k = isoentropic exponent
Bohlokoa ba k bakeng sa valve ea tšireletso
e hlophisitsoeng ke Alessandro Ruzza
by Rentato Pintabona 'me Panio Colacicco
Tekanyo ea li-valve tsa ts'ireletso tse etselitsoeng ho ntša likhase kapa mouoane, ho latela lspesl Collection "E", e hloka tsebo ea exponent ea isoentropic k maemong a ho tsoa.
Tšebeliso e sa tsotelleng ea lspesl Collection "E" khaolo ea "E.1", mabapi le boholo ba li-valve tsa tšireletso, e ka lebisa ho fetelletseng ha matla a ho ntša li-valve le li-discs tsa ho phatloha.
Sengoliloeng sena se fana ka tataiso e itseng ho hakanya boleng ba k bakeng sa likhase tsa sebele le
e totobatsa phoso ka ho nahana ka k e lekanang le karo-karolelano ea mocheso o khethehileng Cp/Cv
Ho phalla ha isoentropic ka nozzle
Mokhoa [1] e sebelisoang pokellong ea "E", hammoho le ka Setaliana se seng [2] le kantle ho naha [3] standLi-arrds, bakeng sa lipalo tsa li-valve tsa tšireletso tse lokelang ho ntša likhase kapa mouoane, ke tsa isoentropic e tsoang ka molomo tlas'a maemo a mahlonoko a ho qhomela, ao bakeng sa khase e loketseng e leng:
moo expansiho coefficient C e fanoa ke:
ho k moemeli oa isoentropic expansika equation: 
| Fluid | P1 (bar) | T1 (°C) | q' (kg/h) | q (kg/h) | (q'/q) x 100 |
|---|---|---|---|---|---|
| Methane | 12 | 50 | 1472 | 1466 | 100.4 |
| Methane | 23 | 200 | 2314 | 2267 | 102.1 |
| propane | 12 | 100 | 2261 | 2181 | 103.7 |
| Hexane | 12 | 178 | 3099 | 2740 | 113.1 |
| Hexane | 23 | 220 | 6519 | 5111 | 127.5 |
| Heptane | 12 | 215 | 3232 | 2821 | 114.4 |
q'= sekhahla sa phallo se baloang ka k = Cp/Cv (20 °C, 1 atm)
q = sekhahla sa phallo se baloang ka k = (Cp/Cv) • (Z/Zp)
Ka ho hlahisa coefficient ea liteko k ea phallo ea valve ea polokeho, eo lefats'e ka bophara e nkang ts'ebetso ea 'nete ea ho tsoa ha valve, coefficient ea polokeho ea 0.9 le compressibility factor Z.1 bakeng sa mokelikeli oa 'nete, re fihla ha ho etsoa pokello ea "E":
The isoentropic exponent k e ka hlalosoa e le:
![[2]](https://i0.wp.com/www.besa.it/wp-content/uploads/2022/06/Schermata-2022-06-30-alle-15.39.24.png?ssl=1)
Bakeng sa khase e loketseng, bakeng sa eng P x V / R x T =1 , ho bontšoa hore k e lekana le karo-karolelano ea Cp / Cv pakeng tsa mocheso o khethehileng khatellong ea kamehla le molumo.
Bakeng sa khase ea sebele, k e ka hlalosoa (sheba Sehlomathiso B) ka:
![[3]](https://i0.wp.com/www.besa.it/wp-content/uploads/2022/07/Schermata-2022-06-30-alle-15.39.46.png?ssl=1)
moo Z e leng ntlha ea compressibility e hlalosoang ke Z=P x V / R x T 'me Zp ke "derived compressibility factor". Ha o sebelisa foromo [3], ho ea ka pokello "E", litekanyetso tsa Cp/Cv, Z le Zp li tlameha ho hlahlojoa maemong a ho ntša P.1 le T1.
Ntho e nkiloeng ea compressibility factor Zp e hlalosoa ka foromo [4] joaloka:
![[3.1]](https://i0.wp.com/www.besa.it/wp-content/uploads/2022/07/Schermata-2022-06-30-alle-15.40.20.png?ssl=1)
The compressibility factor Z e ka hlalosoa ka tsela e latelang:
![[4]](https://i0.wp.com/www.besa.it/wp-content/uploads/2022/07/Schermata-2022-06-30-alle-15.40.29.png?ssl=1){kind=small}
'me ka ho tšoanang, e ka hlalosoa e le:
![[5]](https://i0.wp.com/www.besa.it/wp-content/uploads/2022/07/Schermata-2022-06-30-alle-15.40.36.png?ssl=1){kind=small}
moo boleng ba Z^0, Z^1, Zp^0, Zp^1 bo thathamisitsoeng ho Sehlomathiso sa A e le mosebetsi oa Pr le Tr.
