Ukuze bachaze izinqubo ze-thermodynamic ezingaguquki, ososayensi bakha umthetho wesibili we-thermodynamics. Umthetho wesibili we-thermodynamics uchaza ukuthi yiziphi izinqubo ezingenzeka endaweni yonke nokuthi yiziphi izinqubo ezingenakwenzeka. Usosayensi othile ogama lakhe lingu-RJE Clausius (1822-1888) wenza lesi sitatimende esilandelayo:
Ngokwemvelo, ukushisa kuhamba kusuka ezintweni ezinokushisa okuphezulu kuya ezintweni ezinokushisa okuphansi; ngokwemvelo, ukushisa akuqhubeki kusuka ezintweni ezinokushisa okuphansi kuya ezintweni ezinokushisa okuphezulu (Umthetho wesibili we-thermodynamics—isitatimende sikaClausius).
Isitatimende sikaClausius singenye yezitatimende ezikhethekile zomthetho wesibili we-thermodynamics. Sibizwa ngokuthi isitatimende esikhethekile ngoba sisebenza kuphela enkambisweni eyodwa kuphela, ehlobene nokudluliswa kokushisa. Njengoba lesi sitatimende singahlobene nezinye izinqubo, sidinga isitatimende esibanzi kakhulu. Ukuthuthukiswa kwesitatimende esijwayelekile zomthetho wesibili we-thermodynamics kusekelwe ocwaningweni lwezinjini zokushisa. Ngakho-ke, sixoxa ngokushisa kwenjini kuqala.
Injini Yokushisa
Amandla amaningi esiwasebenzisayo avela emandleni amakhemikhali aqukethwe kuphethiloli, igesi, amalahle. Amandla amakhemikhali aqukethwe ukuze asetshenziswe ngqo kumele ashiswe kuqala. Ngokuvamile, ukushiswa kwamafutha emvelo (uwoyela, igesi, namalahle) kukhiqiza ukushisa. Ukushisa kungasetshenziswa ngqo ukupheka ukudla, igumbi lokufudumeza. Ukuze sithuthe okuthile (njengokuhambisa imoto), kumelwe siguqule ukushisa kube amandla e-kinetic noma amandla e-mechanical (amandla e-mechanical = amandla aqukethwe + amandla e-kinetic).
Ithuluzi elisebenzisa ukushisa ukwenza umsebenzi latholakala ngo-1700. Kwakuyinjini yomusi. Injini yomusi yaqala ukusetshenziswa ukupompa amanzi emayini yamalahle.
Ukusetshenziswa kwezinjini zomusi kungenxa yokuthi umusi ungahambisa izinto. Izinjini zomusi zifaka injini yokushisa (injini yokushisa iyithuluzi lokuguqula ukushisa kube amandla omshini). Manje injini yomusi isetshenziselwa ukukhiqiza amandla kagesi. Izinjini zokushisa zanamuhla ziyizinjini zokushisa zangaphakathi njengezinjini zezimoto, izinjini zezithuthuthu, njll.
Umqondo oyisisekelo ngemuva kokusetshenziswa kwezinjini zokushisa ukuthi ukushisa kungaguqulwa kube amandla omshini uma ukushisa kuvunyelwe ukugeleza kusuka emazingeni okushisa aphezulu kuya emazingeni okushisa aphansi. Phakathi nale nqubo, ukushisa okuthile kuguqulwa kube amandla omshini (ukushisa okuthile kusetshenziselwa ukwenza umsebenzi), ukushisa okunye kukhishwa ezindaweni ezinokushisa okuphansi. Inqubo yokushintsha isimo samandla kanye nokudluliselwa kwamandla enjini yokushisa ibukeka njengale dayagramu.
