I-capillarity kanye nokungangeneki kwenhlabathi

Ukukhuphuka kwamanzi ngama-capillary

Ukuvela kwekapilari

Uma sifaka ishubhu lengilazi elincane esitsheni esinamanzi athule, angenawo ukugeleza, amanzi aseshubhini azokhuphuka afinyelele ukuphakama hk ngaphezu kwezinga N esitsheni, kanti indawo yamanzi eshubhini izokwakha i-meniscus m (umz. 1_a_). Uma ishubhu liba mncane kakhulu, ukuphakama kokukhuphuka kwe-capillary kwamanzi hk kuba kukhulu kakhulu.

Ukukhuphuka kwamanzi nge-capillary kubangelwa amandla aphakamisayo e-meniscus m, futhi kuchazwa ngamandla okuheha phakathi kwamangqamuzana amanzi nengilazi kanye nengcindezi engaphezulu phakathi kwezindonga zepayipi elincane kanye nobuso bamanzi.

Ekuhlanganyeleni phakathi kodonga lwepayipi lengilazi nobuso bamanzi kunomthelela wamandla e-capillary R ohlangothini lwe-tangent ebusweni be-meniscus m, ovezwa ngesilinganiso sesisindo ngeyunithi yobude, ku-p/cm. Ngokuhlukanisa amandla R abe yingxenye J ehambisana nobuso bodonga kanye nengxenye P eqondile odongeni, sithola amandla okuphakamisa e-meniscus (sl. 1_a_):  J = R cosα.

I-engeli α eyenziwa amandla R nobuso bodonga ibizwa ngokuthi i-engeli ye-capillarity futhi inani layo lisukela ku 0 kuye ku 90O. Uma amanzi epayipini le-capillary nezindonga zawo kuhlanzeke ngokuphelele, khona-ke α=0, ubuso be-meniscus buyisiyingi esiyingxenye, amandla okuphakamisa J = R makhulu kakhulu (sl. 1_b_). Uma amanzi equkethe amafutha noma ama-asidi e-organic noma uma izindonga zinamafutha, khona-ke α = 90°, akukho ukwakheka kwe-meniscus, ngakho akukho nokukhuphuka kwamanzi nge-capillary.

Umfanekiso 1. Ukukhuphuka kwamanzi nge-capillary kanye nomthelela wamandla e-capillary

Amandla okuphakamisa J = R cos α siwathola kusimo sokulinganisela, ngokusho kwaso amandla aphelele okuphakamisa J kuwo wonke umjikelezo we-meniscus, okungukuthi wepayipi le-capillary elinobubanzi r, abamba ikholomu yamanzi epayipini enobude h__ₖ:

R cos α · 2π_r_ = π_r_² h__ₖ γ__w

lapho γ__w kuyisisindo somthamo wamanzi.

Kusukela esilinganisweni esingenhla sithola amandla e-capillary okuphakamisa:

R cos α = (r · h__ₖ · γ__w) / 2

okungukuthi ukuphakama kokukhuphuka kwe-capillary:

h__ₖ = (2_R_) / (r · γ__w) · cos α  [cm].

Amanzi ashisayo e-capillary akhuphuka epayipini le-capillary aye phezulu kakhulu kunamanzi abandayo ngenxa yokuba ne-viscosity enkulu. Ngakho-ke, ukuze kutholwe ukuphakama okufanayo kokukhuphuka kwe-capillary h__ₖ, amandla R cos α mancane emanzini ashisayo e-capillary kunasemanzini abandayo. Ngokwezivivinyo ezenziwe emazingeni okushisa ahlukahlukene amanzi t ngaphansi kwezimo ezifanayo zonke, kutholwe lawa manani alandelayo wamandla okuphakamisa R cos α:

Amanzi epayipini le-capillary adonselwa ukungezwani, ngoba amandla R cos α ayawaphakamisa phezulu, kanti amandla adonsela phansi ayawahudulela phansi. Nokho izindonga zepayipi le-capillary zicindezelekile ngaphansi kwesenzo samandla e-capillary R.

