Influence of gas dynamic in intercontact space on migration of gas environment from outside Проблеми трибології (Problems of Tribology) 2015, № 3 113 Kryshtopa L.I., Bogatchuk I.M. Ivano-Frankivs’k National Technical University of Oil and Gas, t. Ivano-Frankivs’k, Ukraine Е-mail: L.I.Kryshtopa@mail.ru INFLUENCE OF GAS DYNAMIC IN INTERCONTACT SPACE ON MIGRATION OF GAS ENVIRONMENT FROM OUTSIDE UDC 621.891 There were showed the necessity of the forced input of gas environment for intercontact space of hard loading fric- tion units of band-block brakes of drilling hoists with surplus pressure which must exceed pressure of gaseous products of destruction of connective asbopolymer materials. System and method of serve of gas environment is developed, for example, exhaust gases of combustion engines on the friction contact with the purpose of increase of liveability of the brake. Keywords: intercontact space, friction contact, surfaces of friction, band-block brakes of drilling hoists, gas dynamic. Entry Laboratory and natural researches [1] showed that on migration of external environment selection of gas on the friction contact influences in intercontact space. Researches on the questions of selection of gas at friction of asbopolymer materials it is conducted ex- tremely small. In work [2] the given question is first affected and influence of gas dynamic is explored on fric- tion widely widespread class of the asbocontaining friction materials ФК-16Л, ФК-24А which are used in band brake winches. At temperatures higher 400 K selection of gas which depends on geometry of contact is marked. Comparison of results of laboratory and natural researches confirms this conformity to the law. At labo- ratory researches on gas dynamic the data got in an interval 370-600 K differ from the results got at natural re- searches. Such distinction can be accounted for to those, that in laboratory terms, measuring of pressures was produced on the capillaries of small section that resulted in falling of pressure on his length, and also difference of the dynamic loadings, affecting the pairs of friction of brake and in the laboratory setting realizing the statisti- cal mode. Raising of problem However, the got results confirm a conclusion that the chemistry physics processes of destruction, re- sulting in the selection of gaseous products, prevail in the process of the FAPM friction. Thus, the selected gaseous products of destruction hinder to the receipt of gas environment from outside in intercontact space. And, consequently, delivery of gas environment from outside can take place only at an ad- sorption effect, when the areas of surface of friction go out from the contact, and a crack effect degenerates here. In a band brake, pumping over is structurally impossible an effect. Thus the superficial and subsuperficial layers FAPM substantially change the properties (density falls to  = 1,6 · 103 kg/m3) and they are composition from an earth-flax, barite and coconut type matter formed at thermo destruction phenolformaldegide resins. Consequently, in the process of friction of asbofriction materials effective influence on the friction pairs of active gas environments is possible at the forced serve of them in intercontact space with pressure exceeding pressure of gaseous products of destruction, so higher Р = 1000 Pa. The forced serve of gas environments in intercontact space allows to render active influence on friction wear properties of friction pairs. The hydraulic calculation of the pneumatic system of serve of exhaust gases was produced coming that from, that exhaust elements represent the mixture of gases, mainly: nitrogen – 77 %; oxygen – 8 %; carbon diox- ide – 12 % and aquatic steam – 3 %. The closeness of mixture of gases is determined by formula:  ii ...01,0 2211 , (1) where, 1 , 2 , 3 – closeness of components; 1 , 2 , 3 – by volume stakes of constituents in percents. Dynamic viscidity of mixture of gases it is determined [4]: i i m          ... 100 2 2 1 1 , (2) where 1 , 2 , i – viscidity of components. mailto:L.I.Kryshtopa@mail.ru Influence of gas dynamic in intercontact space on migration of gas environment from outside Проблеми трибології (Problems of Tribology) 2015, № 3 114 It is set on the basis of laboratory and model researches, that density of mixture of components m = 1,314 · 10 3 kg/m3, viscidity m  1710 · 10 8 kg/m·s and pressure in intercontact space in the period of braking must be no less Pe = 5 kPa. We will define the expense of gas mixture at expiration of it from one opening in a skid [6]: gHFq 200  , (3) where 0F – area of transversal section of the output opening by a diameter d 0 = 0,005 m.   5220 0 1096,14 005,0 4 d F      m2;  – coefficient of expense, attributed to the output opening. At the sharp entrance edges of opening  = 0,82; H – pressure under the centre of gravity of the output opening:    g P H H 2,403 34,181,9 105 3     m. So, it means that 1044,12,40321096,182,0 350 gg  m3/s. General expense of gas on area О – В (fig. 1 ) must be evened: Fig. 1 – Chart of area of the system of admission of exhaust gases: 1 – regulative valve; 2 – skid 05qQ ВО  ; s m Q ВО 3 33 102,71044,15   . For providing of pressure on kPaPe 5 an exit from a regulation valve must be equal: ВОeV PPP  , (4) where ВОP  – losses of pressure at definite area. After valve regulation the gas goes out through twenty two openings in skids. As openings are evenly distributed on the area of gas pipeline so this area we can examine as an area on length l at which is evenly taken away gas by q , where q – specific expense of gas on unit of length of gas pipeline. Analytical expense of gas in any point of gas pipeline can be expressed by linear dependence:  xlqQnx  . (6) Overfall of pressure is determined by formula [6]:       l XB dxxlqDF PP 0 2 1 1 2 1 . 