Pfungwa yeSimba remukati muUinjiniya Masystem eThermodynamic
Mukudzidza nezve thermodynamics yeinjiniya, imwe yepfungwa dzakakosha asi dzakakosha mukuongorora masisitimu isimba remukati. Simba remukati, rinowanzo fananidzirwa naU, chikamu chakakosha chehunhu hwechinhu, chingave chinhu chakachena kana musanganiswa, mukati mesisitimu ye thermodynamic. Kunzwisisa kwakakodzera kwesimba remukati kunobatsira mainjiniya kutsanangura nekuverenga maitiro emasisitimu akadai se steam turbines, compressors, internal combustion engines, boilers, heat exchangers, uye mafiriji. Chinyorwa chino chinokurukura tsananguro yesimba remukati, zvarinoreva mumuviri, hukama hwaro nekupisa nebasa, basa raro muMutemo wekutanga weThermodynamics, uye mashandisirwo aro anoshanda mumasisitimu einjiniya.
1. Kunzwisisa Simba Remukati
Simba remukati isimba rese re microscopic rinochengetwa musystem nekuda kwekufamba uye kudyidzana kwezvikamu zvayo (mamorekuru, maatomu, maerekitironi). Kusiyana nesimba re kinetic ne potential, rinoonekwa pachiyero chikuru (semuenzaniso, chinhu chinofamba kana pakukwirira kwakati), simba remukati rine chekuita nezviitiko pa microscale: kudengenyeka kwemamorekuru, kutenderera, kushandurwa, simba rekubatanidza, uye simba rine chekuita nekugadzirwa kwemukati kwechinhu.
Mukufunga, simba rose rehurongwa rinogona kunyorwa semusanganiswa wesimba remukati nesimba guru:
\[
E = U + KE + PE
\]
ne:
– \(E\) = simba rose rehurongwa
– \(U\) = simba remukati
– \(KE\) = simba remakroskopu rekinetic
– \(PE\) = simba guru rinokwanisa kushandiswa
Mukuongorora kwakawanda kwe thermodynamic yeinjiniya, shanduko mu kinetic uye potential energy dzinowanzova diki pane shanduko mu internal energy kana enthalpy, uye nekudaro dzinowanzoregeredzwa kuti zvive nyore kuverenga (kunyangwe mune mamwe mashandisirwo akadai se nozzles kana turbines, kinetic energy inogona kukosha).
2. Simba remukati sehunhu hweThermodynamic
Simba remukati ibasa remamiriro ezvinhu. Izvi zvinoreva kuti kukosha kwesimba remukati kunoenderana chete nemamiriro aripo ehurongwa (semuenzaniso, tembiricha, kumanikidzwa, uye kuumbwa), kwete panzira inotorwa kusvika pamamiriro iwayo. Muchimiro chakasiyana, shanduko yesimba remukati inoratidzwa se:
\[
\Delta U = U_2 – U_1
\]
Zvinofanira kusimbiswa kuti kukosha kwakakwana kweU kwakaoma kuyera zvakananga, nekuti chinogona kuzivikanwa nekuyedza ndiko kuchinja kwesimba remukati (\(\Delta U\)). Saka, matafura ethermodynamic (semuenzaniso, matafura emvura inopfuta) anowanzo ratidza kukosha kwesimba remukati zvichienderana nemamiriro ekureva.
3. Zvinoreva Muviri: Zvikamu zveSimba reMicroscopic
Simba remukati i "nzvimbo" yesimba isingaonekwe nemaziso akawanda. Kazhinji, mipiro inobva musimba remukati inogona kusanganisira:
1. Simba rekushandura remamorekuru (rinoenderana nekupisa).
2. Simba rekutenderera uye rekudengenyeka (rakakosha mumagasi epolyatomic uye pakupisa kwakakwira).
3. Simba rinowanikwa pakati pemamorekuru (rinonyanya kuwanikwa muzvinwiwa nezvinhu zvakasimba, zvichikanganiswa nemasimba anokwezva ari pakati pemamorekuru).