Ukukhuphuka kwamanzi emhlabathini

I-capillarity ikhona nasezweni, lapho amapayipi e-capillary akha izimbotshana, ezixhumene komunye nomunye kuzo zonke izinkomba. Uma inhlabathi ingenamazimbotshana amancane kakhulu, izimbotshana ziba zincane kakhulu futhi ukuphakama kokukhuphuka kwe-capillary kuba kukhulu. Lokhu kuphakama kuncike futhi esakhiweni senhlabathi. Nokho, izimbotshana emhlabathini zingaba ngosayizi abahlukene futhi kulowo mzila ukuphakama kokukhuphuka kwe-capillary nako kuhlukile. Uma amanzi e-capillary ngesikhathi ekhuphuka efika “ezindaweni ezibanzi”, okungukuthi, embotsheni enkulu kunaleyo ehambisana namandla okuphakamisa ububanzi bembobo emincane ekuphakameni okufinyelelwe, khona-ke ukuqhubeka kokukhuphuka kwe-capillary kuncike kusayizi waleyo mbobo enkulu. Kulokhu sinokuphakama kokukhuphuka kwe-capillary okusebenzayo h__ₖₐ okuncike ezikhaleni ezinkulu kakhulu. Ngokuphambene nalokho, lapho ngesikhathi sehla kwezinga lamanzi angaphansi komhlaba amanzi e-capillary ehla esuka phezulu aye phansi ehlangana “nezindawo ezincane”, azohlala kulokho kujula futhi ngeke ehle ngokuqhubekayo. Kulowo mzila sinokuphakama kwe-capillary okungasebenzi h__ₖₚ, okuncike ezimbotsheni ezincane kakhulu.

Ngokwendawo enemigodi nokwakheka komhlabathi kuhlukaniswa amanzi e-capillary avaliwe kanye avulekile.

Amanzi e-capillary avaliwe axhumene nesibuko samanzi angaphansi komhlaba futhi ngesikhathi sokukhuphuka aphushula umoya ophambi kwawo aye endaweni ephezulu yomhlabathi. Ngenxa yalokho, inani lomoya endaweni ephezulu liyanda, ngaleyo ndlela nengcindezi yomoya, emigodini yaleyo ndawo. Ingcindezi yomoya eyakheka kanjalo iphikisana nokukhuphuka kwe-capillary, ngakho ukuphakama kokukhuphuka kwe-capillary kuba kuncane. Lesi simo senzeka ezingqimbeni eziphansi zomhlaba, ngqo ngenhla kwezinga lamanzi angaphansi komhlaba, lapho izimbobo zincane futhi ngesikhathi sokukhuphuka kwe-capillary amanzi agcwalisa ngokuphelele zonke izimbobo.

Amanzi ekapilari avulekile nawo ahlobene nezinga lamanzi angaphansi komhlaba, kodwa atholakala eduze kwezimbotshana ezigcwele umoya. Lesi simo sivela engxenyeni engenhla yenhlabathi lapho izimbotshana zinosayizi abahlukene khona, ukuze amanzi agcwalise ngokuphelele kuphela izimbotshana ezincane, kanti ezimbotsheni ezinkulu eziseduze kukhona umoya. Ngesikhathi sokukhuphuka kwekapilari, amanzi aphusha umoya aphume ezimbotsheni ezincane aye kwezinye ezinkulu eziseduze, ukuze endaweni engenhla ngaphezu kwekholomu yamanzi ekapilarini kungakhiwa umfutho womoya, ngakho amanzi ekapilari avulekile enyuka abe phezulu kakhulu kunawavaliwe.

Indawo lapho kukhona khona amanzi e-capillary avaliwe noma avulekile inqunywa ngokusekelwe enanini lamanzi w emhlabathini.

Uma kunamanzi e-capillary avaliwe wonke ama-pores agcwele amanzi, okusho ukuthi inani lamanzi enhlabathini w = wZ, okungukuthi izinga lokugcwala S__ᵣ = 1,0.

Kumanzi we-capillary avulekile, ama-pores amancane agcwele ngokuphelele amanzi, kanti ama-pores amakhulu agcwele amanzi ngokwengxenye, okuwufilimu wamanzi ogubuzela izinhlayiya eziqinile kanye namanzi asezingeli (sl. 2) ezindaweni zokuxhumana phakathi kwezinhlayiya eziqinile, kanti ingxenye esele igcwele umoya, ngakho-ke kuleli cala w < wZ, okungukuthi S__ᵣ < 1,0.

Ukuphakama kokukhuphuka kwe-capillary h__ₖ ezinhlotsheni ezihlukene zomhlabathi kunqunywa ngokuhlolwa kwelabhorethri. Ukuphakama okumaphakathi h__ₖ kwezinhlobo ezihlukene zomhlabathi kusezingxenyeni ezilandelayo:

Sl. 2. Ifilimu lamanzi nendawo yamanzi eseceleni

Enhlabathini amandla e-capillary R asebenza ngokucindezela izinhlayiya eziqinile ngendlela yokuthi phakathi kwazo kwakheke lokho okubizwa ngokuthi ukubambisana okubonakalayo, okusebenza njengohlobo oluthile lokunamathelana phakathi kwezinhlayiya eziqinile. Nokho, ukubambisana okubonakalayo kukhona kuphela inqobo nje uma kukhona ukukhuphuka kwamanzi nge-capillary emifantwini yenhlabathi. Ngokucwilisa inhlabathi emanzini, ama-pores agcwala amanzi futhi ukubambisana okubonakalayo kuyeka ukuba khona.

