Te Ariā o te Pūngao Ā-roto i roto i te Hangarau Pūnaha Thermodynamic
I roto i te ako i te thermodynamics hangarau, ko tētahi o ngā ariā tino taketake engari he mea nui rawa atu i roto i te tātari pūnaha ko te pūngao ā-roto. Ko te pūngao ā-roto, e tohuhia ana e te U, he wāhanga nui o ngā āhuatanga o tētahi matū, ahakoa he matū parakore, he ranunga rānei, i roto i tētahi pūnaha thermodynamic. Mā te mārama tika ki te pūngao ā-roto ka āwhina i ngā kaihangarau ki te whakamārama me te tatau i te whanonga o ngā pūnaha pēnei i ngā tāwhana korohū, ngā compressors, ngā miihini mura ā-roto, ngā poiha, ngā whakawhiti wera, me ngā pūnaha pouaka whakamātao. Ka matapakihia e tēnei tuhinga te whakamāramatanga o te pūngao ā-roto, tōna tikanga ā-tinana, tōna whanaungatanga ki te wera me te mahi, tōna tūranga i roto i te Ture Tuatahi o te Thermodynamics, me ōna tono mahi i roto i ngā pūnaha hangarau.
1. Te Mārama ki te Pūngao ā-Roto
Ko te pūngao ā-roto ko te pūngao moroiti katoa e rongoatia ana i roto i tētahi pūnaha nā te nekehanga me ngā taunekeneke o ōna matūriki (ngota, ngota, irahiko). He rerekē ki te pūngao nekeneke me te pūngao pūmanawa, e kitea ana i runga i te tauine makaroiti (hei tauira, he mea e neke ana, e neke ana rānei i tētahi teitei), e pā ana te pūngao ā-roto ki ngā āhuatanga i runga i te tauine moroiti: ngā wiri ngota, ngā hurihanga, ngā nekehanga, te pūngao here, me te pūngao e pā ana ki te whirihoranga ā-roto o tētahi rauemi.
I roto i te ariā, ka taea te tuhi i te pūngao katoa o tētahi pūnaha hei huinga o te pūngao ā-roto me te pūngao makaro:
\[
E = U + KE + PE
\]
me:
– \(E\) = te pūngao katoa o te pūnaha
– \(U\) = pūngao ā-roto
– \(KE\) = pūngao nekeneke makroskopi
– \(PE\) = pūngao pūmanawa makoropiko
I roto i te maha o ngā tātaritanga thermodynamic hangarau, he iti ake ngā panonitanga o te pūngao nekeneke me te pūngao pūmanawa i ngā panonitanga o te pūngao ā-roto, te enthalpy rānei, nō reira ka warewarehia kia māmā ake ngā tataunga (ahakoa i roto i ētahi tono pēnei i ngā nozzles, i ngā turbines rānei, ka nui te pūngao nekeneke).
2. Pūngao Ā-roto hei Āhuatanga Termodynamic
He mahi āhua te pūngao ā-roto. Ko te tikanga o tēnei, ko te uara o te pūngao ā-roto e whakawhirinaki ana ki te āhua o nāianei o te pūnaha (hei tauira, te pāmahana, te pēhanga, me te hanganga), kaua ki te ara tukanga i tangohia hei tae atu ki taua āhua. I roto i te āhua rerekē, ka whakaatuhia te huringa o te pūngao ā-roto penei:
\[
\Delta U = U_2 – U_1
\]
Me whakanui ko te uara tuturu o te U he uaua ki te ine tika, nā te mea ko te mea ka taea te whakatau mā te whakamātautau ko te huringa o te pūngao ā-roto (\(\Delta U\)). Nō reira, ko ngā ripanga thermodynamic (hei tauira, ngā ripanga kohu wai) e whakaatu ana i ngā uara pūngao ā-roto e pā ana ki tētahi āhua tohutoro.
3. Tikanga Ā-tinana: Ngā Wāhanga Pūngao Makariri
He "pūranga" iti rawa te pūngao ā-roto o te pūngao. I te nuinga o te wā, ko ngā takoha mai i te pūngao ā-roto ka uru atu ki:
1. Pūngao whakawhiti o ngā ngota (e pā ana ki te pāmahana).
2. Te pūngao hurihuri me te pūngao wiri (he mea nui i roto i ngā hau polyatomic me ngā pāmahana teitei ake).
3. Te pūngao pūmanawa i waenga i ngā ngota (he mea nui i roto i ngā wai me ngā totoka, e pāngia ana e ngā kaha kukume i waenga i ngā ngota).
