在(zai)航(hang)(hang)天(tian)(tian)工(gong)程(包(bao)括載人與衛星)中(zhong)整機(ji)(ji)(ji)包(bao)含大(da)量(liang)的(de)(de)(de)(de)驅動(dong)器(qi),配電(dian)器(qi),控(kong)制器(qi),分(fen)流調節器(qi)等中(zhong)樞(shu)產(chan)品(pin)(pin),統稱為航(hang)(hang)天(tian)(tian)器(qi)單(dan)機(ji)(ji)(ji)產(chan)品(pin)(pin)。航(hang)(hang)天(tian)(tian)器(qi)單(dan)機(ji)(ji)(ji)產(chan)品(pin)(pin)是飛行器(qi)的(de)(de)(de)(de)控(kong)制中(zhong)樞(shu),在(zai)先期的(de)(de)(de)(de)環境試(shi)驗過程中(zhong),如試(shi)驗問題帶(dai)來了產(chan)品(pin)(pin)損傷而隱(yin)患(huan)未(wei)被發現并及時處理的(de)(de)(de)(de)情況下(xia)進入(ru)航(hang)(hang)天(tian)(tian)軌道,隨著隱(yin)性(xing)損傷在(zai)發射(she)過程中(zhong)通過振動(dong)、氣壓、溫度、濕度、輻射(she)等綜合應力下(xia)出現故障,則航(hang)(hang)天(tian)(tian)器(qi)將(jiang)無法完成預(yu)定功能而出現任務失敗,損失巨大(da)。熱循環試(shi)驗是航(hang)(hang)天(tian)(tian)組件級單(dan)機(ji)(ji)(ji)產(chan)品(pin)(pin)可靠性(xing)驗證(zheng)的(de)(de)(de)(de)一種手段(duan),在(zai)試(shi)驗過程中(zhong)如何(he)保證(zheng)產(chan)品(pin)(pin)不經受凝露帶(dai)來的(de)(de)(de)(de)損傷是本文(wen)研究點。
熱(re)循環(huan)試(shi)驗
通(tong)過正交試驗(yan)設(she)計(ji)以及對(dui)試驗(yan)結果進行極差分析得出(chu)以下結論及建(jian)議:為了對(dui)基(ji)站天線電磁(ci)輻(fu)(fu)射(she)(she)的影(ying)(ying)(ying)響進行充分的了解,國內外有(you)關這方(fang)面的研究(jiu)(jiu)和監測(ce)工(gong)作不斷(duan)增加 ,但對(dui)于移(yi)動通(tong)信基(ji)站電磁(ci)輻(fu)(fu)射(she)(she)影(ying)(ying)(ying)響因素進行綜合(he)優化研究(jiu)(jiu)并不多見。因此,本文(wen)對(dui)移(yi)動基(ji)站電磁(ci)輻(fu)(fu)射(she)(she)影(ying)(ying)(ying)響因素進行研究(jiu)(jiu),得到各個(ge)因素影(ying)(ying)(ying)響基(ji)站電磁(ci)輻(fu)(fu)射(she)(she)大小的主次(ci)順序以及各因素的佳水平,終確立電磁(ci)輻(fu)(fu)射(she)(she)值影(ying)(ying)(ying)響小的布(bu)設(she)方(fang)案,為今后通(tong)信基(ji)站的建(jian)設(she)提供優的建(jian)設(she)依據。
熱循環試驗是一種利用高低溫交變試驗箱對試驗產品進行的預設高低溫交替的應力考核,用以驗證材料和產品是否達到在研發、設計、制造中預期的質量目標的一類可靠性試驗。通過大溫變速率可暴露產品潛在的材料與性能缺陷,經過不斷地質量改進,達到可靠性提升的目的。航天單機類產品一次熱循環示意圖見下圖1所示。
產(chan)品(pin)凝露(lu)帶來(lai)的危害
1)表面(mian)覆蓋層(表面(mian)處理防腐(fu))的(de)化學或電化學破壞。
2)基體材料腐蝕。
3)材料性(xing)能的(de)損壞。
4)元器件電氣性能的損傷。
產(chan)品表面凝露原理
環(huan)境試(shi)驗設備在開展熱循(xun)環(huan)試(shi)驗時(shi),一般的(de)氣(qi)(qi)體介質為濕空氣(qi)(qi),即為氮(dan)氣(qi)(qi)、氧氣(qi)(qi)、二(er)氧化碳和惰性氣(qi)(qi)體等(deng)混(hun)合水蒸汽,也即干空氣(qi)(qi)與(yu)水蒸汽的(de)混(hun)合。