Izinga lokushisa eliphezulu (T)H) kanye nokushisa okuphansi (TL) zibizwa ngokuthi izinga lokushisa lokusebenza komshini. QH ukushisa okugeleza kusuka ekushiseni okuphezulu, kanti u-QL ukushisa kugeleza endaweni enezinga lokushisa eliphansi. Uma kugeleza kusuka emazingeni okushisa aphezulu kuya emazingeni okushisa aphansi, ukushisa okuthile kuguqulwa kube amandla omshini (asetshenziswa ukusebenza), ukushisa okunye kulahlwa njengo-QLKonke ukushisa akukwazi ukuguqulwa kube umsebenzi (W), kuhlala kukhona ukushisa okukhululwayo (QLNgakho-ke, ngokusekelwe ekulondolozweni kwamandla, u-QH = W + QL.
Kunezinjini eziningana zokushisa, okuhlanganisa izinjini zomusi kanye nezinjini zokushisa zangaphakathi.
Injini ye-Steam
Izinjini zomusi zisebenzisa umusi wamanzi njengendlela yokudlulisa ukushisa. Umusi uketshezi olusebenzayo. Kunezinhlobo ezimbili zezinjini zomusi: izinjini zomusi ezishintshanayo kanye nezinjini zomusi we-turbine. Umklamo wale njini uhlukile, kodwa lezi zinhlobo ezimbili zezinjini zomusi zisebenzisa umusi oshiswa ngokushisa uwoyela, igesi, amalahle noma ukusebenzisa amandla enuzi.
Izinjini Zomlilo Zangaphakathi
Izinjini zezithuthuthu nezinjini zezimoto ziyizibonelo zezinjini zokushisa zangaphakathi. Zibizwa ngokuthi injini yokushisa yangaphakathi ngoba inqubo yokushisa yenzeka ngaphakathi kwamasilinda avaliwe. Ukuba khona kwenjini yokushisa yangaphakathi kuwumphumela womqondo wobunjiniyela wokucindezela nokukhulisa i-adiabatic.
Ukusebenza Kahle Kwenjini Yokushisa
Ukusebenza kahle kwenjini yokushisa (e) ukuqhathanisa phakathi komsebenzi (W) owenziwa umshini nge-Heat input ekushiseni okuphezulu (Q).H).
U-W uyinzuzo etholwayo, kanti u-QH yizindleko ezitholakalayo zokuthenga nokushisa uphethiloli. Njengabantu abafuna njalo ukuthola inzuzo ephezulu kanye nezindleko ezincane kakhulu, sithemba ukuthi inzuzo ekhuphukile (W) ilingana nezindleko esizisebenzisayo (Q).HKungenzeka yini lokho?
Ngokusekelwe ekulondolozweni kwamandla, ukushisa (QH) kumele ilingane nomsebenzi (W) + ukushisa okukhishwe (QL).
Faka u-W esilinganisweni 1 no-W esilinganisweni 2
Lesi yisibalo sokusebenza kahle kwenjini yokushisa.
Umbuzo 1:
Injini yokushisa imunca ama-Joules angu-3000 (Q)H) ukushisa, kuyasebenza (W) futhi kususe ama-Joules angu-2500 (Q)L) ukushisa. Bala ukusebenza kahle kokushisa kwenjini.
Isixazululo
Ukusebenza kahle kwenjini yokushisa = 17%.
Umbuzo 2:
Injini yokushisa imunca ukushisa okungu-3000 Joule (Q)H), iyasebenza (W) futhi isusa ukushisa okungu-2000 Joule (Q)LBala ukusebenza kahle kwenjini yokushisa.
Isixazululo
Ukusebenza kahle kwenjini yokushisa = 34%.
Umbuzo 3:
Injini yokushisa imunca ukushisa okungu-3000 Joule (Q)H), iyasebenza (W) futhi iphonsa ukushisa okungafika kuma-Joules angu-1500 (QLBala ukusebenza kahle kwenjini yokushisa?
Isixazululo
Ukusebenza kahle kwenjini yokushisa = 50%.
