Ngā Kaupapa Taketake o te Thermodynamics me tōna Whakamahinga ki ngā Pūnaha Mīhini
Ko te thermodynamics he peka o te ahupūngao e ako ana i ngā whanaungatanga i waenga i te pūngao, te wera, me te mahi, me te pānga ki ngā āhuatanga o tētahi pūnaha. I roto i te hangarau, inā koa te hangarau miihini, he tūāpapa nui te thermodynamics mō te hoahoa, te tātari, me te arotau i te whānuitanga o ngā mīhini—mai i ngā miihini waka me ngā tāpine whakaputa hiko ki ngā pūnaha whakamatao me ngā pēhipereki ahumahi. Mā te mārama ki ōna kaupapa matua ka āwhina i ngā kaihangarau ki te matapae i te pai o te pūnaha, te kai wahie, ngā whakaritenga whakamatao, me ngā rohe mahi.
1. Ngā Ariā Taketake: Pūnaha, Taiao, me te Āhua
Ka tīmata tonu ngā kōrero mō te thermodynamics me ngā whakamāramatanga o te pūnaha me ōna taiao. Ko te pūnaha te wāhanga o te ao whānui e arotahi ana ki te tātari, ko ngā taiao ia ko ngā mea katoa i waho o te pūnaha. Ko te rohe e wehe ana i ngā mea e rua ka kiia ko te rohe pūnaha, ka taea te tūturu (hei tauira, te pakitara o te ngongo) te hangai rānei.
Ko ngā pūnaha thermodynamics e whakarōpūtia ana i te nuinga o te wā ki:
1. Pūnaha kati: kāore te papatipu e whiti i te rohe o te pūnaha, engari ka taea e te pūngao (wera/mahi). Hei tauira, he pūnaha rango-piston kati.
2. Pūnaha tuwhera: ka taea e te papatipu me te pūngao te whiti i ngā rohe. Hei tauira, ko ngā tāpine, ngā pūwhakakoi, ngā poiha, me ngā pūwhakakotahi.
3. Pūnaha motuhake: kāore he whakawhitiwhiti papatipu, pūngao rānei ki te taiao (tino pai).
Ka whakatauhia te āhua o tētahi pūnaha e ngā taurangi pēnei i te pēhanga (P), te pāmahana (T), te rōrahi (V), me te hanganga. Ko ēnei āhuatanga ka taea:
– Ngā āhuatanga kaha: kāore e whakawhirinaki ki te papatipu (hei tauira, T, P).
– Ngā āhuatanga whānui: e whakawhirinaki ana ki te papatipu (hei tauira, te pūngao katoa, te rōrahi katoa).
I roto i te tātari mīhini, he mea nui te whakatau i te āhua o te mīhini nā te mea he nui te awe o ngā āhua o te putanga me te whakaurunga o te wai mahi ki te mahi a te mīhini, hei tauira, te pāmahana me te pēhanga o te mamaoa i roto i te tāpine, te pāmahana rānei o te hau whakamatao i roto i te whakapūhaumāota.
2. Pūngao, Wera, me te Mahi
Ko te Thermodynamics e pā ana ki te pūngao i roto i ngā momo āhua. Ko ngā momo whakawhiti pūngao e rua e tino kitea ana ko te wera (Q) me te mahi (W).
– Ko te wera he pūngao e whakawhitihia ana nā ngā rerekētanga pāmahana.
– Ko te mahi he pūngao e whakawhitihia ana nā te kaha e pā ana ki te nekehanga (hei tauira, te mahi porotaka i runga i te tāpine, te mahi pēhi rānei i runga i te kōpeke).
Hei tāpiritanga, kei reira ngā momo pūngao e rongoa ana i roto i te pūnaha, pēnei i:
– E pā ana te pūngao ā-roto (U) ki te pūngao moroiti o ngā ngota ngota.
He mea nui te pūngao nekeneke (KE) me te pūngao pūmanawa (PE), inā koa i roto i ngā pūnaha rere tere, i ngā rerekētanga teitei rānei.
I roto i tētahi pūnaha mīhini, pērā i te tāpine, ka whakaitihia te pūngao wai (enthalpy) ka hurihia hei mahi poro. I roto i tētahi pūwero, ka puta te ritenga kē: ka whakamahia te mahi poro hei whakanui ake i te pūngao wai.
3. Te Ture Kore o te Thermodynamics: Te Pūtake mō te Ine i te Pāmahana
E mea ana te Ture Kore: mēnā kei roto te pūnaha A i te taurite wera ki a B, ā, kei roto a B i te taurite wera ki a C, kāti kei roto a A i te taurite wera ki a C. Ko tēnei ture te pūtake o te ariā o te pāmahana, ā, ka taea te whakamahi i ngā inemahana.
