Arch. Min. Sci., Vol. 55 (2010), No 3, p

Transkrypt

1 Arch. Mn. Sc., Vol. 55 (2010), No 3, p Electronc erson (n color) of ths paper s aalable: MARIAN BRANNY*, JUSTYNA SWOLKIEŃ* USAGE OF FLUENT APPLICATION IN THE PROCESS OF NUMERICAL CALCULATION OF BARIUM SULPHATE DEPOSITS FLOW THROUGH THE JANKOWICE AND PNIOWEK COAL MINES SETTLING TANKS ZASTOSOWANIE PROGRAMU FLUENT W OBLICZENIACH NUMERYCZNYCH PRZEPŁYWU CZĄSTEK SIARCZANU BARU PRZEZ OSADNIKI KWK JANKOWICE I KWK PNIÓWEK The artcle treats about the process of barum sulphate deposts flow through the Janowce and Pnowe coal mnes settlng tans. The reew s manly focused on the descrpton of the numercal smulaton of deposts flow through the determnaton of ther elocty feld and traectory. These calculatons allow to determne the sedmentaton effcency and the tme of partcles descendng n the settlng tans. Ths nowledge s ery mportant due to the Olza nterceptor sewer s protecton. It allows to protect ppelnes from beng oergrown wth barum sulphate sedment whch s mportant due to ther techncal condton. Keywords: Sedmentaton, sedmentaton s effcency, deposton of barum sulphate, numercal calculaton W artyule podęto próbę opsana procesu przepływu cząste sarczanu baru przez osadn dwóch opalń należących do Jastrzębse Spół Węglowe S.A., a manowce KWK Janowce KWK Pnówe. Obe opalne odprowadzaą slne zaneczyszczone wody opalnane do rze Odry za pośrednctwem systemu retencyno-dozuącego Olza. Charater chemczny wód obu opalń ścśle zależy od warunów hydrogeologcznego uształtowana terenu połudnowo-zachodne częśc Górnośląsego Zagłęba Węglowego. Odprowadzane za pośrednctwem oletora wód o odmennym sładze chemcznym est główną przyczyną wytrącana sę w ego rurocągach osadów stałych, co powodue ch zarastane, zwęszene zużyca energ na przepompowywane wody, a w onsewenc oneczność przeprowadzana osztownych remontów. Na przestrzen lat opracowano szereg metod pozwalaących na zmneszene lośc onów baru onów sarczanowych w samych opalnach, czyl u źródła. W przypadu wymenonych opalń metoda ta * AGH UNIVERSITY OF SCIENCE AND TECHNOLOGY, FACULTY OF MINING AND GEOENGINEERING, AL. MICKIE- WICZA 30, CRACOV, POLAND, emal: branny@ahg.edu.pl; swolen@agh.edu.pl

