Izinqubo ze-athikili ze-Thermodynamic: Isothermal Adiabatic Isochoric Isobaric
Kunezinqubo ezine ze-thermodynamic, okuyizinqubo ze-Isothermal, i-isochoric, i-isobaric kanye ne-adiabatic.
Inqubo ye-Isothermal (izinga lokushisa elihlala njalo)
Enqubweni ye-isothermal, izinga lokushisa lesistimu ligcinwa lingaguquguquki. Ngokwethiyori, uhlelo oluhlaziyiwe luyigesi elifanele. Izinga lokushisa legesi elifanele lilingana ngqo namandla egesi angaphakathi afanele (U = 3/2 n RT). I-T ayishintshi, ngakho-ke i-U nayo ayishintshi. Ngakho-ke, uma isetshenziswa enqubweni ye-isothermal, umthetho wokuqala we-thermodynamic equation uba:
Δ U = Q – W
Amandla angaphakathi awashintshi, ngakho-ke u-Δ U = 0.
0 = Q – W
Q = W
Ngokusekelwe kulesi sibalo, enkambisweni ye-isothermal (izinga lokushisa elihlala njalo), ukushisa (Q) okungeziwe ohlelweni kusetshenziswa uhlelo ukwenza umsebenzi (W).
Ushintsho ekucindezelweni kanye nomthamo wesistimu enqubweni ye-isothermal luboniswa yigrafu engezansi:
Ivolumu yesistimu yokuqala = V1 (ivolumu encane) kanye nokucindezela kwesistimu = P1 (ingcindezi enkulu). Ukuze izinga lokushisa lesistimu lihlale linjalo, ngemva kokufakwa kokushisa ohlelweni, uhlelo luyanda futhi lusebenze endaweni ezungezile. Ngemva kokuba uhlelo lusebenze endaweni ezungezile, ivolumu yesistimu ishintsha ibe yi-V2 (ivolumu yesistimu iyakhuphuka) kanye noshintsho lwengcindezi yesistimu ku-P2 (ukwehla kwengcindezi yesistimu). Ukuma kwegrafu kugobile ngoba ingcindezi yesistimu ayishintshi njalo phakathi nenqubo. Inani lomsebenzi owenziwe ohlelweni = indawo enomthunzi.
Inqubo ye-Adiabatic
Enqubweni ye-adiabatic, akukho ukushisa okungezwa ohlelweni noma okushiya uhlelo (Q = 0). Izinqubo ze-Adiabatic zingenzeka ezinhlelweni ezivaliwe ezihlukanisiwe kahle. Kuhlelo oluvaliwe oluvalwe kahle, ngokuvamile akukho ukushisa okugeleza ohlelweni noma okushiya uhlelo. Izinqubo ze-Adiabatic zingenzeka nasezinhlelweni ezivaliwe ezingahlukanisiwe.
Kulesi simo, inqubo kumele yenziwe ngokushesha ukuze ukushisa kungagelezi ohlelweni noma kuphume ohlelweni. Uma kusetshenziswa inqubo ye-adiabatic, umthetho wokuqala we-Thermodynamic equation uzoshintsha:
Δ U = Q – W
Akukho ukushisa okungaphakathi noma okungaphandle kwesistimu, ngakho-ke u-Q = 0.
Δ U = 0 – W
Δ U = -W
Uma uhlelo lucindezelwa ngokushesha (umsebenzi wenziwa ohlelweni), khona-ke umsebenzi uba muhle. Ngoba u-W uhle, khona-ke u-U uhle (amandla ohlelweni ayanda). Ngokuphambene nalokho, uma uhlelo lukhula ngokushesha (uhlelo luyasebenza), khona-ke u-W uhle. Njengoba u-W ehle, u-U uhle (amandla ohlelweni ancishisiwe). Amandla ohlelweni (igesi efanele) alingana nokushisa (U = 3/2 n RT), ngakho-ke uma amandla ohlelweni enyuka khona-ke izinga lokushisa ohlelweni nalo liyakhuphuka. Ngokuphambene nalokho, uma amandla ohlelweni encishisiwe, khona-ke izinga lokushisa ohlelweni liyancipha.