I roto i te miihini, he maha ngā mea e whakatau ana i te pāmahana: te kounga o te tahunga, ngā herenga rauemi, te whai huatanga, te tere whakawhiti wera, tae atu ki te pumau o te hinu whakahinuhinu.
4. Te Ture Tuatahi o te Thermodynamics: Te Tiakitanga o te Pūngao
E ai ki te Ture Tuatahi o te Thermodynamics, kāore e taea te hanga, te whakangaro rānei i te pūngao; ka taea anake te huri i te āhua. Mō tētahi pūnaha kati, ka taea te tuhi i te huringa o te pūngao ā-roto penei:
\[
\Delta U = Q – W
\]
Arā, ka piki te pūngao ā-roto mēnā ka whiwhi wera, mēnā rānei ka mahia he mahi ki te pūnaha.
Mō ngā pūnaha tuwhera (ngā rōrahi whakahaere) pērā i ngā tāpine, ngā pūwero rānei, ka whakamahia he taurite pūngao rere e uru ana ki te enthalpy (h) me ngā huringa o te pūngao nekeneke me te pūngao pūmanawa. I roto i te ariā, me taurite te whakaurunga pūngao (mā te rere papatipu, te wera, me te mahi) ki te putanga pūngao me ngā huringa o te pūngao rongoa.
Te tono ki ngā mīhini:
– Mīhini mura ā-roto: te pūngao matū o te wahie → te wera o te mura → ka huri tetahi wāhanga hei mahi miihini, ka ngaro te toenga mā roto i ngā hau putanga me te whakamatao.
– Pūwero: te wera mai i te tahunga → ka whakanui i te enthalpy o te wai kia huri rā anō hei mamaoa pēhanga.
– Pūwhakamātao: ka panaia te wera ki te taiao hei huri i te mamaoa hei wai.
Mā te Ture Tuatahi, ka taea e ngā miihini te tatau i ngā whakaritenga wahie, te kaha o te pōro, te mana o te tāpine, ngā whakaritenga whakamatao rānei o te pūwhakamahana.
5. Ture Tuarua o te Thermodynamics: Te Aronga o te Tukanga me te Entropy
Kāore te Ture Tuatahi e whakamārama he aha te ahunga ā-taiao o tētahi tukanga (hei tauira, ka rere tonu te wera mai i te wera ki te makariri). Koinei te wāhi e uru mai ai te Ture Tuarua o te Thermodynamics. I te nuinga o te wā, e kī ana te Ture Tuarua:
– Kāore e taea te hanga i tētahi mīhini wera e huri ana i te wera katoa hei mahi me te kore he pānga kē atu.
– E kore te wera e rere noa mai i tētahi mea matao ki tētahi mea wera me te kore he mahi e whakaurua.
Ko tētahi ariā nui i roto i te Ture Tuarua ko te entropy (S), he ine i te koretake, i te tere rānei o te marara o te pūngao. I roto i ngā tukanga tūturu, ka piki haere te entropy katoa (pūnaha + taiao):
\[
\Delta S_{katoa} \ge 0
\]
Ngā pānga ki ngā pūnaha miihini:
– Kei reira tonu ngā mate (kore e taea te hoki whakamuri) pērā i te waku, te aueue, te whakawhiti wera me ngā rerekētanga pāmahana nui, me ngā tukanga whakawhāiti.
– He rohe ariā tō te whai huatanga o te miihini, hei tauira, ko te whai huatanga mōrahi o tētahi miihini wera tino pai (Carnot) e whakawhirinaki ana ki te pāmahana o te pūtake wera me te pūtake makariri.
I roto i te hoahoa mīhini, ka akiaki te Ture Tuarua i ngā mahi hei whakaiti i te kore e taea te hoki whakamuri: te whakangawari i te rere o te wai, te whakapai ake i te kounga o te whakamarumaru wera, te whakaiti i ngā ngaronga pehanga, me te arotau i ngā tukanga whakawhiti wera.
6. Ngā Āhuatanga o ngā Matū me te Tūranga o te Enthalpy
He maha ngā pūnaha mīhini e whakamahi ana i ngā wai mahi pērā i te hau, te mamaoa, ngā hau mura, ngā pouaka whakamātao rānei. Hei whakahaere i te tātaritanga o ngā pūnaha rere, ka whakamahia te enthalpy (h), e tautuhia ana ko:
\[
h = u + Pv
\]
He tino whai hua te enthalpy i roto i ngā taputapu pēnei i ngā tāpine, ngā compressors, ngā nozzles, ngā boilers, me ngā exchanger wera nā te mea ka māmā ake te tatau i ngā huringa pūngao i roto i te rere.
