1、引(yin)言

    2、制冷工質(zhi)的選擇

    復疊式制(zhi)(zhi)(zhi)冷(leng)(leng)(leng)(leng)系(xi)統需要選擇兩種(zhong)類型的(de)制(zhi)(zhi)(zhi)冷(leng)(leng)(leng)(leng)劑，即中溫制(zhi)(zhi)(zhi)冷(leng)(leng)(leng)(leng)劑和(he)(he)低溫制(zhi)(zhi)(zhi)冷(leng)(leng)(leng)(leng)劑。由于(yu)國際(ji)社(she)會(hui)對環境(jing)安(an)全(quan)的(de)日(ri)益重視，此前廣泛使用的(de)R13、R22等CFC、HCFC類型的(de)制(zhi)(zhi)(zhi)冷(leng)(leng)(leng)(leng)劑已逐步被(bei)代替。鑒于(yu)R23和(he)(he)R404A的(de)ODP為(wei)零，安(an)全(quan)性(xing)(xing)(xing)好(hao)，是環境(jing)友好(hao)型制(zhi)(zhi)(zhi)冷(leng)(leng)(leng)(leng)劑，因此在綜(zong)合考慮制(zhi)(zhi)(zhi)冷(leng)(leng)(leng)(leng)劑的(de)制(zhi)(zhi)(zhi)冷(leng)(leng)(leng)(leng)性(xing)(xing)(xing)能(neng)、壓(ya)縮機工作的(de)可(ke)靠性(xing)(xing)(xing)和(he)(he)環境(jing)友好(hao)性(xing)(xing)(xing)后，選擇R404A/R23作為(wei)復疊式制(zhi)(zhi)(zhi)冷(leng)(leng)(leng)(leng)系(xi)統的(de)制(zhi)(zhi)(zhi)冷(leng)(leng)(leng)(leng)劑， R404A 和(he)(he)R23的(de)性(xing)(xing)(xing)能(neng)參數見(jian)表1。其中，R404A由R125( 標(biao)準(zhun)沸(fei)(fei)點(dian)- 49℃)、R143a(標(biao)準(zhun)沸(fei)(fei)點(dian)-47.2℃)和(he)(he)R134a(標(biao)準(zhun)沸(fei)(fei)點(dian)-26.1℃)按質(zhi)量分(fen)數44:52:4混(hun)合而成，具有(you)與R22(標(biao)準(zhun)沸(fei)(fei)點(dian)-40.8℃ )較為(wei)相(xiang)近的(de)熱物(wu)理性(xing)(xing)(xing)質(zhi)。

    3、實驗(yan)裝置與實驗(yan)

