在氣力(li)輸(shu)送(song)(song)系(xi)統中,由于(yu)不(bu)(bu)同管段(duan)的風(feng)速不(bu)(bu)同,物(wu)料(liao)(liao)的流(liu)動狀態(tai)會發生(sheng)明顯的變化。整個氣力(li)輸(shu)送(song)(song)系(xi)統大致(zhi)可分(fen)為(wei)以下幾類:活塞流(liu)式氣力(li)輸(shu)送(song)(song),是目前氣力(li)輸(shu)送(song)(song)中較*的中距離輸(shu)送(song)(song)方式;集(ji)裝(zhuang)箱式氣力(li)輸(shu)送(song)(song),根據裝(zhuang)載(zai)集(ji)裝(zhuang)箱的不(bu)(bu)同分(fen)為(wei)無輪輸(shu)送(song)(song)油缸(gang)和(he)輪式集(ji)裝(zhuang)箱車兩種;稀相(xiang)氣力(li)輸(shu)送(song)(song),高風(feng)速物(wu)料(liao)(liao);密相(xiang)氣力(li)輸(shu)送(song)(song)物(wu)料(liao)(liao)不(bu)(bu)再均勻分(fen)布在管道中。
根據粉體氣力輸送系統的(de)狀態(tai),在(zai)氣固兩相(xiang)流過程中(zhong),物(wu)料(liao)(liao)的(de)運動(dong)狀態(tai)會(hui)隨著輸送(song)(song)風速和風量的(de)變(bian)化而(er)變(bian)化。可以認為垂直管(guan)內物(wu)料(liao)(liao)均(jun)勻(yun)分(fen)布與水平管(guan)內物(wu)料(liao)(liao)飛揚(yang)輸送(song)(song)的(de)分(fen)界線就(jiu)是(shi)稀(xi)相(xiang)與濃相(xiang)的(de)分(fen)界線。物(wu)料(liao)(liao)風速大時(shi),物(wu)料(liao)(liao)呈懸浮狀態(tai),被氣流均(jun)勻(yun)分(fen)布輸送(song)(song);隨著輸送(song)(song)風速的(de)降低,物(wu)料(liao)(liao)開始結塊;之后,部分(fen)物(wu)料(liao)(liao)聚(ju)集在(zai)管(guan)道(dao)中(zhong),以群脈沖(chong)方式動(dong)態(tai)輸送(song)(song);然后降低輸送(song)(song)風速,不穩定的(de)塞子將在(zai)空(kong)氣壓力的(de)推動(dong)下變(bian)成穩定的(de)塞子。
密度(du)流(liu),當風(feng)速小(xiao)于一定值時,物(wu)料(liao)(liao)開(kai)始在水平管(guan)(guan)道(dao)內呈不均(jun)勻狀態流(liu)動(dong)(dong),管(guan)(guan)中有部(bu)(bu)分(fen)顆粒(li)(li)滑落,但(dan)物(wu)料(liao)(liao)輸送并(bing)未停(ting)止。停(ting)滯不前的(de)流(liu)動(dong)(dong)。隨著氣流(liu)速度(du)的(de)進(jin)一步降低,大部(bu)(bu)分(fen)顆粒(li)(li)開(kai)始失去懸浮(fu)能力(li),停(ting)滯在管(guan)(guan)底(di)。此時,局(ju)部(bu)(bu)管(guan)(guan)道(dao)內截面(mian)因物(wu)料(liao)(liao)堆積而變小(xiao),使該區域的(de)風(feng)速增大,滯留(liu)物(wu)料(liao)(liao)被吹走(zou)。