Hei tauira, i roto i te huringa mamaoa (Rankine), ka whakamahia ngā raraunga enthalpy i ngā pūwāhi rerekē (putanga o te kohua, putanga o te tāpine, putanga o te pūngao, putanga o te papu) hei tatau:
– te mahi a te tāhū,
– te mahi papu,
– ka uru te wera ki roto i te kōhua,
– te wera para o te pūwhakamātao,
– te pai o te huringa wera.
7. Te Huringa Termodynamic i roto i te Pūnaha Mīhini
He maha ngā wā ka tātarihia ngā mīhini tūturu hei huringa, arā, he raupapa tukanga e hoki ana ki tōna āhua tīmatanga. Ko ngā huringa nui i roto i te miihini:
a. Pahikara Otto (mīhini penehīni)
E whakaahua ana i te mura i te rōrahi tata tonu. Ka pāngia te whai huatanga e te ōwehenga kōpeketanga. Ka whakanui ake ngā ōwehenga kōpeketanga teitei ake i te whai huatanga, engari ka whakawhāitihia e te patuki me te kaha o te rauemi.
b. Huringa tīhiera (mīhini tīhiera)
Ka puta te tahunga i te pēhanga tata tonu. Ko te tikanga he nui ake ngā ōwehenga kōpeketanga o ngā miihini tīhiera, ā, ka pai ake te whai huatanga me te taipana nui ake.
c. Huringa Brayton (tāpine hau)
E whakamahia ana i roto i ngā miihini rererangi me ngā tipu hiko tāpine hau. Ko ngā wāhanga matua ko: te compressor, te rūma mura, me te tāpine. Ka piki ake te whai huatanga me te ōwehenga o te pēhanga me te pāmahana o te tāpine, ka nui haere te hiranga o ngā rauemi ātete wera me te pūnaha whakamatao o te mata o te tāpine.
d. Huringa Rankine (whakaputa mamaoa)
E whakamahia ana i roto i ngā tipu hiko waro me ngā pūnaha tāpine mamaoa. Ka whakapai ake i te mahi huringa mā te whakamahana nui, te whakamahana anō, me te whakamahana wai whāngai whakaora.
e. Huringa Whakamatao Kōpeketanga Kohu
E whakamahia ana i roto i ngā hauhautanga me ngā pouaka whakamātao. Ngā wāhanga matua: te pūwhakapūngao, te pūwhakapūngao, te takirere whānui, te pūwhakapūngao. Ko te tauwehenga mahi (COP) he tawhā matua, e pāngia ana e te rerekētanga pāmahana i waenga i te pūwhakapūngao me te pūwhakapūngao me te whai huatanga o te pūwhakapūngao.
8. Te Whakamahinga o te Thermodynamics i roto i te Hoahoa me te Arotautanga Mīhini
I roto i te mahi, kāore te thermodynamics e tū takitahi; e hono ana ki te whakawhiti wera, te miihini wai, ngā rauemi, me te whakahaere. Ko ngā tono noa ko:
– Arotake pūngao: tatauhia te wāhi e tomo ai te pūngao, e ngaro ai, kātahi ka kimihia ngā whai wāhitanga whai hua.
– Te kōwhiringa o ngā tikanga whakahaere: te whakatau i te pēhanga me te pāmahana tino pai i roto i te pōro, te compressor, te turbine rānei.
– Te hoahoa whakawhiti wera: ka whakarite kia nui te whakawhiti wera me te kore e nui te ngaronga pehanga.
– Te whakahaere tukunga: mā te tahunga pai ake ka whakaitihia te whakapaunga wahie me ngā tukunga CO₂; ka pā hoki te whakahaere pāmahana ki te NOx.
– Whakahaere whakamatao: ka pupuri i te pāmahana haumaru o ngā wāhanga miihini, ka roa ake hoki te ora o te miihini.
Whakamutunga
Ko ngā kaupapa matua o te thermodynamics—mai i ngā ariā o ngā pūnaha me ngā āhua, te Ture Kore ki te Ture Tuarua, me ngā āhuatanga o te matū me ngā huringa—ka whakarato i te anga matua mō te mārama ki te mahi a ngā mīhini me ngā rohe o tā rātou mahi. Ka āwhina te Ture Tuatahi ki te whakatū i ngā taurite pūngao me te tatau i te mahi me te wera, ko te Ture Tuarua ia e whakamārama ana i te ahunga o ngā tukanga me ngā pūtake o ngā ngaronga e whakawhāiti ana i te whai huatanga. Mā tēnei māramatanga, ka taea e ngā kaihangarau te hoahoa i ngā mīhini whai hua ake, pono ake, me te pai ake ki te taiao, me te arotau i te mahi a ngā pūnaha pūngao puta noa i ngā momo rāngai ahumahi me te kawe waka.
