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換熱(re)(re)(re),而(er)降(jiang)低了(le)(le)空氣(qi)加熱(re)(re)(re)器(qi)內電(dian)熱(re)(re)(re)元(yuan)件表面溫度(du),不(bu)僅(jin)有利(li)于延長空氣(qi)加熱(re)(re)(re)器(qi)電(dian)熱(re)(re)(re)元(yuan)件的使用壽命,而(er)且使得(de)空氣(qi)電(dian)加熱(re)(re)(re)器(qi)散熱(re)(re)(re)損失(shi)減小,因而(er)空氣(qi)換熱(re)(re)(re)器(qi)的效(xiao)率(lv)提高了(le)(le),但速度(du)如果過大,使得(de)壓(ya)力損失(shi)陡增,這將不(bu)利(li)于加熱(re)(re)(re)效(xiao)率(lv)的提高。
2.若其它條件(jian)不(bu)變,改變表面(mian)(mian)(mian)負(fu)荷,空(kong)氣(qi)加(jia)(jia)熱器(qi)(qi)中(zhong)電熱元(yuan)件(jian)的壁(bi)溫(wen)(wen)將呈直(zhi)線變化(hua),如(ru)(ru)果(guo)表面(mian)(mian)(mian)負(fu)荷增大(da),電熱元(yuan)件(jian)的壁(bi)溫(wen)(wen)將增大(da),這將降(jiang)低空(kong)氣(qi)加(jia)(jia)熱器(qi)(qi)中(zhong)電熱元(yuan)件(jian)的使用壽命(ming),但(dan)是如(ru)(ru)果(guo)表面(mian)(mian)(mian)負(fu)荷過(guo)(guo)小,壁(bi)溫(wen)(wen)過(guo)(guo)低,空(kong)氣(qi)加(jia)(jia)熱器(qi)(qi)換熱器(qi)(qi)的效率又降(jiang)低了,所以空(kong)氣(qi)加(jia)(jia)熱器(qi)(qi)中(zhong)電熱元(yuan)件(jian)的表面(mian)(mian)(mian)負(fu)荷的選擇比較重要。
3.空(kong)氣(qi)加(jia)熱(re)器(qi)中(zhong)空(kong)氣(qi)終(zhong)溫T2提高(gao)時,由于空(kong)氣(qi)粘性增(zeng)加(jia),氣(qi)體雷諾(nuo)數減小,使(shi)得對流換(huan)熱(re)強度降低,空(kong)氣(qi)加(jia)熱(re)器(qi)中(zhong)電熱(re)元(yuan)(yuan)件的(de)表面溫度同時上升,紅外碳硫分析儀使(shi)得散熱(re)損(sun)失增(zeng)加(jia),從而降低換(huan)熱(re)器(qi)的(de)效率。當T2提高(gao)過大時,電熱(re)元(yuan)(yuan)件表面的(de)溫度亦會大大升高(gao),致(zhi)使(shi)一(yi)般電熱(re)元(yuan)(yuan)件無法承受,故T2的(de)增(zeng)加(jia)通常(chang)受到(dao)空(kong)氣(qi)加(jia)熱(re)器(qi)中(zhong)電熱(re)元(yuan)(yuan)件材(cai)料耐熱(re)性能的(de)限(xian)制。