Chii chinonzi Flow Coefficient
Flow Coefficient, inozivikanwa seCv (US/EU Standard), Kv (International Standard), kana kuti C-value, ipfungwa inokosha yehunyanzvi inotsanangura kugona kwekufamba kwemavharuvhu emaindasitiri akadai semavharuvhu ekudzora nemaregulator.
Kutsanangura Kukosha kweCV
Valve Cv inomiririra chiyero chekuyerera kwemvura chinoratidza kugona kwevharuvhu kupfuudza mvura mumamiriro ezvinhu chaiwo. Inoyera huwandu hwekuyerera kwemvura kana gasi kuburikidza nevharuvhu pakuderera kwekumanikidzwa kwakapihwa. Cv yakakwira inoratidza kugona kukuru kwekuyerera kwemvura.
Chii chinonzi Cv (Kukosha Kwesimba)
Valve Cv (Kukosha Kwekugona) inoyera kugona kwekufamba kwemvura uye inoverengerwa pasi pemamiriro ekuyedza akajairwa:
• Vharuvhu rakavhurika zvizere
• Kuderera kwekumanikidzwa (ΔP) kwe1 psi pamusoro pevharuvhu
• Mvura: Mvura pa60°F (15.5°C)
• Mwero wekuyerera kwemvura: Magaloni eUS paminiti (GPM)
Kuvhurwa kweVharuvhu vs. Kukosha kweCv
Cv/Kv nekuvhurwa kwevharuvhu (%) pfungwa dzakasiyana:
• Tsanangudzo yeKv (China Standard):Mwero wekuyerera kwemvura mu m³/h kana ΔP = 100 kPa, huwandu hwemvura mumvura = 1 g/cm³ (mvura patembiricha yemumba).
*Muenzaniso:Kv=50 zvinoreva kuyerera kwe50 m³/h pa100 kPa ΔP.*
• Percentage Yekuvhura:Nzvimbo yevharuvhu/dhisiki (0% = yakavharwa, 100% = yakavhurika zvizere).
Kuverenga maCv & Key Applications
Cv inokonzerwa nekugadzirwa kwevharuvhu, saizi, zvinhu, kuyerera kwemvura, uye hunhu hwemvura (tembiricha, kumanikidzwa, viscosity).
Fomura huru ndeiyi:
Cv = Q / (√ΔP × √ρ)
Kupi:
• Mubvunzo= Mwero wekuyerera kwehuwandu
•ΔP= Musiyano wekumanikidzwa
•ρ= Kuwanda kwemvura
Kuchinja: Cv = 1.167 Kv
Basa muKusarudzwa kweValve & Dhizaini
Cv inokanganisa zvakananga kushanda zvakanaka kwehurongwa hwekudzora mvura:
•Inosarudza saizi yakakwana yevharuvhu uye mhando yehuwandu hwekuyerera kwechinangwa
•Inovimbisa kugadzikana kwehurongwa (semuenzaniso, inodzivirira kufamba kwepombi mukuvaka)
•Zvakakosha pakugadzirisa simba
Kusiyana kweCV muMarudzi eValve
Kugona kuyerera kwemvura kunosiyana zvichienderana nekugadzirwa kwemavharuvhu (data rinobva kuASME/API/ISO zviyero):
| Rudzi rweVharuvhu | Hunhu Hunokosha | Muenzaniso weCV (FCI Standard) |
|---|---|---|
Vharuvhu yeGedhi | Cv yepakati (DN100 ≈ 400); kudzorwa kusina kunaka; dzivisa kuvhurika kwe <30% (njodzi yekukanganisika zvichienderana neASME B16.34) | DN50: ~120 |
Vharuvhu yeBhora | High Cv (1.8× gedhi mavharuvhu); linear flow control; API 6D inokurudzirwa kumapaipi | Bhora reV reDN80: ≈375 |
Vharuvhu yeBhatafurayi | Inodhura zvishoma kune saizi hombe; ±5% chaiyo (triple-offset); kuwedzera kwemvura kushoma >70% kwakavhurika | Chingwa cheDN150: ~2000 |
Vharuvhu Yepasi | Kudzivirira kwakanyanya (Cv ≈ 1/3 yemavharuvhu ebhora); kutonga kwakarurama (kushandiswa kwekurapa/kurabhoritari) | DN50: ~40 |
MaParamita Ekufamba Kwemukati & Zvinhu Zvinopesvedzera
Kushanda kwevharuvhu kunotsanangurwa nematanho matatu (sekureva kweFluid Controls Institute):