1、含(han)濕量
含(han)濕量(liang)為(wei)在濕空氣中(zhong)與1kg干空氣并存的水蒸汽量(liang),即:
2、相隨(sui)濕(shi)度
相隨濕(shi)度就是空氣(qi)中水蒸汽(qi)分壓力和同溫度下飽和水蒸汽(qi)分壓力之比,用(yong)符號φ表示(shi),即:
pq— 水蒸(zheng)汽分壓力(li);
pq,b—同溫(wen)度下飽和(he)水蒸汽分壓(ya)力(li);
db—同(tong)溫度下(xia)飽和(he)含濕(shi)量。
3、露點溫(wen)度
在保持(chi)整個濕(shi)(shi)空(kong)(kong)(kong)氣(qi)含濕(shi)(shi)量不變(bian)的(de)(de)情況下,將(jiang)濕(shi)(shi)空(kong)(kong)(kong)氣(qi)冷(leng)卻,此(ci)時相(xiang)對濕(shi)(shi)度(du)(du)中(zhong)pq,b為(wei)(wei)(wei)(wei)不斷降(jiang)低,pq近似不變(bian),當pq與(yu)pq,b相(xiang)等時,相(xiang)對濕(shi)(shi)度(du)(du)變(bian)為(wei)(wei)(wei)(wei)100%,此(ci)時所(suo)對應(ying)的(de)(de)溫度(du)(du)為(wei)(wei)(wei)(wei)該濕(shi)(shi)空(kong)(kong)(kong)氣(qi)的(de)(de)露(lu)點溫度(du)(du),計為(wei)(wei)(wei)(wei)tl。空(kong)(kong)(kong)氣(qi)相(xiang)對濕(shi)(shi)度(du)(du)為(wei)(wei)(wei)(wei)100%,溫度(du)(du)持(chi)續降(jiang)低時,Pq,b持(chi)續降(jiang)低,此(ci)時空(kong)(kong)(kong)氣(qi)中(zhong)水(shui)蒸汽無法維持(chi)氣(qi)體狀態,開(kai)始出現凝結水(shui)滴現象,此(ci)現象稱(cheng)為(wei)(wei)(wei)(wei)凝露(lu)。
4、試驗過程(cheng)凝露機(ji)理(li)
產(chan)品(pin)在(zai)熱循環過(guo)(guo)(guo)(guo)程(cheng)中分為降溫過(guo)(guo)(guo)(guo)程(cheng),溫度(du)保持過(guo)(guo)(guo)(guo)程(cheng),升(sheng)溫過(guo)(guo)(guo)(guo)程(cheng)和溫度(du)保持過(guo)(guo)(guo)(guo)程(cheng)四個階段。在(zai)降溫過(guo)(guo)(guo)(guo)程(cheng)中,低溫的(de)空氣(qi)經氣(qi)流風道吹出經過(guo)(guo)(guo)(guo)產(chan)品(pin)表面(mian),經過(guo)(guo)(guo)(guo)對(dui)流換熱產(chan)品(pin)表面(mian)開(kai)始降溫。此時對(dui)于(yu)腔體式產(chan)品(pin),產(chan)品(pin)表面(mian)降溫速率大于(yu)產(chan)品(pin)內(nei)(nei)部,在(zai)產(chan)品(pin)內(nei)(nei)部濕空氣(qi)溫度(du)在(zai)產(chan)品(pin)內(nei)(nei)壁降低至露點溫度(du)以下,于(yu)產(chan)品(pin)內(nei)(nei)部形成(cheng)凝露現象。
保溫過(guo)程(cheng):此過(guo)程(cheng)為產品(pin)溫度穩定過(guo)程(cheng),不(bu)會(hui)在此過(guo)程(cheng)形成新的凝露現象。