2 502 opera sę o proces sedymentac sarczanu baru w osadnach przyopalnanych. Suteczność stosowane metody est wysoa, ale aby ne dopuścć do przedostawana sę do rurocągów oletora nestrąconych onów baru onów sarczanowych, oneczne est poznane przebegu procesu sedymentac sarczanu baru, a równeż ego efetywnośc. Przedmotem ponższego artyułu est próba opsana przebegu zawsa sedymentac wytworzonego osadu sarczanu baru w osadnach wymenonych opalń, przy wyorzystanu metod symulac numeryczne ego przepływu. Symulace trówymarowego (3D) przepływu cząste stałych przez osadn opalń Janowce Pnówe wyonano w oparcu o model Eulera-Lagrange a załadaąc, że przepływ est dwufazowy. Fazę cągłą stanow woda zaś fazę rozproszoną cząst stałe o rożnych średncach. Oblczena wyonano z wyorzystanem programu FLUENT 6.1. Wyznaczene pól prędośc traetor cząste sarczanu baru, przedstawonych na rysunach 1,2,3,4,5, pozwolło w przyblżenu oreślć efetywność ch sedymentac (tab. 2) w zależnośc od przyęte do oblczeń średncy oraz czas ch opadana (przebywana cząste stałych w osadnu). Do oblczeń przyęto oba zborn wymenonych opalń, gdyż zasadncze różnce w ch geometr (tab. 1) sprawaą, ż przebeg procesu w ażdym z nch est neco nny. Namnesza efetywność, a tym samym nadłuższy czas opadana występue przy średncy m. W przypadu osadna Janowce średncy cząste sarczanu baru m efetywność sedymentac wynos 62,5%. Neco nższą efetywność otrzymano dla osadna opaln Pnówe. W obu omawanych przypadach wraz ze wzrostem średncy cząste sraca sę czas ch opadana ednocześne wzrasta efetywność sedymentac. Efetywność wynoszącą 100% uzysano w przypadu osadna opaln Pnówe przy średncy zaren m, podczas gdy dla osadna opaln Janowce pratyczne tą samą efetywność uzysue sę uż przy średncy cząste wynoszące m. Różnce w efetywnoścach czasach opadana zależą od geometr zborna, usytuowana mesc dopływu odpływu (zaslana odboru wody), obętoścowego natężena przepływaące wody, a taże przyęte do oblczeń wartośc średncy zaren. Warantowe oblczena przepływu przez osadn zawesny o rożnym strumenu masowym pozwalaą zobrazować przebeg zawsa sedymentac, a wedza ta pozwala ocenć a długo należy przetrzymywać wodę w osadnach wspomnanych opalń, by zapobec przedostanu sę nestrąconych onów baru sarczanowych do rurocągów oletora Olza. Ma to olbrzyme znaczene eonomczne, gdyż bra osadów w rurocągach zmnesza energochłonność systemu, a taże wpływa orzystne na ch stan technczny. Słowa luczowe: sedymentaca, efetywność sedymentac, osadzane sę sarczanu baru w osadnach, symulaca numeryczna 1. Introducton Janowce and Pnowe coal mnes transport ther mne waters through the Olza retanng-dose system. The Waters chemcal character of both mnes strongly depends on the hydrologcal lay of land of the south-western part of Upper Slesa. The dfferent chemcal character of transported waters s a man reason for precptaton of sold sedments n the nterceptor-sewer s ppe-lnes. Ths leads to ther oergrowng wth sedment, ncreasng of water pumpng energy and, n the end, necessty of oerhaul repars. Through the years, n certan mnes specal water cleansng methods were ntroduced. They were focused on remong barum and suphate ons and most of them were hghly effecte (Pluta et al., 2006; Pluta & Potrows, 2000, 2002; Pluta & Szczepańsa, 2002; Badurs et al., 2001; Orzechows et al., 1997). As an eample, Janowce mne, through the medum of one bg settlng tan, drans off ts waters wth ncreased concentraton of barum ons, and also waters of ncreased concentraton of sulphate ons comng from Chwalowce coal mne. The same stuaton s beng proceeded n one of the settlng tans of Pnowe coal mne. Ths settler drans off waters of ncreased concentraton of barum ons from Krupns coal mne and waters of ncreased concentraton of sulphate ons from Koscelno Dumpng Ground. In both cases the process of precptaton of barum sulphate s beng proceed at the source, that s n the settlng tans. In order to preent penetratng the remanng barum

