Laminar da m kwarara. ruwa ya kwarara gwamnatocin

Karatu da kaddarorin taya da gas da kwarara ne da muhimmanci sosai ga tattalin arziki da kuma jama'a utilities. A laminar da m kwarara sakamako a kan ruwa kai kudi, mai, iskar gas bututun domin dalilai daban-daban, rinjayar da sauran sigogi. Wadannan matsaloli yi kimiyya hydrodynamics.

rarrabuwa

A kimiyya yanayi na ruwa ya kwarara gwamnatocin da gas ya kasu kashi biyu sosai jinsin azuzuwan:

• laminar (inkjet).
• m.

Har ila yau rarrabe tsaka mataki. Ba zato ba tsammani, da kalmar "ruwa" yana da fadi da ma'anar: shi iya zama incompressible (ruwa a zahiri shi ne), mai compressible (gas), conductive, da dai sauransu ...

harka tarihi

Wani Mendeleev a 1880 da ra'ayin wanzuwar biyu daura da kwarara gwamnatocin da aka bayyana. Don ƙarin bayani a kan wannan batun nazari Birtaniya likita da m Osborne Reynolds da suka kammala binciken a 1883. Da farko, kusan, sa'an nan ta amfani da dabarbari aka same shi da cewa a wata low kwarara kudi na ruwa kai zama laminar form: yadudduka (barbashi kwarara) ne kusan ba Mix da kuma motsa tare layi daya hanyoyi. Duk da haka, bayan shawo kan wani m darajar (ga yanayi daban-daban shi ne daban-daban), da take Reynolds yawan ruwa ya kwarara yanayi da ake canza: da jet kwarara zama m vortex - Ina nufin, m. Kamar yadda ya juya waje, wadannan sigogi ne wasu har muhimmi da kuma gas.

Practical English masanin kimiyyar lissafin ya nuna cewa da hali na, msl, da ruwa, shi ne sosai dogara a kan siffar da kuma girma na tanki (bututu, tashoshi, capillaries, da dai sauransu), a cikin abin da ta gudana. A bututu da ciwon madauwari giciye sashe (irin amfani ga matsin lambar hawa piping), ta Reynolds da lambar - da dabara na m jihar da aka bayyana kamar haka: Re = 2300. Domin bude kwarara tashar na da Reynolds da lambar shi ne daban-daban: Re = 900. Domin karami dabi'u ga Re da aka yi umurni, a manyan - m.

laminar kwarara

Ba kamar mai laminar kwarara m yanayi ne da kuma shugabanci na ruwa (gas) gudana. Su matsawa da yadudduka ba tare da hadawa da kuma ba tare da pulsations. A wasu kalmomin, da motsi faruwa gaba ɗaya ba tare da erratic tsalle a matsa lamba shugabanci da kuma gudun.

Laminar ruwa ya kwarara da aka kafa, misali, a cikin kunkuntar jini abubuwa masu rai, da shuke-shuke capillaries da kuma karkashin m yanayi, a halin yanzu na sosai viscous taya (man fetur da man fetur ta hanyar bututun). Don ganin da jet kwarara shi ya isa ya bayyana kadan famfo - ruwa zai gudana daga ƙarƙashinsu zare jiki, a ko'ina, ba tare da hadawa. Idan kwance cikin spigot zuwa karshen, da tsarin turawa zai tashi kuma ya kwarara zai zama m.

m kwarara

Ba kamar mai laminar, a cikinsa makwabta barbashi matsawa tare ma layi daya hanyõyi, a m kwarara daga ruwa ne tarwatsettsun yanayi. Idan muka yi amfani da Lagrange m, da trajectories daga cikin barbashi iya siddan zoba da nuna hali quite unpredictably. Movement of taya da gas a karkashin wadannan yanayi ne ko da yaushe mai shudewa, tare da wadannan sigogi nonstationarities iya samun mai fadi da kewayon.

