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Section 10. Technical sciences
Рисунок 1. - Технологическая схема процесса очистки кобальтсодержащих сточных вод 1 — накопительная емкость, 2 — реактор, 3 — электролизер, 4 — ленточный фильтр, 5 — ионообменник
Список литературы:
1. Багровская Н. А., Никифорова Т. Е., Рожкова О. В. и др. патент № 2121008 «Способ извлечения цинка и кадмия из водных растворов электролита» от 27.10. 1998 г.
2. Виноградов С. С.«Экологически безопасное гальваническое производство» под ред. В. Н. Кудрявцева. -Изд. 2-е, перераб. И доп. «Глобус». М., 2002. - 352 с.
3. Родионов, А. И. Технологические процессы экологической безопасности [Текст]: учеб./А. И. Родионов, В. Н. Клушин, В. Г. Систер. - Калуга: Изд. Бочкаревой, 2000. - 800 с.
4. Ямпольский, А. М. Гальванические покрытия [Текст]: учеб./А. М. Ямпольский. - Л.: Машиностроение, 1978. -168 с.
5. Ямпольский, А. М. Краткий справочник гальванотехника [Текст]: справ./А. М. Ямпольский, В. А. Ильин. -3-е изд., перераб. и доп.. - Л.: Машиностроение, 1981. - 270 с.
6. Гальванические покрытия в машиностроении [Текст]: справочник: в 2 т./под ред. М. А. Шлугера. - М.: Машиностроение. Т. 1. - 1985. - 240 с.
7. Вишенков, С. А. Химические и электротермохимические способы осаждения металлопокрытий [Текст]: учеб./С. А. Вишенков. - М.: Машиностроение, 1975. - 312 с.
Provatar Alexey Gennadievich Russia, Astrakhan, Chief of “navigation faculty ", "chief of the practice and assistance to employment of graduates organization center" Caspian institute of sea and river transport FSFEI HE "VSUWT" branch.
E-mail: [email protected]
Additive technologies in engine-building
Abstract: Additive technologies (AF — Additive Manufacturing), or technologies of layer-by-layer synthesis is one of the most dynamically developing directions of “digital" production. The principle is that the product is created by means of layer-by-layer addition of material in various ways, for example, building up or evaporating of metal powder, liquid polymer, composite material. This concept is necessary to add the traditional methods of production based on removal of primary material (for example: milling, turning, planning, grinding). Piston engines are one of most constructionally and technologically difficult complexes. The elements of these complexes forming the power cylinder capacity are cylinder bushing, cylinder heads. Pistons work in the extreme conditions which don’t have analogs in other mechanisms. The cylinder bushing and cylinder head are the characteristic elements of the engine which should have the demanded properties on various surfaces for providing the declared functional characteristics of the mechanism, and such properties are to be given by means of AF technologies.
Key words: Additive technologies, 3D printing technologies, AF technologies, the cylinder bushing, centrifugal molding, cast iron, foundry steel, heat insulators, running-in antifriction coatings, cylinder heads.
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Additive technologies in engine-building
Introduction. Additive technologies are the technological concepts, actively developed from the second half of the XX century. Additivity (from Latin additivus — added) is the type of the relations between something whole and its parts, when properties of the whole are completely defined by properties of parts. Additive technology (AF — Additive Manufacturing), or layer-by-layer synthesis technology, is one of the most dynamically developing direction of “digital” production [1, 2]. The principle is that the product is created by means of layer-by-layer addition of material in various ways, for example, building up or evaporating of metal powder, liquid polymer, composite material. This concept is aimed to the addition of traditional production methods, based on removal ofprimary material (milling, turning, drilling, planning, grinding).
