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(dui)流換(huan)熱(re)(re)(re),而降(jiang)低了空(kong)氣(qi)加熱(re)(re)(re)器內電(dian)(dian)熱(re)(re)(re)元件表面溫度,不僅有利于(yu)延長(chang)空(kong)氣(qi)加熱(re)(re)(re)器電(dian)(dian)熱(re)(re)(re)元件的使用壽命,而且使得空(kong)氣(qi)電(dian)(dian)加熱(re)(re)(re)器散熱(re)(re)(re)損失減小,因而空(kong)氣(qi)換(huan)熱(re)(re)(re)器的效率(lv)(lv)提(ti)高(gao)了,但速(su)度如(ru)果過大(da),使得壓(ya)力損失陡增,這(zhe)將不利于(yu)加熱(re)(re)(re)效率(lv)(lv)的提(ti)高(gao)。
2.若其它條件不(bu)變(bian),改變(bian)表(biao)面(mian)(mian)負荷(he),空氣(qi)加熱(re)(re)器(qi)(qi)中電(dian)熱(re)(re)元件的壁(bi)溫將(jiang)呈直線變(bian)化(hua),如(ru)果(guo)(guo)表(biao)面(mian)(mian)負荷(he)增大,電(dian)熱(re)(re)元件的壁(bi)溫將(jiang)增大,這將(jiang)降低(di)空氣(qi)加熱(re)(re)器(qi)(qi)中電(dian)熱(re)(re)元件的使(shi)用(yong)壽(shou)命(ming),但是如(ru)果(guo)(guo)表(biao)面(mian)(mian)負荷(he)過小(xiao),壁(bi)溫過低(di),空氣(qi)加熱(re)(re)器(qi)(qi)換(huan)熱(re)(re)器(qi)(qi)的效率(lv)又降低(di)了,所以空氣(qi)加熱(re)(re)器(qi)(qi)中電(dian)熱(re)(re)元件的表(biao)面(mian)(mian)負荷(he)的選擇比較重(zhong)要(yao)。
3.空(kong)氣(qi)加(jia)熱(re)(re)器(qi)(qi)中空(kong)氣(qi)終溫(wen)T2提(ti)高時(shi),由于空(kong)氣(qi)粘性增加(jia),氣(qi)體雷(lei)諾數減小,使(shi)得對流換熱(re)(re)強度降(jiang)低(di),空(kong)氣(qi)加(jia)熱(re)(re)器(qi)(qi)中電(dian)熱(re)(re)元(yuan)件的(de)表面(mian)溫(wen)度同(tong)時(shi)上(shang)升,紅(hong)外碳(tan)硫(liu)分(fen)析儀使(shi)得散(san)熱(re)(re)損失增加(jia),從而降(jiang)低(di)換熱(re)(re)器(qi)(qi)的(de)效率(lv)。當T2提(ti)高過(guo)大(da)時(shi),電(dian)熱(re)(re)元(yuan)件表面(mian)的(de)溫(wen)度亦會大(da)大(da)升高,致使(shi)一般電(dian)熱(re)(re)元(yuan)件無法承受,故T2的(de)增加(jia)通(tong)常受到空(kong)氣(qi)加(jia)熱(re)(re)器(qi)(qi)中電(dian)熱(re)(re)元(yuan)件材料耐熱(re)(re)性能的(de)限制(zhi)。