scholarly journals Determination of the Idle Mode of the Stage of Axial Turbine during Operation at Partial Loads

2020 ◽  
Vol 65 (1) ◽  
pp. 103-109
Author(s):  
Aleksandr Shubenko ◽  
Vladimir Goloshchapov ◽  
Daria Senetska ◽  
Oleksandr Senetskyi
Keyword(s):  
Experimental Studies ◽  
Rotor Blades ◽  
Working Fluid ◽  
Idle Mode ◽  
One Dimensional ◽  
Operating Modes ◽  
Wide Range ◽  
The One ◽  
Partial Loads

On the basis of the one-dimensional theory of calculating the operation of steam turbine stages the method for determining the idle mode, the initial data for which are the geometric characteristics of the blade rows is proposed. Formulas have been obtained that make it possible to calculate the efficiency in the proximity of Rotor Blades (RB) at operating modes from nominal to the idle mode, depending on the flow rate of the stage and taking into account the use of kinetic energy with the runaway velocity and losses arising at off-design angles of flow on the Rotor Blade (RB). The results of possible computational studies and their comparison for an incompressible working fluid with the results of experimental studies showed the good possibilities of the proposed method for determining the idle mode in a wide range of the characteristics of stages.

scholarly journals Plane thermonuclear detonation waves initiated by proton beams and quasi-one-dimensional model of fast ignition

2014 ◽  
Vol 33 (1) ◽  
pp. 65-80 ◽  
Author(s):  
Alexander A. Charakhch'yan ◽  
Konstantin V. Khishchenko
Keyword(s):  
Detonation Wave ◽  
Fusion Reaction ◽  
Plasma Heating ◽  
Symmetry Plane ◽  
Detonation Waves ◽  
Proton Beams ◽  
One Dimensional ◽  
Wide Range ◽  
The One ◽  
Α Particles

AbstractThe one-dimensional problem on bilatiral irradiation by proton beams of the plane layer of condensed DT mixture with length 2H and density ρ0 ≤ 100ρs, where ρs is the fuel solid-state density at atmospheric pressure and temperature of 4 K, is considered. The proton kinetic energy is 1 MeV, the beam intensity is 1019 W/cm2 and duration is 50 ps. A mathematical model is based on the one-fluid two-temperature hydrodynamics with a wide-range equation of state of the fuel, electron and ion heat conduction, DT fusion reaction kinetics, self-radiation of plasma and plasma heating by α-particles. If the ignition occurs, a plane detonation wave, which is adjacent to the front of the rarefaction wave, appears. Upon reflection of this detonation wave from the symmetry plane, the flow with the linear velocity profile along the spatial variable x and with a weak dependence of the thermodynamic functions of x occurs. An appropriate solution of the equations of hydrodynamics is found analytically up to an arbitrary constant, which can be chosen so that the analytical solution describes with good accuracy the numerical one. The gain with respect to the energy of neutrons G ≈ 200 at Hρ0 ≈ 1 g/cm2, and G > 2000 at Hρ0 ≈ 5 g/cm2. To evaluate the ignition energy Eig of cylindrical targets, the quasi-1D model, limiting trajectories of α-particles by a cylinder of a given radius, is suggested. The model reproduces the known theoretical dependence Eig ~ ρ0−2 and gives Eig = 160 kJ for ρ0 = 100ρs ≈ 22 g/cm3.

Numerical study of the one-dimensional Hubbard model in determination of trans-polyacetylene properties

2001 ◽  
Vol 296 (4) ◽  
pp. 377-387 ◽  
Author(s):  
S. Goumri-Said ◽  
R. Moussa ◽  
J.P. DuFour ◽  
L. Salomon ◽  
H. Aourag
Keyword(s):  
Hubbard Model ◽  
Numerical Study ◽  
One Dimensional ◽  
The One

Integration of one-dimensional equations of motions

2020 ◽  
pp. 79-90
Author(s):  
Gleb L. Kotkin ◽  
Valeriy G. Serbo
Keyword(s):  
Potential Energy ◽  
Field Change ◽  
One Dimensional ◽  
System A ◽  
Small Correction ◽  
The Law ◽  
The One ◽  
The Given ◽  
Equations Of Motions

If the potential energy is independent of time, the energy of the system remains constant during the motion of a closed system. A system with one degree of freedom allows for the determination of the law of motion in quadrature. In this chapter, the authors consider motion of the particles in the one-dimensional fields. They discuss also how the law and the period of a particle moving in the potential field change due to adding to the given field a small correction.

