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Abstract

Table of contents

1. Goals and tasks of the master's work

The purpose of master's work is the study of the stability of ventilation flows during the fires in inclined workings with the descending and ascending ventilation in the mine them E.T. Abakumov. In this work the following tasks are solved:

2. Relevance of the work of

In accordance with the «Rules of safety in coal mines» [1] and the Recommendations on selection of effective mode of airing of mines in case of accidents [2] in the mines of Ukraine in the preparation of emergency response plans should be carried out evaluation of the sustainability of the upward ventilation of mine workings with exogenous fires. This assessment is conducted twice a year in the preparation of the new plan of liquidation of the accident.

Evaluation of the sustainability of ventilation during the fires in inclined workings According to [2, 3] in determining the sustainability of ventilation of mines is calculated values of thermal depression fire and modeling of its actions in the mine ventilation network. Depending on conditions, the thermal depression can be defined in two ways: замерным and settlement. The first method provides the most reliable results. Consider a test method for determining the thermal depression. Sloping or vertical generation, in which there was a fire, may be ventilated descending or ascending airing. If the action of thermal depression is opposite to the direction of depression, which is created by the fan of the main airing, the increasing loss of energy for the movement of air, which leads to an increase in differential pressure between the ends of the emergency generation. In that case, when the thermal depression works in the same direction as the depression of the fan of the main airing, the cost of energy for the movement of the air are reduced, so the pressure difference between the ends of the production is also reduced. To determine the thermal depression, which occurs when the fires in an inclined development of the downward movement of air, it is necessary to make the following measurements: Pressure difference between the ends of the emergency generation (determined with the help микроманометра or devices barometric type; for the laying of rubber tubing use parallel output); Expense of the air in the emergency development, which are measured above the fire. The amount of thermal depression is calculated by the formula:

hт =hа.з - hа.р.,

where hа.з. and hа.р. - depression emergency generation, received, respectively, as a result of measurements and calculations, PA. Study of the stability of airing of mountain developments of mine «им.Е.Т.Абакумова» when the fires in normal and reverse modes of ventilation In this master's work will be conducted sustainability ventilation flows during the fires in inclined workings with the descending and ascending airing. The stability analysis will be conducted with use of the software complex «IRS Ventilation of the mines - ЭПЛА».(Fig.1)

Figure 1-model of a mine in the software complex IRS Ventilation of the mines - ЭПЛА

The first stage of the work includes the creation of a computer model of a mine ventilation network and its testing [5, 6].(Fig.2). The second stage will be devoted to the simulation of the action of the fire in inclined workings and analysis of simulation results. In the framework of the second stage will be carried out the calculation of the thermal depression of fire:

hт =hа.з - hа.р.,

where hа.з. and hа.р. - depression emergency generation, received, respectively, as a result of measurements and calculations, PA. The third stage includes the development of measures to improve the sustainability of ventilation. The studies include the search for the place of installation of ventilation regulators to improve the sustainability of ventilation flows, definition of their aerodynamic resistance and verification of the effectiveness of the proposed activities on the computer model.

Figure 2-Computer model of the mine them E.T. Abakumov

The feature of this work will simulation of fires in inclined workings, using a new method for determining the sustainability of ventilation.

3. Scientific novelty

In this master's work we propose a new methodology to determine the thermal depression fire in inclined mine workings.

Figure 3 Diagram of уклонного field with two sloping mines.

