Pofuna kufotokoza njira zosasinthika za thermodynamic, asayansi adapanga lamulo lachiwiri la thermodynamics. Lamulo lachiwiri la thermodynamics limafotokoza njira zomwe zingachitike m'chilengedwe chonse ndi njira zomwe sizingachitike. Wasayansi wina dzina lake RJE Clausius (1822-1888) adanena izi:
Mwachibadwa, kutentha kumasuntha kuchokera ku zinthu zotentha kwambiri kupita ku zinthu zotentha kwambiri; mwachibadwa, kutentha sikupitirira kuchokera ku zinthu zotentha kwambiri kupita ku zinthu zotentha kwambiri (Lamulo lachiwiri la thermodynamics—mawu a Clausius).
Mawu a Clausius ndi amodzi mwa mawu apadera a lamulo lachiwiri la thermodynamics. Amatchedwa mawu apadera chifukwa amagwira ntchito pa njira imodzi yokha, yokhudzana ndi kusamutsa kutentha. Popeza mawu awa sakugwirizana ndi njira zina, tikufunika mawu ochulukirapo. Kukula kwa mawu onse a lamulo lachiwiri la thermodynamics kumachokera ku kuphunzira kwa injini zotentha. Chifukwa chake, timakambirana kaye za kutentha kwa injini.
Injini Yotenthetsera
Mphamvu zambiri zomwe timagwiritsa ntchito zimachokera ku mphamvu ya mankhwala yomwe ili mu mafuta, gasi, malasha. Mphamvu ya mankhwala yomwe imagwiritsidwa ntchito kuti igwiritsidwe ntchito mwachindunji iyenera kuyatsidwa kaye. Nthawi zambiri, kuyatsa mafuta (mafuta, gasi, ndi malasha) kumabweretsa kutentha. Kutentha kungagwiritsidwe ntchito mwachindunji kuphika chakudya, kutentha chipinda. Kuti tisunthe china chake (monga kusuntha galimoto), tiyenera kusintha kutentha kukhala mphamvu ya kinetic kapena mphamvu ya makina (mphamvu ya makina = mphamvu yamagetsi + mphamvu ya kinetic).
Chida chomwe chimagwiritsa ntchito kutentha pogwira ntchito chinapezeka mu 1700. Chinali injini ya nthunzi. Injini ya nthunzi inayamba kugwiritsidwa ntchito popopera madzi kuchokera mu mgodi wa malasha.
Kugwiritsa ntchito injini za nthunzi chifukwa nthunzi imatha kusuntha zinthu. Mainjini a nthunzi amaphatikizapo injini yotenthetsera (injini yotenthetsera ndi chida chosinthira kutentha kukhala mphamvu yamakina). Tsopano injini ya nthunzi imagwiritsidwa ntchito popanga mphamvu zamagetsi. Mainjini amakono otenthetsera ndi mainjini oyaka mkati monga mainjini a magalimoto, injini za njinga zamoto, ndi zina zotero.
Lingaliro lalikulu la kugwiritsa ntchito injini zotenthetsera ndilakuti kutentha kumatha kusinthidwa kukhala mphamvu yamakina ngati kutentha kuloledwa kuyenda kuchokera kutentha kwambiri kupita kutentha kochepa. Panthawiyi, kutentha kwina kumasinthidwa kukhala mphamvu yamakina (kutentha kwina kumagwiritsidwa ntchito kugwira ntchito), kutentha kwina kumatulutsidwa m'malo otentha pang'ono. Njira yosinthira mawonekedwe a mphamvu ndi kusamutsa mphamvu mu injini yotenthetsera ikuwoneka ngati chithunzichi.