2 , (7) where 1F – area of transversal section of pipeline; 1D – diameter of pipeline; 1 – coefficient of hydraulic resistance, which depends on the mode of flow. Influence of gas dynamic in intercontact space on migration of gas environment from outside Проблеми трибології (Problems of Tribology) 2015, № 3 115 Research results By a criterion determining the mode of flow of gas there is the Reynolds number determined by formula [3]:    11Re D , (8) where 1 – speed of stream. Speed of stream is determined by formula: 2 11 1 4 D Q F Q nn   ,   4,63 012,0 102,74 2 3 1      m/s. (9) Then 48 1085,5101710 314,1012,04,63 Re      . If, 510Re4000  we have the turbulent mode of motion. In this case 41 Re 3164,0  , 0203,0 58500 3164,0 41  . (10) Losses of friction in a pipeline at even gas extraction at turbulent motion of gas is determined by formula: 4 4 57 1 44 70577,0 DF lQ P ВО     , (11) where l – length of pipeline, m . So,     P ВО 3 4 4 5 72 4 84 73 1026,5 012,0 4 012,0 3314,1101710102,70577,0             , Pa. Thus, pressure on an exit from a valve must be: PV 26,1026,55  kPa. We ignore the losses of pressure in a valve and consider that pressure on the entrance in the valve 10,26 kPa. We will consider the area of the system of admission of exhaust gases “exhaust pipe – regulative valve”. Diameter of pipeline is D2 = 25 mm. We consider that the stream of gas is incompressible. Speed of stream will be:   66,14 025,0 102,74 2 3 1      m/s. The Reynolds Number is 4 8 1082,2 101710 314,1025,066,14 Re      . According to the Reynolds Number Re we have a conclusion that the mode of motion of gas is turbu- lent and in case that in the project system of admission of exhaust gases on the average (on operating standards) 6 turns, 2 sudden expansions and narrowing, the losses of pressure on the given area of pipeline are equal:  P 48,323068,068711,026116,02 2 66,14314,1 025,02 66,14314,121 0244,0 22       , kPa. Conclusions Consequently taking into account the losses of pressure on the entrance in the system of admission of gases pressure must be equal to PPP VE 74,1348,326,10  kPa. On the basis of the conducted laboratory and natural researches gas dynamic effects taking place in in- tercontact space of friction pairs of band brakes of boring winches are studied. So, at the modes of hard loading friction units of band-block brakes of drilling hoists work at surplus pressure is created in intercontact space. The analysis of results of researches showed the necessity of the forced input of gas environment for in- tercontact space with surplus pressure which must exceed pressure of gaseous products of destruction of connec- Influence of gas dynamic in intercontact space on migration of gas environment from outside Проблеми трибології (Problems of Tribology) 2015, № 3 116 tive asbopolymer materials. The system and method of serve of gas environment is developed, for example, ex- haust gases of combustion engines on the friction contact with the purpose of increase of liveability of the brake. Literature 1. Криштопа Л.І. Дослідження механізму поступлення газового середовища з зовні у міжконтакт- ний простір поверхонь тертя (частина 1) / Л.І. Криштопа, І.М. Богатчук // Проблеми трибології (Problems of Tribology). – 2014.– № 4 – С. 31-36. 2. Бакли Д. 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Надійшла в редакцію 16.09.2015 Криштопа Л.І., Богатчук І.М. Вплив газодинаміки у міжконтактному просторі на міграцію газового середовища ззовні. Газодинаміка у міжконтактному просторі відіграє важливу роль та, у залежності від видів тертя, механічних та фізико-хімічних властивостей поверхонь тертя, може набувати як додатних, так і від’ємних значень. Надлишковий тиск перешкоджає міграції газу від міжконтактного простору до навколишнього середовища та створює умови для створення областей зі зменшеним коефіцієнтом тертя. На підставі проведених лабораторних і стендових досліджень вивчені газодинамічні ефекти, які мають місце в міжконтактному просторі фрикційних пар стрічково-колодкових гальм бурових лебідок. Встановлено, що за важко- навантажених режимів тертя, за яких працюють гальма бурових установок, в міжконтактному просторі створюється надлишковий тиск. Аналіз результатів досліджень показав необхідність примусового введення газового середовища в міжконтакт- ний простір з надлишковим тиском, який повинен перевищувати тиск газоподібних продуктів деструкції зв'язуючої речовини азбополімерних матеріалів. Розроблена система і методика підведення газового середовища, наприклад, вихлопних газів двигунів внутрішнього згорання, на фрикційний контакт з метою підвищення довговічності гальма. Ключові слова: міжконтактний простір, фрикційний контакт, поверхні тертя, стрічково-колодкове гальмо бу- рової лебідки, газодинаміка.