Research into ground water parameters on the territory of high-temperature industrial enterprises Текст научной статьи по специальности «Науки о Земле и смежные экологические науки»

ISSN 2313-2159 (print) ISSN 2409-9864(online)

Dniprop. Univer.bulletin. Geology, geography., 25(2), 151-158.

doi: 10.15421/111731

Stanislav V. Zholudiev Dniprop. Univer. bulletin, Geology, geography., 25(2), 151-158.

Research into ground water parameters on the territory of high-temperature industrial enterprises

S. V. Zholudiev

Dniprovs'k National University named after Oles Honchar, e-mail: [email protected]

Received 09 October 2017 Abstract. One of the problems of hydrogeological research is the lack of study

ReCe'Zd in revisedform 10 November 2017 of the factors of development ™d patterns of mteraction between the mpact

Accepted 20 November 2017 and the intensity of technogenic load sources of different character and

hydrogeological objects, i.e. absence of data on cause-and-effect relationships in the hydrogeological system. This can be related to insufficient initial information on natural conditions and insufficient study of their possible changes in the course of their exploitation.

In the conditions prevailing today conducting continuous study of ground water seepage conditions on the territories of industrial enterprises is practically impossible. The characteristics of the conditions are determined discreetly, with further interpolation, extrapolation and blending, the research is strongly influenced by the experience and intuition of the researchers. Also, insufficient information on technogenic conditions (existing and projected) and their possible changes during operation of industrial enterprises (dynamics of usage of water from water lines, character of changes in the conditions of surface flow, temperature conditions, etc.) adds to the difficulty.

The aim of this study is to determine the peculiarities of using methods of hydrogeological studies on the territories of industrial enterprises and to conduct an approximate calculation of certain hydrodynamic and hydraulic parameters of groundwater using these methods.

Geology • Geography

Dnipro university bulletin

Journal home page: geology-dnu-dp.ua

Keywords: underground water, intermediate rolling coolant, heat, Stephen's task, industrial enterprise .

Дослщження параметр1в пщземних вод на територiях високотемпературних промислових пщприемств

С. В. Жолудев

Днiпровський нацюнальний утверситет шет Олеся Гончара, e-mail: [email protected]

Резюме. До проблем пдрогеолопчних доанджень можна вдаести недостатню вивчетсть фактор1в формування та законмрностей взаемодп численних i рiзних за характером впливу та штенсившстю джерел техногенного навантаження з пдрогеолопчними об'ектами, тобто ввдсутшсть даних про причинно-наандковий взаемозв'язок у пдрогеолопчнш систем^ Ця невизначетсть може бути пов'язана з неповнотою первинно! шформаци вдаосно природних умов та недостатньою вивчешстю !х можливих змш у процеа експлуатаци.

На сучасному рiвнi забудованост територiй досить складно виконати всi традицшш етапи гiдрогеологiчних робгг. Тому необхдао дослiджувати геофiльтрацiйнi процеси навколо територш металургiйних пiдприемств для виявлення можливостi змiн геофiльтрацiйних умов за доанджуваний перiод у за заданих природних i техногенних умовах (юнуючих чи проектних). При цьому визначають межi змiн середтх показниюв об'екта прогнозування. Наразi практично неможливо провести безперервнi дослiдження геофшьтрацшних умов промислових територш. 1х характеристики визначають дискретно, iз подальшою iнтерполяцiею, екстраполящею й усередненням, здiйснення яких суттево залежить вiд досвiду та штущп доандниюв. Крiм того, негативно впливае неповнота iнформацii щодо техногенних умов (юнуючих та проектних) i можливих !х змiн у ходi експлуатаци промислових об'ектв (динамжа втрат iз водних комунiкацiй, характер змiн умов поверхневого стоку, температурних умов тощо).

Мета дослiдження - з'ясувати особливост застосування методiв гiдрогеологiчних дослiджень на територшх промислових пiдприемств i провести приблизний розрахунок деяких гiдродинамiчних та гiдравлiчних параметрiв пiдземних вод за цими методами.

Ключовi слова: тдземт води, промiжний рухомий теплоност,

Introduction. When making a hydraulic forecast, the territory of an industrial enterprise should be considered first of all as a part of open (i.e. with interaction of its separate components) natural-technical system, which consists of two subsystems - the geological environment and the technogenic conditions, which could be divided into the systems of a lower order.

It should be mentioned that because the high density of buildings occupying any industrial site today, it is rather difficult to carry out all the traditional stages of hydrogeological work. Therefore, the research should consider the potential possibility of change in groundwater seepage conditions during the studied period under the given natural and technogenic conditions (existing or projected) by studying the groundwater seepage processes in the territories surrounding the metallurgical enterprise. The process of study includes calculating the boundaries of changes in the given average indicators of the object of forecast.