Ushintsho ekucindezelweni kwesistimu kanye nevolumu enqubweni ye-adiabatic luboniswa yigrafu engezansi:
Ijika le-adiabatic kule grafu (amajika 1-2) liphakeme kunejika le-isothermal (amajika 1-3). Lo mehluko wokuqina ubonisa ukuthi ngokwanda okufanayo kwevolumu, ingcindezi yesistimu yehliswa kakhulu enkambisweni ye-adiabatic kunenqubo ye-isothermal. Ingcindezi yesistimu yehla kakhulu enkambisweni ye-adiabatic ngoba lapho ukwanda kwe-adiabatic kwenzeka, izinga lokushisa lesistimu nalo liyehla. Izinga lokushisa lilingana nengcindezi, ngakho-ke uma izinga lokushisa lesistimu lehla, ingcindezi yesistimu nayo iyehla. Ngokungafani nenqubo ye-isothermal, izinga lokushisa lesistimu lihlala linjalo. Ngakho-ke, enkambisweni ye-isothermal, izinga lokushisa alithinti ukwehla kwengcindezi.
Isibonelo esisodwa senqubo ye-adiabatically senzeka enjinini yokushisa yangaphakathi, njengenjini yedizili kanye nenjini yephethiloli. Ezinjinini zedizili, umoya ufakwa esilinda, bese umoya ongaphakathi kwesilinda ucindezelwa ngokushesha kusetshenziswa i-piston (umsebenzi wenziwa emoyeni). Inqubo yokucindezela i-adiabatic (ukunciphisa ivolumu yesistimu) iboniswa ngejika 2-1. Ngenxa yokucindezela okusheshayo kwe-adiabatic, izinga lokushisa likhuphuka ngokushesha. Ngesikhathi esifanayo, i-diesel ifuthwa esilinda nge-injector, bese ingxube ivuselelwa ngokushesha. Enjinini yephethiloli, ingxube yomoya kanye nephethiloli ifakwa esilinda bese icindezelwa ngokushesha kusetshenziswa i-piston. Ngenxa yokuthi icindezelwa ngokushesha kwe-adiabatic, izinga lokushisa likhuphuka ngokushesha. Ngesikhathi esifanayo, ama-spark plugs ayavutha ukuze inqubo yokusha yenzeke.
Inqubo ye-Isochoric (ivolumu eqhubekayo)
Enqubweni ye-Isochoric, ivolumu yesistimu igcinwa ingaguquki. Njengoba ivolumu yesistimu ihlala ingaguquki, isistimu ayikwazi ukusebenza emvelweni. Imvelo nayo ayikwazi ukusebenza ohlelweni. Uma isetshenziswa enqubweni ye-isochoric, umthetho wokuqala we-thermodynamic equation ushintsha ube:
Δ U = Q – W
Uhlelo alusebenzi endaweni ezungezile, ngakho-ke u-W = 0
Δ U = Q – 0
Δ U = Q
Kusukela kulo mphumela, singaphetha ngokuthi enqubweni ye-isochoric (ivolumu eqhubekayo), ukushisa (Q) okungeziwe ohlelweni kusetshenziselwa ukwandisa amandla ohlelweni. Izinguquko ekucindezelweni kwesistimu kanye nevolumu enqubweni ye-isochoric ziboniswa yigrafu engezansi:
Ekuqaleni, ingcindezi yesistimu = p 1 (ingcindezi encane). Ukushisa okwengeziwe kwesistimu kubangela ukuthi amandla ohlelweni akhuphuke. Njengoba amandla ohlelweni ekhuphuka, izinga lokushisa lesistimu (igesi ekahle) liyakhuphuka (U = 3/2 n RT). Izinga lokushisa lilingana ngqo nengcindezi. Ngakho-ke, uma izinga lokushisa lesistimu likhuphuka, khona-ke ingcindezi yesistimu iyakhuphuka (p 2 ). Ngenxa yevolumu yesistimu engaguquki, akukho msebenzi owenziwayo (akukho ndawo enomthunzi).
Enqubweni ye-isochoric, uhlelo alukwazi ukusebenza emvelweni. Ngokufanayo, imvelo ayikwazi ukusebenza ohlelweni. Lokhu kungenxa yokuthi, enqubweni ye-isochoric, ivolumu yesistimu ihlala ingaguquki. Kunezinhlobo ezithile zomsebenzi ezingabandakanyi izinguquko zevolumu. Ngakho-ke noma ivolumu yesistimu ingashintshi, umsebenzi usengenziwa ohlelweni. Isibonelo, kukhona ifeni + ibhethri esitsheni esivaliwe. Ifeni ingajikeleza isebenzisa amandla ngebhethri. Kulokhu, amafeni, amabhethri, nomoya ngaphakathi kwesitsha kubhekwa njengezinhlelo.