3 503 sulphate nto the ppe-lnes t s necessary to get to now the process of ts sedmentaton and effcency. The man reason for ths artcle was to descrbe the process of barum sulphate sedmentaton n both settlng tans mentoned aboe, usng the numercal smulaton method of ts flow. Calculatons were proceeded on both settlers, snce the geometrcal dfferences n ther structure cause the sedmentaton to proceed a lttle bt dfferent n each of them. 2. Computatonal modelng of multphase flows The flow of the suspenson through the settlng tan mght be charactersed as a two-phase flow, n whch the water s a contnuous phase. The second phase conssts of sphercal mneral or chemcal partcles (barum sulphate) dspersed n the contnuous phase. Two-phase flows mght be descrbed usng the same conseraton of mass, energy and momentum as n the one-phase flows. Ths descrpton s much more complcated, what s the consequence of huge dfferences between these flows. The basc meanng has not only occurrng the eternal nteractons from rgd walls and washed bodes on the flud, but also nternal nteractons on the surface of phase separaton. The last ones are arable both n place and tme. Dffcultes wth solng theoretcal models account for startng pont of worng out many methods based on sem-emprcal equatons descrbng partcular two-phase flows cases (Wacław, 1993; Bemonows et al., 1995; Fluent 6.1). Currently n the computatonal flud mechancs there are two approaches for the numercal calculaton of multphase flows: the Euler-Lagrange approach and the Euler-Euler approach (Fluent 6.1). In the frst approach the flud phase s treated as a contnuum by solng the tmeaeraged Naer-Stoes equatons, whle the dspersed phase s soled by tracng a large number of partcles through the calculated flow feld. The dspersed phase can echange momentum, mass and energy wth the flud phase. A fundamental assumpton made n ths model s that the dspersed second phase occupes a low olume fracton, een though hgh mass loadng s acceptable. The partcle traectores are computed nddually at specfed nterals durng the flud phase calculaton. The smulaton of three-dmensonal sold partcles flow through the Janowce and Pnowe settlng tans was made based on Euler-Lagrange approach, assumng the two-phase flow, wth water as a flud phase and sold partcles as a dspersed one. Calculatons were made based on FLUENT Descrpton of Eulera-Lagrange approach The foundaton of descrpton of flud phase moement s a set of equatons based on conseraton of mass and momentum. When the statonary ncompressble flud flow s beng consdered these equatons are presented as follows: contnuum equaton: 0 (1)

4 504 equaton of moton: p ( ) F, (2) t where: center s lnear elocty feld, [m/s], t tme, [s], ρ center s local densty, [g/m 3 ], F local not fluctuatng body force, [N/m 3 ], p local pressure, [Pa], τ local stress deformaton tensor (deator), [Pa], Cartesan component, [m],, = 1,2,3 alues of nde ascrbed to certan spatal arables. In case of Newtonan ncompressble flud, deator s components are presented wth an equaton (3):, (3) Introducng the defnton (3) to equaton of moton (2) and ts transformaton leads to Naer-Stoes equatons. In case of turbulent flow the Reynolds theorem s beng used. Substtutng equaton (3) for (2), ntroducng pro elocty and pressure ther medum and fluctuatng alues and carng out mathematcal transformatons we get the equaton called Reynolds equaton (4). There s an addtonal stress tensor whch s not present durng lamnar flows (5). t ( ) 1 p F ' ' (4) ( ) ' ' (5) Turbulent stress tensor, called Reynolds stress, present n the turbulent flow, causes the set of equatons not to be closed due to the lac of s completng relatons descrbng tensor s components (5). It s necessary to form supplementary equatons, what n the flud modellng termnology s called closng hypothess. One of the frst hypotheses, whch ntroduced the turbulent scosty coeffcent, was proposed by Bousnesqa (1887) (Hnze, 1987). Ths coeffcent was defned based on the stress tensor (5) through the analogy to the Newtonan formula, descrbng stresses n the shear flud. Turbulent scosty s not a physcal flud s feature and therefore t has no clear physcal sense. It s a property arsng durng turbulent flows and dependng on the turbulent ntensty n a specfc elocty feld pont (elocty component s fluctuaton module per ts mean alue). Brngng n some smplfcatons, turbulent scosty creates the scalar feld n the flow area. In realty, t creates second row tensor feld (Tu et al., 2008). Brngng n ths magntude to the Reynolds equatons allows to close the set of equatons descrbng certan flow.