In domestic technological science the principles of an additivizm began to develop in the 80s of the last century. However at that time it was supposed to create machines entirely (by methods of layer-by-layer synthesis), for example piston engines [3, 4]. It appeared that at the technological level of that time and nowadays, and in the short term, realization of the similar concept is premature if at all possible and expedient. Additive technology, in its modern representation, is the SLA technology (from English-Stereolithography Apparatus),
or stereolithograph. In AF technologies various metal-powder compositions on the basis of nickel, cobalt, aluminum and the titan at “cultivation” of threedimensional models are widely used. Work pieces of compression moulds and original details of a difficult configuration which are difficult for receiving by means of molding or machining “are grown up” from metal powders. For small-scale and experimental production it often becomes to be economically advantageous “to print” a small lot of parts on 3D-printer than to produce foundry or die tooling. Besides, the 3D printing technologies allow to reduce a technological chain considerably, reveal all errors of the project at an early stage and get a full-fledged prototype of a product for carrying out of tests and research works [5]. Now the main direction in machine-building AF technologies is the development of one of the most important stages of production — work preparation of work-pieces manufacture (production of foundry and die tooling, foundry models, tools). However, more attention starts to be paid to creation of separate car elements, having non-uniform functional properties diversely or on various surfaces and it becomes an important and actual scientific and technical task which is resolved by methods of additive technologies.
Application of AF technologies.
Figure 1. Position of the cylinder bushing in the block 1 — basic boutique; 2 — cylinder bushing; 3 — block of cylinders; 4 — ring fillers; 5 — heat-absorbing surface; 6 — heat-release surface
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Section 10. Technical sciences
Conventional engine is one ofthe most widespread and thus structurally and technologically difficult mechanisms. The elements of these mechanisms forming the volume of the working cylinder are cylinder bushings, cylinder heads, pistons-work in the extreme conditions which don’t have analogs in other mechanisms. Their work depends on many factors: materials, sizes of details, temperatures and pressure ofa working body, conditions ofa heat transfer and heat exchange and some others. Such variety of the factors effecting on characteristics of engine cooperation creates certain difficulties in identification of the most important ones which action is most effectively shown in these or those conditions.
Cylinder bushing is a specific element of the engine which, for providing of the declared functional mechanism characteristics, has to have the demanded properties on various surfaces. The scheme of position of the cylinder bushing installed in an engine block case is given in fig. 1.
The demanded physicomechanical properties of surfaces of the cylinder plug are the following:
a) the surface 5, is a directing one for the movement of the piston and it is subjected to intensive friction and wear. It also takes up high pressure and temperature of a working body (gas) and, therefore, has to have small frictional coefficient, high wear resistance (and consequently — hardness), durability and thermal stability;
b) the surface 6 is intensively washed by the cooling system heat carrier (water or special liquids) for providing the heat sink, but thus a frequent factor is formation of the corrosion destruction centers; and the bushing vibration, owing to recurrence of working
process and relaying of the piston, promotes formation of cavitation damage centers, first of all in places of an exit to a surface of nonmetallic inclusions (graphite, at production of the plug from cast iron) [6];
c) the body of the cylinder bushing 2 provides a heat transmission from gas and friction forces to the refrigerant agent and the bushing body has to have considerable thermal resistance to a heat transfer for the purpose of increase of intra cylinder process power efficiency.
The most widespread constructional materials for cylinder bushings of high-speed and medium-speed diesels are gray cast irons of the SCh 21 ^ SCh 32 brands (SSS 4832-95) or cast irons ofspecial chemistry modified by nickel, chrome, tungsten. And, if the listed iron carbon alloys generally meet the requirements of point a), in this case they are suited to the points b) and c) a little. For point b) steel, mainly foundry, can suit well and such principle of production of bimetallic cylinder bushings, developed in Murmansk state technical university together with the Ukrainian colleagues, is known [7]. But point c remains. Heat conduction coefficient of steel and cast iron are close to 50 W/(m deg.) so under the terms of a heat transfer the iron-steel wall of the cylinder bushing has no advantages before the iron one. So here it is that a wall of the cylinder bushing should be multilayered: an external layer is from steel, an intermediate layer is from heat insulator and an inside layer is from modified or bearing cast iron. In this case the scheme of cylinder bushing production by method of centrifugal molding will have a form, fig. 2. At first in a mold 1, an internal surface of which is covered with fire-resistant structure, steel of the chosen brand is filled in.