Uma ifeni lijikeleza, ifeni liyasebenza, lidlala likhona esitsheni. Ngesikhathi esifanayo, amandla e-kinetic efeni aphenduka amandla emoyeni. Amandla kagesi ebhethri, vele, ancishisiwe ngoba ashintshe isimo abe amandla emoyeni. Lesi sibonelo sibonisa ukuthi enqubweni ye-isochoric (ivolumu ihlala ingaguquki), umsebenzi usengenziwa ohlelweni (umsebenzi ongahileli izinguquko zevolumu).
Inqubo ye-Isobaric (ingcindezi eqhubekayo)
Enqubweni ye-isobaric, ingcindezi yesistimu igcinwa ingaguquki. Njengoba ingcindezi ingaguquki, ushintsho lwamandla angaphakathi ( Δ U), ukushisa (Q) kanye nomsebenzi (W) enqubweni ye-isobaric akuzona i-zero. Ngakho-ke, ifomula yokuqala ye-thermodynamics ayikashintshi.
ΔU = Q − W
Izinguquko ekucindezelweni kanye nomthamo wegesi enqubweni ye-isobaric ziboniswa yigrafu engezansi:
Okokuqala, ivolumu yesistimu = V1 (ivolumu encane). Ngenxa yokuthi ingcindezi igcinwa ingaguquguquki, ngakho-ke ngemva kokufakwa kokushisa ohlelweni, uhlelo luyanda futhi lusebenze endaweni ezungezile. Ngemva kokusebenza endaweni ezungezile, ivolumu yesistimu ishintshela ku-V2 (ukwanda kwevolumu yesistimu). Inani lomsebenzi (W) uhlelo olwenziwe = indawo enomthunzi.
Umbuzo 1:
Amajika 1-2 kumadayagramu amabili angezansi abonisa ukwanda kwegesi (ukwanda komthamo wegesi) okwenzeka ngokwe-adiabatically kanye ne-isothermally. Kuyiphi inqubo, umsebenzi owenziwa yigesi mncane?
Umsebenzi owenziwa amagesi enqubweni ye-adiabatic ungaphansi komsebenzi owenziwa amagesi enqubweni ye-isothermal. Indawo enomthunzi = umsebenzi owenziwa yigesi ngesikhathi senqubo yokwandisa (ukwanda komthamo wegesi). Indawo enomthunzi enqubweni ye-adiabatic ingaphansi kwendawo enomthunzi yenqubo ye-isothermal.
Umbuzo 2:
Izinqubo ze-Thermodynamic ziboniswe kumdwebo ongezansi. Ama-curves ab kanye ne-dc = izinqubo ze-isochoric (ivolumu eqhubekayo). I-curve bc kanye ne-ad = inqubo ye-isobaric (ingcindezi eqhubekayo). Enqubweni ye-ab, ukushisa (Q) ama-Joules angu-600 kwengezwa ohlelweni. Enqubweni ye-bc, ukushisa (Q) ama-Joules angu-800 kwengezwa ohlelweni.
a) Izinguquko zamandla enqubweni ye-ab
b) Izinguquko zamandla enqubweni ye-abc
c) Ukushisa okuphelele okungeziwe enqubweni ye-ADC
P 1 = 2 x 10 5 Pa = 2 x 10 5 N / m 2
P 2 = 4 x 10 5 Pa = 4 x 10 5 N / m 2
V 1 = 2 amalitha = 2 dm 3 = 2 x 10 -3 m 3
V 2 = 4 amalitha = 2 dm 3 = 4 x 10 -3 m 3
Isixazululo
a) Izinguquko zamandla angaphakathi enqubweni ye-ab
Enqubweni ye-ab, kufakwa ukushisa okungu-600 J ohlelweni. Inqubo ab = inqubo ye-isochoric (ivolumu eqhubekayo). Enqubweni ye-isochoric, ukungezwa kokushisa ohlelweni kwandisa amandla ohlelweni kuphela. Ngakho-ke, amandla ayashintsha ohlelweni ngemva kokuthola ukushisa:
ΔU = Q
ΔU = 600 J
b) Izinguquko zamandla enqubweni ye-abc
Inqubo ab = inqubo ye-isochoric (ivolumu eqhubekayo). Enqubweni ye-ab, ukushisa okungu-600 J kwengezwa ohlelweni. Ngenxa yevolumu eqhubekayo, akukho msebenzi owenziwa uhlelo.