    圖1為(wei)高低(di)(di)(di)溫(wen)(wen)(wen)(wen)沖擊(ji)(ji)試(shi)驗箱(xiang)(xiang)(xiang)(xiang)實驗裝(zhuang)(zhuang)置(zhi)系(xi)統圖。試(shi)驗箱(xiang)(xiang)(xiang)(xiang)本體主(zhu)要包括高溫(wen)(wen)(wen)(wen)箱(xiang)(xiang)(xiang)(xiang)和低(di)(di)(di)溫(wen)(wen)(wen)(wen)箱(xiang)(xiang)(xiang)(xiang)。低(di)(di)(di)溫(wen)(wen)(wen)(wen)箱(xiang)(xiang)(xiang)(xiang)內(nei)(nei)(nei)的(de)復疊制(zhi)(zhi)冷(leng)系(xi)統由高溫(wen)(wen)(wen)(wen)制(zhi)(zhi)冷(leng)循(xun)環和低(di)(di)(di)溫(wen)(wen)(wen)(wen)制(zhi)(zhi)冷(leng)循(xun)環組成，設備主(zhu)要有(you)壓縮(suo)(suo)機、冷(leng)凝器(qi)(qi)、膨(peng)脹閥(或毛細管)、蒸發(fa)冷(leng)凝器(qi)(qi)、蒸發(fa)器(qi)(qi)、油分離器(qi)(qi)，干燥過(guo)(guo)濾(lv)器(qi)(qi)等，兩(liang)個制(zhi)(zhi)冷(leng)循(xun)環通(tong)(tong)過(guo)(guo)蒸發(fa)冷(leng)凝器(qi)(qi)相(xiang)結合。高、低(di)(di)(di)溫(wen)(wen)(wen)(wen)箱(xiang)(xiang)(xiang)(xiang)內(nei)(nei)(nei)部結構相(xiang)似:幾何尺寸(cun)均為(wei)650mmx650mmx600mm，每個箱(xiang)(xiang)(xiang)(xiang)體.上部都(dou)(dou)有(you)兩(liang)個百葉進風口(kou)(kou)，下部有(you)兩(liang)個百葉出(chu)(chu)風口(kou)(kou)，風口(kou)(kou)裝(zhuang)(zhuang)有(you)兩(liang)個循(xun)環風機，且(qie)裝(zhuang)(zhuang)有(you)電加熱盤(pan)管調節溫(wen)(wen)(wen)(wen)度(du)(du)。當風機工(gong)作(zuo)(zuo)時，受迫循(xun)環空氣經過(guo)(guo)熱盤(pan)管、蒸發(fa)器(qi)(qi)調節高低(di)(di)(di)溫(wen)(wen)(wen)(wen)箱(xiang)(xiang)(xiang)(xiang)內(nei)(nei)(nei)的(de)溫(wen)(wen)(wen)(wen)度(du)(du)到達(da)目(mu)標值。測(ce)(ce)試(shi)箱(xiang)(xiang)(xiang)(xiang)內(nei)(nei)(nei)部尺寸(cun)為(wei)500mm x 500mm x 500mm ，容積為(wei)125L，通(tong)(tong)過(guo)(guo)氣缸的(de)運動快(kuai)速拉動測(ce)(ce)試(shi)箱(xiang)(xiang)(xiang)(xiang)，分別在高、低(di)(di)(di)溫(wen)(wen)(wen)(wen)箱(xiang)(xiang)(xiang)(xiang)中進行冷(leng)熱沖擊(ji)(ji)試(shi)驗，氣缸由空壓機的(de)壓縮(suo)(suo)空氣提供(gong)動力。為(wei)了研究測(ce)(ce)試(shi)箱(xiang)(xiang)(xiang)(xiang)內(nei)(nei)(nei)的(de)溫(wen)(wen)(wen)(wen)度(du)(du)均勻(yun)度(du)(du)，在測(ce)(ce)試(shi)箱(xiang)(xiang)(xiang)(xiang)內(nei)(nei)(nei)布置(zhi)了9個T型熱電偶作(zuo)(zuo)為(wei)溫(wen)(wen)(wen)(wen)度(du)(du)測(ce)(ce)試(shi)點。在高、低(di)(di)(di)溫(wen)(wen)(wen)(wen)循(xun)環壓縮(suo)(suo)機的(de)進、出(chu)(chu)口(kou)(kou)布置(zhi)壓力測(ce)(ce)試(shi)點，研究壓縮(suo)(suo)機的(de)工(gong)作(zuo)(zuo)狀況。高、低(di)(di)(di)溫(wen)(wen)(wen)(wen)箱(xiang)(xiang)(xiang)(xiang)內(nei)(nei)(nei)都(dou)(dou)裝(zhuang)(zhuang)有(you)三線(xian)制(zhi)(zhi)PT100溫(wen)(wen)(wen)(wen)度(du)(du)傳感器(qi)(qi)，精度(du)(du)為(wei)±0. 1℃，數據(ju)同步輸(shu)人UMC1000控制(zhi)(zhi)器(qi)(qi)中，控制(zhi)(zhi)制(zhi)(zhi)冷(leng)系(xi)統和加熱系(xi)統工(gong)作(zuo)(zuo)狀況。

