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(er)(er)降低(di)了(le)空(kong)氣(qi)(qi)加(jia)熱(re)(re)器內電熱(re)(re)元(yuan)件表(biao)面(mian)溫(wen)度,不僅有利(li)于延長空(kong)氣(qi)(qi)加(jia)熱(re)(re)器電熱(re)(re)元(yuan)件的使(shi)用(yong)壽命,而(er)(er)且使(shi)得空(kong)氣(qi)(qi)電加(jia)熱(re)(re)器散熱(re)(re)損(sun)失減(jian)小(xiao),因而(er)(er)空(kong)氣(qi)(qi)換(huan)熱(re)(re)器的效率提(ti)高了(le),但速度如果過大,使(shi)得壓力損(sun)失陡增,這將不利(li)于加(jia)熱(re)(re)效率的提(ti)高。
2.若其它條件不(bu)變(bian),改變(bian)表面負(fu)(fu)荷(he),空氣加(jia)(jia)熱(re)(re)(re)器(qi)中(zhong)電(dian)(dian)熱(re)(re)(re)元(yuan)件的壁(bi)溫(wen)將呈直(zhi)線變(bian)化,如(ru)果(guo)(guo)表面負(fu)(fu)荷(he)增大,電(dian)(dian)熱(re)(re)(re)元(yuan)件的壁(bi)溫(wen)將增大,這將降(jiang)低(di)空氣加(jia)(jia)熱(re)(re)(re)器(qi)中(zhong)電(dian)(dian)熱(re)(re)(re)元(yuan)件的使用壽命,但是如(ru)果(guo)(guo)表面負(fu)(fu)荷(he)過小,壁(bi)溫(wen)過低(di),空氣加(jia)(jia)熱(re)(re)(re)器(qi)換(huan)熱(re)(re)(re)器(qi)的效率又降(jiang)低(di)了,所以空氣加(jia)(jia)熱(re)(re)(re)器(qi)中(zhong)電(dian)(dian)熱(re)(re)(re)元(yuan)件的表面負(fu)(fu)荷(he)的選(xuan)擇(ze)比較重要(yao)。
3.空(kong)(kong)氣(qi)加(jia)熱器(qi)(qi)中(zhong)空(kong)(kong)氣(qi)終(zhong)溫(wen)T2提高時,由于空(kong)(kong)氣(qi)粘性增加(jia),氣(qi)體雷諾(nuo)數減小,使(shi)得對流換熱強度降低,空(kong)(kong)氣(qi)加(jia)熱器(qi)(qi)中(zhong)電熱元(yuan)件(jian)的表(biao)面(mian)溫(wen)度同(tong)時上升,紅(hong)外碳硫(liu)分析儀(yi)使(shi)得散熱損(sun)失增加(jia),從而(er)降低換熱器(qi)(qi)的效(xiao)率。當T2提高過(guo)大時,電熱元(yuan)件(jian)表(biao)面(mian)的溫(wen)度亦會(hui)大大升高,致使(shi)一般電熱元(yuan)件(jian)無(wu)法承受,故T2的增加(jia)通(tong)常受到空(kong)(kong)氣(qi)加(jia)熱器(qi)(qi)中(zhong)電熱元(yuan)件(jian)材料耐熱性能的限制。