The existing numerical-analytical and numerical methods are determined; they provide sufficient accuracy of prognoses in the cases with determined groundwater seepage parameters of the environment and hydrodynamic conditions at the borders of water-bearing horizons, and also the functional relation between the forecast values and spatial and time coordinates (E. S. Dzektser, Y. E. Myronov, 1986, Y. A. Rozanov, 1979).

Because in most cases the initial information on natural and technogenic conditions in the studied territories is incomplete, the accuracy of prognoses made using deterministic models decreases. Such peculiarities can be considered using stochastic methods of forecasting, during the consideration of a number of deterministic problems, each corresponding to a certain number of implementations of possible variants (M. V. Bolgov at all, 1998). For considering the stochastic character of hydrogeological studies, stochastic-deterministic models could be used, where boundary conditions and infiltration supply are considered stochastic values or functions.

Materials and methods of study. The main differential equations describe the models of the

теплова енергiя, задача Стефана, промислове тдприемство.

objects of the forecast as a dynamic system with input having processes involving familiar laws of distribution or statistical characteristics. Solving the problem includes determination of characteristics in the output of the studied systems, which are expressed using redistribution of hydrogeological parameters through implementation of theory of stochastic processes or numerical methods, including imitation modeling of boundary conditions and hydrodynamic parameters of groundwater (A. A. Borovkov, 1977, S. M. Yermakov, H. A. Mykhaylov, 1976).

Using such approach allows one to achieve not only engineering-geological and hydrogeological objectives, but also hydraulic, thermodynamic and ecological objectives. Nonetheless, without consideration of thermal factors, it is impossible to arrive at a correct solution. Thus, for metallurgical enterprises, the thermal impact on the geological environment from furnaces and converters equals 2000 - 2200 °С, for machine-building - 400 - 1400 °С, for chemical enterprises the situation is similar. (S. V. Zholudev, 2004, 2008).

Let us consider changes in stressdeformation condition (SDC) of soil structure in case of water filtration in non-isothermal conditions of the territory of an industrial enterprise and estimate its vertical shears.

Field Axis the zone of water-saturated soil, and field A2 is the zone of aeration, the level of groundwater at the depth lx from impermeable horizon (x = 0). Free surface of the level of groundwater (LGW) (x = lx) is considered fixed.

The soil is affected by gravity and in the case of water-saturated soil by Archimedes' principles and filtration force. On the lower surface of the soil at the boundary x = 0, piezometric pressure Hi and temperature T1 were given, and on the free surface of LGW (x = l1) the value of piezometric head H2 was given. The value of temperature T2 is given on the surface of the soil (x = l), and H2 > Hi, T2 > T1. As a result of difference in pressures and temperatures, heat transfer via filtration flow occurs. The filtration of heat is performed according to the laws of Darcy, Fick and Fourier.

* t ,

kt(T), E2 Cli / Hj PrB

k{T), Ei(C), M 7> t Tx 0 H„ T,

Fig. 1. Scheme of soil structure in the conditions of heat transfer during the filtration of groundwater

SDC should be calculated taking into consideration the processes of heat transfer on condition that that there is no shear of lower and upper boundaries of soil or only the lower part of the soil.

The mathematical model of one-dimensional problem of SDC of soil structure in water-saturated and natural conditions has the following expression (I. A. Filatova, 2008, A. P. Vlasyuk, 2000, A. P. Vlasyuk, N. A. Fedorchuk, 2008).

A2ul , du^ „ dTi _ V

aT~X = xi

dx '

dx

( dp

(1)

Ync

i = 2,

Where ui (x) i = 1, 2 - shears in the soil along the OX axis in relation to water-saturated (weighed) (x E (0; l1) i = 1) and natural ((x E (l^ l) i = 2) conditions; Xi - mass forces; T (x, t), i = 1, 2 - temperature in both layers of soil structure, x E (0; l); ywc - specific weight of soil in weighed condition; ync - specific weight of soil in natural condition; p - filtration pressure of water, which is defined by

P = YP"h-x)

(2)

Where h - piezometric head; yp - specific weight of fluid; aT - average coefficient of linear heat distribution in interval of temperatures (T0, T), which is defined by (M. T. Kuzlo, 2006).

aT = = So adT,

(3)

Ml

Where T = T - T0, a = — coefficient of linear expansion; Al — change in linear sizes of the studied sample.