4. Simba remakemikoro (rakakosha mukuita kwekupisa kana maitiro emakemikari).
5. Simba renyukireya (rinowanzo furatirwa mu thermodynamics yeinjiniya yekare kunze kwemu nucleus reactor systems).
Nekuti zvikamu izvi zvinokanganiswa nekupisa uye chimiro chechigadzirwa, simba remukati rine hukama hwakasimba nekupisa. Kune gasi rakakodzera, simba remukati rinonyanya kushanda nekupisa chete.
4. Hukama huripo pakati peSimba remukati nekupisa nebasa
Imwe pfungwa isiriyo inowanzo fungwa ndeyekuti simba remukati rinoonekwa se "rakafanana" nekupisa. Kutaura zvazviri:
– Kupisa (Q) isimba rinofamba richiyambuka muganhu wesystem nekuda kwekusiyana kwekupisa.
– Basa (W) isimba rinopfuudzwa kuburikidza nemuganhu wesisitimu nekuda kwesimba rinoshanda kuburikidza nekubviswa (semuenzaniso basa remuganhu \(P\,dV\), basa remugodhi paturbine, basa remagetsi, nezvimwewo).
– Simba remukati (U) isimba rinochengetwa muhurongwa sepfuma yenyika.
Kana sisitimu inogamuchira kupisa, simba rayo remukati rinogona kuwedzera, asi kwete nguva dzose—nekuti rimwe simba rinouya rinogona kushandurwa kuita basa rinobuda. Kusiyana neizvi, kana sisitimu ikashanda, simba rayo remukati rinogona kudzikira kunyangwe pasina kupisa kunorasika, sezvakaita mukuwedzera kweadiabatic.
5. Simba remukati muMutemo wekutanga weThermodynamics
Mutemo wekutanga weThermodynamics unotaura nezvekuchengetedzwa kwesimba. Kune system yakavharwa, chimiro chinowanzoonekwa ndeichi:
\[
\Delta U + \Delta KE + \Delta PE = Q - W
\]
Kana shanduko mu kinetic uye potential energy dzikagona kuregeredzwa:
\[
\Delta U = Q – W
\]
Equation iyi inotsanangura kuti shanduko yesimba remukati inotsamira pakuenzana kwesimba: simba rinopinda sekupisa richibvisa simba rinobuda sebasa.
Muenzaniso wepfungwa
– Pakudziisa gasi mumudziyo wakasimba (huwandu hunogara huripo), basa remuganhu ndiro \(W = 0\), kuitira kuti kupisa kwese kuri kuuya kuwedzere simba remukati: \(\Delta U = Q\).
– Mukuwedzera kweadiabatic (hapana kutamiswa kwekupisa, \(Q=0\)), sisitimu inoshanda uye simba rayo remukati rinoderera: \(\Delta U = -W\).
6. Musiyano uripo pakati peSimba remukati neEnthalpy
Muinjiniya thermodynamics, kunze kwesimba remukati, enthalpy (H) inozivikanwawo:
\[
H = U + PV
\]
Enthalpy inowanzo shanda zvakanyanya mukushandiswa mumasystem ekuyerera (control volume) akadai sematurbine, macompressor, maboiler, uye ma heat exchangers, nekuti izwi rekuti \(PV\) rinomiririra "basa rekuyerera" rine chekuita nekusundira mvura mukati nekubuda mu control volume.
Zvisinei, simba remukati rinoramba richikosha zvikuru, kunyanya mu:
– masisitimu akavharwa (semuenzaniso cylinder-piston),
- maitiro ehuwandu hunogara huripo,
- ongororo yenguva pfupi pamatangi,
- uye kusarudzwa kwehunhu hwethermodynamic hwezvinhu pasi pemamwe mamiriro ezvinhu.
