CC BY
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UDK 622.755
A.A. Abirov, V.S. Molchanov, E.B. Zharkenov, J.M. Omarov, K.B. Suleymenov
efficiency of hydraulic elevators in the process of water treatment
The article presents the results of an experimental research of examining three types of design for hydraulic elevators: co-current, with tangential inlet of passive current and with tangential inlet of both passive and active currents (with twisted active and passive currents). As can be concludedfrom the results turbulent hydraulic elevator can possess much higher ejection coefficient than two other types.
During a mechanical treatment stage on a sewer water treatment facility, nearly 75% of insoluble impurities such as minor mineral impurities, sand, petroleum, oil, etc., can be removed successfully. Sand and various minor mineral impurities are trapped while passing through the sand trap. The main task then is to displace the forming sediment into the sand pad or bunker. This task is accomplished mainly by using hydraulic elevators.
The main parameters characterizing the work of the hydraulic elevator is an ejection coefficient "q" defined as a ratio of passive and active flow rates.
(1)
It is known that ejection coefficient depends on the intensity of transfer of energy from active stream to passive stream. In other words, the more efficiently the surface of the active stream is utilized, the more energy is transferred from the active stream to the passive one, thus increasing the ejection coefficient.
In order to compare functional possibilities, three types of hydraulic elevators were constructed in the laboratory. Distinctive feature of those sets was the way of input of active and passive currents into the mixing chamber.
In the first design set [1,2] active and passive streams are supplied into the receiving chamber co-currently (fig 1). Such co-current scheme of stream supply is used nowadays in various industrial spheres.
In the second design set active stream is supplied into the receiving chamber by means of a direct current flow, while the passive one is supplied with a twist, by means of a tangential inlet (fig. 2) [3].
In the third construction design (fig 3.) both active and passive streams are supplied into the mixing chamber with twisting [4].
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In the first design geometrical parameters of an elevator are used according to the recommendations made [2].
In the 2nd design geometrical configuration is similar to the first, however it has several distinctive structural features. Passive medium flowing through the suction tube d=50mm, goes into the receiving chamber through tangential hole with dimensions am X bm = 100 X 19,6mm that equals the area of a suction nozzle of a first construction. This is achieved with the help of an adapter used to blend the suction pipe and a tangential opening.
Figure 1 - Co-current hydraulic elevator scheme
- J— L 4 > ■ 1 | T ■'-K.-I'.v. ' L-1P > ' _1
t- ■ 1- 1--
s— -U T^-—■ - 1 ' — L j ч
t
—'—i- ——
Figure 2 - Hydraulic elevator with the tangential inlet of a passive medium
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Figure 3 - Turbulent hydraulic elevator scheme
The third design is different from the previous two designs by the way of supply of an active stream into the mixing chamber. Liquid medium is supplied into the discharge pipe of an elevator through the tangential hole. Dimensions of the hole are 15*18mm, and the square of the hole is equal to the cross-sectional area of a pump pressure line.
Coaxility of elements in the construction of hydraulic elevators is strictly controlled. Thus elements are constructed in the way, that you are able to change the distance between the nozzle and the mixing chamber. Discharge tube with the nozzle has a thread and can easily move axially.
Experimental construction of unit can be seen on a figure 4. It consists of 1 - electric motor; 2 - centrifugal pump 3K-6; 3 - pump discharge pipe, made of flexible hose; 4 - hydraulic elevator; 5 - discharge line of elevator; 6 - tank with outlet 7, which is the feeding tank for the suction lines of hydraulic elevator 8 and a pump 9; 10 - damper; 11 - level indicator for water level determination in a water outlet 7 and a free space in a tank6; 12, 13, 14 - valves; 15 - supply line; 16,17,21 - manometers; 18 - support rods with cross-beams; 19 - stand with piezometers.
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Figure 4 - Experimental construction unit
The main goal of an experiment was determination of ejection coefficient q of medium while different distances between the nozzle and the mouth of mixing chamber and the various flow rates. Results of an experiment showed that maximum achievable positive effect of the design with turbulent inlet of active and passive mediums is much higher while comparing with the other two designs.Twisting both passive and active streams has a significant influence on the entry mechanism of suction fluid into the mixing chamber of a hydraulic elevator.The intensity of twisting is characterized by the spin parameter S, which is a dimensionless ratio of an axial movement momentum to the multiplication of an axial component of momentum and the equivalent radius of nozzle. Twisting parameter for the hydraulic elevator is determined using formulas below [5].
— ■
Ф / 2
1 - (Ф flCi / 2)2
Ф / 2
S — pas '
pas
1 - (Ф pas / 2)2
(2)
(3)
where, ®act = ^ and
ф
■ ratio of tangential and axial velocities of the
active and passive streams.
