![]() 目前在泡(pao)(pao)(pao)沫(mo)滅火系(xi)(xi)統(tong)(tong)(tong)(tong)中(zhong),多數使(shi)用(yong)壓(ya)力式(shi)(shi)(shi)(shi)空氣泡(pao)(pao)(pao)沫(mo)系(xi)(xi)統(tong)(tong)(tong)(tong),壓(ya)力式(shi)(shi)(shi)(shi)空氣泡(pao)(pao)(pao)沫(mo)系(xi)(xi)統(tong)(tong)(tong)(tong)分為正(zheng)壓(ya)平(ping)衡式(shi)(shi)(shi)(shi)泡(pao)(pao)(pao)沫(mo)系(xi)(xi)統(tong)(tong)(tong)(tong)和(he)負壓(ya)環(huan)泵式(shi)(shi)(shi)(shi)泡(pao)(pao)(pao)沫(mo)系(xi)(xi)統(tong)(tong)(tong)(tong)"。正(zheng)壓(ya)平(ping)衡式(shi)(shi)(shi)(shi)泡(pao)(pao)(pao)沫(mo)系(xi)(xi)統(tong)(tong)(tong)(tong)結(jie)構復雜、成本(ben)高(gao)、安裝(zhuang)和(he)使(shi)用(yong)不方(fang)便,使(shi)用(yong)率低。負壓(ya)環(huan)泵式(shi)(shi)(shi)(shi)泡(pao)(pao)(pao)沫(mo)系(xi)(xi)統(tong)(tong)(tong)(tong)是消(xiao)防(fang)車用(yong)泡(pao)(pao)(pao)沫(mo)系(xi)(xi)統(tong)(tong)(tong)(tong)中(zhong)應(ying)用(yong)最廣(guang)泛(fan)的(de),其(qi)中(zhong)全自動(dong)環(huan)泵式(shi)(shi)(shi)(shi)泡(pao)(pao)(pao)沫(mo)系(xi)(xi)統(tong)(tong)(tong)(tong)擁有(you)輸出恒定(ding)泡(pao)(pao)(pao)沫(mo)比例的(de)性能,使(shi)用(yong)更方(fang)便,滅火效率更高(gao)。
全(quan)自動環泵式泡沫(mo)系統主要(yao)由控制(zhi)單元、流(liu)量傳感器(qi)、控制(zhi)閥(fa)及文丘里管組成。文(wen)丘(qiu)(qiu)里(li)管(guan)利用(yong)文(wen)丘(qiu)(qiu)里(li)原理,當壓力水(shui)流(liu)經文(wen)丘(qiu)(qiu)里(li)管(guan)時,在其腔內形成(cheng)負壓,使得泡(pao)(pao)沫(mo)(mo)(mo)(mo)液容器內的泡(pao)(pao)沫(mo)(mo)(mo)(mo)液在大氣壓力作用(yong)下被吸到管(guan)道(dao)內與(yu)水(shui)混(hun)合,通過(guo)控制系(xi)(xi)統調整(zheng)水(shui)與(yu)泡(pao)(pao)沫(mo)(mo)(mo)(mo)液的混(hun)合比(bi)例,形成(cheng)泡(pao)(pao)沫(mo)(mo)(mo)(mo)水(shui)混(hun)合液再由車(che)載管(guan)路系(xi)(xi)統噴射進(jin)行滅(mie)火作業。
文丘里管的(de)(de)結構決定(ding)了環泵式泡沫系統(tong)的(de)(de)吸液性能,是(shi)保證系統(tong)運(yun)行的(de)(de)關鍵裝置(zhi)。隨著負(fu)壓環泵式泡(pao)(pao)(pao)沫系統(tong)的普遍應(ying)用,國(guo)(guo)內和國(guo)(guo)際(ji)產(chan)品種類多樣,性能差別較大,且成本(ben)相差懸殊。本(ben)文(wen)針對核心(xin)結(jie)構(gou)文(wen)丘里管,進行流體仿真模擬計(ji)算和試驗測試,討(tao)論(lun)射流管徑(jing)、水流量(liang)、泡(pao)(pao)(pao)沫液流量(liang)、水泵出口(kou)(kou)壓力(li)、泡(pao)(pao)(pao)沫液入口(kou)(kou)壓力(li)之(zhi)間的關(guan)系,給出適(shi)合(he)消(xiao)防車(che)用的文(wen)丘里管結(jie)構(gou)。 文丘里效應(ying)(ying)也(ye)稱(cheng)文氏效應(ying)(ying),該效應(ying)(ying)表現在受限流動(dong)通過縮(suo)小的(de)過流斷面時,流體(ti)出現流速(su)增大的(de)現象(xiang),其流速(su)與過流斷面成(cheng)反比。 |