    4、實(shi)驗研(yan)究(jiu)

    實(shi)(shi)驗(yan)選取兩組沖(chong)(chong)擊溫(wen)(wen)(wen)(wen)(wen)(wen)(wen)(wen)(wen)(wen)(wen)(wen)度(du)(du)(du)(du)進(jin)行(xing)測試，分(fen)別用(yong)實(shi)(shi)驗(yan)1和(he)(he)實(shi)(shi)驗(yan)2表示。實(shi)(shi)驗(yan)1:沖(chong)(chong)擊溫(wen)(wen)(wen)(wen)(wen)(wen)(wen)(wen)(wen)(wen)(wen)(wen)度(du)(du)(du)(du)為(wei)(wei)(wei)- 55℃和(he)(he)200℃ ;實(shi)(shi)驗(yan)2:沖(chong)(chong)擊溫(wen)(wen)(wen)(wen)(wen)(wen)(wen)(wen)(wen)(wen)(wen)(wen)度(du)(du)(du)(du)為(wei)(wei)(wei)-45℃和(he)(he)150℃。測試箱(xiang)(xiang)由高(gao)(gao)(gao)溫(wen)(wen)(wen)(wen)(wen)(wen)(wen)(wen)(wen)(wen)(wen)(wen)箱(xiang)(xiang)沖(chong)(chong)擊到(dao)低(di)(di)(di)(di)溫(wen)(wen)(wen)(wen)(wen)(wen)(wen)(wen)(wen)(wen)(wen)(wen)箱(xiang)(xiang)時，高(gao)(gao)(gao)、低(di)(di)(di)(di)溫(wen)(wen)(wen)(wen)(wen)(wen)(wen)(wen)(wen)(wen)(wen)(wen)箱(xiang)(xiang)的預熱(re)(re)、預冷(leng)(leng)(leng)溫(wen)(wen)(wen)(wen)(wen)(wen)(wen)(wen)(wen)(wen)(wen)(wen)度(du)(du)(du)(du)分(fen)別為(wei)(wei)(wei)200℃、- 70 ℃(實(shi)(shi)驗(yan)1)和(he)(he)150℃、-60℃(實(shi)(shi)驗(yan)2);測試箱(xiang)(xiang)由低(di)(di)(di)(di)溫(wen)(wen)(wen)(wen)(wen)(wen)(wen)(wen)(wen)(wen)(wen)(wen)箱(xiang)(xiang)沖(chong)(chong)擊到(dao)高(gao)(gao)(gao)溫(wen)(wen)(wen)(wen)(wen)(wen)(wen)(wen)(wen)(wen)(wen)(wen)箱(xiang)(xiang)時，高(gao)(gao)(gao)、低(di)(di)(di)(di)溫(wen)(wen)(wen)(wen)(wen)(wen)(wen)(wen)(wen)(wen)(wen)(wen)箱(xiang)(xiang)的預熱(re)(re)、預冷(leng)(leng)(leng)溫(wen)(wen)(wen)(wen)(wen)(wen)(wen)(wen)(wen)(wen)(wen)(wen)度(du)(du)(du)(du)分(fen)別為(wei)(wei)(wei)210℃、-55℃(實(shi)(shi)驗(yan)1)和(he)(he)160℃、-45℃(實(shi)(shi)驗(yan)2)。實(shi)(shi)驗(yan)前使(shi)用(yong)真空泵將(jiang)高(gao)(gao)(gao)、低(di)(di)(di)(di)溫(wen)(wen)(wen)(wen)(wen)(wen)(wen)(wen)(wen)(wen)(wen)(wen)制(zhi)(zhi)冷(leng)(leng)(leng)循環系(xi)統抽真空后(hou)，再將(jiang)選擇的制(zhi)(zhi)冷(leng)(leng)(leng)劑R404A和(he)(he)R23分(fen)別充(chong)人到(dao)高(gao)(gao)(gao)、低(di)(di)(di)(di)溫(wen)(wen)(wen)(wen)(wen)(wen)(wen)(wen)(wen)(wen)(wen)(wen)制(zhi)(zhi)冷(leng)(leng)(leng)循環系(xi)統內，并用(yong)電(dian)(dian)子(zi)稱測出(chu)制(zhi)(zhi)冷(leng)(leng)(leng)劑的充(chong)人量。