Cavitation chirwere chinokuvadza chinowanzoitika mu centrifugal pumping units. Cavitation inogona kuderedza kushanda kwepombi, kukonzeresa kuzununguka uye ruzha, uye kutungamirira kukukuvara kwakakomba kune impeller yepombi, imba yepombi, shaft, uye zvimwe zvikamu zvemukati. Cavitation inoitika apo kudzvinyirirwa kwemvura mupombi inodonha pasi pemhepo inopisa, zvichiita kuti mhepo inoputika iite munzvimbo yakaderera. Aya mabhuru emhute anodonha kana kuti "implode" zvine chisimba kana achipinda munzvimbo ine-high-pressure. Izvi zvinogona kukonzera kukuvadzwa kwemuchina mukati mepombi, kugadzira mapoinzi asina simba anogona kukukurwa nekuora, uye kukanganisa kushanda kwepombi.

Kunzwisisa uye kushandisa nzira dzekudzikisa cavitation kwakakosha kuchengetedza kuvimbika kwekushanda uye hupenyu hwesevhisi. kupatsanura casing pombi .

Mhando dzeCavitation mumapombi

Kuti uderedze kana kudzivirira cavitation mupombi, zvakakosha kuti unzwisise marudzi akasiyana e cavitation anogona kuitika. Mhando idzi dzinosanganisira:

1.Vaporization cavitation. Iyo inozivikanwawo se "classic cavitation" kana "net positive suction head available (NPSHa) cavitation," iyi ndiyo inonyanya kuzivikanwa mhando ye cavitation. Split casing pombi dzinowedzera kukurumidza kwemvura sezvainopfuura nepaburi rekusveta impeller. Kuwedzera kwevelocity kwakaenzana nekuderera kwemvura. Kudzikiswa kwemutsindo kunogona kuita kuti imwe mvura ifashaire (vaporize) uye igadzire mhute inopfungaira, iyo inodonha zvine chisimba uye kuburitsa masaisai madiki anovhundutsa kana asvika pakakwirira-pressure.

2. Turbulent cavitation. Zvikamu zvakaita semagokora, mavharuvhu, mafirita, nezvimwewo mupombi system inogona kunge isingakodzeri huwandu kana chimiro chemvura inopomba, iyo inogona kukonzera eddies, mhirizhonga uye kudzvanywa mutsauko mukati memvura yese. Kana zviitiko izvi zvikaitika pakupinza kwepombi, zvinogona kukanganisa zvakananga mukati mepombi kana kuita kuti mvura ipere.

3. Blade syndrome cavitation. Iyo inozivikanwawo se "blade pass syndrome", iyi mhando ye cavitation inoitika kana iyo impeller dhayamita yakakurisa kana mukati mukati mepombi imba yakanyanyisa kukora / pombi yemukati dhayamita idiki. Chero kana ese maviri emamiriro aya anoderedza nzvimbo (kucheneswa) mukati mepombi imba kusvika pasi pemazinga anogamuchirwa. Kuderedzwa kwemvumo mukati mepombi yepombi kunokonzera kuyerera kwemvura kunowedzera, zvichiita kuti kuderera kwekumanikidzwa. Kudzikiswa kwekumanikidza kunogona kuita kuti mvura inyunguduke, ichigadzira cavitation mabhubhu.

4.Internal recirculation cavitation. Kana pombi yepakati-inopatsanura isingakwanise kuburitsa mvura pachiyero chinoyerera, inoita kuti imwe kana yese yemvura itenderere yakatenderedza impeller. Recirculating fluid inopfuura nenzvimbo dzakaderera uye dzakanyanya kudzvanywa, izvo zvinogadzira kupisa, high velocity, uye inoumba vaporization mabhubhu. Chikonzero chinowanzokonzera kutenderera kwemukati ndechekumhanya pombi nevhavha yepombi yakavharwa (kana pachiyero chekuyerera).

5. Air entrainment cavitation. Mhepo inokwanisa kukweverwa mupombi kuburikidza nevharuvhu yakundikana kana kuti yakasununguka. Kana wapinda mupombi, mhepo inofamba nemvura. Kufamba kwemvura nemhepo kunogona kuumba mabubbles "anoputika" kana akaiswa kune yakawedzera kudzvanywa kwepombi impeller.

Zvinhu zvinopa cavitation - NPSH, NPSHa, uye NPSHr

NPSH chinhu chakakosha mukudzivirira cavitation mukupatsanura casing pombi. NPSH ndiwo mutsauko uripo pakati pekusveta chaiko uye mhute yehutsi, inoyerwa papombi inopinza. NPSH tsika dzinofanirwa kunge dzakakwirira kudzivirira mvura kuti isapfutike mukati mepombi.

NPSHa ndiyo chaiyo NPSH pasi pepombi yekushanda mamiriro. Net positive yekuyamwa musoro inodiwa (NPSHr) ndiyo shoma NPSH inotsanangurwa nemugadziri wepombi kudzivirira cavitation. NPSHa ibasa rekusveta pombi, kuisirwa, uye mashandiro epombi. NPSHr ibasa rekugadzira pombi uye kukosha kwayo kunotarirwa nekuyedzwa kwepombi. NPSHr inomiririra musoro unowanikwa pasi pemamiriro ekuedzwa uye inowanzoyerwa sekudonha kwe3% mumusoro wepombi (kana yekutanga nhanho impeller musoro wemapombi akawanda) kuona cavitation. NPSHa inofanirwa kugara yakakura kupfuura NPSHr kudzivirira cavitation.

