The results of a complex of experimental studies of thermal and aerodynamic indicators of water-heating heat-recovery exchangers of dusty exhaust gases from glass-making furnaces are presented. The studies were carried out on an experimental installation located behind a glass-melting furnace, and in the process of start-up operations during the introduction into operation of modular-type water-heating heat exchangers (HWM) developed by IET NAS of Ukraine at various glass-producing enterprises. The studies were carried out using modern measuring equipment according to certified methods of the services of metrological adjustment of glass-making enterprises, with the participation of which the experiments were carried out. In the process of research, the heating capacity, average values of the heat transfer coefficients and aerodynamic resistance of heat exchange surfaces, which are assembled from of panel packages formed by pipes with membranes, under conditions of heat-recovery of dusty furnace gases, were determined. The dynamics of the formation of a layer of deposits of technological dust on the surface of the panels on the gas side and the contamination coefficient of surface were also subject to research. According to the data on the heat-recovery exchanger heating capacity, the rational period of its operation between cleaning the working surfaces was determined. The experimental parameters obtained were also compared with their calculated values, as well as with the data of other researchers. According to the results of the studies, it is shown that TVM heat exchangers when used in conditions of dusty furnace gases are characterized by high thermal efficiency due to the layout of the heat exchange surface from the packets of panels formed by pipes with membranes, and the possibility of cleaning these surfaces from deposits of technological dust with practical restoration of the initial indicators. Based on the data obtained, the duration of the cycles for cleaning membrane heating surfaces from dust deposits was determined: for furnaces for the production of glass packaging, this period was 10-14 days, and for furnaces for melting medical glass - 5-7 days.
Technology organic and inorganic substances 49 1. Introduction Polymeric micro-and nanocomposites occupy an important place among synthetic materials, which successfully replace traditional natural materials. This is largely due to the complex of unique physical and technological properties of such composites. The possibility of obtaining new polymer composite materials by varying their components-such as polymer matrix and filler-deserves special attention.
Встановлено закономірності структуроутворення під час кристалізації полімерних нанокомпозитів на основі поліетилену, наповненого вуглецевими нанотрубками. Виявлено ефекти впливу на ці закономірності таких факторів, як масова частка наповнювача, швидкість охолодження і метод отримання композитів. Розгляду підлягали нанокомпозити, отримані методом, що базується на змішуванні компонентів у сухому вигляді і в розплаві полімеру. Виконано зіставлення експериментальних екзотерм кристалізації для досліджуваних композитів за зазначених методів їх отримання. З використанням екзотерм кристалізації і рівняння нуклеації отримано дані про особливості структуроутворення на початковій стадії кристалізації композитів. Встановлено, що на цій стадії наявний площинний і об'ємний механізм структуроутворення за деякого переважання останнього. Виконано аналіз закономірностей структуроутворення на стадії кристалізації в об'ємі композитів у цілому в припущенні наявності двох механізмів кристалоутворення, перший з яких пов'язаний з кристалізацією на флуктуаціях густини полімеру, другий – із кристалізацією, в якій роль її центрів відіграють частинки наповнювача. Показано, що механізми кристалізації на частинках наповнювача істотно залежать від його масової частки і методу отримання композиційних матеріалів.
A set of experimental studies has been carried out to establish the effect of the mixing time of components of nanocomposite materials on their thermal conductivity, specific heat, and density. The physical properties of polypropylene-carbon nanotube composites were to be studied. During the experiments, the duration of mixing of the components in the melt of the polymer varied from 5 to 52 minutes, the mass fraction of the filler ‒ in the range of 0.3...10 %, and nanocomposite temperature – from 290 K to 475 K.
It was found that an increase in the mixing time of components of nanocomposite materials could lead to a significant (more than 70 times) increase in their thermal conductivity. It is also shown that the influence of the specified time is limited to its value equal to 27 minutes, above which the change in the thermal conductivity of nanocomposites can be neglected. It was found that the sensitivity of the thermal conductivity of nanocomposites to the time of mixing of their components decreases with a decrease in the mass fraction of the filler.
Temperature dependences of the specific heat capacity of the studied composites were obtained by varying the mixing time of their components and the mass fraction of the filler. It was found that with an increase in the specified time, there is a decrease in the heat capacity of nanocomposites, which is significantly manifested only in the region of temperatures close to the melting point of the composite matrix.
It is shown that the dependence of the density of nanocomposites on the mixing time of their components in qualitative terms is similar to the corresponding dependence for their thermal conductivity. The obtained data can be used to choose the mixing time of components of nanocomposite materials in the development of appropriate technology for their production
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.