Issue 1 (147)
Section 1. Refrigeration engineering
AIR FLOW CHARACTERISTICS IN MICROCHANNEL CONDENSER
Heat transfer and air flow aerodynamic characteristics in the microchannel condenser are examined in the paper. These characteristics were calculated in a wide range of air velocities for a particular model of heat exchanger.
Key words: air – heat transfer coefficient – pressure drop – friction factor – louvers.
Authors IDs: Olga Olshevska 0000-0002-4512-3915
V. Kogut, I. Butovskyi, M. Khmelniuk
HYDROCARBON CONDENSATION METHOD IN THE EJECTOR EXCHANGER INDUSTRIAL UTILIZATION
The possibility of applying of the hydrocarbons condensation method in the stream in the ejector heat exchanger in the areas of transportation, storage, or overflow from tank to tank and selling in small quantities is examined in the paper.
Key words: ejector heat exchanger – cavitation mode – hydrocarbons condensation
THE CREATION METHODS OF HEAT-USING REFRIGERATION MACHINE WITH CARBON DIOXIDE AS WORKING SUBSTANCE PATTERN
The article describes the method of creating a cyclic-scheme decision of heat-using compressor re- frigerating machine with carbon dioxide as the working substance, based on the thermodynamic anal- ysis of the «method of cycles». The method of creating of the cyclic-scheme decision of the heat-using compressor machinery with carbon dioxide is based on the thermodynamic analysis of the "method of cycles". Through a phased build-up of irreversible in the cycle - sample (consistent «deterioration» of the ideal cycle) caused by the actual conditions of each element work in the composition of the refrig- eration machine, reference cycles of valid machines were formed. Based on analysis, minimum ele- mental composition was defined, which provided real processes of heat transfer, expansion, compres- sion in total with safe machine operation conditions with carbon dioxide. The estimation of the ther- modynamic efficiency of cycles for real temperature machine operation modes was made.
Key words: Refrigeration machine using heat energy - Carbon dioxide - Thermodynamic analysis - Method of cycles.
Section 2. Power engineering and energy saving
М. Kordyukov, V. Deshko, I. Sukhodub
HEAT AND MASS TRANSFER PROCESSES IN AIR-TO-AIR MEMBRANE RECUPERATIVE HEAT EXCHANGER IN SUMMER
The article describes experimental and calculated data on air temperature and moisture content before and after heat exchanger, heat fluxes and energy savings during summer period of 2013 in Kiev. Accord- ing to the results of experimental studies using a membrane exchanger in summer can increase the recov- ered heat flux due to the latent heat up to 20 % as compared with sensible heat exchanger. Calculation methods in comparison with the actual effect give more significant reduction of energy consumption due to decreasing supply air moisture content – 78.5 % (for one day), the average for the summer season – 74.6 % (using IWEC data). Average actual effectiveness ratios for summer period are 73.2 % for the sen- sible heat, 63.8 % for latent heat and 71.0 % for total heat.
Key words: Keywords: heat recovery, moisture recovery, energy efficient ventilation, membrane heat exchanger, ef- fectiveness, sensible heat, latent heat.
EFFECTIVENESS OF STIRLING ENGINE HEAT REGENERATOR
The analysis of the heat regeneration process in the Stirling engine is carried out. The impact of the regeneration on the performance coefficient and capacity of Stirling engine is considered.. How the thermal efficiency of the engine changes in the case of the nozzle design characteristics of the regenerator changing is shown.
Key words: Stirling engine Regenerator Thermal process Efficiency
R.K. Nikulshin, L.I. Morosuk, V.V. Sokolovskaya
ANALYSIS OF THE SHELL-IN-TUBE CONDENSER CHARACTERISTICS FOR ENERGY CON- SERVATION
In this paper an analysis of the basic characteristics of heat exchangers by the method of the minimization entropy generation for energy conservation is presented. The specific examples of analysis for a real shell-in-tube condenser in order to assess its energy efficiency are studied. The results of condenser main characteristics theoretical studies: heat flow density, the second refrigerant (water) velocity and hydraulic diameter as well as their comparison with experimental data are showed.