1. Kukosha kweCV:Kuyerera kweGPM pa1 psi ΔP (semuenzaniso, vharuvhu yebhora yeDN50 ≈ 210 vs. vharuvhu yegedhi ≈ 120).
2. Chiyero chekudzivirira kuyerera kwemvura (ξ):
•Vharuvhu yeshavishavi: ξ = 0.2–0.6
•Vharuvhu yeguruva: ξ = 3–5
Nhungamiro dzeSarudzo & Pfungwa Dzakakosha
Kugadziriswa kweViscosity:
Isa ma multipliers kuCv (semuenzaniso, mafuta asina kucheneswa: 0.7–0.9 pa ISO 5208).
Mavharuvhu Akangwara:
Kugadzirisa Cv munguva chaiyo (semuenzaniso, Emerson DVC6200 positioner).
Masisitimu Ekuyedza Kuyerera Kwemafuta
Kuyedza kunoda mamiriro akadzorwa nekuda kwekukwanisa kuyera:
•Kugadzika (Semufananidzo 1):
Chinoyera kufamba kwemvura, thermometer, mavharuvhu ekudzora, vharuvhu yekuyedza, geji yeΔP.
1. Chiyero chemvura 2. Thermometer 3. Vharuvhu yethrottle yekukwira 4 ne7. Maburi ekudzvanya pressure tapping 5. Vharuvhu yekuyedza 6. Mudziyo wekuyera musiyano wepressure 8. Vharuvhu yethrottle yekudzika stream
4. Kureba kuri pakati pegomba rekubata pressure nevharuvhu kwakapetwa kaviri kupfuura dhayamita yepombi
7. Kureba kuri pakati pegomba rekubata pressure nevharuvhu kwakapetwa katanhatu kupfuura dhayamita yepombi
•Kudzora Zvikuru:
- Vharuvhu rinokwira pamusoro rinogadzirisa kumanikidzwa kwekupinda kwemvura.
- Vharuvhu repasi rinochengetedza kumanikidzwa kwakasimba (hukuru hwepakati > vharuvhu yekuyedza kuona kuti kuyerera kwakavharwa kunoitikainvharuvhu yekuyedza).
•Mitemo:
JB/T 5296-91 (China) vs. BS EN1267-1999 (EU).
•Zvinhu Zvakakosha:
Nzvimbo yekudonhedza mvura, magadzirirwo epombi, nhamba yeReynolds (zvinwiwa), nhamba yeMach (magasi).
Miganhu Yekuyedza & Mhinduro:
•Mavharuvhu ekuyedza masisitimu aripo iye zvino ≤DN600.
•Mavharuvhu makuru:Shandisa bvunzo yekuyerera kwemhepo (hazvina kutsanangurwa pano).
Kukanganiswa kweNhamba yaReynolds: Ruzivo rwekuyedza runosimbisa kuti nhamba yaReynolds inokanganisa zvakanyanya mhedzisiro yebvunzo.
Zvinhu Zvinokosha Zvaunofanira Kuziva
•Cv/Kv inotsanangura kugona kwevharuvhu pasi pemamiriro ezvinhu akajairwa.
•Rudzi rwevharuvhu, saizi, uye hunhu hwemvura zvinokanganisa zvakanyanya Cv.
•Kuyedza kunoda kutevedzera mitemo (JB/T 5296-91/BS EN1267) kuti zvive zvechokwadi.
•Kugadziriswa kunoshanda pakukora, tembiricha, uye kumanikidzwa.
(Ruzivo rwese rwunobva kuASME/API/ISO standards uye mawhitepaper emugadziri wemavharuvhu.)
Nguva yekutumira: Ndira-06-2025