Boundary conditions for shears are the following

Lj Ui (0) = 0, L2 U2 (l) = 0, (4)

Where L\, L2 - differential operators define boundary conditions according to x = 0 and x = l.

Conditions of conjugation on the surface of the level of groundwater for shears

E1(c)

Ui (li) = U2 (li), du. (Ii)

dx

-- aT(Ti -

aT(T2 - T0),

To) = E

(5)

du2(l.)

dx

(6)

Where Ei(c) - elastic modulus (for soil in water-saturated condition), its dependency on concentration of solutions was obtained in [(M. T. Ku-zlo, 2006); E2 - module of deformation of soil in natural condition.

Solving the problem of change of stressdeformation condition of multi-layer soil structure as a result of filtration flow and change of environmental temperature allows one to define vertical shears of surface of soil structure (Table 1, Fig. 2).

Table 1 Vertical deformation of soil massive

Soil conditions X u(x), *10-4

0 0

0,1 -6,64277

0,2 -1,24801

weighed condition 0,3 -1,79217

0,4 -2,03353

0,5 -2,19563

0,6 -2,20619

0,7 -1,97431

0,7 -1,97431

natural condition 0,8 -2,08038

0,9 -2,14395

1 -2,16503

Another important issue is change in properties of groundwater as a fluid affected by thermal processes in the zone of a high-temperature industrial enterprise. The relevance of this research lies

in the clear influence of properties of fluid on all seepage, hydrodynamic and migration processes in underground hydrosphere

X

08 0 7 \ \ V

06

0.5

04 \V "2OO

03

02

0.1 -4-

u(x)

Fig.2. Chart of distribution of vertical shears of soil structure

Dissolved gas and rise in the temperature increase the compressibility of water, though it decreases as the pressure increases.

Density is defined using the following formula

P =

(13)

Where y -mass of a unit of volume of water; g — accelaration of free fall.

The density decreases as the temperature increases and increases as the pressure increases. The change in the density of water depends on the change of its temperature, mineralization and compound of dissolved components. For example, viscosity 6 of fresh and low-mineralized water at 0 °C is 1,78-10"3 Pa s, at 10 °C - 1,3110-3 Pa s, at 20 °C - 10-3 Pas, and at 90 °C - 0,3-10"3 Pas.

In a fluid in a quiescent state, pressure connected to its surface, according to Pascal's law, is

transmitted with no change to all points of fluid volume (Fig. 3).

If additional external forces are absent, hydrostatic pressure p, which is additional to the atmospheric pressure, inside a fluid in a quiescent state at any point of volume is defined only through mass of above located column of fluid with height h8 which in these conditions equals 0.85 MPa.

p = hp = pghv

(14)

Because the temperature around the depth changes, the density of water changes also along the depth and the fluid becomes non-homogenous. In this case, hydrostatic pressure in it is defined as follows

V = g So p"z)dz, Where (z) is a vertical coordinate.

(15)

Fig.3. The scheme of hydrostatic pressure and head (a) and hydrodynamic head (b)

1 - Capillary tube; 2 - measuring tube; 3 - elementary unit A; 4 - Pito' tube; 5, 6 - surfaces (5 - hydrodynamic heads of perfect fluid, 6 - hydrostatic heads of moving viscous fluid)

Based on the distribution of the temperature along the depth under a thermal industrial object (S. V. Zholudev, 2004, 2008) and dependency of density of water on the temperature, we can follow the

change of water state. At the temperature of 374 °C,

water reaches a critical point and transitions into the state of oxygen and hydrogen gases, at further depth density will increase as the temperature decreases (Fig. 4).

Fig.4. Change in groundwater density by depth under the impact of change in temperature from an industrial object Change in hydrostatic pressure at variables of density of fluid looks as follows (Fig.5):

Fig.5. Chart of dependency of hydrostatic pressure on density of water

The net force of hydrostatic pressure pushes out a body placed in water with a force which equals the mass of water in the volume of the body. Water in the capillaries forms concave meniscuses; the difference between pressures lifts the water in a capillary with radius to the height, which equals according to Laplace's formula the point until equilibrium (see Fig. 3, a).

in the capillary as its density decreases, i.e. as the temperature of the geological environment increases.

For non-homogenous fluids in conditions where the density of water changes along the depth of water-bearing horizon, i.e. y = f"z), the head becomes a variable and can be introduced as head pressure Hav

h> = 2aK/pgrK,

(16)

1 2 Hav = — (p + ' Ydz),

Yo Do

(17)

The radius of the capillary of the studied water-bearing horizon - = 6.75 m. The analysis of the results of the calculation according to (16) shows increase in the height of the rise of the water

Where y0 is mass of unit of volume of water on the area of comparison z0 (mass of unit of volume of fresh water may be used); p - layer pressure, measured at the depth z.