7. Simba remukati muGasi Rakakodzera
Kuti pave negasi rakakodzera, simba remukati rinongoenderana chete nekupisa:
\[
U = U(T)
\]
Saka shanduko yesimba remukati inogona kuverengerwa nehukuru hwekupisa pahuwandu husingachinji (\(C_v\)):
\[
\Delta U = m\int_{T_1}^{T_2} C_v(T)\, dT
\]
Kana \(C_v\) ichionekwa seisina kuchinja:
\[
\Delta U = m C_v (T_2 – T_1)
\]
Inobatsira zvikuru pakuverenga nekukurumidza pane zvikamu zveinjiniya zvakaita semagadzirirwo ekudzvanywa/kuwedzera kwegasi, kuongorora kwakakodzera kwemafambiro (Otto, Diesel, Brayton), uye kuverenga kwekufambiswa kwesimba rekutanga.
8. Simba remukati muzvinhu chaizvo uye utsi hwemvura
Muzvinhu chaizvo zvakaita semvura, mafiriji, kana musanganiswa wemahydrocarbon, simba remukati harisi nguva dzose rinokonzerwa nekupisa chete. Rinokanganiswawo nekumanikidzwa uye chikamu (mvura, utsi, musanganiswa). Saka, ongororo yesimba remukati inowanzoreva:
– tafura yethermodynamic (tafura yemhepo),
– madhayagiramu e \(Pv\), \(Ts\), kana \(hs\),
- kana kuenzanisa kwemamodheru ehurumende nepfuma.
Semuenzaniso, mumvura: simba remukati rinowedzera zvakanyanya kana paine shanduko yechikamu kubva pamvura yakasviba kuenda kumhepo yakasviba nekuda kwesimba rakavanda rine chekuita nekuputsika kwemasimba ekukwezva pakati pemamorekuru.
9. Kushandiswa kweSimba remukati muMainjiniya eThermodynamic Systems
Kunzwisisa simba kune simba rakananga pakugadzirwa uye kuongororwa kwekushanda kwemidziyo yeinjiniya, semuenzaniso:
1. Kamuri rekupisa uye injini yekupisa mukati: shanduko musimba mumagasi ekupisa dzine chekuita nekuburitswa kwesimba remakemikari uye tembiricha yegesi.
2. Matangi ekuchengetera ane pressurized: maitiro ekuzadza/kubvisa zvinhu anogona kuongororwa kuburikidza nekuchinja kwesimba remukati memvura iri mutangi, kunyanya mumamiriro ezvinhu e adiabatic kana transient.
3. Mabhoyira nemakondensa: kunyangwe kuongorora kuyerera kwemvura kuchiwanzoshandisa enthalpy, simba remukati rinobatsira kunzwisisa shanduko dzechikamu uye kuenzana kwesimba remukati memvura.
4. Sisitimu yekuisa mufiriji: simba remukati rinotsanangura shanduko dzesimba mufiriji panguva yekudzvanywa, kuwedzeredzwa, uye kutamiswa kwekupisa, kunyanya kana ikaongororwa sesisitimu yakavharwa mune zvimwe zvikamu.
10. Mhedziso
Simba remukati ipfungwa huru muinjiniya yethermodynamics nekuti inomiririra simba re microscopic rinochengetwa musystem sepropathi yenyika. Kuburikidza neMutemo wekutanga weThermodynamics, shanduko musimba remukati dzine chekuita nekutamiswa kwekupisa nebasa, nokudaro zvichigadzira hwaro hwekuongorora simba remaitiro akasiyana-siyana einjiniya. Mumagasi akakodzera, simba remukati rinonyanya kutsamira pakupisa, nepo muzvinhu chaizvo, simba remukati rinokanganiswa nemamiriro echikamu nekumanikidzwa. Nekunzwisisa simba remukati zvakadzama, mainjiniya anogona kuvaka mamodheru akanyatsojeka, kuita kuverenga kwakanaka, uye kuita sarudzo dzakakodzera dzekugadzira mukushandiswa kwakasiyana-siyana kwesystem yekupisa.
Kana muchida, ndinogona kuwedzera mienzaniso yekuverenga nhamba (semuenzaniso kupisa gasi mu cylinder kana kuwedzera adiabatic) kuti pfungwa yesimba remukati ive yakasimba.