5 Lst of dfferental equatons used n the turbulent model Prandtl mng length model (1925) was the frst turbulent model to use concept of the turbulent scosty (Hnze, 1987). Models whch use ths concept, Reynolds stress tensor s components (5) are presented throughout the components of the mean moement s elocty deformaton tensor (6). T 3 2 ' ' (6) where:, ' as follows: -drecton mean and fluctuatng elocty ector s component, δ Kronecer delta functon, υ T turbulent scosty coeffcent, turbulence netc energy. For the wde rage of researches most practcal flow calculatons soled by CFD (Computatonal Flud Dynamcs) were based on the two-equatons -ε model (turbulence netc energy and ts dsspaton rate) (Fluent 6.1; Hnze, 1987). Turbulent scosty was calculated ether from the algebrac relatons or turbulent netc energy transport equaton (one-equaton model) and addtonal dfferental equaton (two-equaton model). The turbulent scosty n two-equaton -ε model s computed by relaton (7): 2 C T (7) where: C µ constant, ε dsspaton of turbulence netc energy. The turbulence netc energy,, and ts rate of dsspaton, ε, are obtaned from the followng transport equatons (8) and (9) (Tu et al., 2008): T ' ' ) ( (8) C C T ' ' ' ( ) (9) where: C 1, C 2, δ ε, δ constans. Tang nto account flud ncompressblty, equatons (6) to (9) account for closed set of equatons.

6 506 There are a few modfcatons of standard -ε model nown and t s usually hard to choose the one whch reflects the real flow parameters the best. In ths specfc case the RNG model (Renormalzaton Group) was chosen, especally because ts recommendaton for the low- Reynolds number flows (Fluent 6.1). That nd of low Reynolds number ranges hae to be taen nto consderaton n these cases. The man dfference between the RNG and standard -ε models les n the addtonal term n the transport equatons for the dsspaton rate of turbulence netc energy, gen by: R 3 C (10) where: S Effecte Prandtl number s computed usng the formula (11) ef (11) where: µ, µ ef dynamc scosty accordngly lamnar and effecte, α ners effecte Prandtl number, α 0 constant. Ecept for solng transport equatons for contnuous phase, ths model requres computng the traectores of the dspersed phase enttes. It s done by ntegratng the force balance on the partcle, whch s wrtten n a Lagrangan reference frame. Ths force balance equates the partcle nerta wth forces actng on the partcle, and can be wrtten (12): d dt p g ( p ) FD ( p) (12) p The frst term on the rght - sde hand s the drag force per unt partcle mass, and F D s: FD where: p -drecton partcle elocty component, -drecton flud phase elocty component, g -drecton gratatonal acceleraton component, ρ p, ρ p accordngly: partcle and flud denstes, µ dynamc scosty, d p partcle dameter. 18 CD Re 2 (13) d 24 p p

7 507 The drag coeffcent, C D, whch s the functon of the relate Reynolds number defned as: dp p Re (14) For sub-mcron partcles, wth dameter lower then m, F D s defned as (15): FD 18 2 (15) d C Where C e s the Cunnngham correcton to Stoes drag law. In the FLUENT the fnte dfference method s used to resole equaton (12), and the traectory of a certan partcles are computed tang nto consderaton equaton (16) p p e d p (16) dt 5. Boundary condtons For the contnuous phase (water) followng condtons were made: boundary condtons of the frst nd were made n the nflow caty n the form of constant flowng n elocty to water area. Turbulence netc energy and rate of ts dsspaton were computed prodng 5% of turbulence ntensty on the nlet, the constant alue of statc pressure n the et secton and, for the other arables, zero alue of gradent n the drecton of flow were assumed, so called pressure condtons, nonsd flow on the rgd walls and classcal wall functon model on the boundary areas were assumed, free surface was modeled assumng zero alues of shear stresses. Boundary condtons for the dspersed phase are brought n to set the place where the sold partcles are released and to defne condtons of ther collson a the wall. There were two types of boundary condtons for the dscrete phase assumed: partcle s beng reflected a collson wth the wall. Ths condton s beng determned through the amount of momentum lost a collson and was used for the sde walls of the settlng tans, partcle after reachng the edge dsappears (t s stopped or t flows out of the area). Its traectory calculatons are beng stopped. Ths condton was set for the bottom surface of settlng tans and n the nlet and et secton cates.

