Ko te tōtika o engines wera. Ko te tōtika o te pūkaha wera - Tātai

mau Modern rapu engines wera mahi whanui. whakamātau maha ki te whakakapi a ratou ki motors hiko i pangia ana kore. Ko te raruraru e pā ana ki te haaputuputuraa o te kaha i roto i ngā pūnaha motuhake, e faatiti'aifarohia ki uaua nui.

Tonu raruraru hāngai o hokohoko hangarau mana pūhiko e hāngai ana i runga i to ratou whakamahi wā roa-. He tawhiti āhuatanga tere o waka hiko i te hunga i roto i waka, engines parariraa ā-.

Ko te kaupae tuatahi i roto i te hanga o engines ranu tino e taea te whakaiti i te tukunga kikino i roto i ngā wāhi tāone, whakaoti rapanga taiao.

He hītori iti

Kua te taea o te huringa o te pūngao o te mamaoa ki te pūngao neke kua mohiotia mai nga wa onamata. 130 BC: tohe Geron Aleksandriysky aroaro ki te ha'uti whakarongo mamaoa - eolipil. Poi ki tonu i te korohū, ka haere mai ki hurihanga i raro i te mana ahu i ona seti. e kore e kitea tenei tauira o te mīhini huri hiko mamaoa hou i te wa o te tono.

No te tau maha, me te whanaketanga rau philosopho i whakaaro ai tika te takawairore ngahau. I roto i 1629 i hanga te Italian D. Branca te mīhini huri hiko kōkiri. Couples whakaturia i roto i te nekehanga i te kōpae whakaratohia ki matatahi.

Mai i taua wa i timata ai te whanaketanga tere o engines korohū.

pūkaha wera

Ko te huringa o te pūngao ā-o te wahie ki te pūngao o te nekehanga o te mihini me te ngā tikanga e whakamahia ana i roto i engines wera.

wāhanga Main o mīhini: he whakamahana (pūnaha fariiraa i pūngao i waho), i te tinana te mahi (mahi he pānga painga), pouaka.

hangaia te whakamahana te hoki ki te inu mahi whakaemi nui kararehe o te pūngao ā-mō te mahi whai hua. e atu mātao pūngao i te taikaha.

huaina te huru matua o te kakama ko te tōtika o engines wera. E whakaatu ana tēnei rahinga aha wahi o te pūngao i whakapaua i roto i te pau ki te mahi mahi whai hua whakawera. E kore ai te teitei te tōtika, te mahi pai o te mīhini, ko tenei uara nui 100%.

Tātaitanga o te kakama

Kia whakawera pūngao riro waho rite ki Q _1. Utauta tinana mahia te mahi A, i ko te pūngao pouaka homai Q _2.

I runga i te faaotiraa, tātai tatou te uara pai:

η = A / Q _1. amo tatou e A = Q ₁ - Q _2.

No reira te tōtika o te pūkaha wera, homai te tātai o nei e η = (Q ₁ - Q ₂₎ / Q ₁ = 1 - Q ₂ / Q _1, taea te whakatau e whai ake nei:

• e kore e taea e te kaha nui 1 (100% ranei);
• ki te whakanui i tēnei rahinga me te whakanui ake i roto i te pūngao rānei whiwhi i te whakamahana, i te hekenga o te pūngao homai pouaka ranei;
• te whakanui ake i te mana whakamahana whakatutuki i te huringa o te kounga wahie;
• whakaiti pūngao, homai te pouaka, tukua ki te whakatutuki i te āhuatanga hoahoa o nga engines.

He pūkaha wera pai

He taea te hanga o te pūkaha taua, te tōtika o e pai hei te mōrahi (i roto i te pai - rite ki te 100%)? Kimihia te whakahoki ki tenei pātai tamata ki ahupūngao Wīwī me te mataaro pūkaha pūmanawa Sadi Carnot. I te tau 1824 i tukua ana tātaitanga ariā e pā ana ki te tukanga e puta ana i roto i te hau.

