空氣電磁加熱器影響因素
1.增大空氣加熱器的氣體入口流速,能夠加強空氣電加熱器對流(liu)換(huan)熱(re)(re),而降低了(le)空(kong)氣(qi)加(jia)熱(re)(re)器(qi)內電熱(re)(re)元(yuan)件(jian)表面溫度,不(bu)僅有利于延(yan)長空(kong)氣(qi)加(jia)熱(re)(re)器(qi)電熱(re)(re)元(yuan)件(jian)的使(shi)用壽命,而且使(shi)得(de)空(kong)氣(qi)電加(jia)熱(re)(re)器(qi)散(san)熱(re)(re)損失減小,因而空(kong)氣(qi)換(huan)熱(re)(re)器(qi)的效率提高(gao)了(le),但速度如(ru)果(guo)過大,使(shi)得(de)壓(ya)力損失陡增(zeng),這(zhe)將不(bu)利于加(jia)熱(re)(re)效率的提高(gao)。
2.若其它條件(jian)不變,改變表面(mian)負(fu)(fu)荷,空氣(qi)加(jia)(jia)熱器(qi)中電(dian)(dian)(dian)熱元(yuan)件(jian)的壁溫(wen)將呈直線變化,如果表面(mian)負(fu)(fu)荷增大,電(dian)(dian)(dian)熱元(yuan)件(jian)的壁溫(wen)將增大,這(zhe)將降(jiang)低空氣(qi)加(jia)(jia)熱器(qi)中電(dian)(dian)(dian)熱元(yuan)件(jian)的使用壽命,但是如果表面(mian)負(fu)(fu)荷過小,壁溫(wen)過低,空氣(qi)加(jia)(jia)熱器(qi)換熱器(qi)的效(xiao)率又降(jiang)低了,所以空氣(qi)加(jia)(jia)熱器(qi)中電(dian)(dian)(dian)熱元(yuan)件(jian)的表面(mian)負(fu)(fu)荷的選擇(ze)比(bi)較重要。
3.空氣加(jia)熱(re)(re)器中(zhong)空氣終溫(wen)T2提(ti)高時(shi),由于空氣粘(zhan)性(xing)增(zeng)加(jia),氣體雷諾數減小,使得(de)對流換熱(re)(re)強度(du)降(jiang)低,空氣加(jia)熱(re)(re)器中(zhong)電(dian)(dian)(dian)熱(re)(re)元(yuan)(yuan)件(jian)的表面(mian)溫(wen)度(du)同時(shi)上升,紅外碳硫分(fen)析儀(yi)使得(de)散熱(re)(re)損失增(zeng)加(jia),從而降(jiang)低換熱(re)(re)器的效率。當T2提(ti)高過大時(shi),電(dian)(dian)(dian)熱(re)(re)元(yuan)(yuan)件(jian)表面(mian)的溫(wen)度(du)亦會大大升高,致使一般(ban)電(dian)(dian)(dian)熱(re)(re)元(yuan)(yuan)件(jian)無法承受(shou),故T2的增(zeng)加(jia)通(tong)常受(shou)到(dao)空氣加(jia)熱(re)(re)器中(zhong)電(dian)(dian)(dian)熱(re)(re)元(yuan)(yuan)件(jian)材料耐熱(re)(re)性(xing)能的限(xian)制。