection system exit in order to complete the data base with the boundary conditions for the liquid phase. In addition the flame was visualised qualitatively. The picture of the stabilized flame was processed with an Abel transform to compare the LDA/PDA measurements with the flame structure, obtained under the reactive conditions. Finally, unsteady pressure measurements were taken under non-reactive conditions and the LDA measurements processed, close to the injection system exit, to get the PVC (Precessing Vortex Core) frequency. The data were analysed to determine the influence of the spray combustion on the two-phase flow. The geometry of the whole experimental setup and the data base are available to other researchers for testing and validating spray combustion models and unsteady two-phase flow numerical simulations.

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Thermal-Hydraulic Experiments Under High Pressure Condition

18th International Conference on Nuclear Engineering: Volume 4, Parts A and B ◽

10.1115/icone18-30167 ◽

2010 ◽

Cited By ~ 1

Author(s):

Wei Liu ◽

Tamai Hidesada ◽

Kazuyuki Takase ◽

Hiroki Hayafune ◽

Satoshi Futagami ◽

...

Keyword(s):

Heat Transfer ◽

High Pressure ◽

Pressure Drop ◽

Flow Instability ◽

Homogeneous Model ◽

Pressure Condition ◽

Transfer Coefficients ◽

Two Phase ◽

Transfer Tube ◽

Churn Flow

For steam generator with straight double-walled heat transfer tube that used in sodium cooled Faster Breeder Reactor, flow instability is one of the most important items need researching. As the first step of the research, thermal hydraulics experiments with water were performed under high pressure condition in JAEA with using a circular tube. Pressure drop, heat transfer coefficients and void fraction data were derived. This paper summarizes the pressure drop characteristics under 15MPa. Several two-phase flow multiplier models were checked and Chisholm model and homogeneous model were found being the best ones for the prediction of present data. A sudden pressure drop decreasing tendency was observed when flow pattern shifts from bubbly/churn flow to annular flow. The reason for this decrease is tried interpreted.

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