4. Pūngao here matū (he mea nui i roto i ngā tauhohenga tahunga, i ngā tukanga matū rānei).
5. Pūngao karihi (kāore i te arohia i roto i ngā mahi whakamahana hangarau tawhito engari i roto i ngā pūnaha tauhohenga karihi).
Nā te mea ka pāngia ēnei wāhanga e te pāmahana me te hanganga o te matū, he hononga tata te pūngao ā-roto ki te pāmahana. Mō te hau pai, ko te pūngao ā-roto he mahi matua nā te pāmahana anake.
4. Te Hononga i waenga i te Pūngao ā-Roto me te Wera me te Mahi
Ko tētahi whakaaro hē noa ko te whakaaro ko te pūngao ā-roto he "rite" ki te wera. Heoi anō:
– Ko te wera (Q) he pūngao e neke ana puta noa i te rohe o te pūnaha nā ngā rerekētanga pāmahana.
– Ko te mahi (W) te pūngao e whakawhitihia ana puta noa i te rohe pūnaha nā te kaha e pā ana ki te nekehanga (hei tauira, te mahi rohe \(P\,dV\), te mahi pou i runga i te tāpine, te mahi hiko, me ētahi atu).
– Ko te pūngao ā-roto (U) te pūngao e rongoatia ana i roto i te pūnaha hei taonga ā-motu.
Ina whiwhi te pūnaha i te wera, ka piki ake tōna pūngao ā-roto, engari kāore i te katoa—nā te mea ka taea te huri i ētahi o te pūngao e haere mai ana hei putanga mahi. I tetahi atu taha, ina mahi te pūnaha, ka heke tōna pūngao ā-roto ahakoa kāore he wera e ngaro, pērā i te whakawhanuitanga adiabatic.
5. Te Pūngao ā-Roto i roto i te Ture Tuatahi o te Thermodynamics
E kī ana te Ture Tuatahi o te Thermodynamics i te tiakitanga o te pūngao. Mō tētahi pūnaha kati, ko te āhua tino noa ko:
\[
\Delta U + \Delta KE + \Delta PE = Q – W
\]
Mena ka taea te wareware i ngā panonitanga o te pūngao nekeneke me te pūngao pūmanawa:
\[
\Delta U = Q – W
\]
E whakamārama ana tēnei whārite ko te huringa o te pūngao ā-roto ka whakatauhia e te taurite pūngao: te pūngao e tomo mai ana hei wera ka tangohia te pūngao e puta atu ana hei mahi.
Tauira ariā
– Ina whakamahanahia he hau i roto i tētahi oko mārō (rōrahi pumau), ko te mahi rohe ko \(W = 0\), nō reira ka whakanuia e te wera katoa e tomo mai ana te pūngao ā-roto: \(\Delta U = Q\).
– I roto i te whakawhanuitanga adiabatic (kāore he whakawhiti wera, \(Q=0\)), ka mahi te pūnaha, ā, ka heke tōna pūngao ā-roto: \(\Delta U = -W\).
6. Te Rerekētanga i waenga i te Pūngao ā-Roto me te Enthalpy
I roto i te hangarau thermodynamics, i tua atu i te pūngao ā-roto, e mōhiotia ana hoki te enthalpy (H):
\[
H = U + PV
\]
He maha ngā wā ka whai hua ake te enthalpy mō te whakamahi i roto i ngā pūnaha rere (rōrahi whakahaere) pērā i ngā tāpine, ngā compressors, ngā poiha, me ngā whakawhiti wera, nā te mea ko te kupu \(PV\) e tohu ana i te "mahi rere" e pā ana ki te pana i te wai ki roto, ki waho hoki i te rōrahi whakahaere.
Heoi anō, he mea tino nui tonu te pūngao o roto, inā koa i roto i:
– ngā pūnaha kati (hei tauira, te rango-piston),
– te tukanga rōrahi pumau,
– te tātaritanga rangitahi mō ngā tāke,
– me te whakatau i ngā āhuatanga pāmahana o ngā matū i raro i ētahi tikanga.
