KumiswaAmakolishi namanyuvesi

Laminar futhi flow yezinxushunxushu. uketshezi ukugeleza Imibuso

Ukutadisha izakhiwo uketshezi kanye amagesi ukugeleza ibaluleke kakhulu embonini kanye Izinsiza zomphakathi. I laminar futhi zeziyaluyalu ukugeleza nomthelela emanzini ezokuthutha isilinganiso, uwoyela, igesi yemvelo amapayipi izinjongo ezihlukile, kuthinta neminye imingcele. Lezi izinkinga ukwenza hydrodynamics isayensi.

ngezigaba

In imvelo yesayensi uketshezi ukugeleza imibuso futhi amagesi zihlukaniswe namakilasi ezimbili ezihlukene kakhulu:

  • laminar (inkjet);
  • zeziyaluyalu.

Futhi ukuhlukanisa esiteji zesikhashana. Phela, igama elithi "ketshezi" linencazelo ebanzi: kungaba incompressible (uketshezi empeleni kuyinto), a liminyaniseke (igesi), conductive, njll ...

icala umlando

Enye Mendeleev ngo-1880 i-umbono wokuba khona ababili okuphambene ukugeleza Imibuso of wavezwa. Ukuze uthole imininingwane eyengeziwe ngalolu daba bahlola physics British kanye unjiniyela Osborne Reynolds abaqede isifundo ngo-1883. Okokuqala, cishe, bese usebenzisa i-amafomula kutholakala ukuthi ngesikhathi ongaphakeme ukugeleza rate zokuthutha ketshezi kuba ifomu laminar: izingqimba (kuyizinhlayiyana ukugeleza) cishe akuhlangani futhi iqhubeka izindlela ngokulinganisa. Nokho, ngemva kokunqoba inani elithile ezibucayi (izimo ezahlukene ke ihlukile), isihloko inombolo Reynolds izimo liquid ukugeleza ashintshiwe: ukugeleza jet iba vortex kunezinxushunxushu - okuyile, zeziyaluyalu. Kwabe sekuvela ukuthi, lezi nemingcele ngezinga elithile nokungapheleli esakuzuza amagesi.

Practical IsiZulu usosayensi izibalo wabonisa ukuthi ukuziphatha, isib, amanzi, sixhomeke kakhulu ukuma Ubukhulu ethangini (amapayipi, iziteshi, ama-capillary, njll), lapho kugeleza. Ngo amapayipi kokuba ingxenye engu- isiyingi (okufana esetshenziswa lokukhuphula ingcindezi piping), inombolo yayo Reynolds - ifomula isimo esibucayi kuchazwa kanje: Re = 2300. Ukuze uvule isiteshi ukugeleza inombolo Reynolds kuyinto ehlukile: Re = 900. Ukuze amagugu ezincane Re kuyalwa, wonkana - kunezinxushunxushu.

laminar ukugeleza

Ngokungafani zeziyaluyalu laminar ukugeleza Uyinhloboni nesiqondiso yamanzi (igesi) ageleza. Beyikhipha izingqimba ngaphandle ukuxuba futhi ngaphandle pulsations. Ngamanye amazwi, ukunyakaza senzeka nombala ngaphandle kuzuba abathathela ohlangothini ingcindezi kanye nesivinini.

kwakhiwa Laminar ukugeleza woketshezi, isibonelo, ewumngcingo imithambo yegazi zezinto eziphilayo, izitshalo capillary nangaphansi kwezimo ezifanayo, ngesikhathi samanje uketshezi viscous kakhulu (uwoyela fuel ngokusebenzisa iphayiphi). Ukuze ubone ukugeleza jet yanele ukuba embule empompini kancane - amanzi agobhoze buthule, ngokulinganayo, ngaphandle ukuxuba. Uma uyasikrufulula spigot kuze kube sekupheleni, ingcindezi ohlelweni uzovuka futhi ukugeleza iyoba kunezinxushunxushu.

flow yezinxushunxushu

Ngokungafani laminar, lapho izinhlayiyana angomakhelwane ukuhambisa ezindleleni kakhulu okufanayo, ukugeleza sesiyaluyalu ketshezi imvelo disordered. Uma sisebenzisa Lagrange ndlela, trajectories izinhlayiya ungakwazi ezinqumela kuyendlulela futhi eziphatha ngendlela ongayilindele. Movement of uketshezi kanye amagesi ngaphansi kwalezi zimo zihlale lezivakashi, nalezi nemingcele nonstationarities ungaba ezihlukahlukene kakhulu.