Feature determine the sustainability of the flow of air under the simultaneous action of thermal depression fire in several circuits is that this should take into account the growth of resistance emergency production due to the expansion of the air in the hearth of fire [4]. The resistance of the emergency generating the maximum can be increased three times [7]. In other words, the action of the fire in one circuit reduces the critical depression other circuits with sloping mines. If a fire occurs in division 1-2 (Figure 3), then in addition to the introduction in the generation of thermal depression (- ht1) it is necessary to simultaneously increase the resistance of this branch. In the current methodology of this phenomenon is not taken into account because the stability of the air flow is defined only in one branch-making, and the resistance of emergency generation (plots) does not affect its stability. While simulating the steps of the thermal depression in several areas inclined generation, increasing resistance to the emergency area, the hearth fire, reduces the critical depression all the other branches, which are inclined production. This should take into account that the costs of the air almost no effect on the value of thermal depression fire. Summarizing, we can offer a new scenario determine the sustainability of ventilation inclined workings. It should be used in case, when calculations showed that the existing method of airing inclined workings - airing stable. It is proposed the following sequence of actions:

This option definitions of sustainability ventilation does not take into account the phenomenon of cooling fire gases along emergency generation, but it is quite simple and allows you to separate generation, in which the ventilation will be sustainable in all cases except when, in the hearth of fire had already taken place by the collapse of rocks. If the simulation show that the ventilation is unstable, it is necessary to move to a second stage calculations and take into account the regularities of cooling fire gases along the angular generation. To do this, you need to calculate the maximal temperature of air in the hearth of fire (Tmax) and the temperature in the end of the plot is inclined generation (Тк.о.). In the next section the air temperature at the beginning of the accepted this, which was in the end of the previous section (in the direction of air movement). This assumption it is possible to develop downward ventilation (1-2-3-4), because in every node of the air comes in one branch, and leaves in two branches. For the elaboration of the rising air stream the initial temperature in the branches of the hearth fire should be considered as medium balanced, taking into account all the flows of air, which are connected to the node. Knowing the initial and final temperatures in all areas of the inclined generation, one can calculate the thermal depression fire in each circuit. At the same time the number of existing heat sources need to determine how and when descending aeration, i.e. taking account of the critical length of the cooling fire gases (400m). After that you need to simultaneously enter into a computer model ventilation network all thermal depression (for two adjacent contours), emergency resistance branches of the hearth fire and run the simulation. If the results of the simulation show that the ventilation is not sustainable, it is necessary to develop measures for its improvement.

4. Conclusion

Анимация - Моделирование пожара в горной выработке

Количество повторений - 5, кадров - 7, размер анимации - 84КБ

Красный - аварийная выработка

Желтый - зона распространения пожарных газов до опрокидывания вентиляционной струи

Голубой - зона распространения пожарных газов после опракидывания вентиляционной струи

At the present time in the master's work the method was developed for determining thermal depression fire, developed a computer model of the mine them. Е.Т.Абакумова, prepared a database consisting of graphical and numerical information (introduced 3400 units of information). In the future, studies will be made of the sustainability of airing of mines with the descending and ascending airing in fires, using a new method for determining the thermal depression fire and assessment of the results of modeling.

5. References

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    2. Рекомендації по вибору ефективних режимів провітрювання шахт при аваріях// НДIГРС. — Донецьк. — 1995. — 165 с.
    3. Болбат И.Е., Лебедев В.И., Трофимов В.А. Аварийные вентиляционные режимы в угольных шахтах — М.: Недра, 1992 г.,— 204с.
    4. Осипов С.Н., Жадан В.М. Вентиляция шахт при подземных пожарах. -М.: Недра, 1973
    5. Каледіна І.О., Романченко С.Б., Трофимов В.О. Комп'ютерне моделювання шахтних вентиляційних мереж: Методичні вказівки. — М.: Видавництво МГГУ. 2004 72 с.
    6. Каледіна І.О., Романченко С.Б., Трофімов В.О., Горбатов В.А. Комп'ютерне моделювання задач протиаварійного захисту шахт: Методичні вказівки. — М.: Видавництво МДГУ. 2004 — Частина 1. — 45 с.
    7. Зинченко И.Н., Романченко С.Б., Ревякин А.В. Расчет на IBM PC температуры и депрессии вентиляционной струи при пожарах/ Горноспасательное дело: Cб.науч.тр. / НИИГД. – Донецк, 1986