Kamar yadda laminar gas kwarara cikin m gwamnatin Saide, za a iya kula da misali wisps hayaki na mai kona taba a yanzu iska. Da farko, da barbashi matsawa kusa layi daya hanyoyi canzawa a lokaci. Smoke alama gyarawa. Sa'an nan a wani matsayi kwatsam akwai manyan eddies cewa matsawa gaba daya da ka. Wadannan vortices karya up cikin karami su - a cikin ko karami da sauransu. A karshen, kusan hayaki Mixes da kewaye iska.

haukan kogi hawan keke

A bisa misali ne mai littafi, kuma daga lura masana kimiyya sun sanya wadannan karshe:

1. Laminar da m kwarara ne probabilistic a cikin yanayi: miƙa mulki daga wanda yanayin zuwa wani ne ba a daidai hakkin wuri, da kuma a cikin wani fairly sabani, bazuwar wuri.
2. Da farko, akwai manyan vortices cewa ne ya fi girma fiye da girman da wisps na hayaki. Movement zama unsteady da kuma karfi da anisotropic. Manyan gudana zama m da kuma karya up cikin karami da kuma karami. Saboda haka, akwai wani matsayi na eddies. A samar da makamashi na motsi da aka canjawa wuri daga manyan zuwa kananan, kuma a karshen wannan tsari vuya - makamashi masha'a auku a kananan ma'auni.
3. M kwarara ne erratic: wani musamman vortex iya zama a cikin gaba daya bazuwar, unpredictable wuri.
4. Hadawa hayaki da na yanayi iska ba ya dauki wuri a karkashin laminar kwarara, kuma a cikin m - ne sosai m.
5. Duk da cewa da iyaka yanayi ne na kullum, da haukan kogi kanta tana da pronounced dõgẽwa a cikin yanayi - duk gas-tsauri sigogi canza a kan lokaci.

Akwai wani muhimmanci dũkiyar haukan kogi: shi ne ko da yaushe uku-girma. Ko da idan muka yi la'akari da daya-girma ya kwarara a cikin bututu ko biyu-girma iyaka Layer har yanzu motsi na m eddies faruwa a cikin kwatance na uku tsara gatura.

Reynolds da lambar: da dabara

A miƙa mulki daga laminar zuwa haukan kogi halin da ake kira m Reynolds da lambar:

_{Re cr = (ρuL / μ)} cr,

inda ρ - yawa rafi, u - kwarara kudi halayyar. L - gudãna daga ƙarƙashinsu halayyar size, μ - da coefficient na tsauri danko, cr - domin da wani bututu da wani madauwari giciye sashe.

Alal misali, a kwarara da gudu u a cikin bututu L aka yi amfani da matsayin da bututu diamita. Osborne Reynolds ya nuna cewa, a wannan yanayin, 2300 cr <20000. A baza ne manya-manyan, kusan wani tsari na girma.

A irin wannan sakamakon da aka samu a cikin iyaka Layer a kan wafer. A halayyar size aka dauka a matsayin nesa daga gaban gefen farantin, sa'an nan 3 × ¹⁰ Mayu cr <4 × ¹⁰ Afrilu. Idan L aka bayyana a matsayin kauri daga cikin iyaka Layer, da 2700 cr <9000. Akwai gwaji nazarin cewa sun nuna cewa, darajar Re _cr iya zama ma fi girma.

A ra'ayi na gudu perturbation

A laminar kuma m ruwa ya kwarara, kuma daidai da, da m darajar da Reynolds lamba (Re) dogara a kan wani babban yawan abubuwan. Daga cikin matsin dan tudu, da tsawo daga bumps roughness, halin rashin kwanciyar hankali tsanani a waje kwarara, bambanci zazzabi, da dai sauransu. Domin saukaka, wadannan tara dalilai ake kira perturbation gudu tun suna da wani tasiri a kan kwarara kudi. Idan wannan tashin hankali ne kananan, shi za a iya zaunar da danko sosai sojojin da ke neman tsara a layi da gudu filin. Ga manyan perturbations na kwarara iya zama m, da kuma haukan kogi ya auku.

Ganin cewa jiki ma'anar Reynolds da lambar - da rabo daga inertial da sojojin da kuma danko sosai sojojin, fushi gudana ta rufe dabara:

Re = ρuL / μ = ρu ² / (μ × (u / L )).