Ngo-cohesion ebonakalayo kuchazwa umbono wokuthi isihlabathi esincane, esisesimweni esomile sikhululekile, esimweni esimanzi sithola ukubambeka okuthile ukuze sikwazi ukubunjwa, into engenzeki ngesihlabathi esomile.

Kuyaziwa ukuthi isihlabathi (uma singeyona udaka noma uthuli) emabhishi olwandle, uma simanziswe amagagasi, sinamandla okuthwala umthwalo amahle kangaka, kangangokuthi kungagitshezwa ibhayisikili noma imoto phezu kwaso, kuyilapho kancane kude, lapho amagagasi engafiki khona, leso sihlabathi esifanayo sisesimweni esomile futhi amasondo acwila kuso, ngaleyo ndlela noma yiluphi uhambo lungenzeki.

UKUDLULISEKA

Ukugeleza kwamanzi ngokusebenzisa inqwaba evumela ukudlula

Ake sibheke izitsha ezixhunyiwe A, B, C, D, no E (fig. 3), ingxenye yazo kusukela ku-a kuya ku-b enobude L igcwaliswe ngesinto evumela ukungena, isibonelo isihlabathi. Uma sithela amanzi ekugcineni okukodwa kwezitsha ezixhunyiwe afike ezingeni N₁, khona-ke izinga lamanzi ezitsheni ezixhunyiwe lizobe lihlukene, okungukuthi lizokwehla ngokwandisa ubude bendlela amanzi edlule ngayo.

Sl. 3. Ukugeleza kwamanzi phakathi kobuningi obudlulisayo amanzi

Ngesikhathi ukuphakama kwekholomu yamanzi h₁ sekufinyelelwe phambi kwesihlungi, ngemuva kwesihlungi kuzoba h₂. Umehluko phakathi kwamazinga N₁ no N₂ ngaleso sikhathi ngu:

h = h₁ − h₂

Umehluko h umele ukulahleka kwengcindezi ye-hydrostatic, esetshenziselwe ukunqoba ukumelana nokugeleza kwamanzi ngesihlungi. Lesi simo satholwa usosayensi waseFrance uDarcy kakade ngo-1856. ngonyaka. Wabe esebeka futhi le fomula elandelayo yokubala isivinini sokugeleza kwamanzi emzimbeni ovumela ukungena kwamanzi:

V = k × (dh/dL) = ki

kuphi:

• V = ijubane lokugeleza kwamanzi ngohlaka olungangeneki, [cm/sec],
• k = inhlanganisela yokungangeneki encike ezimfanelweni zenhlabathi [cm/sec],
• dh = ubude obutholakala uma ukuphakama h kuhlukaniswa kube ungqimba oluningi oluncane [cm],
• dL = ubude obutholakala lapho ubude L buhlukaniswa ngenani elifanayo lobude njengesigaba esingu h, [cm].

Ubudlelwano dh/dL = i buyisilinganiso sobude obulahlekile ekucwileni uma siqhathaniswa nendlela eyahanjwa amanzi futhi bubizwa ngokuthi ukwehla kwe-hydraulic, i-hydraulic gradient noma futhi ukuthambeka kwe-piezometer. Leli gama lokugcina livela emapayipini B, C no D, abizwa ngokuthi amapayipi e-piezometer. Ifomula engaphambili ibizwa ngokuthi umthetho ka-Darcy wokuhamba kwamanzi ngesihlungi.

Inani eliphelele lamanzi q, adlula phakathi nesikhathi esithile t ngesihlungi esinendawo yokusika A lithi

q = kAti,

lapho kuvela khona

k = q / (Ati),  okungukuthi k = qL / Ath,

lapho i = h / L = ukuwa kwe-hydraulic ngobude L (uma kuqondile ngomugqa oqondile).

I-coefficient k iveza ukungangeni kwenhlabathi ekushiseni 10°C.

k = V / i  [cm/sec]

Ijubane lokugeleza kwamanzi emhlabathini litholakala kusukela kufomula

V = q / A  [cm/sec],

lapho q = inani lamanzi adlula enhlabathini ngo-cm³ ngomzuzwana, ezingeni lokushisa lika-10°C, A = indawo yesiqephu esiphambene senhlabathi, lapho amanzi edlula khona, [cm²].

