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)(re)(re),而(er)降低了空(kong)氣(qi)加(jia)熱(re)(re)(re)器(qi)(qi)內電熱(re)(re)(re)元件表(biao)面(mian)溫度(du),不僅有利于(yu)延長空(kong)氣(qi)加(jia)熱(re)(re)(re)器(qi)(qi)電熱(re)(re)(re)元件的使用壽命,而(er)且(qie)使得空(kong)氣(qi)電加(jia)熱(re)(re)(re)器(qi)(qi)散熱(re)(re)(re)損失減小,因而(er)空(kong)氣(qi)換熱(re)(re)(re)器(qi)(qi)的效率(lv)提高了,但速(su)度(du)如果過大,使得壓(ya)力損失陡增,這將不利于(yu)加(jia)熱(re)(re)(re)效率(lv)的提高。
2.若其它條件(jian)(jian)不變(bian),改變(bian)表面負(fu)荷(he),空(kong)(kong)氣(qi)(qi)(qi)加(jia)(jia)熱(re)器(qi)中電(dian)熱(re)元(yuan)(yuan)件(jian)(jian)的(de)壁(bi)溫將(jiang)呈(cheng)直線變(bian)化,如果表面負(fu)荷(he)增大,電(dian)熱(re)元(yuan)(yuan)件(jian)(jian)的(de)壁(bi)溫將(jiang)增大,這將(jiang)降低空(kong)(kong)氣(qi)(qi)(qi)加(jia)(jia)熱(re)器(qi)中電(dian)熱(re)元(yuan)(yuan)件(jian)(jian)的(de)使用壽命,但是如果表面負(fu)荷(he)過小,壁(bi)溫過低,空(kong)(kong)氣(qi)(qi)(qi)加(jia)(jia)熱(re)器(qi)換熱(re)器(qi)的(de)效(xiao)率(lv)又(you)降低了,所(suo)以(yi)空(kong)(kong)氣(qi)(qi)(qi)加(jia)(jia)熱(re)器(qi)中電(dian)熱(re)元(yuan)(yuan)件(jian)(jian)的(de)表面負(fu)荷(he)的(de)選擇(ze)比較重要。
3.空(kong)(kong)(kong)氣(qi)加(jia)熱(re)器(qi)中(zhong)(zhong)空(kong)(kong)(kong)氣(qi)終溫(wen)(wen)T2提高時(shi),由于空(kong)(kong)(kong)氣(qi)粘性(xing)增(zeng)加(jia),氣(qi)體雷諾(nuo)數減小(xiao),使(shi)得(de)對流(liu)換熱(re)強度(du)降低,空(kong)(kong)(kong)氣(qi)加(jia)熱(re)器(qi)中(zhong)(zhong)電熱(re)元件的(de)表面溫(wen)(wen)度(du)同時(shi)上(shang)升,紅外(wai)碳硫分析(xi)儀(yi)使(shi)得(de)散熱(re)損失增(zeng)加(jia),從而降低換熱(re)器(qi)的(de)效率。當T2提高過大時(shi),電熱(re)元件表面的(de)溫(wen)(wen)度(du)亦會大大升高,致使(shi)一般電熱(re)元件無(wu)法承受,故T2的(de)增(zeng)加(jia)通常受到(dao)空(kong)(kong)(kong)氣(qi)加(jia)熱(re)器(qi)中(zhong)(zhong)電熱(re)元件材料(liao)耐(nai)熱(re)性(xing)能的(de)限制。