8 Three dmensonal numercal calculatons of two-phase flow through the settlng tans and ther analyss Numercal partcles flow calculatons were made for two geometrcally dfferent settlng tans. The water from Janowce and Chwałowce coal mne s draned off to Janowce settlng tan. The stuaton s almost the same n the Pnowe settlng tan, whch adopts water from Krupns coal mne and Koscelno Dampng Ground. The characterzaton of the settlers was presented n the table 1. Characterzaton of settlng tans TABLE 1 Name Dmensons [m] Flow [m 3 /24 h] Janowce settlng tan Pnówe settlng tan , Descrpton Not structural numercal net wth oer nots Settler n the shape of cubod. Structural numercal net wth around nots Numercal calculatons were proceeded assumng homogenous dluted suspenson flow through the settlers. Monodspersed, sub-mcron barum sulphate partcles are of sphercal shape wth dameter of m and densty of 4500 g/m 3 (Lebeca, 1994). The sedmentaton process s of contnuous character whch means that dfferent concentraton of partcles wthn the settlers s seen. The flow s stable and three dmensonal. Volume and mass flu on the nlet and outlet s equal (tab. 1). It means that mass of the settlng partcles due to the nlet and outlet mass flu balances s neglgble. The numercal calculatons brought the three-dmensonal (3D) elocty, pressure, turbulence netc energy and ts dsspaton rate felds for the contnuous phase. Moreoer, the traectores of the dscrete phase (barum sulphate) were calculated. It all allowed to defne the sedmentaton effcency as a rato of the number of partcles settled on the bottom of the settler per total number of released partcles. Solutons ndependency of the numercal net densty was checed out through ts densfcaton. In the fgures 1, 2, 3, 4 and 5 stream lnes comng out from the surface of nlet, elocty felds n the plane of water table and path lnes of barum sulphate deposts of dfferent dameter were presented. In both cases barum sulphate s released from the pont of nlet streams mng. In the Pnowe settler ths pont s about 8-10 m away from the nlet, whch was presented n the fgure 3a. Addtonally n the table 2 the lst of partcles dameter dependency of sedmentaton effcency was presented. There are dfferences between stream lnes and elocty felds presented n the fgures 1, 3a and b. It results from dfferent settlers shape and nlet and et cates poston. Stll, n both settlers there are two zones wth recrculaton flow to be mared out. The dfference s both n range and ntensty of flow. Fgures and data (tab. 2) analyss llustrate the sedmentaton effcency dependency of the partcle dameter. The lowest effcency, and the longest descendng tme s characterstc for the

9 509 a) b) Fg. 1. a) Stream lnes comng out from the surface of nlet of Janowce settler b) Velocty feld plane of water table n the Janowce settler dameter of m. Ths dameter n the Janowce settler allows to attan effcency of the magntude of 62,5%. A lttle bt lower effcency was reached n the Pnowe settler. It s mportant to remember that Janowce settler has a much bgger surface and olume flues on the nlets. The colour scale presented n the fgures 2, 4a, b and 5 corresponds to the tme of partcles abdng n the settler. Accordng to the boundary condtons the partcle ether settles on the bottom or flows out through the et caty. The abdng tme s a functon of many arables, among whch geometry of the settler, mass flu of the flowng suspenson as well as physcal features

10 510 a) b) Fg. 2. Path lnes of barum sulphate deposts (ρ = 4500 g/m 3 ) released from the pont of nlet streams mng n Janowce settler a) dameter d = m, b) dameter d = m of partcles themseles, hae an essental meanng. Knowledge of partcles abdng tme mght be useful durng the settlers modernzaton. Not only does t concern the optmzaton of the settlers shape and arrangng nlet and et cates but also desgnng new obects. In both cases, along wth ncreasng partcles dameter, sedmentaton effcency s ncreasng whereas descendng tme s decreasng. 100% effcency was acheed n Pnowe settler at m dameter, whereas n the Janowce settler practcally the same effcency was acheed already at m dameter.