Njengoba laminar igesi ukugeleza ku zeziyaluyalu umbuso ukuqhutshwa, ingaqashwa isibonelo wisps intuthu of ugwayi ovuthayo e namanje emoyeni. Ekuqaleni, izinhlayiya ukuhambisa izindlela cishe parallel ezingaguquliwe isikhathi. Intuthu kubonakala isilungisiwe. Khona-ke ngesikhathi esithile konke kusenjalo kukhona eddies esikhulu ukuhambisa ngezikhathi ngokuphelele. Lezi vortices ukuzobhidliza zenziwe kancane kancane - ku ngisho ezincane nokunye. Ekugcineni, cishe awuthunqise amamiksi nge emoyeni ezungeze.

omawala imijikelezo

Isibonelo ngenhla incwadi, futhi kusukela imibono yakhe ososayensi baye benza iziphetho elandelayo:

  1. Laminar futhi flow yezinxushunxushu kukhona probabilistic ngokwemvelo: ukushintshela kwimodi eyodwa kuya kwenye alikho ncamashi endaweni efanele, futhi kahle kabi amandla akhe, indawo okungahleliwe.
  2. Okokuqala, kukhona vortices iningi labo kunangendlela usayizi wisps intuthu. Movement iba ongagxilile futhi kakhulu anisotropic. notshwala elikhulu abe engazinzile ibhidlize ku amancane. Ngakho, kukhona isigaba sabefundisi eddies. Amandla of ukunyakaza budluliselwe kusuka omkhulu encane, futhi ekupheleni le nqubo ubalekela - amandla ukushabalalisa kwenzeka ngesikhathi izikali ezincane.
  3. flow yezinxushunxushu ingalunganga: a vortex esithile kungaba ngendlela okungahleliwe ngokuphelele, indawo ezingalindelekile.
  4. Ukuxuba intuthu nge air ambient akuthathi indawo ngaphansi laminar ukugeleza, futhi zeziyaluyalu - ijulile kakhulu.
  5. Naphezu kweqiniso lokuthi izimo umngcele ukuphi umile, le omawala ngokwayo has a lezivakashi evelele ngokwemvelo - yonke nemingcele igesi-ashukumisayo zingashintsha ngokuqhubeka kwesikhathi.

Kunenye impahla ebalulekile omawala: kuba njalo ngakuthathu. Ngisho noma sicabanga ukugeleza eyodwa-ntathu in ipayipi noma ezimbili-ntathu umngcele ungqimba namanje motion eddies zeziyaluyalu zenzeka tinkhombandlela Ukudidiyela izimbazo ezintathu.

inombolo Reynolds: ifomula

Inguquko kusuka laminar ukuba omawala libhekene okuthiwa ezibucayi inombolo Reynolds:

Re cr = (ρuL / μ) cr,

lapho ρ - ukuminyana ukusakaza, u - ukugeleza isilinganiso isici; L - ageleze usayizi isici, μ - Coefficient ka viscosity ashukumisayo, cr - I-ngumuntu tube ne ingxenye isiyingi esiphambanweni.

Ngokwesibonelo, i-ukugeleza nge velocity u ku L ipayipi isetshenziswa njengoba ububanzi ipayipi. Osborne Reynolds yabonisa ukuthi kuleli cala, 2300 cr <20000. Ukubhebhetheka likhulu kakhulu, cishe i-oda ezidlula.

A yi ofanayo etholwe ungqimba umngcele phezu esilucwecwana. Usayizi isici sithathwa ibanga kusukwa phambi ipuleti, bese 3 × 10 Meyi cr <4 × 10 Apreli. Uma L lichazwa ngokuthi ukushuba we ungqimba umngcele, lo 2700 cr <9000. Kukhona izifundo zokuhlola ukuthi luye lwabonisa ukuthi ukubaluleka Re cr kungase isikhathi eside nakakhulu.

Umqondo Isivinini perturbation

I laminar futhi zeziyaluyalu uketshezi ukugeleza, futhi ngokufanelekile, ukubaluleka abagxeka inombolo Reynolds (Re) kuncike inqwaba yezinto. Kusukela umyela ingcindezi, ukuphakama uhlevane maholoholo, isiyaluyalu umfutho e ukugeleza zangaphandle, umehluko lokushisa, njll Ukuze kube lula, kulezi zici aggregate abizwa ngokuthi perturbation Isivinini ngoba nethonya ezithile ku-ukugeleza rate. Uma ngabe le ukuphazamiseka incane, kungaba ixazululwe amabutho viscous efuna ukuvumelanisa Isivinini ensimini. Ukuze perturbations enkulu ukugeleza bangaba engazinzile, futhi omawala kwenzeka.

Njengoba sazi ukuthi incazelo ezingokomzimba inombolo Reynolds - isilinganiso amabutho inertial namabutho viscous, ukucasuka ageleza imbozwe ifomula:

Re = ρuL / μ = ρu 2 / (μ × (u / L )).