升溫(wen)(wen)(wen)(wen)過(guo)(guo)程(cheng)(cheng)(cheng):熱(re)(re)循環試(shi)驗的升溫(wen)(wen)(wen)(wen)過(guo)(guo)程(cheng)(cheng)(cheng)是產(chan)品(pin)凝露的關鍵過(guo)(guo)程(cheng)(cheng)(cheng)。降溫(wen)(wen)(wen)(wen)過(guo)(guo)程(cheng)(cheng)(cheng)中(zhong)(zhong)(zhong),濕空(kong)氣(qi)在經過(guo)(guo)蒸(zheng)(zheng)(zheng)(zheng)發(fa)器(qi)(qi)時,水(shui)蒸(zheng)(zheng)(zheng)(zheng)汽凝結在蒸(zheng)(zheng)(zheng)(zheng)發(fa)器(qi)(qi)表(biao)(biao)面(mian),低(di)溫(wen)(wen)(wen)(wen)保溫(wen)(wen)(wen)(wen)過(guo)(guo)程(cheng)(cheng)(cheng)中(zhong)(zhong)(zhong),由于(yu)箱內(nei)形(xing)(xing)成負(fu)壓,外界環境中(zhong)(zhong)(zhong)濕空(kong)氣(qi)不斷(duan)進入(ru)試(shi)驗設(she)備中(zhong)(zhong)(zhong),凝結在蒸(zheng)(zheng)(zheng)(zheng)發(fa)器(qi)(qi)上,低(di)溫(wen)(wen)(wen)(wen)保溫(wen)(wen)(wen)(wen)時間越久,則蒸(zheng)(zheng)(zheng)(zheng)發(fa)器(qi)(qi)凝結霜層(ceng)越厚(hou)。在低(di)溫(wen)(wen)(wen)(wen)轉高溫(wen)(wen)(wen)(wen)過(guo)(guo)程(cheng)(cheng)(cheng)中(zhong)(zhong)(zhong),熱(re)(re)空(kong)氣(qi)經過(guo)(guo)蒸(zheng)(zheng)(zheng)(zheng)發(fa)器(qi)(qi)表(biao)(biao)面(mian),將蒸(zheng)(zheng)(zheng)(zheng)發(fa)器(qi)(qi)表(biao)(biao)面(mian)霜層(ceng)融化形(xing)(xing)成大量(liang)水(shui)蒸(zheng)(zheng)(zheng)(zheng)汽隨氣(qi)流進入(ru)試(shi)驗箱內(nei)部,而由于(yu)試(shi)驗產(chan)品(pin)熱(re)(re)容比空(kong)氣(qi)大,產(chan)品(pin)表(biao)(biao)面(mian)熱(re)(re)滯后(hou)于(yu)空(kong)氣(qi)溫(wen)(wen)(wen)(wen)度(du),濕空(kong)氣(qi)在產(chan)品(pin)表(biao)(biao)面(mian)溫(wen)(wen)(wen)(wen)度(du)降至露點(dian)溫(wen)(wen)(wen)(wen)度(du)以(yi)下(xia),在產(chan)品(pin)表(biao)(biao)面(mian)析出水(shui)分(fen),凝結在產(chan)品(pin)表(biao)(biao)面(mian),可能造(zao)(zao)成內(nei)部空(kong)腔吸入(ru)水(shui)分(fen)的問題。產(chan)品(pin)在考核高溫(wen)(wen)(wen)(wen)過(guo)(guo)程(cheng)(cheng)(cheng)中(zhong)(zhong)(zhong),增加了(le)濕熱(re)(re)試(shi)驗的綜合應力影響,可能會(hui)對產(chan)品(pin)造(zao)(zao)成未知傷害。
防(fang)凝露(lu)試驗技術(shu)
產(chan)品(pin)出現凝露(lu)存在(zai)一個根本問(wen)題(ti)為產(chan)品(pin)表(biao)面(mian)流(liu)經的濕(shi)空氣在(zai)產(chan)品(pin)表(biao)面(mian)降至露(lu)點溫度(du)以(yi)下,導致產(chan)品(pin)表(biao)面(mian)析出水(shui)分。而露(lu)點溫度(du)tl與d和db有關(guan)(guan),因此,只要控制d與db的關(guan)(guan)系(xi),就可控制產(chan)品(pin)凝露(lu)問(wen)題(ti)。
含(han)(han)濕量d,為相對濕度(du)中(zhong)分子量,為尋求(qiu)空氣相對濕度(du)越(yue)(yue)低,則研究(jiu)中(zhong)需控制含(han)(han)濕量越(yue)(yue)低。含(han)(han)濕量為空氣中(zhong)存(cun)(cun)在(zai)的水(shui)蒸汽的質量,即為考(kao)慮如何將空氣中(zhong)存(cun)(cun)在(zai)的水(shui)蒸汽控制到限度(du)。
