Chiyambi cha mawu a pampu wamba (6) - Pump cavitation theory

Cavitation of Pump: Chiphunzitso ndi Kuwerengera

Chidule cha cavitation phenomenon
Kuthamanga kwa madzi vaporization ndi vaporization kuthamanga kwa madzi (zimalimbikitsa nthunzi kuthamanga). Kuthamanga kwa vaporization kwamadzi kumakhudzana ndi kutentha. Kutentha kwapamwamba, kumapangitsanso kuthamanga kwa vaporization. Kuthamanga kwa vaporization kwa madzi oyera pa kutentha kwa 20 ℃ ndi 233.8Pa. Pamene kuthamanga kwa vaporization kwa madzi pa 100 ℃ ndi 101296Pa. Chifukwa chake, madzi oyera kutentha kutentha (20 ℃) ​​amayamba kuphweteka pomwe kuthamanga kumatsika mpaka 233.8Pa.
Pamene kuthamanga kwa madzi ndi kuchepetsedwa kwa vaporization kuthamanga pa ena kutentha, madzi adzabala thovu, amene amatchedwa cavitation. Komabe, nthunzi mu kuwira kwenikweni si nthunzi kwathunthu, komanso muli mpweya (makamaka mpweya) mu mawonekedwe a kuvunda kapena phata.
Pamene thovu kwaiye pa cavitation otaya mkulu kuthamanga, buku amachepetsa ndipo ngakhale anaphulika. Chodabwitsa ichi kuti thovu kutha mu madzi chifukwa kuthamanga nyamuka amatchedwa cavitation kugwa.

Chodabwitsa cha cavitation mu mpope
Pamene mpope ikugwira ntchito, ngati dera la m'deralo la gawo lake likusefukira (kawirikawiri penapake kuseri kwa cholowera cha impeller tsamba). Pazifukwa zina, pamene kuthamanga mtheradi wa madzi amapopedwa akutsikira kwa vaporization kuthamanga panopa kutentha, madzi amayamba nthunzi kumeneko, kupanga nthunzi ndi kupanga thovu. Mivubu imeneyi imayenderera kutsogolo ndi madziwo, ndipo ikafika kumtunda wina wake, madzi othamanga kwambiri ozungulira mavuvuwo amachititsa thovulo kuti liphwanyike kwambiri ngakhalenso kuphulika. Pamene kuwira kuphulika, madzi particles adzadzaza patsekeke pa liwiro lalikulu ndi kugundana wina ndi mzake kupanga madzi nyundo. Chodabwitsa ichi chidzapangitsa kuwonongeka kwa dzimbiri pazigawo zomwe zikupitilira apo zikachitika pakhoma lolimba.
Njira imeneyi ndi mpope cavitation ndondomeko.

Mphamvu ya pampu cavitation
Kupanga phokoso ndi kugwedera
Kuwonongeka kwa dzimbiri kwa zigawo zomwe zatsala pang'ono
Kuwonongeka kwa magwiridwe antchito

a

Pampu cavitation Basic equation
NPSHr-Pump cavitation allowance imatchedwanso zofunika cavitation allowance, ndipo imatchedwa mutu wofunikira kunja.
NPSHa-Cavitation allowance ya chipangizocho imatchedwanso kuti cavitation allowance, yomwe imaperekedwa ndi chipangizo choyamwa. Kukula kwa NPSHA, m'pamenenso mpopeyo udzakhala cavitation. NPSha imachepa ndi kuchuluka kwa magalimoto.

b

Ubale pakati pa NPSHa ndi NPSHr pakapita kusintha

Kuwerengera njira ya chipangizo cavitation

hg=Pc/ρg-hc-Pv/ρg-[NPSH]

[NPSH]-Chilolezo chovomerezeka cha cavitation
[NPSH] = (1.1 ~ 1.5) NPSHr

Pamene kuthamanga kuli kwakukulu, tengani mtengo waukulu, ndipo pamene kuthamanga kuli kochepa, tengani mtengo wochepa.


Nthawi yotumiza: Jan-22-2024