scholarly journals Experimental studies and numerical modelling of heat and mass transfer process in shell-and-tube heat exchangers with compact arrangements of tube bundles

2018 ◽  
Vol 240 ◽  
pp. 02006 ◽  
Author(s):  
Valery Gorobets ◽  
Yurii Bohdan ◽  
Viktor Trokhaniak ◽  
Ievgen Antypov
Keyword(s):  
Mass Transfer ◽  
Numerical Modelling ◽  
Heat And Mass Transfer ◽  
Heat Exchangers ◽  
Experimental Studies ◽  
Mass Transfer Process ◽  
Experimental Investigations ◽  
Transfer Processes ◽  
Tube Bundles ◽  
Shell And Tube

Shall-and-tube heat exchangers based on the bundles with in-line or staggered arrangements have been widely used in industry and power engineering. A large number of theoretical and experimental works are devoted to study of hydrodynamic and heat transfer processes in such bundles. In that, works the basic studies of heat and mass transfer for these bundles are found. However, heat exchangers of this type can have big dimensions and mass. One of the ways to improve the weight and dimensions of the shell-and-tube heat exchangers is to use compact arrangement of tube bundles. A new design of heat exchanger is proposed, in which there are no gaps between adjacent tubes that touch each other. Different geometry of these tube bundles with displacement of adjacent tubes in the direction of transverse to the flow is considered. Numerical modelling and experimental investigations of hydrodynamic, heat and mass transfer processes in such tube bundles has been carried out. The distribution of velocities, temperatures, and pressure in inter-tube channels have been obtained.

scholarly journals Experimental and numerical studies of heat and mass transfer in low-temperature heat accumulator with phase transformations of accumulating material

2018 ◽  
Vol 240 ◽  
pp. 01009 ◽  
Author(s):  
Valery Gorobets ◽  
Ievgen Antypov ◽  
Viktor Trokhaniak ◽  
Yurii Bohdan
Keyword(s):  
Mass Transfer ◽  
Phase Transformations ◽  
Heat And Mass Transfer ◽  
Thermal Energy ◽  
Experimental Studies ◽  
Experimental Plant ◽  
Chemical Transformations ◽  
Heat Accumulator ◽  
Tube Bundles ◽  
Melting And Crystallization

Accumulation of thermal energy is produced with the aim of storing at certain times, when there is an overabundance of this energy and its further use in other periods of time when there is a deficit thermal energy. Thermal energy storage may be carried out under heating of any material (water, solid materials etc.) or by using the phase or chemical transformation of the material (melting and crystallization processes, direct and reverse chemical reaction). Thermal accumulators with phase or chemical transformations are allowed to concentrate a large amount of energy in a relatively small volume of accumulating material. In this paper an experimental study and numerical modeling of heat and mass transfer in the heat accumulator during phase transformations of the accumulating material are presented. The experimental plant consists of a chamber filled with paraffin. In experimental studies, the changes of the temperature distribution in heat accumulating material and tube bundles have investigated. Numerical simulation of melting and solidification of heat accumulating material during the heated and cooled of tube bundles were performed. As the results of research, the basic laws of melting and crystallization processes in heat accumulator during phase transformations of heat accumulating material were determined.

scholarly journals The influence of airflow on the effectiveness of rotary heat exchangers operating under high-speed rotor conditions

2019 ◽  
Vol 116 ◽  
pp. 00032
Author(s):  
Paulina Kanaś ◽  
Andrzej Jedlikowski ◽  
Sergey Anisimov ◽  
Borys Vager
Keyword(s):  
Mass Transfer ◽  
Heat Exchanger ◽  
Heat And Mass Transfer ◽  
Heat Exchangers ◽  
Heat Recovery ◽  
High Speed ◽  
Airflow Rate ◽  
Sharp Drop ◽  
Transfer Processes ◽  
Mass Transfer Processes

The paper presents an analysis of heat and mass transfer processes occurring inside the rotary heat exchanger operating under high-speed rotor conditions for different values of the airflow rate. For this purpose the original mathematical α-model was used. Conducted computer simulations allowed to determine the influence of Number of Transfer Units (NTU) of airflow on the temperature effectiveness as well as on the distribution of different active heat and mass transfer zones: “dry”, “wet” and “frost”. It was found that the increase of the values of NTU strictly affects the increase of the effectiveness of heat recovery. Another issue emerging from this study is the fact that in the certain range of low values of NTU there is no “dry” area created. It was established that at low values of NTU (NTU≈1) “frost” area extremum and sharp drop in the “frost” area accumulation are observed.

scholarly journals Cell membranes of plant materials anatomical integrity changes under the influence of filamentary microplasma treatment assisted by thermionic emission

2021 ◽  
Vol 9 (3) ◽  
pp. 235-244
Author(s):  
Ivan Shorstkii ◽  
Maksim Sosnin
Keyword(s):  
Mass Transfer ◽  
Cell Membranes ◽  
Raw Materials ◽  
Experimental Studies ◽  
Thermionic Emission ◽  
Mass Transfer Process ◽  
Plant Materials ◽  
Plant Raw Materials ◽  
Transfer Processes ◽  
Mass Transfer Processes

The effect of low-temperature filamentary microplasma treatment on the anatomi-cal integrity of cell membranes of plant raw materials was studied. It is shown that microplasma treatment forms a through channels in the structure of plant materi-als and accelerate mass transfer process. The effect on the cell membrane of plant raw materials leads to a change in the capillary-porous structure with the for-mation of additional pores formed by microplasma discharge, oriented along the direction of the electric field strength. It was found that the dependence of the number of destroyed cells on the intensity of microplasma treatment is limited and decreases with longer processing of plant raw materials. According to the results of experimental studies, it was established that with microplasma treatment assis-tant, it is possible to control mass transfer processes which are important for the further processing of plant raw materials, such as drying and extraction

HEAT AND MASS TRANSFER AND RESISTANCE CHARACTERISTICS OF EVAPORATIVE AIR COOLER WITH HIGH FINNED-TUBE BUNDLES

2018 ◽  
Vol 49 (17) ◽  
pp. 1705-1720 ◽  
Author(s):  
Qing Zhang ◽  
Xuesheng Wang ◽  
Weicheng Ruan ◽  
Qinzhu Chen ◽  
Zilong Liu
Keyword(s):  
Mass Transfer ◽  
Heat And Mass Transfer ◽  
Finned Tube ◽  
Tube Bundles ◽  
Air Cooler
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