Ka taea te whakaaro te whakaaro taketake whakaurua i roto i te mīhini pai tukanga reversible whakahaere ki hau pai. Tīmata ki roha o te isothermally hau i te pāmahana T _1. Ko te nui o te wera e hiahiatia mo tenei whakaaro, - Q _1. I muri hau i waho whakawhänui wera (he tukanga adiabatic). I muri pa i te pāmahana T _2, kōpeke te hau e isothermally e haere i te pūngao Q pouaka _2. whakamana hoki hau ki tona āhua taketake te adiabatically.

Ko te tōtika o te Carnot pūkaha wera pai ki te tātai tangohia ko te ōwehenga o te rerekētanga pāmahana i waenganui i te whakawera, me te meangiti pūrere ki te pāmahana, e kua he whakamahana. / T ₁ - η = (T ₂ T _1): rite tenei titiro te _reira.

Pea kakama waiariki o te mīhini, e tātai kua te puka: η = 1 - T ₂ / T _1, tei anake i runga i te uara o te whakamahana me te mātao pāmahana, me te kore e taea e nui ake i te 100%.

Ano, tenei hononga e āhei tetahi ki te whakamatau e taea e rite ki te kotahitanga anake, no te te pouaka te tōtika o engines wera tino kore te pāmahana. Ka rite ki mohiotia te, he roaahia'tu tenei uara.

tātaitanga ariā Carnot tukua ki te whakatau i te tōtika mōrahi o te pūkaha o tetahi hoahoa wera.

ture tauwehe kï a Carnot ko e whai ake. pūkaha wera noho i raro i kore tūkunga taea ki te whai tōtika ki runga ake i te taua uara o te tōtika pūkaha wera pai.

He tauira o te whakaoti rapanga

TAUIRA 1. He aha te pai o te pūkaha wera pai, ka te pāmahana whakamahana he 800 C me ^te pāmahana o te pouaka 500 ^C i raro?

T ₁ = 800 ^{° C} = 1073 K, ΔT = 500 ^{° C} = 500 K, η -?

otinga:

Na roto i te definition: η = (T ₁ - T ₂₎ / T _1.

kihai i hoatu e matou te pāmahana o te pouaka, engari ΔT = (T ₁ - T _2), i konei:

η = ΔT / T ₁ = 500 K / 1073K = 0,46.

Whakautu: kakama = 46%.

Tauira 2. Te whakatau i te tōtika o te pūkaha wera pai, ki te tika ana ki te pūngao i mahi riro tetahi mano waengao whakawera mahi whai hua 650 J. He aha te mea te pāmahana o te whakamahana o te pūkaha wera, ki te coolant pāmahana -. 400 K?

Q ₁ = 1 kJ = 1000 J He = 650 J, T ₂ = 400 K, η - ?, T ₁ =?

otinga:

I roto i tenei mahi, ko reira te tāutanga waiariki, te tōtika o e taea te tatau e te tātai:

η = A / Q _1.

Hei whakatau i te pāmahana o te whakamahana whakamahi tātai tōtika o te pūkaha wera pai:

η = (T ₁ - T ₂₎ / T ₁ = 1 - T ₂ / T _1.

Mahi panoni pāngarau, whiwhi tatou:

T ₁ = T ₂ / (1- η).

T ₁ = T ₂ / (1- A / Q _1).

whakatatau matou:

η = 650 J / 1000 J = 0,65.

T = 400 K ₁ / (1- 650 J / 1000 J) = 1142.8 K.

Whakahoki kupu: η = 65%, T ₁ = 1142.8 K.

tikanga tūturu

He pūkaha wera pai hangaia ki te tukanga pai. whakamana ana te mahi kei te anake i roto i ngā tukanga isothermal, kua tautuhi reira rite te wāhi rohe e te kauwhata o te huringa Carnot.

