Перегляд за Автор "Petrenko, Valentin"

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Dynamics of changes in temperature of batch sterilizers with backpressure
(2017) Klimenko, Oleg; Petrenko, Valentin; Tregub, Victor
The article describes the construction of dynamic subsystem logical and dynamic model for batch sterilizer with counter pressure needed for the construction of programmer. To describe the dynamic of counter-pressure autoclave is used mathematical method that takes into account the sequence of the autoclave. Modeling scheme for areas of heating and shutter, and cooling area are programmed in MatLab with the heat balance equation. There are circuit modeling temperature changes in blanks in areas of heaing and shutter speed and cooling section.
Heat Transfer in Down flowing Turbulent Evaporating Liquid Films with Developed Wavy Structure and co-Current Steam Flow
(2016) Petrenko, Valentin; Zasiadko, Yaroslav
The result of heat transfer modeling in down flowing turbulent films with the developed wavy structure at the regime of evaporation from film interface at free falling and with co-current steam flow, a heat transfer model, which takes into account a cyclic process of temperature field relaxation with the periodic mixing of film by big waves, has been presented. Temperature profiles along with the integral heat transfer coefficients (HTC) were obtained as a result of approximate solutions of heat transfer differential equations of in turbulent flows, adapted thus film flux with large surface waves, utilizing turbulent transport model by M. D. Millionschykov.
Heat transfer in the evaporation channels of film evaporators
(2013) Ryabchuk, Alexander; Petrenko, Valentin
There is an urgent need in the reliable correlation allowing calculation of heat transfer coefficients to highly concentrated films boiling at vacuum, which refers to the operational regimes of vacuum pans of multistage evaporators in the sugar industry. According to the stated objective, a rigorous study into thermo - and hydrodynamic parameters of film flows has been carried out. For this purpose a special experimental rig aimed at the modeling of two - phase flows with independent phases’ flow rates formation has been developed and erected. Experimentation enveloped the regimes of evaporation free interphase surface as well as boiling at forced convection in down falling liquid films of sugar solutions within a wide range of concentrations at atmospheric pressure and vacuum. The solution mass concentration range d within 0…72%. Analysis of the obtained data has proven, firstly, that the resultant of correlation may be based on the idea of the inter – phase turbulence suppression. Secondly, experimental data showed that the simple criteria of the onset of the nuclear boiling in – films could be formed with the limiting condition of the steam phase appearing: which is overheating of the heat transfer surface with the given roughness of it. The resultant equation which can be used for the calculations of heat transfer coefficients to the saturated gravitational falling films in pipes is derived. This equation can be used equally within the regime of evaporation from the interphase as well as within the regime of nucleate boiling at forced convection.
Heat Transfer Modeling Downflowing Laminar Films with the Developed Wavy Structure with co-Current Steam Flow
(2016) Petrenko, Valentin; Zasiadko, Yaroslav
The result of heat transfer modeling in down flowing viscous laminar films with the developed wavy structure at the regime of evaporation from film interface at free falling and with co-current steam flow, a heat transfer model, which takes into account a cyclic process of temperature field relaxation with the periodic mixing of film by big waves, has been presented. A mathematical model of heat transfer in laminar, heated to the saturation temperatures liquid films with the developed wavy structures on the free interface have been developed. The model takes into consideration cyclic relaxation of transient temperature field which happens right after the passage of a powerful big wave. The developed mathematical model describes the time history of the two dimensional temperature fields as a function of the Peclet number and the core characteristic of the wavy motion (the length of big waves). Based upon the proposed model a set of correlations have been obtained. These are proposed as a means for the generalization of heat transfer experimental data, obtained within the experimental studies of liquid films, heated to the saturation temperatures and evaporating from the interface. A generalized equation has been derived, which can be used for the calculations of Heat Transfer Coefficients (HTC) to the saturated sugar solutions liquid films.
Modeling of heat transfer in down flowing annular vapor-liquid flows
(2022) Petrenko, Valentin; Pryadko, Nikolai; Ryabchuk, Alexander; Boyko, Volodymyr
Modeling of heat transfer in free down flowing laminar liquid films with development wavy structure at the regime of evaporation from the interface
(2016) Petrenko, Valentin; Pryadko, Nikolai; Zasiadko, Yaroslav; Miroshnik, Maria
A mathematical model of heat transfer in laminar, heated to the saturation temperatures liquid films with the developed wavy structures on the free interface have been developed. The model takes into consideration cyclic relaxation of transient temperature field which happens right after the passage of a powerful big wave. The developed mathematical model describes the time history of the two dimensional temperature fields as a function of the Peclet number and the core characteristic of the wavy motion (the length of big waves). Based upon the proposed model a set of correlations have been obtained. These are proposed as a means for the generalization of heat transfer experimental data, obtained within the experimental studies of liquid films, heated to the saturation temperatures and evaporating from the interface. A generalized equation has been derived, which can be used for the calculations of Heat Transfer Coefficients (HTC) to the saturated sugar solutions liquid films. This equation contains wavy characteristics of down flowing films and valid within the range of parameters characteristic for the sugar industry evaporators, namely: concentrations – 0…70 % dry matter; liquid mass flow rate density–0.01×10-3…0.6×10-3 m2/sec, the Peclet number range – 400…25000. The mathematical model of the temperature field cyclic relaxation turned out efficient for generalization of heat transfer experimental data not only laminar, but turbulent liquid films either, despite of the fact that the transport equations do not contain turbulent characteristics.