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(huan)熱(re),而(er)降(jiang)低了空氣加熱(re)器(qi)內(nei)電(dian)熱(re)元件表面溫度(du),不僅有利于(yu)(yu)延長空氣加熱(re)器(qi)電(dian)熱(re)元件的(de)使用(yong)壽命,而(er)且使得空氣電(dian)加熱(re)器(qi)散熱(re)損失減小,因而(er)空氣換(huan)熱(re)器(qi)的(de)效率提高了,但(dan)速(su)度(du)如果過大(da),使得壓力(li)損失陡增,這將不利于(yu)(yu)加熱(re)效率的(de)提高。
2.若(ruo)其它條件不變,改變表面(mian)(mian)(mian)(mian)負(fu)荷,空(kong)氣(qi)加熱(re)器中(zhong)電(dian)(dian)熱(re)元(yuan)(yuan)(yuan)件的(de)(de)壁溫(wen)(wen)將(jiang)呈直(zhi)線變化(hua),如果表面(mian)(mian)(mian)(mian)負(fu)荷增大,電(dian)(dian)熱(re)元(yuan)(yuan)(yuan)件的(de)(de)壁溫(wen)(wen)將(jiang)增大,這(zhe)將(jiang)降(jiang)低(di)空(kong)氣(qi)加熱(re)器中(zhong)電(dian)(dian)熱(re)元(yuan)(yuan)(yuan)件的(de)(de)使用壽命,但是如果表面(mian)(mian)(mian)(mian)負(fu)荷過小,壁溫(wen)(wen)過低(di),空(kong)氣(qi)加熱(re)器換熱(re)器的(de)(de)效率(lv)又降(jiang)低(di)了(le),所以空(kong)氣(qi)加熱(re)器中(zhong)電(dian)(dian)熱(re)元(yuan)(yuan)(yuan)件的(de)(de)表面(mian)(mian)(mian)(mian)負(fu)荷的(de)(de)選擇比(bi)較重(zhong)要。
3.空氣(qi)加熱(re)(re)器(qi)(qi)中空氣(qi)終溫(wen)(wen)T2提高(gao)(gao)時(shi),由于空氣(qi)粘性增加,氣(qi)體(ti)雷諾數減小(xiao),使得(de)對流換(huan)熱(re)(re)強度降(jiang)(jiang)低(di),空氣(qi)加熱(re)(re)器(qi)(qi)中電(dian)(dian)熱(re)(re)元(yuan)件(jian)的(de)表面溫(wen)(wen)度同時(shi)上升,紅外(wai)碳硫(liu)分析(xi)儀使得(de)散熱(re)(re)損失增加,從而(er)降(jiang)(jiang)低(di)換(huan)熱(re)(re)器(qi)(qi)的(de)效率。當T2提高(gao)(gao)過大時(shi),電(dian)(dian)熱(re)(re)元(yuan)件(jian)表面的(de)溫(wen)(wen)度亦會大大升高(gao)(gao),致使一般電(dian)(dian)熱(re)(re)元(yuan)件(jian)無法承受,故T2的(de)增加通常(chang)受到(dao)空氣(qi)加熱(re)(re)器(qi)(qi)中電(dian)(dian)熱(re)(re)元(yuan)件(jian)材料耐(nai)熱(re)(re)性能的(de)限制。