經過調試，制(zhi)(zhi)冷(leng)(leng)(leng)系(xi)統工作(zuo)(zuo)(zuo)正(zheng)常。電(dian)(dian)源接通(tong)后(hou)，高(gao)(gao)(gao)溫(wen)(wen)(wen)(wen)(wen)(wen)(wen)(wen)(wen)(wen)(wen)(wen)區(qu)內的電(dian)(dian)加熱(re)(re)管(guan)立即工作(zuo)(zuo)(zuo)，通(tong)過PID調節將(jiang)高(gao)(gao)(gao)溫(wen)(wen)(wen)(wen)(wen)(wen)(wen)(wen)(wen)(wen)(wen)(wen)箱(xiang)(xiang)環境(jing)預熱(re)(re)到(dao)目標(biao)溫(wen)(wen)(wen)(wen)(wen)(wen)(wen)(wen)(wen)(wen)(wen)(wen)度(du)(du)(du)(du)。為(wei)(wei)(wei)確保壓(ya)(ya)(ya)縮(suo)機安全工作(zuo)(zuo)(zuo)，防止誤操作(zuo)(zuo)(zuo)，電(dian)(dian)源接通(tong)后(hou)30s，高(gao)(gao)(gao)溫(wen)(wen)(wen)(wen)(wen)(wen)(wen)(wen)(wen)(wen)(wen)(wen)級(ji)壓(ya)(ya)(ya)縮(suo)機啟動(dong)，當高(gao)(gao)(gao)溫(wen)(wen)(wen)(wen)(wen)(wen)(wen)(wen)(wen)(wen)(wen)(wen)級(ji)蒸發(fa)溫(wen)(wen)(wen)(wen)(wen)(wen)(wen)(wen)(wen)(wen)(wen)(wen)度(du)(du)(du)(du)達到(dao)低(di)(di)(di)(di)溫(wen)(wen)(wen)(wen)(wen)(wen)(wen)(wen)(wen)(wen)(wen)(wen)級(ji)冷(leng)(leng)(leng)凝溫(wen)(wen)(wen)(wen)(wen)(wen)(wen)(wen)(wen)(wen)(wen)(wen)度(du)(du)(du)(du)時，低(di)(di)(di)(di)溫(wen)(wen)(wen)(wen)(wen)(wen)(wen)(wen)(wen)(wen)(wen)(wen)級(ji)壓(ya)(ya)(ya)縮(suo)機再啟動(dong)。低(di)(di)(di)(di)溫(wen)(wen)(wen)(wen)(wen)(wen)(wen)(wen)(wen)(wen)(wen)(wen)級(ji)制(zhi)(zhi)冷(leng)(leng)(leng)劑進(jin)人蒸發(fa)器將(jiang)低(di)(di)(di)(di)溫(wen)(wen)(wen)(wen)(wen)(wen)(wen)(wen)(wen)(wen)(wen)(wen)箱(xiang)(xiang)環境(jing)預冷(leng)(leng)(leng)到(dao)目標(biao)溫(wen)(wen)(wen)(wen)(wen)(wen)(wen)(wen)(wen)(wen)(wen)(wen)度(du)(du)(du)(du)，同時低(di)(di)(di)(di)溫(wen)(wen)(wen)(wen)(wen)(wen)(wen)(wen)(wen)(wen)(wen)(wen)箱(xiang)(xiang)內電(dian)(dian)加熱(re)(re)盤(pan)管(guan)在PID調節下工作(zuo)(zuo)(zuo)，使(shi)低(di)(di)(di)(di)溫(wen)(wen)(wen)(wen)(wen)(wen)(wen)(wen)(wen)(wen)(wen)(wen)箱(xiang)(xiang)內穩定后(hou)的溫(wen)(wen)(wen)(wen)(wen)(wen)(wen)(wen)(wen)(wen)(wen)(wen)度(du)(du)(du)(du)波動(dong)范圍控制(zhi)(zhi)在±0.5℃。