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)(re),而降低(di)了(le)空(kong)氣(qi)加熱(re)(re)(re)器(qi)(qi)內(nei)電熱(re)(re)(re)元件表面溫度,不(bu)僅有利于(yu)延長空(kong)氣(qi)加熱(re)(re)(re)器(qi)(qi)電熱(re)(re)(re)元件的使用壽命(ming),而且使得空(kong)氣(qi)電加熱(re)(re)(re)器(qi)(qi)散熱(re)(re)(re)損失減小,因而空(kong)氣(qi)換(huan)熱(re)(re)(re)器(qi)(qi)的效率提高了(le),但速度如果(guo)過大,使得壓力(li)損失陡增(zeng),這將(jiang)不(bu)利于(yu)加熱(re)(re)(re)效率的提高。
2.若其(qi)它條件(jian)(jian)不變(bian)(bian),改變(bian)(bian)表(biao)(biao)面(mian)(mian)負荷,空氣(qi)(qi)加(jia)(jia)熱(re)(re)器(qi)(qi)中(zhong)電(dian)(dian)熱(re)(re)元件(jian)(jian)的(de)壁(bi)溫將(jiang)(jiang)呈(cheng)直線(xian)變(bian)(bian)化,如果(guo)表(biao)(biao)面(mian)(mian)負荷增(zeng)(zeng)大(da),電(dian)(dian)熱(re)(re)元件(jian)(jian)的(de)壁(bi)溫將(jiang)(jiang)增(zeng)(zeng)大(da),這將(jiang)(jiang)降低(di)空氣(qi)(qi)加(jia)(jia)熱(re)(re)器(qi)(qi)中(zhong)電(dian)(dian)熱(re)(re)元件(jian)(jian)的(de)使用壽命,但是如果(guo)表(biao)(biao)面(mian)(mian)負荷過小,壁(bi)溫過低(di),空氣(qi)(qi)加(jia)(jia)熱(re)(re)器(qi)(qi)換(huan)熱(re)(re)器(qi)(qi)的(de)效率又降低(di)了,所以(yi)空氣(qi)(qi)加(jia)(jia)熱(re)(re)器(qi)(qi)中(zhong)電(dian)(dian)熱(re)(re)元件(jian)(jian)的(de)表(biao)(biao)面(mian)(mian)負荷的(de)選擇比(bi)較重要。
3.空(kong)氣(qi)(qi)加(jia)熱器(qi)中空(kong)氣(qi)(qi)終溫T2提(ti)高(gao)時,由于(yu)空(kong)氣(qi)(qi)粘(zhan)性(xing)增加(jia),氣(qi)(qi)體雷諾數減小,使得對流換熱強度降(jiang)低,空(kong)氣(qi)(qi)加(jia)熱器(qi)中電熱元件(jian)的表面溫度同(tong)時上(shang)升,紅外(wai)碳硫分析(xi)儀使得散(san)熱損失增加(jia),從而降(jiang)低換熱器(qi)的效率。當T2提(ti)高(gao)過大時,電熱元件(jian)表面的溫度亦(yi)會大大升高(gao),致使一般電熱元件(jian)無法承受,故(gu)T2的增加(jia)通常受到空(kong)氣(qi)(qi)加(jia)熱器(qi)中電熱元件(jian)材料耐熱性(xing)能(neng)的限制。