Key words: Heat exchanger – Water cooled condenser – Characteristics – Method of the minimization entropy generation – Energy conversation.
Section 3. Refrigerating and accompanying technologies
V.L. Bondarenko, T.V. Diachenko, O.V. Diachenko
DESIGN CALCULATION METHOD OF THE TOWARD FLOW REFLUX CONDENCERS, USED IN THE TECHNOLOGIES OF NE-HE MIXTURE ENRICHMENT
Designs of straight pipes flow condencers are investigated. The optimization results of devices on specific heat exchanger surface are shown. The energy analysis of reflux condensers for Ne-He mixture receiving is organized, the ways of their settlement are analysed. Methods of flow conden- sers (reflux condensers) constructive calculating is offered, the results are given and are com- pared with data, got under operating condition of industrial reflux condensers.
Key words: Condencer-evaporater – Neon-helium mixture – Reflux condencer.
MATHEMATICAL MODEL OF THE CONDITIONED ROOM TAKING INTO ACCOUNT NON- STATIONARY EXTERNAL AND INTERNAL HEATMOIST LOADINGS
In article the author considered the conditioned room with non-stationary heatmoist loadings. The mathematical model, allowing to analyse the hard currency work depending on intensity of change of warm and moisture receipts indoors was offered. In the form of example the room of of- fice appointment for which it is calculated time of necessary parameters achievement is considered.
Key words: Conditioning – Heatmoist loading – Air parameres – Temperature – Relative humidity – Air consumption– Mathematical model.
PROCEDURE OF EXPERIMENTAL RESEARCH OF INJECTION IN THE VANELESS DIFFUSER OF CENTRIFUGAL COMPRESSOR
Procedure of experimental research of injection in the vaneless diffuser of centrifugal compressor is presented in the paper. The test rig, measuring system and calculation procedure are described.
Key words: Centrifugal compressor – Experimental investigation – Vaneless diffuser – Extending of the stable operating range.
Section 4. Automatic, computer and telecommunication technologies
RESEARCH OF STATISTICAL LOAD FLUCTUATIONS IN THE TELECOMMUNICATION NET- WORK DEVELOPMENT PROCESS
The problems of the design and development of telecommunication networks in the modern world are considered. An approach to the development of a mathematical model of the tel- ecommunications network is offered. Solution of the problem includes the study of require- ments model for the development of the network by increasing its capacity, the amount and kinds of information and communication services.
Key words: Telecommunication network – Mathematical model – Network requirements – Development of the telecommunication network.
APPLICATION OF NEURO-FUZZY APPROACH TO IMPROVE RELIABILITY AND OPTIMAL WORK OF COMPUTER NETWORK
The paper presents analysis of the existing traditional methods of finding the best route for routing in networks. As an alternative to the traditional method, was proposed a neuro-fuzzy approach for the opti- mization of the routing process with the prediction of failure of the server's hard disk drive. For the pre- diction we used the package FuzzyTech environment Matlab. The program that is based on the unit neu- ro-fuzzy logic was written. The initial data are taken data corporation Google, which was published at a conference in Toronto. Based on these data, the predicted probability of failure of the hard disk server, resulting in changes in the architecture of a corporate network, and consequently bring changes in the routing process. Specific advantages of the neuro-fuzzy method over the traditional, namely, accounting expert opinion, the ability to self-learning and the ability to work with non-linear functions.
Key words: neuro-fuzzy network, adaptive routing, intelligent prediction, neural network, training of the network, matrix algorithm, self-learning network, learning rules, activation function, hybrid network
P.I. Chernobay, D.A. Makoveyenko
ANALYSIS OF INCREASE CAPACITY E-UTRA NETWORK USING SFR
The article analyzes the increase capacity E-UTRA network using soft frequency reuse. The technique of network bandwidth mobile broadband wireless LTE using SFR and adaptation mode parameters modulation-coding schemes to the radio wave propagation.
Key words: LTE MCS –SFR – capacity.