I roto i te meka, ki te hanga i nga tikanga mo te rere o huringa mana hau i roto i te tukanga, i waho tahi huringa i roto i te pāmahana e kore e taea e. No rauemi taua, e kia tutakina te utu wera ki te taonga e karapoti ana. riro taea tukanga Adiabatic ki te kawe i roto i. I roto i te take o te utu wera pāmahana hau tika me huri.

Ko te tōtika o mihini waiariki hanga i roto i ngā āhuatanga tūturu rerekē tino i te tōtika pai o engines. Kia mōhio e tupu te rere o ngā tukanga i roto i engines tūturu na nohopuku e kore e taea te utua te rerekētanga o te pūngao ngāwhā ā o te mahi taonga i roto i te tukanga o te huri tona rōrahi mā te tomonga o te nui o te whakamahana wera me te hoki mātao.

Ētahi atu engines wera

whakahaere engines Real i runga i huringa rerekē:

• huringa Otto tukanga rōrahi tamau ki huringa adiabatic, te hanga he koropiko kati;
• Diesel huringa isobar, adiabatic, isochore, adiabatic;
• he mīhini huri hiko hau: tukanga e puta ana i te pēhanga tamau, whakakapi adiabatic kati te koropiko.

Waihanga i te tukanga taurite i roto i engines tūturu (ki te kawe ia ratou ofi ki te pai) i roto i te hangarau hou e kore e taea. Ko tino raro te kaha o engines wera, ara ki te tikanga pāmahana taua rite i roto i te tautuhinga wera pai.

Otiia e kore e te mea e tika ana ki te whakaiti i te tūranga tātaitanga tātai tōtika o te huringa Carnot, rite he reira, riro te reira i te wāhi tohutoro i roto i te tukanga ki te whakapai ake i te tōtika o engines tūturu.

Ara ki te huri i te tōtika

Na roto i rite o engines wera pai, me te tūturu, kia tuhia te reira e kore e taea e noho te pāmahana whakamutunga o te pouaka. Ko te tikanga pouaka whakapono te kōhauhau. Ki te tango i te pāmahana o te kōhauhau taea tātai āwhiwhiwhi anake. E whakaatu ana Experience e te pāmahana coolant ko te hau whakapau i roto i engines, rite tupu te reira i roto i engines parariraa ā-(haapotohia rite DVS).

Hoki - te tino noa i roto i to tatou ao o te engine wera. engine wera te kaha i roto i tenei take, tei runga i te pāmahana i hanga e tahu wahie. Ko te rerekētanga faufaa i engines mamaoa hoki ko te mahi whakamahana fusion me te tinana pūrere mahi i roto i te ranunga rangi-wahie. He wera ranunga hanga pēhanga ki runga ki nga wahi neke o te pūkaha.

Te whakatairanga i te pāmahana hau mahi e tutuki, tino huri nga āhuatanga o te wahie. Kia aroha mai, e kore e taea ki te mahi i waho rohe. Tetahi rauemi o te hanganga o te ruma ngingiha pūkaha he tona ira whakakoero. Ko te ātete waiariki o taua rauemi - te āhuatanga taketake o te pūkaha, me te ki tino pā te tōtika.

pai Uara pūkaha

Ki te whakaaro tatou ki te mīhini huri hiko mamaoa, te pāmahana o te kokoru mamaoa mahi i te mea e rite ana ki te 800 K, me te hau whakapau - 300 K, he rite ki te 62% te tōtika o te mīhini. I roto i te vairaa mau, Heoi, tenei uara e kore nui ake 40%. Puta tika ki te mate te wera i roto i whare whakawera mīhini huri hiko tenei whakaiti.

E kore e te uara teitei o te tōtika o engines parariraa ā-nui 44%. Te whakanui ake i tēnei uara - te pātai o te heke mai e tata ana. Te huri i nga āhuatanga o ngā rauemi, wahie - ko te raruraru ki runga i kaimahi te feruriraa pai o te taata tenei.