同溫(wen)度(du)(du)下(xia)飽(bao)和含(han)濕(shi)量(liang)db為(wei)分(fen)母(mu)量(liang),為(wei)尋求空氣相對濕(shi)度(du)(du)越(yue)低(di)(di),則研(yan)(yan)究db需要越(yue)高越(yue)好(hao),db隨著溫(wen)度(du)(du)的(de)(de)升(sheng)高而升(sheng)高,因(yin)此要求產品(pin)表面的(de)(de)溫(wen)度(du)(du)與(yu)設備風口溫(wen)度(du)(du)越(yue)接近(jin)越(yue)好(hao)。然(ran)而產品(pin)實時溫(wen)度(du)(du)與(yu)產品(pin)形狀、產品(pin)比(bi)熱容、產品(pin)重量(liang)與(yu)溫(wen)度(du)(du)變化速率(lv)有關(guan),為(wei)產品(pin)與(yu)試(shi)驗(yan)參數固有條(tiao)件(jian)決定,無法通過試(shi)驗(yan)技(ji)術對委托試(shi)驗(yan)方進行約束修改。因(yin)此本文(wen)防凝露(lu)試(shi)驗(yan)技(ji)術通過研(yan)(yan)究降低(di)(di)含(han)濕(shi)量(liang)d來達到(dao)航天器(qi)單機產品(pin)的(de)(de)試(shi)驗(yan)保障。
設(she)備內部(bu)空氣中(zhong)水蒸汽主要來源于蒸發(fa)器的化霜,如何含濕量則需考(kao)慮如下三(san)個問題(ti):
1)如何控制蒸發(fa)器表面低溫(wen)凝霜;
2)如(ru)何(he)控(kong)制蒸發(fa)器升(sheng)溫化霜;
3)如何降低設備內部含濕量。
1、控制蒸發(fa)器表面低溫凝霜
蒸(zheng)發(fa)(fa)器表面低溫(wen)凝霜為蒸(zheng)發(fa)(fa)器在低溫(wen)過(guo)程中設備內部及外界環境(jing)水蒸(zheng)汽不斷在蒸(zheng)發(fa)(fa)器表面凝霜的(de)現(xian)象。因此在低溫(wen)過(guo)程中需要保(bao)持(chi)設備的(de)密封與箱內的(de)正壓。
1)設(she)備如(ru)果不密(mi)封(如(ru)測試孔(kong)堵塞不嚴密(mi),見(jian)示意圖2,大門密(mi)封不嚴密(mi)),則會(hui)形成(cheng)濕氣(qi)進入試驗設(she)備的通(tong)路。
因此測試電纜口處不可使用(yong)硬質堵頭,建(jian)議(yi)使用(yong)棉花(hua),軟(ruan)布(bu)類,見(jian)圖3,內外(wai)封(feng)堵壓緊。
圖2(左)測試電纜密封不嚴示意圖;圖3(右) 軟體堵頭示意
2)對于(yu)設(she)(she)備內部(bu)正(zheng)壓則是為(wei)了防止低溫過(guo)程中,設(she)(she)備內部(bu)形成(cheng)負壓造成(cheng)濕(shi)空(kong)氣(qi)從密(mi)封(feng)不嚴(yan)的縫隙,螺紋(wen)孔(kong),測(ce)試(shi)孔(kong)等處進入設(she)(she)備內部(bu),形成(cheng)蒸(zheng)發器積(ji)霜。可在設(she)(she)備內部(bu)風道持續充注(zhu)0.1Mpa壓力氮氣(qi),使設(she)(she)備內部(bu)持續正(zheng)壓。(由于(yu)整個過(guo)程氮氣(qi)消耗量大(da),如能保證設(she)(she)備單(dan)向(xiang)密(mi)封(feng),可對此(ci)過(guo)程進行相應(ying)裁剪)。
2、如何控制蒸發(fa)器升溫化(hua)霜
蒸(zheng)發(fa)(fa)(fa)器升(sheng)溫(wen)(wen)(wen)化(hua)霜(shuang)是整個(ge)環境試(shi)驗(yan)中(zhong)(zhong)升(sheng)溫(wen)(wen)(wen)過(guo)(guo)程的隱患,蒸(zheng)發(fa)(fa)(fa)器霜(shuang)層越厚,則升(sheng)溫(wen)(wen)(wen)過(guo)(guo)程空氣(qi)中(zhong)(zhong)的含濕(shi)量(liang)越多。如何控制蒸(zheng)發(fa)(fa)(fa)器升(sheng)溫(wen)(wen)(wen)化(hua)霜(shuang)是升(sheng)溫(wen)(wen)(wen)控濕(shi)技術的關(guan)鍵所(suo)在。