Abstract
on theme of master's work

TABLE OF CONTENTS

Introduction

1.The state of the question

2.The topicality of the issue

3.Tasks and goals

4.Current result

The summary results and key findings

References

Introduction

At all mining enterprises drainage installation is one of the most responsible and energy-intensive units, requiring careful and timely services as normal and uninterrupted operation of mine water ensures the normal operation of other stationary companies and eliminates accidental flooding of mine workings, ensuring normal working conditions.

Field water production of existing drainage, taking into account projected construction and dewatering systems group covers the range of the closed mines (100 ... 2500) m. 3/chas for water lifting heights from 200 to 1600 m. More than 50% of the units operated in the range of tributaries (100 ... 300 ) m3 / h and water lifting height (100 ... 700) m. At the overwhelming majority of the drainage study use pumping units with a power consumption not exceeding 800 kW. But in recent years have seen a steady significant increase in unit capacity pump units up to 1600 kW. Total power drives of pump units at these installations may reach causeway (8000 ... 10000) kW.

Figure 1 - Scheme of pump-type CMP.

Currently, as a means of dewatering in the mining industrysion used multiple pumps, centrifugal types of CNS and NSSH. The manufacturers guarantee reliable operation of pumps at the mine water, which contains suspended solids of less than 0.1 mm. Work on the mine water containing solid particles larger than 0.1 mm leads to a rapid exit from pump failure, due to the fact that the ingress of solid particles in the suction line, they cause abrasive wear and fracture of elements of the flow part, the impeller and gap seals.

Figure 2 - Pump type PSM.

Standages of operating pumping options of mines are, as a rule, a network of the horizontal mountain making executed with a small slope toward a receiving well. In the complex of pumping standages are used for the accumulation of mine waters, with the purpose of indemnification of difference of inflow and serve of pumps, and similarly for their lighting up by defending. Loss of solids from mine water leads to the fact that decreases the amount of usable water collectors and there is a need for frequent pump start up, which in turn entails the active wear of pumping units for start-up mode. In addition, there is a drift accumulations of solid particles from the water tanks into the receiving wells. This does not exclude the possibility of overlapping holes of suction devices and increase the likelihood of pump cavitation regimes.

1. The state of the question

Great contribution to the development of schemes and funds mine water have A. Herman, M. Fedorov, V. Pak, V. Geyer, A. Dokukin, G. Yelanchyk, V. Popov, N. Logvinov, V. Rough, V. Pak, P. Belikov, N. Bogomolov, G. Timoshenko, M. Ripp, N. Burr, A. Kaplyuhin, N. Ofengen den, A. Dawn, V. Mazurenko, G. Nechushkin, E. Volovik, O. Adam, N. Palamarchuk, E. Antonov, I. Kurenkov, M. Rabinowitz, Y. Timo-hin, V. Fadin, V. Maleev, V. Yakovlev, E. Danilov, S. Malygin, and V. Romanov, and many other professionals Donetsk National Technical University, NIIGM them. M. Fedorov, Tula Polytechnic Institute, Moscow State Mining University, Dnipropetrovsk National Mining University, "Yuzhgiproshaht "," Dongiproshaht "," Dongiprouglemash", DonUGI, "Dneprogidroshaht", Yasnogorsk corn plant, IHM them. Skochinskogo, as well as many other scientists and engineers of the near and far abroad. Performing the work of professionals and organizations dedicated to solving some specific areas of mine water in Ukraine and abroad, have identified a total system approach to addressing cleaning dewatering tanks from deposited sludge. On this basis, a number of original technological circuits and means of disposal of sludge from the water catchment tanks; hydroelevating drainage installation. (Figure 3)

Figure 3 - Scheme of hydraulic elevator,
where 1 - a mixing chamber and 2 - slurry pipeline.

However, despite the large number of works devoted to the choice and design of schemes and funds lighten mine water from the solids in underground conditions, we can not mention them fragmented and incomplete in principle. In our view, insufficient attention was paid to improve the efficiency of hydraulic means for removing solid particles from the places of their accumulation in the cells of mine water. In the literature, there are no data on the studies of the hydraulic elevator without the diffuser in the vacuum mode.