11 511 a) b) Fg. 3. a) Stream lnes comng out from the surface of nlet of Pnowe settler b) Velocty feld plane of water table n the Pnowe settler TABLE 2 Lst of dameters and effcency of sedmentaton n settlng tans Name dameter effcency dameter effcency dameter effcency [m] [%] [m] [%] [m] [%] Janowce settlng tan , Pnówe settlng tan , , Dffcultes wth clear specfcaton of the barum sulphate partcles dameter reflect on the apprasng ther free descendng elocty and n the end on the sedmentaton effcency. Pnpontng the real partcles dameter s qute dffcult and lterature data publcze only ts range (Machere, 2006). Accordng to those data, contnuous steerng would allow to obtan crystals of dameter around 6 µm to 8 µm, whereas, ntense, mechanc steerng crystals of dameter

12 512 a) b) Fg. 4. Path lnes of barum sulphate deposts (ρ = 4500 g/m 3 ) released from the pont of nlet streams mng n Pnowe settler a) dameter d = m, b) dameter d = m around 3 µm to 1 µm. It s qute mportant to now that barum sulphate has an ablty to occlude, adsorb and create mng crystals, what all the more, obstructs settng ts dameter. Analyss of numercal calculatons data (tab. 2) and assumpton of the most probable barum sulphate partcles dameter (Lebeca, 1994), around m, would brng us to the statement, that durng the water flow regulaton t s necessary to lengthen the contact tme of the chemcally dfferent waters. It would surely hae a large effect on the protecton of the nterceptor-sewer s ppe-lnes from beng oergrown wth barum sulphate sedment. Ths specfc partcles dameter allows to gan, n the Pnowe coal mne, sedmentaton effcency around 84,4%.

13 513 Fg. 5. Path lnes of barum sulphate deposts (ρ = 4500 g/m 3 ) released from the pont of nlet streams mng n Pnowe settler, dameter d = m 7. Test of the Eulera-Lagrange approach s erfcaton The erfcaton of the appled two-phase flow model was based on the classcal method of apprsng free sold partcle s descendng elocty n the lqud. Ths elocty s a result of the force of graty, lft force, and the drag center force acton: where: d partcle s dameter, [m], ρ c and ρ accordngly: partcle and lqud denstes, [g/m 3 ], λ(re) ppe frcton factor. 4d( c ) g c (17) 3(Re) Ppe frcton factor s beng determned through Stoes, Allen and Newtonan equatons. Classcal Hazen s sedmentaton theorem concerns free descendng partcles n the oblong settler, and t s based on (Machere, 2006) an assumpton of non-agglomeratng, sphercal partcles descendng wth constant elocty. Water nflow and outflow s beng proceeded throughout the entre cross-secton of the settler (deal settler). The flow s stable, and the elocty feld s homogenous. Partcles whch hae descended on the bottom are not rased agan. Sedmentaton effcency s pnponted wth Hazen number as follows: tp E 100 (18) t c