一般(ban)升(sheng)溫(wen)(wen)(wen)過(guo)(guo)程中(zhong)(zhong),蒸(zheng)發(fa)(fa)(fa)器關(guan)閉或(huo)調節(jie)(jie)制冷(leng)劑流量(liang)來節(jie)(jie)約能源維(wei)持(chi)(chi)(chi)升(sheng)溫(wen)(wen)(wen)速(su)率(lv)(lv)。對于控濕(shi)考慮,可在升(sheng)溫(wen)(wen)(wen)過(guo)(guo)程中(zhong)(zhong)持(chi)(chi)(chi)續大流量(liang)制冷(leng)劑輸出(chu),保持(chi)(chi)(chi)蒸(zheng)發(fa)(fa)(fa)器開(kai)啟,調節(jie)(jie)加熱絲(si)功率(lv)(lv)來維(wei)持(chi)(chi)(chi)升(sheng)溫(wen)(wen)(wen)速(su)率(lv)(lv)。此(ci)時霜(shuang)層由于蒸(zheng)發(fa)(fa)(fa)器的冷(leng)量(liang)維(wei)持(chi)(chi)(chi)而不出(chu)現化(hua)霜(shuang)現象,僅(jin)有表(biao)面(mian)熱氣(qi)通過(guo)(guo)時攜帶水(shui)(shui)蒸(zheng)汽(qi)通過(guo)(guo)氣(qi)流進(jin)入(ru)試(shi)驗(yan)設(she)(she)備(bei)(bei)中(zhong)(zhong),試(shi)驗(yan)設(she)(she)備(bei)(bei)中(zhong)(zhong)輔助充注氮氣(qi)或(huo)者露(lu)點溫(wen)(wen)(wen)度小(xiao)于-50℃的干燥空氣(qi),可在升(sheng)溫(wen)(wen)(wen)階段大量(liang)減(jian)少含濕(shi)量(liang)進(jin)入(ru)設(she)(she)備(bei)(bei)內部。而蒸(zheng)發(fa)(fa)(fa)器的化(hua)霜(shuang)階段可選擇(ze)在產(chan)品(pin)溫(wen)(wen)(wen)度到達試(shi)驗(yan)設(she)(she)備(bei)(bei)溫(wen)(wen)(wen)度后(可選擇(ze)30min后),關(guan)閉蒸(zheng)發(fa)(fa)(fa)器,蒸(zheng)發(fa)(fa)(fa)器進(jin)行化(hua)霜(shuang),化(hua)霜(shuang)的水(shui)(shui)經過(guo)(guo)底部排水(shui)(shui)孔排出(chu),而進(jin)入(ru)設(she)(she)備(bei)(bei)中(zhong)(zhong)的水(shui)(shui)蒸(zheng)汽(qi)由于產(chan)品(pin)表(biao)面(mian)與設(she)(she)備(bei)(bei)內部空氣(qi)溫(wen)(wen)(wen)度一致,不會在產(chan)品(pin)表(biao)面(mian)出(chu)現凝露(lu)現象。
3、如何降低設(she)備(bei)內部(bu)含濕量(liang)
降低(di)設備內(nei)部含濕(shi)量(liang)是(shi)考慮已經存(cun)在于(yu)設備內(nei)部環境空氣中(zhong)的水蒸汽如何(he)排除。常規(gui)的做(zuo)法為低(di)露點氣體置換法和吸附式(shi)除濕(shi)法。
1)低露點干燥空氣(qi)除濕法
開展單(dan)機熱循(xun)環(huan)試驗(yan)應采用(yong)電容式濕(shi)度(du)(du)(du)(du)(du)傳(chuan)感器試驗(yan)設(she)備(bei),可(ke)實時監(jian)控試驗(yan)設(she)備(bei)內部環(huan)境濕(shi)度(du)(du)(du)(du)(du)。