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)流換熱(re),而(er)(er)(er)降低了空(kong)(kong)(kong)氣(qi)(qi)(qi)加熱(re)器(qi)內電(dian)熱(re)元(yuan)件表面溫度,不僅有利于延長空(kong)(kong)(kong)氣(qi)(qi)(qi)加熱(re)器(qi)電(dian)熱(re)元(yuan)件的使用(yong)壽(shou)命,而(er)(er)(er)且使得空(kong)(kong)(kong)氣(qi)(qi)(qi)電(dian)加熱(re)器(qi)散(san)熱(re)損(sun)失(shi)減小,因(yin)而(er)(er)(er)空(kong)(kong)(kong)氣(qi)(qi)(qi)換熱(re)器(qi)的效率(lv)(lv)提(ti)高了,但速度如果(guo)過(guo)大(da),使得壓力損(sun)失(shi)陡增(zeng),這(zhe)將不利于加熱(re)效率(lv)(lv)的提(ti)高。
2.若其(qi)它(ta)條件不變,改變表(biao)(biao)面(mian)(mian)負(fu)荷(he),空氣(qi)加(jia)(jia)熱(re)(re)器(qi)(qi)(qi)中電(dian)熱(re)(re)元件的壁溫將呈直線變化,如(ru)果表(biao)(biao)面(mian)(mian)負(fu)荷(he)增大,電(dian)熱(re)(re)元件的壁溫將增大,這(zhe)將降(jiang)低空氣(qi)加(jia)(jia)熱(re)(re)器(qi)(qi)(qi)中電(dian)熱(re)(re)元件的使用壽命,但是如(ru)果表(biao)(biao)面(mian)(mian)負(fu)荷(he)過(guo)小,壁溫過(guo)低,空氣(qi)加(jia)(jia)熱(re)(re)器(qi)(qi)(qi)換熱(re)(re)器(qi)(qi)(qi)的效(xiao)率又降(jiang)低了,所(suo)以空氣(qi)加(jia)(jia)熱(re)(re)器(qi)(qi)(qi)中電(dian)熱(re)(re)元件的表(biao)(biao)面(mian)(mian)負(fu)荷(he)的選擇比(bi)較重(zhong)要。
3.空(kong)氣加(jia)熱(re)器中(zhong)空(kong)氣終(zhong)溫(wen)T2提高(gao)時,由(you)于空(kong)氣粘性增(zeng)加(jia),氣體雷諾數減小,使(shi)得對流(liu)換(huan)熱(re)強度(du)(du)降低,空(kong)氣加(jia)熱(re)器中(zhong)電(dian)熱(re)元(yuan)件(jian)的(de)(de)(de)表(biao)(biao)面溫(wen)度(du)(du)同(tong)時上升,紅外(wai)碳(tan)硫(liu)分析儀使(shi)得散熱(re)損(sun)失增(zeng)加(jia),從而降低換(huan)熱(re)器的(de)(de)(de)效率。當T2提高(gao)過大時,電(dian)熱(re)元(yuan)件(jian)表(biao)(biao)面的(de)(de)(de)溫(wen)度(du)(du)亦會大大升高(gao),致使(shi)一般(ban)電(dian)熱(re)元(yuan)件(jian)無法承(cheng)受,故T2的(de)(de)(de)增(zeng)加(jia)通常受到空(kong)氣加(jia)熱(re)器中(zhong)電(dian)熱(re)元(yuan)件(jian)材料耐熱(re)性能的(de)(de)(de)限(xian)制。