Fig. 2. Scheme of bushing work piece centrifugal molding 1 — mold; 2 — casting; 3 — supporting structure; 4 — mechanical transmission; 5 — electric drive motor; 6 — trough
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Additive technologies in engine-building
After the beginning of crystallization the heat insulator 2 with a layer about 0,3 ^ 0,4 mm, for example zirconium dioxide — ZrO2 is applied on an internal surface (heat-conduction coefficient 2 ^ 3 W/m deg.). Heat insulator can be applied by means of laser (SLA technology), plasma coating or a bulk way. The following stage: at sufficient temperature of steel crystallization, cast iron of the accepted brand and thickness of a layer, which isn’t exceeding necessary and sufficient allowance for the subsequent operations mechanical, the thermal and finishing machining, is filled in a mold.
Increase of the overall thermal resistance of a cylinder bushing wall to a heat transmission to the cooling system will lead to increase of a temperature pressure (a difference of temperatures between heat-absorbing and heat-release bushing walls) at the expense of increase in temperature of the heat-absorbing wall at permanent temperature of the heat-release wall. We will consider structure of internal engine heat balance,
Qv = Or + Qg + Q Q
where Qav — available heat which is equivalent to the heat added to the cylinder with fuel; Q. — indicated heat which is equivalent to indicated work of gases in the cylinder; Qg — heat which is cleared away from the cylinder with the discharge gases; Q — heat which is cleared away to the cooling system; Q—heat, generally lost because of incompleteness of fuel combustion.
The increase in temperature of heat-absorbing wall at the increased temperature pressure is possible only at the expense of increase in temperature of gas in the cylinder. The increase in gas temperature leads to increase of its heat content (enthalpy) that raises gas working capacity due to pressure buildup in the cylinder. Therefore the increase in indicated work and, as a result, increase in indicated efficiency, П = Qi/Qav, takes place. The increase in indicated efficiency causes increase of effective efficiency at the permanent level of engine intrinsic losses. The balance remains constant due to decrease of heat losses in the cylinder because of degree reduction of fuel combustion incompleteness. It is a consequence of intra cylinder process temperature increase. It is a positive effect of the proposed constructional solutions and their additive technological realization.
Here it should be noted that the last stage of this AF technology is an application of a running-in antifrictional composite polymer-graphite-metal covering (for example: ftoroplast-graphite-copper-tin) also by means of a laser or plasma dusting. This layer is necessary for the correct position of piston rings during
the period of breaking-in (80-100 hours) then it is worn, but its particles remain in blanket micro hollows. The conducted researches [8] showed efficiency of this approach for providing of the demanded functional engine characteristics.
By means of AF technologies other elements of engines, such as cylinder heads, which under the terms of operation also should have different physicomechanical and thermo-physical properties on surfaces — durability, heat resistance, rigidity on the fire bottom, can be made (cast iron and steel). It is necessary in connection with the increased level of ICE speeding up on the average effective pressure, when, for supplying ofgas j oint density, at the socket “block case — cylinder head”, absence of fire bottom deformations is required. Head body isn’t subject to influence of pressure forces and high temperature of a working body. Therefore as material of the body it is desirable to have such material which can be casted in metal forms (with in-house system of wire-sand cores) at the maximum approximation ingoing size to the sizes of a ready detail, and, perhaps, with absence of necessity of tooling on some surfaces. Thus material of the head body has to be well processed on all other surfaces (for example — aluminum alloys). Besides such combination of materials will allow to improve heat removal from the fire bottom, from multiperforated injecting nozzles as well, which are subject to nozzle hole coking at excessive admissible temperatures. Such constructional variants of cylinder heads were successfully approved several times [9; 10].