常規單(dan)機溫(wen)(wen)(wen)度(du)(du)(du)(du)(du)循(xun)環(huan)試驗(yan)速率為3℃/min~5℃/min,根(gen)據經(jing)驗(yan)得知(zhi)一(yi)般常規航(hang)天組件(jian)級單(dan)機熱滯后(hou)設(she)備(bei)溫(wen)(wen)(wen)度(du)(du)(du)(du)(du)20℃左右,根(gen)據濕(shi)空(kong)氣(qi)焓濕(shi)圖(tu)可(ke)以(yi)得知(zhi),只要設(she)備(bei)升(sheng)溫(wen)(wen)(wen)過程相對濕(shi)度(du)(du)(du)(du)(du)小于(yu)25%可(ke)避免產品(pin)表(biao)面(mian)空(kong)氣(qi)降至露(lu)點(dian)溫(wen)(wen)(wen)度(du)(du)(du)(du)(du)以(yi)下出現凝(ning)露(lu)現象。可(ke)在(zai)升(sheng)溫(wen)(wen)(wen)過程中充注(zhu)(zhu)(zhu)氮氣(qi)或者露(lu)點(dian)溫(wen)(wen)(wen)度(du)(du)(du)(du)(du)小于(yu)-50℃干燥空(kong)氣(qi),并根(gen)據空(kong)氣(qi)相對濕(shi)度(du)(du)(du)(du)(du)進行低露(lu)點(dian)氣(qi)體(ti)充注(zhu)(zhu)(zhu)。一(yi)般經(jing)驗(yan)表(biao)明低露(lu)點(dian)氣(qi)體(ti)閥后(hou)壓力在(zai)0.5MPa以(yi)上可(ke)避免產品(pin)表(biao)面(mian)凝(ning)露(lu)。對于(yu)其他(ta)類(lei)結(jie)構(gou)復(fu)雜單(dan)機,可(ke)在(zai)產品(pin)代(dai)表(biao)位(wei)置黏貼多個產品(pin)溫(wen)(wen)(wen)度(du)(du)(du)(du)(du)傳(chuan)感器,通(tong)過溫(wen)(wen)(wen)度(du)(du)(du)(du)(du)點(dian)與(yu)設(she)備(bei)溫(wen)(wen)(wen)度(du)(du)(du)(du)(du)差值,再結(jie)合試驗(yan)環(huan)境濕(shi)度(du)(du)(du)(du)(du)進行焓濕(shi)圖(tu)查詢,調(diao)節低露(lu)點(dian)氣(qi)體(ti)充注(zhu)(zhu)(zhu)量(liang)避免產品(pin)表(biao)面(mian)凝(ning)露(lu)。
2)吸附式除濕法
吸(xi)(xi)附(fu)(fu)式除(chu)濕(shi)(shi)一(yi)般選(xuan)擇親(qin)水(shui)類材(cai)料(liao)如硅膠(jiao)、分子篩和活(huo)性碳等產品。在(zai)(zai)風道處安(an)裝一(yi)個(ge)吸(xi)(xi)附(fu)(fu)式過(guo)(guo)濾器(qi)(qi),設備空氣經(jing)過(guo)(guo)吸(xi)(xi)附(fu)(fu)式過(guo)(guo)濾器(qi)(qi)時,水(shui)蒸汽吸(xi)(xi)附(fu)(fu)在(zai)(zai)過(guo)(guo)濾器(qi)(qi)中(zhong)(zhong)(zhong),不斷除(chu)濕(shi)(shi)。過(guo)(guo)濾器(qi)(qi)可在(zai)(zai)高溫中(zhong)(zhong)(zhong)再生重復下一(yi)次吸(xi)(xi)附(fu)(fu)過(guo)(guo)程。試驗中(zhong)(zhong)(zhong)常用干(gan)燥(zao)(zao)劑為硅膠(jiao),藍色(se)代(dai)表(biao)具有(you)吸(xi)(xi)濕(shi)(shi)能(neng)力(li),紅(hong)色(se)代(dai)表(biao)已吸(xi)(xi)濕(shi)(shi)飽和。吸(xi)(xi)附(fu)(fu)式干(gan)燥(zao)(zao)存(cun)在(zai)(zai)一(yi)定(ding)的弊端,如解吸(xi)(xi)溫度高,吸(xi)(xi)濕(shi)(shi)溫度低,無(wu)法在(zai)(zai)整個(ge)熱(re)循環過(guo)(guo)程中(zhong)(zhong)(zhong)持續(xu)有(you)效(xiao)吸(xi)(xi)濕(shi)(shi)。因此一(yi)般作為熱(re)循環過(guo)(guo)程中(zhong)(zhong)(zhong)輔助除(chu)濕(shi)(shi)手段(duan),不單獨采取此一(yi)種手段(duan)。
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