HEAT-AND-POWER ENGINEERING FUNDAMENTALS
MASS TRANSFER IN COUNTER — CURRENT FLOWS
M. Doichinova, P. Popova, Chr. Boyadjiev
e-mail: chboyadj@bas.bgchboyadj@bas.bg
Bulgarian Academy of Science, Institute of Chemical Engineering,
Sofia 1113, Bl.103, Bulgaria
Keywords: efficiency, mass transfer, velocity distribution, column apparatuses, circulation zones.
A theoretical analysis of gas-liquid counter-current flow in laminar boundary layers with flat phase boundary based on similarity variables method has been done. The obtained numerical results for the energy dissipation, mass transfer rate and their ratio are compared with analogous results for co-current flows. A diffusion type of model is proposed for modeling of the mass transfer with chemical reaction in the column apparatuses in the cases of circulation zones. The presence of rising and descending flows (the change of the velocity direction in this liquid counter-current flow) leads to using three coordinate systems. An iterative algorithm for the concentration distribution calculation is proposed. The influence of the zones breadths on the mass transfer efficiency in the column is investigated.
LOCAL MEASUREMENTS OF INSTANTANEOUS SKIN FRICTION IN FLOW BEHIND BACKWARD-FACING STEP: LIMITATIONS AND PERSPECTIVES
N.I. Mikheev, V.M. Molochnikov, P.S. Zanko
e-mail: zanko_philipp@mail.ruzanko_philipp@mail.ru
Research Center for Power Engineering Problems of the Russian Academy of Sciences
Keywords: skin friction, separated flow, backward-facing step, hot-wire, turbulent structure
A set of problems connected with skin friction measurements in a flow behind a backward-facing step is considered. Using the example of instantaneous skin friction vector probe developed and applied in some investigations by the authors fundamental and technical difficulties of local skin friction measurements in complex turbulent separated flows are analyzed. A brief review of the main experimental results on skin friction in a flow behind backward-facing step connected with the real space-time flow pattern is presented. On the basis of the accumulated experience some recommendations for future local skin friction measurements in separated flows are proposed.
POWER GENERATION STATIONS
PROSPECTS OF ENVIRONMENTALLY FRIENDLY THERMAL POWER PLANT DEVELOPMENT
N.D. Chichirova*, A.A. Chichirov*, I.H. Gaifullin**, A.I. Lyapin*, A.G. Korolev***
e-mail: pinpin3@yandex.rupinpin3@yandex.ru
*Kazan State Power Engineering University
**«Generating Company»
***Research Center for Power Engineering Problems of the Russian Academy of Sciences
Keywords: environmentally friendly thermal power plant, electromembrane technology, electrodialysis, water treatment, waste water, evaporator installations, water desalination.
The article is devoted to the design and development of environmentally friendly thermal power plants. The analysis of the use of environmentally friendly and energy efficient technologies in thermal power plants in Russia and other countries that reduce negative impact on the environment is carried out. The results of the introduction of excessive breed water processing technologies of thermal demineralizing complex on the basis of electromembrane installation with alkali and softened water obtained at Kazan TPP-3 are presented. The mechanism of blowdown water electrodialysis is described and electromembrane installation specifications are given.
ALGORITHMIZATION AND SOFTWARE IMPLEMENTATION OF COMPLEX METHODOLOGY FOR SOLID FUEL PREPARATION SYSTEM EFFICIENCY ESTIMATION ON THERMAL POWER STATIONS AND BOILER-HOUSES
G.R.Mingaleeva, G.R.Halitova
e-mail: mingaleeva-gr@mail.rumingaleeva-gr@mail.ru
Research Center for Power Engineering Problems of the Russian Academy of Sciences
Keywords: fuel preparation system, solid fuels, a methodology, an estimation of efficiency, algorithm, a program
The algorithm of a complex methodology of solid fuel preparation systems efficiency estimation on thermal power stations and boiler-houses is presented. On the basis of the algorithm the program for conducting multiple calculations and choosing an optimum solid fuel preparation system is developed. As an example the calculations results of thermal and thermodynamic efficiency at replacement of designed Kuznetsk lean coal by not designed Kizel gas coal for various systems are presented.
THE IMPROVEMENT TECHNOLOGIES OF THE THERMAL LOAD REGULATION FOR COGENERATION SYSTEMS IN URBAN AREAS
V.I. Sharapov, P.V. Rotov, M.E. Orlov
e-mail: vlad-sharapov2008@yandex.ruvlad-sharapov2008@yandex.ru
The Ulyanovsk State Technical University
Keywords: cogeneration systems in urban areas, central regulation of the thermal load, quantitative and qualitative-quantitative technologies of regulation, improvement of the structure, increasing energy efficiency
The modern condition of urban cogeneration systems is analysed and technologies of regulation of their thermal loading are considered. The main directions of development of urban cogeneration systems are determined. Energy efficient technologies of thermal loading regulation are offered in view of structural changes in cogeneration systems.
POWER-AND-MECHANICAL ENGINEERING
SURFACE FLAW MIXED MODE 3D STRESS FIELDS AND PARAMETERS
V.N. Shlyannikov, A.V. Tumanov
e-mail: shlyannikov@mail.ru
Research Center for Power Engineering Problems of the Russian Academy of Sciences
Keywords: inclined semi-elliptical crack, load biaxiality, mode mixity, surface flaw geometry
Abstract
The elastic-plastic stress fields and mode mixity parameters for semi-elliptical surface crack have been investigated in biaxial loaded plates by detailed three-dimensional finite element calculations. Different degrees of mode mixity are given by combinations of far-field stress level, biaxial stress ratio and inclined crack angle. The analyses are performed for different surface flaw geometry to study combined load biaxiality and mode mixity effect on the crack front stress fields and the size and shape of the plastic zones. By the theoretical analysis the new formulae have been introduced for both the elastic and plastic mode mixity parameters accounting for ratios between I/II, II/III, III/I modes. Attention is paid on the strong variations of the mode mixity parameters along of the semi-elliptical surface crack front.
Полнотекстовые версии статей находятся на www.e-library.ru[/vc_column_text][/vc_column][/vc_row]