Fig.6. Chart of dependency between height of rise of water in capillary and change of water density

A connection between gradient of head and speed and flow rate of a real fluid can be calculated using the hydraulic values of velocity u and discharge QT, which are characterized by striate flow of viscous fluid in a tube of radius R. Velocity u at the distance r from the axis of this tube is described with an equation which shows that velocity in a transversal section of tube changes in accordance with parabolic law (Fig.7) , which in these conditions equals 125.4 cm/hour.

U = Pg^(R2-r2), hi v

UK

PglM2 Hi '

(18) (19)

As a result, the obtained values of velocities of groundwater flow for conditional sandy waterbearing horizon, where values y and I equal rela-

kN

tively 19.7 — and 28 m, and r is 1 - 6 m (fig. 8).

Fig.7. Diagram of velocities uS according to transversal section of tube at viscous flow of fluid

.'el o city of groundwater \ Fig. 8. Velocity of groundwater (u) at the distance (r) from the axis of filtration tube of radius R

Flow rate of fluid QT in tube is defined as volume of solid of revolution, section of which is given in Fig. 7.

rR

QT = 2t Jn urdr =

npgRVl 8i

(20)

The radius of tube (water-bearing horizon) R equals 6.5 m, 6 = 1.5. In this case, the flow rate of liquid QT is 83225,8 m2/hour.

Let us consider that inside the tube of radius R at the distance r from its axis, there is a flow with section x = nr2 and length l. The left part of the equation will be expressed using yAH, and the right part will be expressed through tangent pressures z,

active on the side surface 2Tr, i.e. 2nlrz. As a result

2ulrr 2 lr

yAH = 2U2r = — a6o t = 0,5yrl , (21)

ur2l r

This dependency is known as the Hagen-Poiseuille equation. Average velocity uav is found as a ratio of QT to the area of section of tube t J2

In thin capillaries, water, apart from viscosity, has additional structural density as a result of molecular impact of solid surface. Water is a visco-elastic body with initial shear stress z0 . In this case, it is considered that structural (molecular) bonds at a crossing of rocks are distributed uniformly. For such conditions, the tangent stress according to the law of viscoelastic flow (Bingham-Shvedov law) can be expressed as follows (Fig.9)

UL17

pgR2* 8i

(22)

T = T,

(23)

According to the formula (22), the average velocity is proportional to the square of radius of the tube. It equals 62.7 cm/hour.

Fig.9. Chart of relation of values of tangent stress to the distance from axis of tube

As we see from (23), at z < zn the flow is absent: fluid can move only at the conditionz > zn. The changes of tangent stress t correspond to changes of the physic-mechanical properties of the underlying rocks. If the difference between heads H1 - H2 is added to the ends of capillary of radius R, the net force of hydrostatic pressure equals P = Pg"Hi — H2)tR2. Initial gradient of flow I0, which corresponds to the moment of start of water flow, can be found as follows

I _ dl~d2 = 2r0 = 2r0 (24)

n _ l pgR yR'

The value of I0 for these conditions obtained through the calculations equals 1.5 m.

Conclusions. Analysis of the existing methods and calculation of several significant physical, hydraulic and hydrodynamic parameters of a hydrogeolog-ical environment which was made using these methods, showed that:

- At constant temperature, the change in pressure causes change of initial volume of water according to Hooke's law;

- Presence of dissolved gas and rise in the temperature increase the water density;

- The density decreases as the temperature rises and increases as the pressure rises;

- Change of water viscosity depends on the change of its temperature, mineralization and compound of dissolved components.

We calculated:

- The values of vertical shears of soil structure;

- The change in the density of groundwater in relation to temperature;

- Hydrostatic pressure p inside fluid in a quiescent state at any point of volume;

- Hydrostatic pressure in case of change in temperature of rocks along the depth and viscosity of water at condition of non-homogenous fluid;

- The height of water rise in the capillary according to Laplace's formula;

- The velocity of flow of groundwater u at the distance r from the tube axis;

-average velocity ucp and flow rate QT in the tube according to the Hagen-Poiseuille equation;

- Initial gradient of groundwater flow I0.

Thus, the results of the calculations show the clear influence on hydrogeological conditions of changes in thermal regime of groundwater of

territories adjacent to high-temperature industrial enterprises and prove the necessity of taking into consideration thermal processes during hydrogeo-logical and engineering-geological research.

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