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),而降低了空(kong)(kong)(kong)氣(qi)加熱(re)(re)器內電(dian)熱(re)(re)元件表面溫度(du),不僅有利于延長空(kong)(kong)(kong)氣(qi)加熱(re)(re)器電(dian)熱(re)(re)元件的(de)使(shi)(shi)用壽命,而且使(shi)(shi)得空(kong)(kong)(kong)氣(qi)電(dian)加熱(re)(re)器散熱(re)(re)損(sun)失減(jian)小,因而空(kong)(kong)(kong)氣(qi)換(huan)熱(re)(re)器的(de)效率提(ti)高了,但速度(du)如(ru)果過大,使(shi)(shi)得壓力損(sun)失陡增,這將不利于加熱(re)(re)效率的(de)提(ti)高。
2.若其它(ta)條件不(bu)變(bian),改變(bian)表(biao)面(mian)負荷(he),空(kong)(kong)氣加(jia)(jia)熱(re)器中電(dian)熱(re)元(yuan)件的(de)壁(bi)溫(wen)(wen)將呈直線(xian)變(bian)化,如(ru)果表(biao)面(mian)負荷(he)增(zeng)大(da),電(dian)熱(re)元(yuan)件的(de)壁(bi)溫(wen)(wen)將增(zeng)大(da),這將降低(di)空(kong)(kong)氣加(jia)(jia)熱(re)器中電(dian)熱(re)元(yuan)件的(de)使用(yong)壽命(ming),但是如(ru)果表(biao)面(mian)負荷(he)過(guo)小,壁(bi)溫(wen)(wen)過(guo)低(di),空(kong)(kong)氣加(jia)(jia)熱(re)器換熱(re)器的(de)效率又降低(di)了,所以空(kong)(kong)氣加(jia)(jia)熱(re)器中電(dian)熱(re)元(yuan)件的(de)表(biao)面(mian)負荷(he)的(de)選(xuan)擇(ze)比較(jiao)重要。
3.空氣(qi)(qi)加(jia)熱(re)(re)(re)器中(zhong)空氣(qi)(qi)終溫T2提高時(shi),由于空氣(qi)(qi)粘性增加(jia),氣(qi)(qi)體雷諾數減小,使(shi)得對(dui)流換熱(re)(re)(re)強度降(jiang)低,空氣(qi)(qi)加(jia)熱(re)(re)(re)器中(zhong)電熱(re)(re)(re)元(yuan)件(jian)的表(biao)(biao)面(mian)溫度同時(shi)上升(sheng),紅外碳(tan)硫(liu)分析儀(yi)使(shi)得散熱(re)(re)(re)損(sun)失增加(jia),從而降(jiang)低換熱(re)(re)(re)器的效(xiao)率。當T2提高過大(da)時(shi),電熱(re)(re)(re)元(yuan)件(jian)表(biao)(biao)面(mian)的溫度亦會大(da)大(da)升(sheng)高,致使(shi)一(yi)般電熱(re)(re)(re)元(yuan)件(jian)無法(fa)承受,故T2的增加(jia)通常受到空氣(qi)(qi)加(jia)熱(re)(re)(re)器中(zhong)電熱(re)(re)(re)元(yuan)件(jian)材料耐熱(re)(re)(re)性能(neng)的限制。