Inqubo bc = inqubo ye-isobaric (ingcindezi eqhubekayo). Enqubweni ye-bc, ukushisa (Q) 800 Joules kwengezwa ohlelweni. Enqubweni ye-isobaric, uhlelo lungenza umsebenzi. Inani lomsebenzi owenziwe uhlelo enqubweni ye-bc (inqubo ye-isobaric) yileli:
W = P (V 2 – V 1 ) — ukucindezela okungaguquki
W = P 2 (V 2 – V 1 )
W = 4 x 10 5 N/m 2 (4 x 10 -3 m 3 – 2 x 10 -3 m 3 )
W = 4 x 10 5 N/m 2 (2 x 10 -3 m 3 )
W = 8 x 10 2 amaJoule
W = 800 Joule
Ukushisa okuphelele okungeziwe ohlelweni enqubweni ye-abc yilokhu:
Ingqikithi ye-Q = Q ab + Q bc
Ingqikithi ye-Q = 600 J + 800 J
Ingqikithi ye-Q = ama-Joules angu-1400
Umsebenzi ophelele owenziwe uhlelo enqubweni ye-abc uwukuthi:
Ingqikithi engu-W = W ab + W bc
Ingqikithi engu-W = 0 + u-W bc
Ingqikithi engu-W = 0 + 800 amaJoule
Ingqikithi engu-W = 800 Joule
Izinguquko zamandla angaphakathi enqubweni abc = 600 J
c) Ukushisa okuphelele okungeziwe enqubweni ye-ADC
Ukushisa okuphelele okungeziwe ohlelweni kungabalwa ngesibalo esingezansi:
ΔU = Q - W
Q = ΔU + W
Ukushisa okuphelele okungeziwe ku-process adc = izinguquko zamandla angaphakathi ku-adc + umsebenzi ku-process adc.
Ukushisa nomsebenzi kuhilelekile ekudlulisweni kwamandla phakathi kwezinhlelo nendawo ezungezile, kuyilapho izinguquko zamandla zangaphakathi ziwumphumela wokudluliselwa kwamandla phakathi kwesistimu nendawo ezungezile. Ngakho-ke, ushintsho lwamandla aluxhomekile enqubweni yokudluliselwa kwamandla. Ngakolunye uhlangothi, ukushisa nomsebenzi kuncike enqubweni. Enqubweni ye-isochoric (uhlelo lwevolumu oluqhubekayo), ukudluliselwa kwamandla kwenzeka kuphela ngesimo sokushisa, kuyilapho umsebenzi ungenjalo. Enqubweni ye-isobaric (ukucindezela okuqhubekayo), ukudluliselwa kwamandla kuhilela ukushisa nomsebenzi. Nakuba kungaxhomekile enqubweni, amandla ayashintsha kuye ngesimo sokuqala nesimo sohlelo lokugcina. Uma izimo zokuqala nezokugcina zifana, izinguquko zamandla zihlala zifana, nakuba inqubo ihlukile.
Izimo zokuqala nezokugcina zenqubo ye-abc kugrafu engenhla = izimo zokuqala nezokugcina zenqubo ye-adc. Ngakho-ke, amandla angaphakathi ayashintsha enqubweni ye-adc = 600 J.
Umsebenzi ophelele (W) owenziwe ku-adc = W inqubo kusikhangiso + W inqubo ye-dc.
Inqubo yesikhangiso iyinqubo ye-isobaric (ukucindezela okuqhubekayo), kuyilapho inqubo ye-dc iyinqubo ye-isochoric (umthamo oqhubekayo). Ngenxa yevolumu engaguquki, akukho msebenzi owenziwayo enqubweni ye-dc. Okokuqala, sibala umsebenzi owenziwe enqubweni yesikhangiso.
