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ISSN 2410-6070_ИННОВАЦИОННАЯ НАУКА_№4 / 2021
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• Потребление • Солнечная установка • Батарея
Figure 2 - Graph of measurement of generated and consumed electricity by day.
As we can see, both theoretical calculations and measurement results give a conclusion about the economic feasibility of using solar energy in the month of March, as well as about the transition to autonomous power supply.
The use of solar panels is particularly advantageous where there are no centralized electrical networks, and the energy supply is provided by diesel generators. And there are a lot of such areas in Russia. Moreover, even where there are networks, the use of solar panels running in parallel with the network can significantly reduce energy costs.
References:
1. Ryazanov K. V. Prospects for the development of solar energy // CABLE-news. - 2009, No. 12-1. - P. 81-85.
© Канарейкин А.И., 2021
УДК 536.244
Канарейкин А.И.
кан. техн. наук, доцент Российский государственный геологоразведочный университет
имени Серго Орджоникидзе, г. Москва, РФ
ПРИМЕНЕНИЕ ТЕПЛОФИЗИКИ В ГОРНОМ ДЕЛЕ Аннотация
В статье рассматривается вопрос о роли и применении теплофизики в горном деле. Так ка изменение температурного поля приводит к изменению условий теплообмена между породным массивом и воздухом в выработке, то такие процессы являются нестационарными, что усложняет их инженерный расчёт. В работе показан метод расчёта коэффициент нестационарного теплообмена. Что может быть полезным для практических навыков расчета ряда инженерных задач в области теплофизики горного дела.
Ключевые слова
Теплофизика, нестационарный теплообмен, теплофизика горного дела, коэффициент нестационарного
теплообмена, критерий Кирпичева.
Since thermophysics is the study of the transfer of energy and mass, the phenomena of heat and mass transfer act as the causes, content or consequences of almost any natural and man-made processes of the material world. Heat and mass transfer patterns play an important role in agrophysics, hydrology, atmospheric physics, and meteorology, and especially in permafrost, glaciology, geothermy, volcanology, mineralogy, and other Earth sciences.
The development of the entire complex of natural resources of the earth's interior, which belongs to the competence of mining sciences, is associated with the creation and operation of mining natural-technological systems: quarries, mines, mines, fields, wells and various underground structures. With a huge variety of characteristics of such systems, the conditions for the development of heat and mass transfer processes in them differ in some general features. The most important of them is the non-stationary nature of the heat exchange of elements of engineering structures with an unlimited or semi-limited rock mass under various, and often variable, conditions at natural or artificial media interfaces and phase transition fronts.
Mining thermophysics is a set of knowledge about thermal processes and phenomena that develop in rocks, their massifs and mining operations during the development of mineral and other natural resources of the earth's interior.
The goal of mining thermophysics is to predict the thermal effects and changes in the thermodynamic parameters of the state of its objects under various kinds of man-made impacts, using the obtained information in managing these effects and changes to ensure the safety of the relevant technological processes and their optimization according to economic and environmental criteria.
As is known, the heating and cooling of bodies in real conditions is accompanied by a change in the temperature field of the body over time. A change in the temperature field leads to a change in the heat exchange conditions between the rock mass and the air in the mine. This change in the heat transfer conditions is taken into account by the non-stationary heat transfer coefficient (kT). Thus, the coefficient of non-stationary heat transfer characterizes the amount of heat given by the rock mass (or received by the mass when it is heated) to the air from 1 m2 of the walls of the workings for 1 hour at a temperature difference between the deep uncooled rocks and the
The analytical dependence for the coefficient of nonstationary heat exchange in the criterion form is written as follows
where:
KuT - Kirpichev's kit criterion - dimensionless coefficient of non-stationary heat transfer;
F0 - Fourier criterion-dimensionless time;
Bi - criterion of the boundary conditions of the Bio.
The criteria presented above can be determined based on the following functional dependencies:
where:
a - is the thermal conductivity coefficient of the array, m2/h; X - coefficient of thermal conductivity of the array, kcal/(h*m°C);
kt - coefficient of non-stationary heat transfer between the infinite array and the air, kcal/(hm2°C); t - time of ventilation of the mine, h;
a - coefficient of heat transfer from the walls of the mine (rocks), kcal/(h * m2°C); R0 - is the reduced (equivalent) working radius, defined from the expression:
air of 1 °C.
KuT= f (F0, Bi )
(1)
(2)
(3)
(4)
R = 0,564a/S
где: S - is the cross-sectional area of the output, m2. the heat transfer coefficient is determined by the formula
U 02
a = 2sШ G
0,8
S
(5)
(6)
where:
G - is the mass flow rate of air, kg/s;
8m - coefficient that takes into account the influence of the roughness of the walls of the workings; U - is the perimeter of the mine, m.
To determine the coefficient of non-stationary heat transfer between the air and the rock mass for any time of ventilation of the workings, you can use the criterion nomogram (Fig. 1).
Figure 1 - The dependence of KuT = f(F0, Bi).
The coefficient of non-stationary heat transfer is determined by calculating the Bio (Bi) and Fourier (F0) criteria according to the above formulas, then the Kirpichev non-stationary heat transfer criterion is found on the nomogram, and the heat transfer coefficient is found on it
KuRn
k =
гT 41
я
(7)
In the case of intensive evaporation of moisture from the walls of the mine, the criterion of non-stationary heat transfer of Kirpichev must be determined for the Bio criterion equal to infinity.
Thus, the paper reveals the application of thermophysics in mining and considers the method of finding the criterion of non-stationary heat exchange of Kirpichev, which can be used to determine the heat exchange coefficient. What can be useful for practical skills in calculating a number of engineering problems in the field of thermal physics of mining.
References:
1. Mountain thermophysics [Electronic resource]: textbook / P. Yu. Kuznetsov, Yu. N. Skomoroshko, N. N. Grib. Saratov: Ai Pi Er Media, 2018. 126 p.
© KaHapeHKHH A.H., 2021