7. Pūngao Ā-roto i roto i te Hau Pai
Mō te hau tino pai, ko te pūngao ā-roto e whakawhirinaki ana ki te pāmahana anake:
\[
U = U(T)
\]
Nō reira, ka taea te tatau i te huringa o te pūngao ā-roto mā te whakamahi i te kaha wera i te rōrahi pumau (\(C_v\)):
\[
\Delta U = m\int_{T_1}^{T_2} C_v(T)\, dT
\]
Mena ka kiia a \(C_v\) he pumau:
\[
\Delta U = m C_v (T_2 – T_1)
\]
He tino whai hua mō ngā tataunga tere mō ngā wāhanga hangarau pēnei i ngā tukanga kōpeketanga/whanuitanga hau, te tātari huringa pai (Otto, Diesel, Brayton), me ngā tataunga whakawhiti pūngao taketake.
8. Te Pūngao ā-Roto i roto i ngā Matū Tuturu me te Kohu Wai
I roto i ngā matū tūturu pēnei i te wai, ngā pouaka whakamātao, ngā ranunga hauwaiwai rānei, ehara i te mea ko te pāmahana anake te mahi a te pūngao ā-roto. Ka pāngia hoki e te pēhanga me te āhua (wai, mamaoa, ranunga). Nō reira, ko te tātari pūngao ā-roto e pā ana ki:
– tepu pāmahana (tepu mamaoa),
– Ngā hoahoa \(Pv\), \(Ts\), \(hs\) rānei,
– ngā whārite rānei o ngā tauira āhua me ngā tauira rawa.
Hei tauira, i roto i te wai: ka tino piki te pūngao ā-roto ina huri te āhua mai i te wai mākū ki te mamaoa mākū nā te pūngao huna e pā ana ki te pakaru o ngā kaha kukume i waenga i ngā ngota.
9. Te Whakamahinga o te Pūngao Ā-roto i roto i ngā Pūnaha Termodinamika Hangarau
He pānga tika tō te mārama ki te pūngao ki te hoahoa me te aromatawai mahi o ngā taputapu hangarau, hei tauira:
1. Te rūma mura me te mīhini mura ā-roto: e pā ana ngā panonitanga o te pūngao i roto i ngā hau mura ki te tukunga o te pūngao matū me te pāmahana o te hau.
2. Ngā tāke rokiroki pēhanga: ka taea te tātari i te tukanga whakakī/whakawātea mā roto i ngā huringa o te pūngao ā-roto o te wai i roto i te tāke, inā koa i raro i ngā āhuatanga adiabatic, i ngā āhuatanga rangitahi rānei.
3. Ngā kohua me ngā pūwhakapūmau: ahakoa he maha ngā wā ka whakamahia e te tātari rere te enthalpy, ka āwhina te pūngao ā-roto ki te mārama ki ngā huringa āhua me te taurite pūngao ā-roto o te wai.
4. Pūnaha whakamatao: ka whakamārama te pūngao ā-roto i ngā huringa pūngao i roto i te hau whakamatao i te wā e pēhia ana, e whakawhanuitia ana, e whakawhitia ana te wera, inā koa ka tātarihia hei pūnaha kati i roto i ētahi wāhanga.
10. Whakamutunga
Ko te pūngao ā-roto tētahi ariā matua i roto i te hangarau thermodynamics nā te mea e tohu ana i te pūngao moroiti e rongoatia ana i roto i tētahi pūnaha hei āhuatanga o te āhua. Mā te Ture Tuatahi o te Thermodynamics, ka honoa e ngā huringa o te pūngao ā-roto te whakawhiti wera me te mahi, ā, koinei te pūtake mō te tātari pūngao o ngā tukanga hangarau. I roto i ngā hau pai, ko te pūngao ā-roto e whakawhirinaki ana ki te pāmahana, i roto i ngā matū tūturu, ka pāngia te pūngao ā-roto e ngā āhuatanga ā-wāhanga me te pēhanga. Mā te mārama hohonu ki te pūngao ā-roto, ka taea e te miihini te hanga tauira tika ake, te mahi tātaitanga whai hua, me te whakatau whakatau hoahoa tika i roto i ngā tono pūnaha wera rerekē.
Ki te hiahia koe, ka taea e au te tāpiri i ngā tauira o ngā tātaitanga tau (hei tauira, te whakamahana i te hau i roto i te rango, te whakawhānui adiabatic rānei) kia mārama ake ai te ariā o te pūngao ā-roto.