Isikhangiso se-W = P (V 2 - V 1 )
Isikhangiso se-W = P 1 (V 2 - V 1 )
I-Wad = 2 x 10 5 N/m 2 (4 x 10 ‐3 m 3 ‐ 2 x 10 ‐3 m 3 )
I-Wad ad = 2 x 10 5 N/m 2 (2 x 10 ‐3 m 3 )
Isikhangiso se-W = 4 x 10 2 Joule
Isikhangiso se-W = ama-Joule angu-400
Ingqikithi engu-W = u-W enqubweni a-d + u-W enqubweni d-c
Isamba esingu-W = amaJowule angu-400 + 0
Ingqikithi engu-W = 400 Joule
Ngakho-ke, inani lokushisa elingeziwe enqubweni ye-ADC yileli:
Q = ΔU + W
Q = 600 J + 400 J
Q = 1000 J
Umbuzo 3:
Ilitha eli-1 lamanzi liphenduka amalitha ayi-1671 esitimu uma libilisiwe ngomfutho we-atm ongu-1. Bala ushintsho lwamandla angaphakathi kanye nomsebenzi owenziwa amanzi uma ehwamuka … (Ukushisa kokuhwamuka kwamanzi = L V = 22.6 x 10 5 J/Kg)
Isixazululo
Ubuningi bamanzi = 1000 kg/ m3
Ukushisa kokuhwamuka kwamanzi (L V ) = 22.6 x 10 5 J / Kg
P = 1 atm = 1.013 x 10 5 Pa = 1.013 x 10 5 N/m 2
V 1 = 1 ilitha = 1 dm 3 = 1 x 10 -3 m 3 (Umthamo wamanzi)
V 2 = 1671 amalitha = 1671 dm 3 = 1671 x 10 -3 m 3 (Umthamo womusi)
a) Izinguquko emandleni angaphakathi
Izinguquko emandleni angaphakathi = Ukushisa okungeziwe emanzini ngaphandle komsebenzi owenziwe ngamanzi lapho ehwamuka. Ukubala kokuqala Ukushisa (Q) okungeziwe emanzini …
Q = m L V
Ubuningi bamanzi = isisindo samanzi / umthamo wamanzi
Isisindo samanzi (m) = ukuminyana kwamanzi x ivolumu yamanzi
Isisindo samanzi (m) = (1000 kg/m3 ) ( 1 x 10 -3 m3 )
Isisindo samanzi (m) = (1000 kg/m3 ) (0.001 m3 )
Isisindo samanzi (m) = 1 kg
Q = (1 kg) (22.6 x 10 5 J / kg)
Q = 22.6 x 10 5 J
Bala umsebenzi (W) owenziwe ngamanzi lapho ehwamuka. Ukubila kwamanzi kwenzeka ngokucindezela okungaguquki (inqubo ye-isobaric).
W = p (V 2 – V 1 )
W = 1.013 x 10 5 N/m 2 (1671 x 10 -3 m 3 – 1 x 10 -3 m 3 )
W = 1.013 x 10 5 N/m 2 (1670 x 10 -3 m 3 )
W = 1691.71 x 105 amaJoules
W = 1.7 x 105 amaJoules
Izinguquko emandleni angaphakathi emanzini:
ΔU = Q - W
ΔU = 22.6 x 10 5 J – 1.7 x 10 5 J
ΔU = 20.9 x 10 5 J
ΔU = 21 x 10 5 J
Ukushisa okungu- 21 x 10 5 Joule okufakwe emanzini kusetshenziselwa ukwandisa amandla angaphakathi (ukunqoba amandla okudonsa phakathi kwama-molecule agcina amanzi egeleza). Ngamanye amazwi, u-21 x 10 5 J usetshenziselwa ukuguqula amanzi abe umusi. Uma amanzi esephenduke umusi, u-1.7 x 105 J osele usetshenziselwa ukwenza umsebenzi.
Umbuzo 4:
I-mole eyodwa yegesi esilinda ikhula ngokushesha ngokushesha. Ekuqaleni, izinga lokushisa legesi = 1000 K. Ngemva kokukhula, izinga lokushisa legesi lehla liye ku-500 K. Thola umsebenzi owenziwe yigesi …
Isixazululo
Ukwanda kwegesi kwenzeka ngesikhathi sokushisa. Enqubweni ye-adiabatic, akukho ukushisa okungena noma okuphuma ohlelweni. Ngakho-ke, umsebenzi owenziwa kugesi = izinguquko zamandla kugesi.
ΔU = Q – W noma W = Q – Δ U → Q = 0
W = 0 – ΔU
W = – ΔU
Singabala izinguquko zamandla kugesi sisebenzisa i-energy equation kugesi efanele:
ΔU = 3/2 (1 mol) (8.315 J / mol. K) (500 K – 1000 K)
ΔU = 3/2 (1 mol) (8.315 J / mol. K) (- 500 K)
ΔU = -6236.25 J
Ngakho-ke, inani lomsebenzi owenziwa yigesi yileli:
W = – ΔU
W = – (- 6236.25 J)
W = 6236.25 J