A numerator sau biyu yake da gudu kai da kuma hada - da darajar ne na tsari na frictional danniya, idan L aka dauka a matsayin kauri daga cikin iyaka Layer. Dynamic matsa lamba o ƙarin tabbatar da halaka auna da kuma gogayya dakarun adawa da wannan. Duk da haka, shi ne m dalilin da ya sa sojojin na inertia (ko gudu matsa lamba) ta kai ga canje-canje kawai idan sun 1000 sau mafi danko sosai sojojin.

Lissafi da kuma facts

Kila, mafi dace a yi amfani a matsayin halayyar gudun Re _Kr ba cikakkar kwarara gudu u, da kuma gudu perturbation. A wannan yanayin, da m Reynolds yawan zai zama game da 10, Ina nufin idan wucewa da tsauri matsa lamba tashin hankali da danko sosai gajiyan kan 5 sau da laminar kwarara cikin wani m ruwa gudana. Wannan definition Re a cewar wasu masana kimiyya ne da bayyana ta da wadannan gwaje tabbatar facts.

Domin a daidai uniform gudu profile on daidai m surface gargajiyance ƙaddara da yawan Re _cr o ƙarin tabbatar da rashin iyaka, wato, da mi} a mulki zahiri faruwa ga haukan kogi. A nan Reynolds da lambar da aka ƙaddara da girma da perturbation gudu a kasa da m darajar, wanda shi ne daidai da 10.

A gaban na wucin gadi haukan kogi, haddasa fantsama rate m da asali kudi, da ya kwarara zama m at yawa ƙananan Reynolds lambobi fiye da Re _cr, m daga cikin cikakkar darajar da gudun. Wannan damar yin amfani da coefficient Re _cr = 10, inda halayyar gudu ne cikakkar darajar da gudu perturbation sa ta sama dalilai.

Stability na laminar kwarara gwamnatin a cikin bututun

A laminar da m kwarara ne ga kowa da kowa iri taya da gas a karkashin daban-daban yanayi. A laminar yanayi na kwarara ne m, kuma an halin, misali, ga kunkuntar karkashin kasa da kõguna filayen. Fiye da, wannan batu ne na damuwa da masana kimiyya a cikin mahallin m aikace-aikace ga harkokin sufuri da bututun ruwa, man, gas da kuma sauran ruwaye.

Q laminar kwarara kwanciyar hankali ne a hankali alaka da nazari gaji da damuwa da tashin na babban kwarara. Yana da aka samu da za a shafi da ake kira kananan perturbations. Dangane da ko su girma ko gushe a kan lokaci, da asali da kwarara aka dauke su barga ko m.

Domin compressible kuma ba compressible ruwaye

Daya daga cikin abubuwan da shafi cikin laminar kuma m ruwa ya kwarara ne ta compressibility. Wannan ruwa dukiya ne da muhimmanci musamman a nazarin da zaman lafiyar na ba-tsit matakai tare da m canji a cikin primary halin yanzu.

Nazarin ya nuna cewa laminar kwarara daga wani incompressible ruwa a cikin shambura na cylindrical sashe ne resistant zuwa gwada da kananan axisymmetric da kuma wadanda ba axisymmetric disturbances a lokacin da sarari.

Kwanan nan, lissafin suna da za'ayi a rinjayar disturbances a kan axisymmetric kwarara juriya a cikin mashiga rabo daga cylindrical tube inda babban halin yanzu shi ne dogara a kan biyu tsarawa. A daidaita axis na bututu yana dauke da siga da cewa rinjayar da gudu profile tare da radius daga cikin manyan kwarara bututu.

ƙarshe

Duk ƙarni na nazari, ba za mu iya ce cewa laminar da m kwarara ne sosai karatu. Abubawan da karatu a kan micro matakin, tãyar da sabon al'amurran da suka shafi bukata a muhawwara lissafi gaskata. A yanayi na gudanar da bincike ne da aikace-aikacen da amfani: duniya ta dubban kilomita na ruwa, da man fetur, gas da kuma samfurin. A daina da gabatar da fasaha mafita ga rage haukan kogi a lokacin da sufuri, da mafi tasiri da shi zai kasance.