Diagrams that depict the dependence of qe on the distance between the nozzle and the mouth of the mixing chamber are shown below. qB = f(Spas),
qB = f(Sact), <JB = a^nct/5,pnsj- By analyzing curves depicted, it can be noted that the highest value for ejection coefficient of a turbulent hydraulic elevator (g=l,32) is achieved when = 0.1, = 0.22, and S^/S^ = 0.48
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Figure 5 - Dependence of efficiency coefficient on the twisting parameter for the active stream
0.04 0,08 0,12 0.16 0.20 0,24 0,28 s
Figure 6 - Dependence of efficiency coefficient on the twisting parameter for the passive stream
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Figure 7 - Dependence of efficiency coefficient on the twisting param-
ejer S^/S pas
The optimal distance between the nozzle and the mouth of the mixing chamber Al is 30 mm. Figures 8, 9, 10 depict the dependence of the ejection coefficient on the flow rate which is dictated by the Reynolds number R .
Figure 8 - Dependence of ejection coefficient on Reynolds number Re
of anactive stream
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4.0 6,0 8.0 10,0 12,0 14,0 16,0 18,0 20,0 ^xlO4
Figure 9 - Dependence of ejection coefficient on Reynolds number Re
of active stream
a
T
0,4 0,8 1,2 " 1,6 2,0 2,4 2,8 3,2
Rax 10;
Figure 10 - Dependence of ejection coefficient on Reynolds number Re
of active stream
Diagrams above are obtained for different values of Al - the distance between the nozzle and the mixing chamber inlet.
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As can be seen from the diagrams, ejection coefficient q =1,32 of a turbulent hydraulic elevator is much higher than q =1,01 and q =0,95 for
J ° ± max ± max
elevators with tangential inlet of passive medium and elevators with co-current medium inlet respectively. It is clearly seen that for the turbulent hydraulic elevator optimal value for Al is 30 mm.
Figure 11 shows a plot how ejection coefficient depends on a relative discharge rate Qtota/Qp. The diagram clearly shows that ejection coefficient of a turbulent hydraulic elevator exceeds coefficient for elevators with tangential inlet of passive stream and co-current inlet.
Thus, the results of experiments show that due to the liquid particles being absorbed by the boundary layer, the spreading in the mixing chamber will be observed in a co-current suction layer.
0,5 LO 1.5 2.0 2.5 3,0 Figure 11 - Dependence of ejection coefficient on relative flowrate
In a turbulent hydraulic elevator, mutual penetration of spiral-shaped active and passive streams is observed. This takes place between the nozzle and the mixing chamber.
LIST OF REFERENCES 1 Лямаев, Б. Ф. Гидроструйные насосы и установки. - М. : Машиностроение. 1988, 277 с.
2 Соколов, Е. Я., Зингер, Н. М. Струйные аппараты. 2-ое изд. - М. : Энергия, 1970. - 288 с.
3 Струйный насос. Предварительный патент РК №8699, заявка №981073.1 от 23.11.98 / А. А. Абдураманов, И. С. Сейтасанов.
4 Струйный насос. Предварительный патент РК №9752, заявка №990875.1 от 03.08.99 /А. А. Абдураманов, А.А. Абиров
5 Гупта А., Лилли, Д., Сайред, Н. Закрученные потоки. Пер. с англ. - М. : Мир, 1987. - 589 с.
LLP "Kazakhstan Scientific and technical center for HCS development", STE "Ertis". The material received on 21.09.12.
А.А. Абиров, Д.А. Молчанов, Е.Б. Жаркенов, Б.У. Есенов, Ж.М. Омаров, К.Б. Сулейменов
Суды тазалау Yрдiсiнде гидрожетек лифттыц тшмдшт
А.А. Абиров, В.С. Молчанов, Е.Б. Жаркенов, Б.У. Есенов, Ж.М. Омаров, К.Б. Сулейменов
Эффективность гидроприводного лифта в процессе очистки воды
Бершген мацалада швгудщ: турацты пассивтi потоктщ тангенциалды келтiруiмен жэне цуйын тэрiздi ^m^mi жэне m^mmi потоктыц жабылуымен) тасымалдауы кезтде су тазалаудыц технологиялыц процестде цадагаланатын гидроэлеватордыц уш конструкциясыныц эксперименталдыц нэmижесi келmiрiлген. Куйын mэрiздi гидроэлеватор екеун цараганда эжекциясыныц жогаргы коэффициента не екеш кврсетшген.
В данной статье представлены результаты экспериментальных исследований трех конструкций гидроэлгваторов, применяемых в технологических процессах водоочистки при транспортировании осадков: прямоточного, с тангенциальным подводом пассивного потока и вихревого (с закруткой активного и пассивного потоков). Показано, что вихревой гидроэлеватор обладает более высоким коэффициентом эжекции, чем две другие.
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