Kutentha kwambiri (T)H) ndi kutentha kochepa (TL) amatchedwa kutentha kwa makina. QH ndi kutentha komwe kumachokera kutentha kwambiri, pomwe QL kutentha kumayenda kupita kumalo otentha kwambiri. Kutenthako kukachokera kutentha kwambiri kupita ku kutentha kochepa, kutentha kwina kumasanduka mphamvu yamakina (yogwiritsidwa ntchito), kutentha kwina kumatayidwa ngati QLKutentha konse sikungasinthidwe kukhala ntchito (W), nthawi zonse pamakhala kutentha komwe kumatulutsa (QLChoncho, potengera kusunga mphamvu, QH = W + QL.
Pali injini zambiri zotenthetsera, kuphatikizapo injini za nthunzi ndi injini zoyatsira moto mkati.
SteamEngine
Mainjini a nthunzi amagwiritsa ntchito nthunzi ya madzi ngati njira yosamutsira kutentha. Nthunzi imagwira ntchito ngati madzi. Pali mitundu iwiri ya mainjini a nthunzi: injini zosinthirana za nthunzi ndi injini za nthunzi za turbine. Kapangidwe ka injini iyi ndi kosiyana, koma mitundu iwiriyi ya mainjini a nthunzi imagwiritsa ntchito nthunzi yomwe imatenthedwa ndi mafuta, gasi, malasha kapena kugwiritsa ntchito mphamvu ya nyukiliya.
Zipangizo Zoyaka Mkati
Injini za njinga zamoto ndi injini zamagalimoto ndi zitsanzo za injini zoyatsira mkati. Zimatchedwa injini zoyatsira mkati chifukwa njira yoyatsira imachitika mkati mwa masilinda otsekedwa. Kupezeka kwa injini yoyatsira mkati ndi chifukwa cha lingaliro la uinjiniya la kupsinjika ndi kukulitsa kwa adiabatic.
Kugwiritsa Ntchito Injini Yotenthetsera
Kugwira ntchito bwino kwa injini yotenthetsera (e) ndi kuyerekeza pakati pa ntchito (W) yochitidwa ndi makina pogwiritsa ntchito chotenthetsera kutentha kwambiri (Q H ).
W ndiye phindu lomwe limalandiridwa, pomwe Q H ndiye mtengo womwe umagwiritsidwa ntchito pogula ndikuwotcha mafuta. Monga anthu omwe nthawi zonse amafuna kupeza phindu lalikulu komanso ndalama zochepa zomwe amagwiritsa ntchito, tikukhulupirira kuti kuwonjezeka kwa phindu (W) kukugwirizana ndi mtengo womwe timagwiritsa ntchito (Q H ). Kodi zingatheke?
Kutengera ndi kusunga mphamvu, kutentha (Q H ) kuyenera kukhala kofanana ndi ntchito (W) + kutentha kotulutsidwa (Q L ).
M'malo mwa W mu equation 1 ndi W mu equation 2
Iyi ndi njira yowerengera mphamvu ya injini yotentha.
Funso 1:
Injini yotenthetsera imatenga kutentha kwa ma Joules 3000 (Q H ), imagwira ntchito (W) ndikuchotsa kutentha kwa ma Joules 2500 (Q L ). Werengani momwe kutentha kwa injini kumagwirira ntchito.
Anakonza
Kugwiritsa ntchito bwino kwa injini yotenthetsera = 17%.
Funso 2:
Injini yotenthetsera imatenga kutentha kwa 3000 Joule (Q H ), imagwira ntchito (W) ndikuchotsa kutentha kwa 2000 Joule (Q L ). Werengani momwe injini yotenthetsera imagwirira ntchito.
Anakonza
Kugwiritsa ntchito bwino kwa injini yotenthetsera = 34%.
Funso 3:
Injini yotenthetsera imatenga ma Joules 3000 a kutentha (Q H ), imagwira ntchito (W) ndipo imatulutsa ma Joules 1500 a kutentha (Q L ). Muwerengere momwe injini yotenthetsera imagwirira ntchito?
Anakonza
Kugwiritsa ntchito bwino kwa injini yotenthetsera = 50%.
