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Vol 109, No 3 (2020)
- Year: 2020
- Articles: 12
- URL: https://journal-vniispk.ru/0023-124X/issue/view/5213
Articles
Mirovoy rynok kholodil'nogo oborudovaniya
Refrigeration Technology. 2020;109(3):6-9
6-9
Reshenie novogo pokoleniya dlya upravleniya torgovym oborudovaniem Danfoss ADAPCOOL®
Refrigeration Technology. 2020;109(3):10-13
10-13
Novye elektronnye komponenty ot becool
Refrigeration Technology. 2020;109(3):14-17
14-17
Vybor setochnoy modeli i otsenka vliyaniya izmeritel'nykh priborov v zadachakh modelirovaniya vyazkogo potoka v maloraskhodnykh stupenyakh tsentrobezhnogo kompressora
Abstract
The paper deals with the choice of a grid model and estimation of the influence of measurement devices placed in the flow part (FP) at numerical simulating (RANSapproach) a viscous gas flow in a lowflow stage of a centrifugal compressor at conditional flow coefficient Ф = 0.008 using the Numeca Fine/Turbo program. The influence of measurement devices total pressure tubes placed in three sections along the diameter of the diffuser was estimated. The conclusion obtained is that the measurement devices affected slightly the losses as compared with other types of losses in the lowflow stage of the centrifugal compressor. The problem of the grid independence of the solution of a calculation model in the working path of the stage as well as in the adjacent areas was examined. It was shown that ensuring the grid independence of the solution in the adjacent areas of the lowflow stage was of no less importance than in blade apparatuses of the flow part. The influence of the dimensionless distance of the first nearwall layer y+, when using the SpalartAllmaras low Reynolds number model of turbulence was evaluated
Refrigeration Technology. 2020;109(3):18-23
18-23
Rezul'taty chislennogo modelirovaniya vyazkogo potoka v maloraskhodnykh stupenyakh tsentrobezhnykh kompressorov kak osnova sozdaniya matematicheskoy modeli napora
Abstract
The paper envisages the results of calculation of a threedimensional viscous flow in 18 lowflow stages of centrifugal compressors in the range of optimal conditional flow coefficient Фopt = 0.007-0.018. Gasdynamic characteristics of the internal and polytropic pressure coefficients in full parameters were plotted and compared with experimental data. The calculated gasdynamic characteristics of viscous flow satisfying the engineering accuracy of calculations and experimental character of the curves were obtained using Ansys CFX software
Refrigeration Technology. 2020;109(3):24-29
24-29
Osobennosti fizikokhimicheskikh, pozharovzryvoopasnykh svoystv ammiaka i pozharnaya opasnost' ob\"ektov zashchity, v kotorykh on ispol'zuetsya
Abstract
An overview of ammonia physicochemical fire and explosion hazardous properties reports that this gas has its own distinctive features to be taken into account when estimating the level of fire risks of the facilities, in which it is used. In the open air at atmospheric pressure, the burning of ammonia is relatively slow, and not accompanied by a sharp increase in pressure and sound effect. Due to this, the shock waves are not formed when burning ammoniaair cloud in the open area. So, the installations using ammonia and mounted outside are not related to explosive ones. In a confined space ammonia is burning quicker, and the gas pressure increases gradually. Therefore, the explosion in the premises is dangerous for people, equipment and building units. Emissions of gas, vapor and leakage of liquid NH3 are the greatest fire and explosion hazard when operating with ammonia. When ammonia is released, the mixture of the gas with air can vary in density from the formation of gasair clouds at density lower than air density to the floatability with exceeding air density depending on the discharge conditions. Refrigeration industry is the greatest user of ammonia. The work highlights the issues of fire safety and fire protection of industrial cold stores
Refrigeration Technology. 2020;109(3):30-37
30-37
Vliyanie teploakkumuliruyushchey steny s vodyanym teploobmennikom na okhlazhdayushchuyu nagruzku v zdanii. Chast' 1
Abstract
The paper presents the results of mathematical modeling and experimental research of the effect of a heataccumulating wall with a water heat exchanger on building cooling. The first part describes the mathematical model of the building. The modeling was carried out using the TRNSYS program that allowed computing an hourly load of cooling the heataccumulating walls with a water heat exchanger for the purpose of subsequent comparison with the cooling load of a sample room. The building modeling scheme, the heat network model, and the method of calculating the total thermal resistance of the thermosetting wall layer are given as well
Refrigeration Technology. 2020;109(3):38-43
38-43
Matematicheskoe modelirovanie raboty absorbera pri pogloshchenii CO2 v sistemakh regeneratsii vozdukha
Abstract
The paper considers the mathematical model of the counterflow laminar motion of liquid and gas in an absorber with the ordered (layerwise) packing of packed bodies. Every bed of the packing is presented in the form of an equivalent (conditional) channel, the dimensions of which are defined by the specific surface and the portion of the free volume of packed bodies. An optimization problem is formulated that allows, at the initial stage of design, determining the main parameters of the absorber providing the design efficiency of CO2 absorption, taking into account the given design and technological conditions. It is offered to examine the hydrodynamic processes in the packed beds, having respect to the value of the flow velocity at the phase boundary
Refrigeration Technology. 2020;109(3):44-48
44-48
Vliyanie zamorazhivaniya na dinamiku aminokislotnogo sostava belkov telyatiny
Abstract
The results of study of effect of freezing temperature on the change of amino acid content and the ratio of essential and nonessential amino acids in veal proteins are given. The meat of calves at the age of 3 months, bred in the Leningrad region of the RF, was the object of research. The amino acid composition of veal proteins was analyzed using the Shimadzu 20AD Chromatograph with precolumn phenylisothiocyanate derivatization and spectrophotometric detection at 254 nm by reversedphase gradient highperformance liquid chromatography (HPLC). The Kjeldahl method was used to define the protein content on the basis of the sample mineralization. It was shown that the change of the amount and ratio of essential and nonessential amino acids of veal proteins depended on the freezing temperature as well as on structural features of Rside radicals. Also it was established that the total amount of essential and nonessential amino acids in veal proteins during freezing at -24 and -35 °С temperatures decreased by 13,5 and 8,2%, respectively; the total of essential amino acids by 11 an 7%, nonessential ones by 22 and 11%, respectively. It was proved that significant changes were characteristic of amino acids with polar anionic and cationic radicals. So, the amount of amino acids with polar negatively charged radicals during veal freezing at temperatures -24 and -35 ° С decreased by 22 and 16,5%; with polar positively charged radicals - by 17 and 13,5%, respectively. At the same time, the freezing temperature affects slightly the change in the content of amino acids with nonpolar (hydrophobic) Rgroups and polar nonionogenic radicals. It was shown that the total amount of free amino acids increased independently of the freezing temperature. However, more essential amino acids were accumulated in veal frozen at a temperature of -24 ° С (2,33 times) than at -35 ° С (1,80 times). The amount of free nonessential amino acids changed to a lesser extent
Refrigeration Technology. 2020;109(3):49-55
49-55
Uspekh - eto ne final
Refrigeration Technology. 2020;109(3):56-57
56-57
«Prodekspo2020»: kurs na eksport, zdorovyy obraz zhizni i organiku
Refrigeration Technology. 2020;109(3):58-61
58-61
Novye patenty Rossii po kholodil'noy tekhnike i teplovym nasosam
Refrigeration Technology. 2020;109(3):62-68
62-68