scholarly journals THE ONE-DIMENSIONAL WAVE SPECTRA AT LIMITED FETCH

1972 ◽  
Vol 1 (13) ◽  
pp. 13
Author(s):  
Hisashi Mitsuyasu
Keyword(s):  
Similarity Theory ◽  
Wind Waves ◽  
Laboratory Data ◽  
Peak Frequency ◽  
Wave Spectra ◽  
One Dimensional ◽  
Wide Range ◽  
Laboratory Tank ◽  
The One ◽  
Dimensional Wave

The data for the spectra of wind-generated waves measured in a laboratory tank and in a bay are analyzed using the similarity theory of Kitaigorodski, and the one-dimensional spectra of fetch-limited wind waves are determined from the data. The combined field and laboratory data cover such a wide range of dimensionless fetch F (= gF/u2 ) as F : 102 ~ 10 . The fetch relations for the growthes of spectral peak frequency u)m and of total energy E of the spectrum are derived from the proposed spectra, which are consistent with those derived directly from the measured spectra.

scholarly journals Rare temperature histories and cirrus ice number density in a parcel and a one-dimensional model

2014 ◽  
Vol 14 (23) ◽  
pp. 13013-13022 ◽  
Author(s):  
D. M. Murphy
Keyword(s):  
Temperature Dependence ◽  
Low Temperatures ◽  
Ice Crystals ◽  
Strong Increase ◽  
Number Density ◽  
Dimensional Model ◽  
One Dimensional ◽  
Slow Growth Rate ◽  
Wide Range ◽  
The One

Abstract. A parcel and a one-dimensional model are used to investigate the temperature dependence of ice crystal number density. The number of ice crystals initially formed in a cold cirrus cloud is very sensitive to the nucleation mechanism and the detailed history of cooling rates during nucleation. A possible small spread in the homogeneous freezing threshold due to varying particle composition is identified as a sensitive nucleation parameter. In a parcel model, the slow growth rate of ice crystals at low temperatures inherently leads to a strong increase in ice number density at low temperatures. This temperature dependence is not observed. The model temperature dependence occurs for a wide range of assumptions and for either homogeneous or, less strongly, heterogeneous freezing. However, the parcel model also shows that random temperature fluctuations result in an extremely wide range of ice number densities. A one-dimensional model is used to show that the rare temperature trajectories resulting in the lowest number densities are disproportionately important. Low number density ice crystals sediment and influence a large volume of air. When such fall streaks are included, the ice number becomes less sensitive to the details of nucleation than it is in a parcel model. The one-dimensional simulations have a more realistic temperature dependence than the parcel mode. The one-dimensional model also produces layers with vertical dimensions of meters even if the temperature forcing has a much broader vertical wavelength. Unlike warm clouds, cirrus clouds are frequently surrounded by supersaturated air. Sedimentation through supersaturated air increases the importance of any process that produces small numbers of ice crystals. This paper emphasizes the relatively rare temperature trajectories that produce the fewest crystals. Other processes are heterogeneous nucleation, sedimentation from the very bottom of clouds, annealing of disordered to hexagonal ice, and entrainment.

Structural determination of the group K capsular polysaccharide of Neisseriameningitidis: a 2D-NMR analysis

1985 ◽  
Vol 63 (10) ◽  
pp. 2781-2786 ◽  
Author(s):  
Francis Michon ◽  
Jean Robert Brisson ◽  
René Roy ◽  
Harold J. Jennings ◽  
Fraser E. Ashton
Keyword(s):  
Capsular Polysaccharide ◽  
2D Nmr ◽  
Ion Exchange Chromatography ◽  
Exchange Chromatography ◽  
Electronic Effects ◽  
Nmr Studies ◽  
Polysaccharide Antigen ◽  
One Dimensional ◽  
The One

The capsular polysaccharide antigen of Neisseriameningitidis group K was isolated by Cetavlon precipitation and purified by ion-exchange chromatography. The structure of the K polysaccharide was determined to a large extent by comprehensive proton and carbon-13 nuclear magnetic resonance (nmr) studies. In these studies one-dimensional and two-dimensional experiments were carried out directly on the K polysaccharide. The K polysaccharide is composed of the following repeating unit: -4)β-D-ManpNAcA(1→3) [4-OAc]β-D-ManpNAcA(1→. Except for the one-bond couplings between their anomeric carbons and protons [Formula: see text], all the nmr spectroscopic evidence was consistent with both 2-acetamido-2-deoxy-D-mannopyranosyluronic acid residues adopting the 4C1 (D) conformation and having the β-D-configuration. This ambiguity in [Formula: see text] is probably due to through-space electronic effects generated by the presence of contiguous carboxylated sugar residues in the K polysaccharide. The O-acetyl substituents of the K polysaccharide are essential for its antigenicity to group K polysaccharide-specific antibodies.

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