Conclusion. Having analyzed the directions of modern additive technologies we came to a conclusion that:
— layer-by-layer production of difficult constructional elements at a stage of technological preparation of production (foundry models, prototypes of die and foundry tooling, models of the difficult combined tools) is rather well mastered, considerably reduces time of preproduction and restrains its temper only because of high cost of the demanded equipment;
— transition to layer-by-layer formation of finished products due to necessity of giving to them various physicomechanical or heat-transfer properties in different directions or on different surfaces. It depends on a functional purpose of a product and becomes an important and actual scientific-and-technological task which decision will fully promote increasing of a technological level and competitiveness of domestic motor power.
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References:
1. Bayeva L. S., Marinin A. A. Modern technologies of additive production of objects//Vestnik of MSTU, volume 17, No. 1, 2014. P. 7-12.
2. Additive technologies - website: konstruktor.net/.. ./additivnye-te • • • hlennosti.html
3. Scientific bases of progressive technology/G. I. Marchuk, A.Yu. Ishlinsky, P. I. Fedoseyev, etc. - M.: Mechanical engineering, 1982. - 376 p.
4. Scientific bases ofprogressive equipment and technology/V. S. Avduyevsky, A.Yu. Ishlinsky, I. F. Obraztsov, etc. -M.: Mechanical engineering, 1985. - 376 p.
5. Zlenko M. A., Popovich A. A., Mutylina I. N. Additive technologies in the mechanical engineering/Tutorial. - St. Petersburg, St.Petersburg State University, 2013. - 221 p.
6. Abacharayev M. M. Cavitation and protection of metals against cavitational destructions. S-Pb, Publishing house
S-PBPU, 2012. - 198 p.
7. Bimetallic cylinder bushings. Website - www.ideasandmoney.ru/Ntrr/Details/117390
8. Dorokhov A. F., Sanayev N. K., Masuyev M. A. Power loss enhancement on friction forces overcoming in ship high-speed diesels/Friction and greasing in machines and mechanisms. No. 9, 2008. P. 18-21.
9. Dorokhov A. F., Bochkaryov V. N., Kryzhanovsky K. F. Analysis of technological effectiveness of different constructional variants of small-sized diesel cylinder head. From col. “Combustion-type engine”. Issue 4. N 13. M.: BCSRITEITyazhmash, 1983. P. 5-8.
10. Dorokhov A. F., Shakhov V. V., Dorokhov P. A. Application of bimetallic and multilayered designs in structure of conventional engine/Technologies of repair works, reconstruction and hardening of car details, mechanisms, equipment, tool and production tooling from nano- to macrolevel. In 2 p. P.1. Materials of the 13 th International scientific and practical conference (12-15.04.2011). - SPb.: Publishing house of Polytechnic University, 2011-482 p. P. 337-344.
Rudnev Sergey Georgievitch, Kuban State Agrarian University, postgraduate student, the Faculty of Mechanization E-mail: [email protected]
Options of discrete capacity in postharvest technology of cereals
Abstract: questions of the movement of grain material in various parts of discrete capacity are considered. The design is also presented and calculation of its outlet is made. Its durability and rigidity is checked.
Keywords: seeds, discrete capacity, grain mix, motion, properties, shutter.
Руднев Сергей Георгиевич, Кубанский государственный аграрный университет, аспирант, факультет механизации E-mail: [email protected]
Параметры дискретной емкости в технологии послеуборочной обработки зерновых культур
Аннотация: рассматриваются вопросы движения зернового материала в различных частях дискретной емкости. Также представлена конструкция и произведен расчет ее выпускного отверстия. Проверена его прочность и жесткость.
Ключевые слова: семена, дискретная емкость, зерновая смесь, движение, свойства, затвор.
Существующие способы уборки зерновых коло- их машинно-технологические комплексы перемеща-
совых и зернобобовых культур, а также реализующие ют урожай зерна в емкостях различной конструкции
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