當高(gao)(gao)(gao)、低(di)(di)(di)(di)溫(wen)(wen)(wen)(wen)(wen)(wen)(wen)(wen)(wen)(wen)(wen)(wen)箱(xiang)(xiang)達到(dao)預熱(re)(re)、預冷(leng)(leng)(leng)溫(wen)(wen)(wen)(wen)(wen)(wen)(wen)(wen)(wen)(wen)(wen)(wen)度(du)(du)(du)(du)并穩定后(hou)，測試箱(xiang)(xiang)在氣缸的拉動(dong)下瞬(shun)間(jian)(jian)從高(gao)(gao)(gao)溫(wen)(wen)(wen)(wen)(wen)(wen)(wen)(wen)(wen)(wen)(wen)(wen)箱(xiang)(xiang)沖(chong)(chong)擊到(dao)低(di)(di)(di)(di)溫(wen)(wen)(wen)(wen)(wen)(wen)(wen)(wen)(wen)(wen)(wen)(wen)箱(xiang)(xiang)(或低(di)(di)(di)(di)溫(wen)(wen)(wen)(wen)(wen)(wen)(wen)(wen)(wen)(wen)(wen)(wen)箱(xiang)(xiang)沖(chong)(chong)擊到(dao)高(gao)(gao)(gao)溫(wen)(wen)(wen)(wen)(wen)(wen)(wen)(wen)(wen)(wen)(wen)(wen)箱(xiang)(xiang)) ， 測試箱(xiang)(xiang)內溫(wen)(wen)(wen)(wen)(wen)(wen)(wen)(wen)(wen)(wen)(wen)(wen)度(du)(du)(du)(du)迅速變(bian)化，終穩定在沖(chong)(chong)擊溫(wen)(wen)(wen)(wen)(wen)(wen)(wen)(wen)(wen)(wen)(wen)(wen)度(du)(du)(du)(du)設(she)定值。在這期間(jian)(jian)，記錄(lu)下壓(ya)(ya)(ya)縮(suo)機進(jin)、排氣口壓(ya)(ya)(ya)力和(he)(he)高(gao)(gao)(gao)、低(di)(di)(di)(di)溫(wen)(wen)(wen)(wen)(wen)(wen)(wen)(wen)(wen)(wen)(wen)(wen)箱(xiang)(xiang)內的溫(wen)(wen)(wen)(wen)(wen)(wen)(wen)(wen)(wen)(wen)(wen)(wen)度(du)(du)(du)(du)隨(sui)時間(jian)(jian)變(bian)化的值。

    5、結果與(yu)討論

    圖4和圖5分別表示(shi)在(zai)整個沖(chong)擊循環(huan)試驗(yan)(yan)過程(cheng)中高(gao)(gao)、低溫(wen)(wen)箱內環(huan)境溫(wen)(wen)度隨(sui)時間的(de)變(bian)化(hua)曲(qu)線。圖4表明，在(zai)實驗(yan)(yan)的(de)預熱(re)段(O41A41或O42A42段)，高(gao)(gao)溫(wen)(wen)箱溫(wen)(wen)度在(zai)電源啟動后迅速(su)上升，隨(sui)著溫(wen)(wen)度接近預熱(re)溫(wen)(wen)度，電加熱(re)管輸(shu)出功率減小(xiao)、溫(wen)(wen)升速(su)率降低，箱內溫(wen)(wen)度逐近穩定(ding)。實驗(yan)(yan)1經過770s(約12. 8min) ，高(gao)(gao)溫(wen)(wen)箱從室溫(wen)(wen)(13.8℃)升到200℃。

    6、結論