2. The topicality of the issue

The main task of the diffuser, as one of the constituent elements of the hydraulic elevator - is the transformation of the velocity head at the outlet of the mixing chamber to a static pressure required for transporting liquid over long distances. But in mine water or mineral processing plants, where there is a need for systematic cleaning, reception of sludge, You can restrict ourselves to lift sludge from the tank and its subsequent refinement. In such cases, the question arises of whether to use the diffuser as an element of the flow part. Its absence greatly simplifies the design. In addition, when operating hydraulic elevator without the diffuser is possible to reduce the consumption of the working of water.

As a result, the design of technological schemes and means of dewatering plants continue, mainly dominated by outdated methods and approaches that do not allow you to create systems that meet modern requirements for drainage facilities. Therefore, all the above determines the urgency of working towards a solution to this problem, the essence of which is to justify the choice of schemes and lighten mine water from the solids and the rational parameters of cleaning agents, dewatering tanks from deposited sludge, the realization of experiments, processing and interpretation of their results.

3.Tasks and goals

The aim is to enhance the efficiency of the mine water, reducing energy consumption and reducing the proportion of manual labor in his service on the basis set of rational parameters of the mine's pumping installation with hydrodynamic cleaning dewatering tanks of sludge deposited in them.

To achieve this objective in the work necessary to solve the following problem:

1.Teoreticheskie study hydraulic elevator without diffuser: a geometric model of the flow of hydraulic elevator and the similarity criteria, the dimensionless characteristic equation, and analysis of the cavitation characteristics of water jet vacuum pump.

2.Eksperimentalnye study hydraulic elevator without diffuser: experimental design, analyzed hydraulic elevator and the experimental setup.

3.Poluchenie curves to determine optimal geometric and operational parameters of hydraulic elevator without the diffuser, which operate in the vacuum mode.

4.Ekonomichesky effect of the application of the developed sump setup.

4.Current results

The geometric model of the flow hydraulic elevator and the similarity criteria.

Modeling and the use of similarity criteria that take into account the ratio of the quantities characterizing the operating conditions and geometric dimensions of the model and nature, will expand the boundaries of the use of experimental data to calculate the natural samples and simplify the calculation.

To conduct research form part of running a closed type hydraulic elevator designed to be carried out in the literature recommendations /1, 2, 3, 4/. Adopted simple to make, but very efficient conical nozzle 4 with a cylindrical section at the end of a length equal to a quarter of the diameter (Figure 4). To cap this form of speed ratio is equal to the flow due to the lack of compression of the jet at the exit. In the mine water working and transported water contains abrasive solid material, so the thickness of the edges on the cut nozzle must be at least three to four millimeters, and slice nozzle is offset from the beginning of the mixing chamber. According to the recommendations in the literature, the distance from the outlet nozzle prior to the mixing chamber taken to be(1,2-2,0) d_н.

Figure 4– Scheme of hydraulic elevator without diffuser.
(animation: size – 21,6 КB; shots quantity – 5;
number of repetition cycles – 5)

In the investigated hydraulic elevator adopted cylindrical shape of the mixing chamber 5. Inlet flow of transported fluid to the mixing chamber is carried out in confused channels 3, which houses the nozzle. The lowest coefficient of resistance has confuser with cone angle is equal to forty or fifty degrees /5, 6/. When performing the outer surface of nozzle with the same angles, transported stream moving with constant acceleration, which helps equalize the velocity diagrams of the channel cross section and increases the efficiency of hydraulic elevator at the expense of reducing the difference between the rates of labor and transported in liquid when they met at the entrance to the mixing chamber.

Cross-sectional area receiving chamber 2 and nozzle 1 for supplying a working water to the nozzle is recommended to perform such that the fluid velocity in these sections in conditions close to the optimum, were roughly the same and equal to one and a half to two meters per second.

Form the basis of modeling the similarity criteria are determined either from the condition of the identity of the equations describing the processes, or from the dimensional analysis. The high degree of turbulence and uncertainty of the effect of individual elements of the flow part and the uncertainty of the effect of individual elements of the flow path at this stage of our knowledge do not represent an opportunity to describe the process in a hydraulic elevator differential equation. Therefore, the definition of similarity be based on the theory of dimension.

Relationship between the independent parameters characterizing the operating conditions and geometric dimensions of the hydraulic elevator, expressed in general functional equation:

(1)

Where P₂-full, taking into account the hydrodynamic pressure generated by hydro elevator;

u₁, u₂-speed, respectively, the working flow and transported to the entrance to the mixing chamber;

?_н, ?_к- cross-sectional area nozzle and the chamber;

?-viscosity of the fluid and transported;

?- density of liquids.

