Refrigeration engineering and technology

4 - 10

Authors: V.P. Zhelezny; А.V. Melnik

Experimental data for refrigerant R600a mixed with the compressor mineral naphthenic oil ISO VG 15 boiling in the smooth small-diameter (5.4 mm) tube are reported. The tests were conducted at the inlet pressure psuc in the range from 62.3 to 82.2 kPa, heat flux from 2754 to 4105 W/m2, mass velocity varied between 11.90 to 18.54 kg/(m2∙s) and oil concentrations at the inlet to the evaporator from 0.25 to 0.5 % by mass. The results of the research of the local heat transfer coefficient at the boiling of the isobutane/compressor oil solution flow are given in the paper. It is shown that the substantial reduction of heat transfer coefficient was observed at high concentrations of oil. In addition, during the boiling of the refrigerant/oil solution the heat transfer coefficient in the lower part of the pipe is decreasing with mass velocity increasing.

16 - 26

Authors: V.О. Ierin

In this paper an innovative micro-trigeneration system composed of a cogeneration system and a cascade refrigeration cycle is presented. The cogeneration system is a combined heat and power (CHP) system for electricity generation and heat production. The cascade refrigeration cycle is the combination of a CO2 sub-critical mechanical compression refrigeration machine (MCRM), powered by generated electricity, and an ejector cooling machine (ECM), driven by waste heat and using refrigerant R717. Refrigerant R717 as the working fluid for ejector cooling cycle is selected in the present study. Effect of the cycle operating conditions on ejector and ejector cycle performances is studied. Optimal geometry of the ejector and performance characteristics of ECM are determined at wide range of the operating conditions. The paper also describes the theoretical analysis of the CO2 sub-critical cycle and shows the effect of the MCRM evaporating temperature on the cascade system performance. The obtained data provide necessary information to design a pilot small-scale cascade CO2 sub-critical mechanical compression / ammonia ejector refrigerating unit with cooling capacity of 10 kW for application in micro-trigeneration systems incorporating reciprocating internal combustion engines and gas micro-turbines.

36 - 41

Authors: A.V. Bondarenko; V.E. Volkov; M.V. Maksimov

Research of the flare instability development and the laminar-to-turbulent transition for the flares was executed. It was proved that the effects of viscosity and compressibility have the stabilizing influence on the gas flame. The study of the individual flare stability makes the theoretical basis of the fuel burning technology in combustion chambers and for the burner combustion control.

51 - 54

Authors: N.V. Kulikova; А.А. Red'ko

The heat-utilizer thermodynamic model based on the account of heat- carriers entropy change has been presented. The rated dependences for thermotechnical calculation of devices using the criteria, taking into account heat-exchange process nonequilibrium have been obtained.

60 - 63

Authors: M.M. Kologrivov; V.P. Buzovskiy

The experimental research results of water cooling efficiency in various constructions ventilator cooling towers at relative expenditures of water and air in a wide range is presented in the article. The obtained data were compared with similar characteristics of the absorbers.

71 - 75

Authors: R.U. Turna; P.G. Gakal; E.P. Ganja

Mathematical models of heat transfer for stream cooling lines of poultry carcasses, as well as methods of cooling time prediction in such systems are presented in the paper. The main goal of paper is the review of existing models and methods to define advantages and disadvantages each of them. The review allows to choice more appropriating models and methods and requirements for them in frame of stream cooling lines designing on the base of system principles. The basic requirements are: the model should be universal and doesn’t depend on form of carcasses; the models must take into account the non uniform heat transfer conditions on the product surface; the model should be experimentally approval and should be simplified enough to include it into the system model of stream cooling line.

79 - 82

Authors: G.S. Gayvoronskaya; M.Y. Solomitsky

Some results of messages streams’ research at the convergence of technologies in the telecommunication network are given in the paper. Object of study is the convergent telecommunication network in the process of interaction with external information metastructure. Network-forming process of convergent telecommunication network is the process of information transforming, implemented by a set of information technologies, including: computational process of information transforming in the space (input, output, storage, data processing) and information process of information transforming in time (collection, distribution, transmission, switching of the streams). Herewith streams, incoming and circulating in the convergent telecommunication network, are complex in nature and structure. In order to research quantitative aspects of information transformation’s network processes it seems appropriate to study a conception of the messages streams – the aggregate of any information, transformed into electromagnetic signals, which is have to be transported within the convergent telecommunication network. At the study of the network during its functioning, it is assumed that it already existed for quite a long time before the study in order to reach the stationary functioning mode and it would function so after the finish of the study. A hypothesis about the stochastic nature of the messages streams in the convergent telecommunication network is formulated. Distribution function of the messages number (or the sequence of messages’ arrival times, or the sequence of intervals between these times, or the sequence of messages number, received during time intervals), the distribution function of the information content in the messages stream, the distribution function of the delivery time of the entire sequence of messages, forming the flow under the study, the function of the information value are researched at the formalization of messages streams.