I numerator kabili ekhanda Isivinini kanye zihilela - ukubaluleka kuyinto ye-oda yokucindezeleka kokukhuhlana, uma L sithathwa ukushuba we ungqimba umngcele. ingcindezi Dynamic ivame ukuba abhubhise ukulinganisela ngomshikisho amabutho phikisa lo. Nokho, akucaci ukuthi kungani amabutho inertia (noma Isivinini ingcindezi) kuholele izinguquko kuphela lapho izikhathi 1000 amabutho viscous ngaphezulu.

Kubala amaqiniso

Mhlawumbe, more sizikhandle ingasetshenziswa njengendlela isivinini isici Re cr esingaphelele ukugeleza Isivinini u, kanye perturbation velocity. Kulokhu, inombolo ezibucayi Reynolds kuyoba-10, okungukuthi uma kokweqa ashukumisayo ingcindezi ukuphazamiseka ekucindezelekeni viscous phezu izikhathi 5 ukugeleza laminar ibe notshwala zeziyaluyalu uketshezi. Lenchazelo Ukunikeza ngokuvumelana ososayensi abathile kahle zachazwa yisigaba maqiniso alandelayo Ucwaningo efakazelwe.

Ukuze uthole ngokuphelele iyunifomu iphrofayela Isivinini phezu ngokuphelele bushelelezi is ngokwesiko kunqunywa inani Re cr ivame infinity, okungukuthi, ushintsho empeleni kwenzeka ukuze omawala. Lapha inombolo Reynolds kunqunywa ubukhulu bale Isivinini perturbation ngezansi ukubaluleka esibucayi, okuyinani elilingana 10.

Ephambi kwezinduna omawala yokufakelwa, okubangela splash izinga ufana izinga eyisisekelo, ukugeleza iba zeziyaluyalu ngamanani aphansi kakhulu Reynolds izinombolo kuka Re cr, kwanqunywa kusukela inani eliphelele isivinini. Lokhu kuvumela ukusetshenziswa Coefficient Re cr = 10, lapho Isivinini isici kuba inani eliphelele le perturbation Isivinini kubangelwa izizathu ngenhla.

Ukuzinza laminar ukugeleza kwamanzi iphayiphi

I laminar futhi flow yezinxushunxushu kuvamile kubo bonke izinhlobo zoketshezi bese kuthi amagesi ngaphansi kwezimo ezihlukahlukene. Imvelo laminar ukugeleza awatholatholakali futhi izimpawu, isibonelo, ewumngcingo ukusakaza komhlaba emathafeni. Okuningi, lolu daba emkhathaza lososayensi esimeningcondvo ngokoqobo zokuhamba amanzi amapayipi, uwoyela, igesi kanye nezinye izinto eziwuketshezi.

Q laminar ukugeleza ukuzinza kuyinto ahlobene eduze ekutadisheni siyabhubha motion ukugeleza main. Kwatholakala okuthintekayo okuthiwa perturbations encane. Kuye ngokuthi zikhula noma ishabalale ngokuhamba kwesikhathi, ukugeleza eziyisisekelo ubhekwa esitebeleni noma ingazinzi.

Ukuze uketshezi liminyaniseke hhayi liminyaniseke

Enye yezinto ezithinta laminar futhi zeziyaluyalu uketshezi ukugeleza kuyinto compressibility yayo. Le mpahla uketshezi kubaluleke ngokukhethekile ekutadisheni ukuzinza izinqubo ze-non-umile ne yokuguquka wamanje eyinhloko.

Ucwaningo lubonisa ukuthi laminar ukugeleza i uketshezi incompressible ku amashubhu esigabeni cylindrical olumelana axisymmetric futhi okungezona axisymmetric thuthuva elincane ngesikhathi nendawo.

Muva nje, izibalo eyenziwa lixhomeke ethonyeni yokuphazamiseka ku ukumelana axisymmetric ukugeleza engxenyeni itheku tube cylindrical lapho wamanje main luncike izixhumanisi ezimbili. I Ukudidiyela ahlangene ipayipi kubhekwa njengento ipharamitha esithinta iphrofayli Isivinini kanye lo engaba main ukugeleza ipayipi.

isiphetho

Naphezu eminyaka yocwaningo, asikwazi ukuthi laminar futhi zeziyaluyalu ukugeleza is balitadishisise. izifundo kokulinganisa ezingeni micro, ziphakamisa izinkinga ezintsha ezidinga wabonisana ukubala ngukulungisiswa. Ubunjalo cwaningo isicelo kanye nokusetshenziswa: izinkulungwane emhlabeni amakhilomitha yamanzi, uwoyela, igesi kanye umkhiqizo. Ukuqhubeka kwethulwa nezixazululo lobuchwepheshe nokwehlisa omawala ngesikhathi ezokuthutha, ephumelela kakhudlwana kuyoba.

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