Matanho ekudzikisa Cavitation - Wedzera NPSHa Kudzivirira Cavitation

Kuve nechokwadi chekuti NPSHa yakakura kupfuura NPSHr yakakosha kudzivirira cavitation. Izvi zvinogona kuwanikwa ne:

1. Kudzikisa kureba kwepombi yekasi yakapatsanurwa maererano nedhishi rekusveta / sump. Huyero hwemvura mudhishi rekusveta / sump inogona kuwedzerwa kana pombi inogona kuiswa pasi. Izvi zvichawedzera NPSHa pane pombi inopinza.

2. Wedzera dhayamita yepiping yekusveta. Izvi zvinoderedza kukurumidza kwemvura panguva yekuyerera nguva dzose, nekudaro kuderedza kurasikirwa kwemusoro wekusveta mumapombi uye mafittings.

2.Deredzai kurasikirwa kwemusoro mukugadzirisa. Deredza huwandu hwemajoini mumutsara wekudhonza wepombi. Shandisa zvigadziriso zvakaita seredhiyasi magokora, mavharuvhu akazara, uye tapered zvinoderedza kubatsira kudzikisa kurasikirwa kwemusoro nekuda kwekuiswa.

3.Dzivisa kuisa zvidzitiro uye mafirita pamutsetse wekusveta pombi pose pazvinenge zvichiita, sezvo zvinowanzokonzera cavitation mumapombi ecentrifugal. Kana izvi zvisingakwanisi kudzivirirwa, ita shuwa kuti masikirini uye mafirita pamutsetse wekukweva pombi anogara achiongororwa nekucheneswa.

5. Tonhodza mvura inopomba kuderedza mhute yayo.

Nzwisisa NPSH Margin kudzivirira Cavitation

NPSH margin ndiwo mutsauko uripo pakati peNPSHa neNPSHr. Iyo yakakura NPSH margin inoderedza njodzi yecavitation nekuti inopa chengetedzo yekudzivirira NPSHa kubva pakudonha pasi peyakajairika maitiro ekushanda nekuda kwekushanduka kwemamiriro ekushanda. Zvinhu zvinokanganisa NPSH margin zvinosanganisira hunhu hwemvura, kumhanya kwepombi, uye kusveta mamiriro.

Kuchengetedza iyo Minimum Pombi Kuyerera

Kuve nechokwadi chekuti pombi ye centrifugal iri kushanda pamusoro peiyo yakataurwa zvishoma kuyerera kwakakosha kudzikisa cavitation. Kushandisa pombi yakapatsanurwa pazasi payo yakakwana yekuyerera huwandu (inobvumirwa nzvimbo yekushanda) inowedzera mukana wekugadzira yakaderera nzvimbo yekumanikidza iyo inogona kupinza cavitation.

Impeller Dhizaini Kufunga Kudzikisa Cavitation

Iyo dhizaini yeimpeller inoita basa rakakosha kana centrifugal pombi inoenderana ne cavitation. Makuru mapeller ane mashoma mablades anowanzo kupa mashoma emvura acceleration, izvo zvinoderedza njodzi yecavitation. Pamusoro pezvo, mapeller ane madhayamita akakura ekupinza kana mablades akatemerwa anobatsira kubata kuyerera kwemvura zviri nani, kuderedza mhirizhonga uye kuumbwa kwebubble. Kushandisa zvinhu zvinoramba kukuvadzwa kwecavitation zvinogona kuwedzera hupenyu hweiyo impeller uye pombi.

Kushandisa Anti-Cavitation Devices

Anti-cavitation zvishandiso, senge kuyerera conditioning accessories kana cavitation suppression liners, inoshanda mukudzikisa cavitation. Midziyo iyi inoshanda nekudzora kutenderera kwemvura kutenderedza impeller, ichipa kuyerera kwakadzikama uye kuderedza mhirizhonga uye nzvimbo dzakaderera-dzinokonzeresa cavitation.

Kukosha Kwemapombi Yakakodzera Saizi mukudzivirira Cavitation

Kusarudza mhando yepombi chaiyo uye kutsanangura saizi chaiyo yeimwe application kwakakosha kudzivirira cavitation. Pombi yakanyanyisa inogona kusashanda seyakanaka pakuyerera kwakadzika, zvichiita kuti kuwedzera kwengozi ye cavitation, nepo pombi yakaderera inogona kushanda nesimba kuti isangane nezvinodiwa zvekuyerera, izvo zvinowedzerawo mukana we cavitation. Kusarudzwa kwepombi kwakakodzera kunosanganisira kuongororwa kwakadzama kwehupamhi, hwakajairika uye hudiki hwekuyerera zvinodiwa, hunhu hwemvura uye masisitimu ehurongwa kuti ive nechokwadi chekuti pombi inoshanda mukati meiyo yakatarwa yekushanda. Yakarurama saizi inodzivirira cavitation uye inowedzera kushanda uye kuvimbika kwepombi mukati mehupenyu hwayo hwese.