In [4] 'me [5], Ω ke ntlha ea bohlokoa ea Pitzer e hlalosoang ke:
![[10]](https://i0.wp.com/www.besa.it/wp-content/uploads/2022/07/Schermata-2022-06-30-alle-15.40.44.png?ssl=1){kind=small}
Moo Pr^SAT e leng khatello e fokotsehileng ea mouoane e tsamaellanang le boleng bo fokotsehileng ba mocheso Tr=T/Tc=0,7. Sehlomathiso A se bonts'a boleng ba Ω ba maro a mang. Z e Zp e ka boela ea nkiloe ka ho toba ho equation ea tlhahlobo ea naha.
Mohlala oa lipalo
Ha re retelehela ho mohlala oa linomoro, ha re re re hloka ho bala matla a ho ntša valve tlas'a maemo a latelang:
| Fluid | n-Butano | |
| Boemo ba mmele | mouoane o chesang haholo | |
| Boima ba limolek'hule | M | 58,119 |
| Beha khatello | P | 19,78 bar |
| Ho imeloa kelellong | 10% | |
| Mocheso oa metsi | T | 400 K |
| Efflux coefficient | 0,9 | |
| Bophara ba Orifice | Do | 100 limilimithara |
khatello ea mali e fanoa ke:
ho ba bakeng sa n-Butane: Tc=425,18 K le Pc=37,96 bar, re na le:
'me re sebelisa litafole tse Sehlomathisong sa A, re na le:
Ho tseba bophahamo bo itseng ba mouoane maemong a ho tsoa (P1, T1) e lekanang le 0,01634 m^3/kg (0,0009498 m^3/g-mole), re ka boela ra bala Z ho tsoa ho:
Ha ho nahanoa karo-karolelano ea mocheso o ikhethileng khatellong e sa feleng le molumo, maemong a ho tsoa (P1, T1), e lekanang le 1,36, ho tsoa ho foromo [3] re na le:
147060
Ho sebelisa foromo [1], e ileng ea rarolloa bakeng sa ho baloa ha sekhahla sa phallo, re na le tekanyo ea phallo ea phallo ea 147.060 lik'hilograma / h.
174848
Haeba ho e-na le hoo re sebelisitse boleng ba Cp/Cv ho 1 atm le 20 °C, re ka be re bile le k =1,19 le ho tsoa ho foromo [1] sekhahla sa phallo ea phallo ea 174.848 lik'hilograma / h.
Sena se ka be se ile sa re lebisa ho feteletsa ho tsoa bokhoni ba valve ea tšireletso ka ho pota-pota 19%
TEMENYETSO:
Phoso e ka etsoang ka ho abela boleng ba Cp/Cv ho k e ka ba holimo haholo ho feta mohlala ona.
HO FETA 20%
Ho fana ka maikutlo, tafole e latelang e bonts'a sekhahla sa phallo ea 18-mm orifice bakeng sa li-hydrocarbon tse ling tse tletseng, tse baloang maemong a mabeli. Lipalo li entsoe ka ho khetheha developed Software.
| Fluid | P1 (bar) | T1 (°C) | q' (kg/h) | q (kg/h) | (q'/q) x 100 |
|---|---|---|---|---|---|
| Methane | 12 | 50 | 1472 | 1466 | 100.4 |
| Methane | 23 | 200 | 2314 | 2267 | 102.1 |
| propane | 12 | 100 | 2261 | 2181 | 103.7 |
| Hexane | 12 | 178 | 3099 | 2740 | 113.1 |
| Hexane | 23 | 220 | 6519 | 5111 | 127.5 |
| Heptane | 12 | 215 | 3232 | 2821 | 114.4 |
Software ha e sebelise liforomo [4] [5] empa, ho qala ho e fetotsoeng Redlich le Kwong equation of state, e lekanya boleng ba exponent ea isoentropic ho sebelisa likhokahano tsa thermodynamic.