(1) is written for the case when the working fluid and transported have the same density and viscosity on the basis of published data on the effect of each of the parameters on the energy transfer process in a hydraulic elevator.

In the analysis assumes first and foremost, compliance with the geometric similarity model and nature. Therefore, in equation (1) does not contain parameters that express the geometric similarity - namely, the ratio of areas of sections of the mixing chamber and nozzle, the relative length of the mixing chamber and its relative roughness.

Expressing the geometric similarity parameter is the distance from the edge nozzle prior to the mixing chamber. Adopted in the optimal model, according to the literature, the value of this distance can be assumed that the mixing process flow begins in the mixing chamber.

Independent variables take for the analysis of the conditions of inequality, determinant of the matrix consisting of their dimensions. In our case, we assume.

u₁(l¹ m ⁰ t ^-1),?_н(l² m ⁰ t ⁰), ?(l^-3 m ¹ t ⁰)

Determinant of the matrix:

Determining the second ? - theorem dimensionless complexes, we write the criterial equation of:

(2)

The first dimensionless complex is a criterion of Euler that expresses the similarity of hydrodynamic processes. Velocity jet of working fluid is determined by the known dependence of the hydraulic:

(3)

Where- the speed factor;

?_н- the drag coefficient of nozzle;

P₁- complete with a view of the hydrodynamic, the pressure in the flow of hydraulic fluid to the nozzle;

P_к- pressure in the flow at the inlet into a mixing chamber.

Using equation (3) and expressing the pressure before nozzle through a full head of working fluid flow in this section, and the pressure through the hydraulic elevator full of pressure, reported by the flow of transported fluid, we obtain:

(4)

Where H₁ - full pressure of working fluid flow to the nozzle;

H₂- total head, reported by a hydraulic elevator transported fluid flow;

- oefficient of pressure hydraulic elevator;

- the relative pressure at the beginning of the mixing chamber.

The complex , which is the ratio of the areas of sections of the mixing chamber and nozzle, is the basic condition of geometrical similarity of hydraulic elevator. From the literature it is known that the ratio of areas of sections of the mixing chamber and nozzle has a decisive influence on the characteristics of the hydraulic elevator. Most authors refer to this option module and represent - m. That is usually the camera and nozzles have a circular cross section. In this case, the complex can be represented as:

(5)

Где d_к - the diameter of the mixing chamber;

d_н- diameter of the nozzle.

Dimensionless complex is an expression of the kinetic similarity to the entrance to the mixing chamber. The rate ratio of the working and transported flows defines the process of mixing in the chamber. This criterion can be expressed in terms of the parameters that characterize the operating mode and the geometric size of the hydraulic elevator:

(6)

Where Q₂ - supply hydraulic elevator;

Q₁ -expense of the working of water;

- delivery rate hydraulic elevator.

Presented in this form, the criterion has a definite physical meaning - it is a delivery rate per unit area (the ratio of annular transported inlet flow into a mixing chamber to the nozzle cross-sectional area). Denote the criterion -

With a round cross-section nozzle parameter can be written as , where ?- the kinematic viscosity of the liquid.

In this representation, the complex is the Reynolds number and expresses the similarity of hydrodynamic fluid flow at the exit nozzle. The published data on the effect of this criterion on the characteristics of hydraulic elevator contradictory.

Criterion equation takes the form of:

(7)

Using the property of dimensionless complexes (the possibility of multiplication, division, exponentiation), one can obtain a sufficiently large number of them. In our case, interest is the product of the first and second dimensionless complexes . According to L. Berman, for optimal operating conditions the product of the coefficient of hydraulic elevator pressure on the modulus is unity. Complex shows that the pressure of hydraulic elevator as many times smaller than the head before the nozzle, how much cross-sectional area greater than the mixing chamber section nozzle. Denote the complexes and solve the criterion equation with respect to it:

(8)

For such processes must comply with:, , .

Establish a link between the obtained dimensionless complexes, as well as to determine the number of criteria to achieve the similarity, we can experimentally.

The summary results and key findings

To research the geometric shape of the flow hydraulic elevator without diffuser made in view of the operating conditions for excavating and dewatering of the recommendations in the literature. The analysis of dimensions derived similarity criteria and criterion equation workflow to waterjet vacuum pump. To establish a functional relationship derived criteria, as well as the number of criteria to achieve the similarity, it is necessary to conduct experimental research hydraulic elevator without the diffuser.

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