Umthetho ka-Darcy usebenza ku ukunyakaza kwe-laminar kwamanzi, okusho ukunyakaza okuzolile, ngaphandle kwemijikelezo futhi ngejubane elincane.

Ijubane lokuhlunga V liyisivinini esimaphakathi sokunyakaza kwamanzi emhlabathini futhi alihambisani nesivinini sangempela sokugeleza kwamanzi, esikhulu kakhulu. Uma amanzi edlula esihlungini, izingxenye ezilinganayo zokungena dh zivame kakhulu ukusetshenziswa ngobude obungalingani bomzila wamanzi dL, ngakho-ke i-hydraulic gradient iyashintshashintsha ukusuka kwelinye iphuzu lomhlabathi kuya kwelinye.

Ukudlula kwamanzi emhlabathini kuncike kusayizi wezimbobo ezikuwo. Uma silayisha umhlaba, izimbobo ziyancipha futhi ukudlula kwamanzi kuba kuncane. Ngakho-ke, emhlabathini ofanayo, i-coefficient yokudlula k ilingana ngqo nobukhulu bokungena komoya, okungukuthi ne-coefficient yako yokungena komoya e. Kodwa-ke, ezinhlotsheni ezahlukene zomhlaba, ukungena komoya okuchazwe nge-coefficient yokungena komoya e akukwazi ukuba isilinganiso sokudlula kwamanzi, ngoba lokhu kudlula akuxhomeki kakhulu ekungena komoya okuphelele komhlaba, kodwa kubukhulu bezimbobo ezikuwo. Ngakho-ke, isibonelo, isihlabathi esinegravel esine-porosity e = 0,25, sinokudlula okukhulu kakhulu, k = 2–3 cm/sec, kanti ubumba oluthambile, oluporosity yalo ingu 60%, i-coefficient yokungena komoya e = 1,50, lunokudlula okuncane, k = 10_⁻⁶ kuze kube 10⁻_¹¹ cm/sec.

I-coefficient yokuvumela ukudlula k inganqunywa ngokubala, ekuhlolweni kwelabhorethri kanye nokuhlolwa kwensimu.

Ukunqunywa kwe-coefficient ngendlela yokubala kusekelwa ekwakhekeni kwenhlayiya zosayizi womhlabathi. Ukuze kunqunywe i-coefficient k kuthathwa isilinganiso sokuthi izinhlayiya eziqinile zomhlabathi zinesimo esiyisiyingi, okungahambisani neqiniso ikakhulukazi emhlabathini ohlangene. Ngakho-ke amanani e-coefficient k atholwe ngale ndlela awamukelwa njenganembile.

Ukunqunywa kwe-coefficient k ngezivivinyo zaselabhorethri kusakazeke kakhulu futhi kwenziwa kumasampula enhlabathi angaphazamisekile. Kodwa-ke ukunemba kwe-coefficient k enqunywe ngale ndlela kuncike ezintweni eziningi ezifana nokuthi, ingabe futhi ngezinga elingakanani isampula lapho kuqhutshwa khona ukuhlolwa limelela ungqimba olungena amanzi enhlabathini, bese kusuka esimweni sokungaphazamiseki kwesampula emshinini wokuhlola nasendleleni yokwenza ukuhlolwa. Ngokuhlola inani elanele lamasampula azomela inhlabathi ethile, ngokuthatha isampula ensimini kumasilinda omshini wokuhlola uqobo nangendlela efanele yokwenza ukuhlolwa, kungatholakala amanani acishe abe nembile we-coefficient k angasetshenziswa njengokwanela.

Ukunqunywa kwe-coefficient k ngovivinyo lwensimu kunikeza amanani anembe kakhulu, ngoba kuhambisana ngokuphelele nokwakheka nokuhlelwa kwezingqimba zenhlabathi lapho ikhona khona. Nokho le ndlela yokunquma i-coefficient k idinga isikhathi esiningi nezindleko ezinkulu, ngenxa yalokho ayivamisile ukwenziwa futhi yenziwa kuphela ezimeni lapho inani layo elinembile ngokuphelele liyadingeka kakhulu.

Ngokwemithetho yethu yokusungula, kuthathwa njengokuthi inhlabathi enokuhlangene kokungena:

• k < 10_⁻_¹¹ cm/sec — cishe ayingeni
• k < 10_⁻_⁹        — kungena amanzi kancane kakhulu
• k < 10_⁻_⁷        — kudlula kancane amanzi
• k < 10_⁻_⁵        — evumela ukudlula ngokulinganisela
• k < 10_⁻_³        — idlula amanzi kalula kakhulu
• k > 10_⁻_³        — okudlula kakhulu