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Proceedings of the Technical university of Sofia, 1995 -: Recent submissions

Now showing items 521-540 of 853

Title: Дългосрочни климатични характеристики за проектиране и анализ на пасивни слънчеви системи в Сирия Author: Фарес, Амине; Fares, Amine Date: 1995 Abstract: For the design and evaluation of the effectiveness of passive systems it is necessary to know the long-term characteristics of the main climatic factors which also determine the basic input energy flow. A data base for a 25 year period for five representative areas in Syria has been analyzed and the substantial long -term characteristics ... Library:
TECHNICAL UNIVERSITY - SOFIA
Title: Прибор за непрекъснато измерване влагосъдържанието на пряснята пара в АЕЦ Author: Иванов, Георги Рампов; Ivanov, Georgi Rampov Date: 1995 Abstract: In the article are described the basic requirements, used for the design of a real microprocessor-based device for continuous fresh steam wetness fraction measurement in a nuclear power plant with saturated steam turbines. The throttling calorimeter has been chosen, as the most accurate and applicable for the Nuclear Power Plant (NPP) ... Library:
TECHNICAL UNIVERSITY - SOFIA
Title: Влияние на началното влагосъдържание на парата върху ефективността на турбина К 220-44 Author: Иванов, Георги Рампов; Маринов, Марин Александров; Ivanov, Georgi Rampov; Marinov, Marin Alexandrov Date: 1995 Abstract: By means of a computer software, an investigation was made for the influence of the inlet steam wetness fraction on the power and turbine Efficiency of the high pressure stage of the saturated steam turbine type K.220-44 at different load levels. Due to the reheat after the high pressure stage, the influence of the inlet parameters is limited ... Library:
TECHNICAL UNIVERSITY - SOFIA
Title: Анализ на чувствителността на температурното поле в стена на тромб Author: Калоянов, Никола; Фарес, Амине; Fares, Amine; Kaloyanov, Nikola Date: 1995 Abstract: The modelling of heat transfer processes in an accumulating Trombe-Michel wall is connected inevitably with the character of the input energy flow. It is exceptionally dcult to obtain common mathematical description of the dynamic heat exchange process involving all the components of the input energy flow. In order to simplify the problem ... Library:
TECHNICAL UNIVERSITY - SOFIA
Title: Приложение на регулатори с променлива структура за управление на енергийни обекти Author: Каранешев, Светослав Ангелов; Ганев, Ивайло Гинев; Karaneshev, Svetoslav Angelov; Ganev, Ivailo Guinev Date: 1995 Abstract: A control structure is proposed, consisting of PID controller with variable structure and a block for independent compensation of the disturbances in the control loop. A comparison of the transient processes and amplitude, vs frequency characteristics of the proposed control structure and digital PI and PID controllers is made. Library:
TECHNICAL UNIVERSITY - SOFIA
Title: Технически средства за измерване на разход с гарантирани метрологични характеристики Author: Ганев, Ивайло Гинев; Каранешев, Светослав Ангелов; Начев, Георги Начев; Ganev, Ivailo Ginev; Karaneshev, Svetoslav Angelov; Nachev, Georgi Nachev Date: 1995 Abstract: Aproaches to minimise the systematic and additional errors when measuring flow with Ventoury type trans:niter are discussed. An evaluation of the influencing factors and the incertainty limits of the apriori information is made. A conclusion is made regarding the possibility to design intelligent flowmeters with improved metrological characteristics. Library:
TECHNICAL UNIVERSITY - SOFIA
Title: Динамични свойства на пламъчно - тръбни котли Author: Григоров, Александър Данчев; Grigorov, Alexandar Danchev Date: 1995 Abstract: In this paper on the basis of the power engineering approach, in analytical way, are obtained mathematical models, describing the dynamics of the flame-tube boilers that are manufactured and widely distributed in the notional decentralized power economy. There are included both the control and disturbances dynamical canals of steam and water ... Library:
TECHNICAL UNIVERSITY - SOFIA
Title: Annual energy consumption of air - conditioning systems Author: Stoichkov, Nikola Yordanov; Стоичков, Никола Йорданов; Димитров, Генко; Dimitrov, Genko Date: 1995 Abstract: An algorithm and software for air-conditioning systems annual energy consumption is carried out on the basis of hourly simulations. For external loads estimation the Test Reference Year for Sofia is used. The same room with constant internal loads was examined. Simulation models for systems with constant (CAV and variable (VAV) air volume ... Library:
TECHNICAL UNIVERSITY - SOFIA
Title: Test reference year for Sofia Author: Stoichkov, Nikola Yordanov; Стоичков, Никола Йорданов; Калоянов, Никола Георгиев; Димитров, Генко Иванов; Kaloyanov, Nikola Georgiev; Dimitrov, Genko Ivanov Date: 1995 Abstract: Test Refence Year (TRY) is it set of 8760 hourly coincident data for air temperature and relative humidity,, duration' sunshine, intensity of total solar radiation on horizontal surface, wind velocity and direction. TRY is used as a data base for simulating the performance of solar energy systems, building energy consumption and for indoor ... Library:
TECHNICAL UNIVERSITY - SOFIA
Title: Моделиране обтичането на крило с несвиваема вискозна среда Author: Савов, Владимир Светославов; Гешев, Диан Ненов; Savov, Vladimir Svetoslavov; Geshev, Dian Nenov Date: 1995 Abstract: Smooth flow around a wing of moderate aspect ratio and sweepback is simu-lated by the discrete vortex method assuming that the medium is inviscous and the wing is replaced with its middle surface. The effective wing section angle of attack is derived and using two-dimensional boundary layer with pressure gradient is calculated by the Polhausen ... Library:
TECHNICAL UNIVERSITY - SOFIA
Title: Methods for numerical simulation of three – dimensional turbulent flows Author: Stankov, Petar; Станков, Петър Date: 1995 Abstract: The paper presents an analysis of the methods of simulating turbulent flows of practical importance. An assessment of Direct Numerical Simulation, Large Eddy Simulation and Simulation by Turbulence Transport models is made concerning the possibility of predicting three-dimensional turbulent flows. The analysis is made in view of present and ... Library:
TECHNICAL UNIVERSITY - SOFIA
Title: Numerical prediction of comfort and ventilation efficiency in ventilated rooms Author: Denev, Yordan A; Денев, Йордан А.; Stankov, Petar; Станков, Петър Date: 1995 Abstract: The paper presents investigation of comfort and ventilation efficiency in a typically chemical laboratory room with two fume cupboards. The investigation is based on the detailed results obtained from the numerical solution of a system of seven partial differential equations on a numerical grid of 245000 points. The assessment of comfort ... Library:
TECHNICAL UNIVERSITY - SOFIA
Title: Диапазон на регулиране на дебита при бутални дозиращи помпи Author: Симов, Симеон Теофилов; Кичев, Вълко Маринов; Обретенов, Валентин Славов; Simov, Simeon Teofilov; Obretenov, Valentin Slavov; Kichev, Valko Marinov Date: 1995 Abstract: The range and accuracy of controlling the flow rate of metering limps are of special interest as concerns the industrial applications of this type of pumps. The design solutions known so far provide a range of controlling the flow rate from 30% to 100% of the rated flow rate. Another solution with considerably widened range of controlling ... Library:
TECHNICAL UNIVERSITY - SOFIA
Title: Определяне на КПД. на водни турбини тип Пелтон от ВЕЦ „Пещера“ Author: Обретенов, Валентин Славов; Кичев, Вълко Маринов; Симов, Симеон Теофилов; Obretenov, Valentin Slavov; Kichev, Valko Marinov; Simov, Simeon Teofilov Date: 1995 Abstract: The paper presents the results of experiments made with Pelson water turbines operating at HG1 at PESHTERA HPS (Hydroelectric Power Station). Experiments were made with the aim to determine the efficiency of .the two turbines before and after the modernization of impellers and regulating system carried out by Sulzer (Switzerland). Measurements ... Library:
TECHNICAL UNIVERSITY - SOFIA
Title: Върху задачата за ососиметрично потенциално течение в тръба Author: Варсамов, Кирил Георгиев; Varsamov, Kiril Georgiev Date: 1995 Abstract: Two methods for analysis of axisymmetric potential flow in duct are discussed in this paper, namely the method of Amromin and Ivanov (1975) and the one of Varsatnov and Haimov (1978). On the basis of identical theoretical model (steady potential flow of an incompressible fluid) and similar techniques of reducing the boundary value problems ... Library:
TECHNICAL UNIVERSITY - SOFIA
Title: Система за компенсация на реактивните товари в съответствие с изискванията на новата cosȹ тарифа Date: 1995 Abstract: This paper presents from schemetechnical point of view the principles of reactive loads control by means of microprocessor regulator of reactive power criterion and additional controllers for capacitor batteries control. There are present different cases for compensation of centralized and uncentralized distributed compensated powers in ... Library:
TECHNICAL UNIVERSITY - SOFIA
Title: Изчисление на загубите на енергия в електрическите мрежи по данни от телеизмерване Author: Боцов, Марин Николов; Botsov, Marin Nikolov Date: 1995 Abstract: The teleirlfonnation in our power system can't be used directly for calculation of energy losses. In this paper is given method for calculation of missing powers in branches and minimization of mismathes. By this method computer program is realized It is tested by real data from network 110 KV in district Gorna Oriahovitsa. Library:
TECHNICAL UNIVERSITY - SOFIA
Title: Съвременен информационен подход при изчисляване на загубите на енергия в електрическите мрежи 100 kv Author: Захариев, Васил Тодоров; Боцов, Марин Николов; Zahariev, Vasil Todorov; Botsov, Marin Nikolov Date: 1995 Abstract: In this a new information report is given relating the calculation of the loses of energy in electrical networks. It is based on information from telemetering or processing of real power diagrams data. By this method computer program is realised, used for calculation of loses of the energy in real electrical networks. Library:
TECHNICAL UNIVERSITY - SOFIA
Title: Метод за определяне на скоростната характеристика на системата секционен изолатор – токоснемател Author: Бакалов, Здравко Станчев; Bakalov, Zdravko Stanchev Date: 1995 Abstract: In the paper are described the developed analytical method for determination of the speed characteristic of the section insulator-current collector system as well as methods for determinated of the basic magnitudes, which are used for the calculations and at the same time have been determined the design and the maximum admissible running ... Library:
TECHNICAL UNIVERSITY - SOFIA
Title: Специфични проблеми на заземяване на съоръженията по електрифицираните жп участъци Author: Вичева, Нели Тодорова; Андрова, Наталия Иванова; Андреев, Радослав Владимиров; Vicheva, Neli Todorova; Androva, Natalia Ivanova; Andreev, Radoslav Vladimirov Date: 1995 Abstract: In the paper has been examined the equipment earthing around the electrified railway sections and have been analysed the problems that appear in terms of assuring normal operation-of the relay protection, .man steely at work, as well as compatibility and correct operation of the mil circuits of the safety installations. At the same time are ... Library:
TECHNICAL UNIVERSITY - SOFIA