14 514 where: t p theoretcal water flow through the settler, t c partcles descendng tme from water surface on the bottom of the settler. Verfcaton of Euler-Lagrange approach was made for the oblong settler of 30 m long and 2 m hgh (2D-two dmensonal). Fulfllng the lmtaton accepted by Hazen forced certan assumptons to be adopted whle descrbng boundary condtons. On the sde of nlet, along the edge, the constant water nflow elocty was assumed (0,002 m/s). On the upper and lower edge (water table and the bottom of the settler) zero alue of shear stresses were assumed. Ths assumpton (the edge of the bottom) s non-physcal, but allows to obtan requested elocty feld. Settng up so called pressures condtons on the outlet s analogcal as n the boundary condtons. The elocty feld of the contnuous phase (water), obtaned durng the smulaton, s humongous. It means that elocty layout n the cross sectons along the settler s dentcal (fg. 6). The traectores of partcles were computed assumng that they had been realsed from equally dstant ponts, placed along the nflow edge. Partcles whch traectores ended on the bottom of the settler were treated as anshng ones. Fg. 6. Image of water elocty feld n the deal settler (usng stream lnes) Calculatons data carred out for sphercal partcles wth densty of 1800 g/m 3 and dameter of m to m were presented n the table 3. Free partcles descendng eloctes calculated from the equaton (17) were placed n the second column and the response Hazen s sedmentaton effcences (18) were placed n the fourth column. Data of the sedmentaton effcences for the deal settler, fulfllng Hazen s assumptons, but calculated through the E-L approach, were presented n the ffth column. Moreoer, calculatons for the model of the settler more smlar to the real obect than the mentoned aboe, but stll 2D, were made. Keepng the geometrc dmenson of the settler and the flowng water olume flu not changed, water nflow and outflow s beng proceeded through the cates 0,05 m hgh, placed under the water table. The dentcal boundary condtons for the nlet (elocty of 0,08 m/s), outlet and water table were made. Durng the descrpton of the boundary condton on the bottom edge (the settler s bottom), the classc wall functon model was used. The mage of water elocty was presented n the fgure 7. Calculated sedmentaton effcences for the partcles released from the edge of the nlet caty were presented n the sth column of the table 3. The mamum error made n the calculated sedmentaton effcences alues s about 9% and t refers to the partcles of the lowest dameter. It s worth to notce that for ths dameter Reynolds number reaches the alue around the lower boundary of the Stoes formula aldty (Orzechows et al., 1997). In other cases ths error does not eceed 4%. Despte the mportant dfferences n the eloctes feld mages, computed through CDF smulaton, n the frst eample elocty feld s homogeneous (fg. 6), and n the second one (fg. 7) almost 1/3 of ts length s noled wth recrculaton flow. In both cases the sedmentaton process, on account of ts effcency, s beng proceeded smlarly.

15 515 It mght be conceded that on the account of ths one parameter (sedmentaton effcency) calculatons of the two-phase flow made by the Euler-Lagrange approach reflect the real flow. It s necessary to remember that the proceeded erfcaton s fragmentary and t does not prode for seres of parameters of great mportance, as for eample elocty feld erfcaton. Lst of calculatons results of Euler-Lagrange approach s erfcaton TABLE 3 Depost s dameter [m] Velocty of depost s free descendng [m/s] Reynolds number Effcency of sedmentaton accordng to Hazen [%] Effcency of sedmentaton n the deal settler [%] Effcency of sedmentaton n the oblong settler 2D [%] Fg. 7. Image of water elocty feld n the oblong settler wth dmensons of 30 m 2 m 8. Concluson Numercal smulaton of the sold partcles flow (barum sulphate) proceeded n ths artcle throughout Fluent 6.1, was the way of descrbng the sedmentaton process. Usage of the twophase model flow throughout the calculatons of the elocty feld and traectory of barum sulphate partcles, allowed to pnpont the sedmentaton effcency and the partcles descendng tme (tme of partcles beng n the settler). The calculated sedmentaton effcency for the partcles of m dameter for the Janwce settler was 99% and for Pnowe 84%. The Dfferences n the sedmentaton effcency and descendng tme depend on the settler geometry, nlet and outlet placng (water nflow and outflow), flowng water olume flu and n the end on partcles dameter. Numercal calculatons of the dfferent mass flu suspenson flow through the settler allow to demonstrate the process of sedmentaton. Ths nowledge s ery mportant due to the Olza nterceptor sewer s protecton. It has a great economc alue because the lac of sedments n the ppe-lnes decreases power-consumng and s benefcal for ther techncal condton. Ths paper was carred out as a part of Scentfc Research (AGH) nr fnanced from the means of Mnstry of Scence and Hgher Educaton

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