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TURBULENCE AS A WAY TO INCREASE THE EFFICIENCY OF HEAT
EXCHANGE EQUIPMENT Bulov A.O. (Russian Federation)
Bulov Artem Olegovich - graduate Student, DEPARTMENT OF REFRIGERATION CRYOGENIC ENGINEERING AND AIR CONDITIONING, INSTITUTE OF MECHANICAL ENGINEERING AND MECHATRONICS RESHETNEV SIBERIAN STATE UNIVERSITY OF SCIENCE AND TECHNOLOGY,
KRASNOYARSK
Abstract: this article discusses the issue of improving the efficiency of heat exchange equipment. One of the promising ways to solve this problem is the intensification of heat exchange. The main ways of intensifying the heat exchange process are shown. Intensification is one of the most effective ways to reduce energy costs. The specifics of the use of profiled pipes in heat exchange equipment are described in detail. The use of profiled pipes in heat exchange equipment contributes to an increase in the contact area and turbulence. Conclusions are drawn about the efficiency of using profiled pipes in heat exchangers. Keywords: heat exchanger, profiled pipes, turbulence, intensification.
ТУРБУЛИЗАЦИЯ КАК СПОСОБ ПОВЫШЕНИЯ ЭФФЕКТИВНОСТИ ТЕПЛООБМЕННОГО ОБОРУДОВАНИЯ Булов А.О. (Российская Федерация)
Булов Артём Олегович - аспирант, кафедра холодильной криогенной техники и кондиционирования, институт машиноведения и мехатроники Сибирский государственный университет науки и технологий им. М.Ф. Решетнева,
г. Красноярск
Аннотация: в рамках данной статьи рассмотрен вопрос повышения эффективности теплообменного оборудования. Одним из многообещающих путей решения данной проблемы является интенсификация теплообмена. Показаны основные способы интенсификации процесса теплообмена. Интенсификация является одним из эффективных способов снижения энергетических затрат. Подробно описана специфика использования профилированных труб в теплообменном оборудовании. Использование профилированных труб в теплообменном оборудовании способствует увеличению площади контакта и турбулизации. Сделаны выводы об эффективности использования профилированных труб в теплообменных аппаратах.
Ключевые слова: теплообменный аппарат, профилированные трубы, турбулизация, интенсификация.
At modern industrial enterprises of chemical, gas, petroleum, petrochemical, food and other industries, as well as in energy, aviation and space technology, heat exchangers are widely used for cooling, heating, evaporation and condensation of liquid, steam and their mixtures.
There is a wide variety of heat exchangers, which differ in the method of heat transfer, as well as in design and functionality. With the development of energy capacities and the increase in production volume, the mass and dimensions of the heat exchangers used are growing more and more. A large amount of non-ferrous and alloyed metals is spent for their production [1].
Therefore, the optimization of such complex thermal power systems will allow us to find ways to improve the efficiency of equipment. It also opens up the possibility of maintaining the working condition of thermal power equipment in the required temperature ranges, not to mention reducing capital costs and energy resources.
The efficiency of a heat exchanger is determined by the amount of thermal energy it transfers over a certain time. Reducing the size and weight of heat exchangers is an urgent problem today. One of the promising ways to solve this problem is the intensification of heat exchange. Intensification of the heat exchange process in a heat exchanger is one of the most effective ways to reduce energy consumption, which is of great interest and has great economic importance. There are many ways to intensify heat exchange: increasing the speed of the coolant, increasing the temperature difference between cold and hot heat carrier, during steam condensation - reducing the resistance of the condensate film and increasing the steam velocity (during liquid evaporation) increasing the number of vaporization centers, turbulence of the flow, etc.
When choosing the method of heat exchange intensification, it is necessary to take into account the universality of the method for various heat carriers, the contamination of the surface, the manufacturability of the manufacture and assembly of the heat exchanger and the features of operation. All these limitations significantly reduce the possibility of choosing one of the possible methods of intensification [2]. As a practical example, we
will further consider the use of periodically annular protrusions - one of the most effective ways of intensification. Turbulators create eddy zones in the boundary layer, which leads to its reduction. It is worth noting that the use of annular tubulizers is quite technologically advanced, because the outer diameter of the pipes does not increase, this allows the use of such pipes in tight bundles and does not change the assembly technology of heat exchangers, which already exists. When using annular grooves and diaphragms, the flow turbulence occurs in the wall layer, which provides an intensification of heat exchange (Fig. 1) [3].
Fig. 1. Longitudinal section of the pipe (with grooves)
The intensification of heat exchange from the outside is determined by the change in the hydrodynamics of the heat carrier flow on the profiled surface of the tube. The intensification from the inside is also determined by the hydrodynamics of the flow — a violation of the ordered flow of liquid in a viscous sublayer due to its turbulence and twisting. Hydraulic resistance of profiled tubes (fig. 2) at the same time, it is higher than that of smooth tubes, which requires a corresponding increase in the power to pump the heat carrier through them [4].
Fig. 2. Profile circular tube
Fig. 3, as an example, presents calculated and averaged experimental data on the effectiveness of the use of profile scew tube in low-pressure heaters of steam turbine plant in nominal and variable operating modes [5].
Fig. 3. Increase in the heat transfer coefficient of the apparatus with profiled tubes compared with smooth ones
The use of profiled pipes in heat exchange equipment contributes to an increase in the contact area and turbulence. In addition, different profiles of grooves in pipes will give different results of heat exchange modeling, and the main result is practical recommendations in the improvement and manufacture of heat exchange equipment.
References / Список литературы
1. Kuzma-Kitscha Yu.A. Methods of heat transfer intensification. Moscow: Publishing House of the MEI, 2001. 112 p.
2. Heat exchangers and equipment. [Electronic resource]. URL: https://gas-burners.ru/teploobmennoe-oborudovanie/teploobmennye-apparaty-i-oborudovanie/?ysclid=l7nknzkhhz981521728/ (date of access: 10.20.2022).
3. Ibragimov U.H. Intensification of heat exchange in channels / Young scientist, 2016. № 8 (112). Pp. 225229.
4. Heat exchange in energy heat exchangers of thermal power plants. [Electronic resource]. URL: https://www.rosteplo.ru/Tech_stat/stat_shablon.php?id=713/ (date of access: 20.10.2022).
5. Promising developments to improve heat exchangers. [Electronic resource]. URL: https://openedu.urfu.ru/files/book/%D0%93%D0%BB%D0%B0%D0%B2%D0%B0%2013.html?ysclid=l7n k4s0iq5535338289/ (date of access: 10.20.2022).
