Gabatarwa ga sharuɗɗan famfo gama gari (6) - Ka'idar cavitation ta famfo

Cavitation na famfo: Ka'idar da Lissafi

Bayyani na cavitation sabon abu
Matsi na ruwa tururi matsa lamba na ruwa (cikakken tururi matsa lamba). Matsin turɓayar ruwa yana da alaƙa da zafin jiki. Mafi girman zafin jiki, mafi girma matsa lamba na vaporization. Matsayin tururi na ruwa mai tsabta a dakin da zafin jiki na 20 ℃ shine 233.8Pa. Yayin da matsa lamba na ruwa a 100 ℃ shine 101296Pa. Saboda haka, ruwa mai tsabta a dakin da zafin jiki (20 ℃) ​​ya fara yin tururi lokacin da matsa lamba ya sauka zuwa 233.8Pa.
Lokacin da aka rage matsa lamba na ruwa zuwa matsa lamba na vaporization a wani zazzabi, ruwan zai haifar da kumfa, wanda ake kira cavitation. Duk da haka, tururin da ke cikin kumfa a zahiri ba tururi ba ne, amma kuma yana ƙunshe da iskar gas (mafi yawan iska) ta hanyar rushewa ko tsakiya.
Lokacin da kumfa da aka haifar yayin kwararar cavitation zuwa babban matsa lamba, ƙarar su yana raguwa har ma fashewa. Wannan al'amari da kumfa ke bacewa a cikin ruwa saboda hawan matsin lamba ana kiransa rushewar cavitation.

Abubuwan da ke faruwa na cavitation a cikin famfo
Lokacin da famfo yana aiki, idan yanki na yanki na ɓangaren ɓoyayyen sa (yawanci wani wuri a bayan mashigin ruwa na impeller). Don wasu dalilai, lokacin da cikakken matsa lamba na ruwan famfo ya faɗi zuwa matsa lamba na vaporization a yanayin zafi na yanzu, ruwan ya fara yin tururi a wurin, yana haifar da tururi da samar da kumfa. Wadannan kumfa suna gudana gaba tare da ruwa, kuma lokacin da suka isa wani babban matsi, babban ruwan da ke kewaye da kumfa yana tilasta kumfa suyi raguwa sosai har ma da fashewa. Lokacin da kumfa ta fashe, ɓangarorin ruwa za su cika ramin cikin sauri kuma su yi karo da juna don samar da guduma na ruwa. Wannan al'amari zai haifar da lalacewa ga abubuwan da suka wuce-nauyi lokacin da ya faru akan katangar bango.
Wannan tsari shine tsarin cavitation na famfo.

Tasirin cavitation na famfo
Samar da hayaniya da girgiza
Lalacewar abubuwan da suka wuce na yanzu
Lalacewar ayyuka

a

Pump cavitation asali equation
NPSHr-Pump cavitation alawus kuma ana kiran shi wajibi cavitation alawus, kuma ana kiran shi zama dole net tabbatacce shugaban a waje.
NPSHa-Alamar cavitation na na'urar kuma ana kiranta ingantaccen izinin cavitation, wanda na'urar tsotsa ke bayarwa. Mafi girma da NPSHA, ƙananan yuwuwar famfo zai cavitation. NPSHa yana raguwa tare da karuwar zirga-zirga.

b

Dangantaka tsakanin NPSHa da NPSHr lokacin da kwarara ya canza

Hanyar lissafin cavitation na na'ura

hg = PC / ρg -hc - Pv / ρg - [NPSH]

[NPSH] - Izinin cavitation da aka yarda
[NPSH] = (1.1 ~ 1.5) NPSHr

Lokacin da yawan kwarara ya yi girma, ɗauki ƙima mai girma, kuma lokacin da adadin ya ƙanƙanta, ɗauki ƙaramin ƙima.


Lokacin aikawa: Janairu-22-2024