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),而降低了(le)空(kong)(kong)氣(qi)加(jia)(jia)熱(re)(re)器(qi)內電(dian)熱(re)(re)元件(jian)表面溫度(du)(du),不(bu)僅有利于(yu)延(yan)長空(kong)(kong)氣(qi)加(jia)(jia)熱(re)(re)器(qi)電(dian)熱(re)(re)元件(jian)的使用壽命,而且使得(de)空(kong)(kong)氣(qi)電(dian)加(jia)(jia)熱(re)(re)器(qi)散熱(re)(re)損失減小,因而空(kong)(kong)氣(qi)換熱(re)(re)器(qi)的效率提(ti)高了(le),但速度(du)(du)如果過(guo)大,使得(de)壓力(li)損失陡(dou)增,這將不(bu)利于(yu)加(jia)(jia)熱(re)(re)效率的提(ti)高。
2.若其它條件(jian)(jian)不變,改變表(biao)面負(fu)(fu)荷(he),空氣(qi)加(jia)(jia)熱(re)器(qi)中電熱(re)元件(jian)(jian)的(de)壁溫(wen)(wen)將(jiang)呈直線(xian)變化,如果(guo)表(biao)面負(fu)(fu)荷(he)增(zeng)大,電熱(re)元件(jian)(jian)的(de)壁溫(wen)(wen)將(jiang)增(zeng)大,這將(jiang)降低空氣(qi)加(jia)(jia)熱(re)器(qi)中電熱(re)元件(jian)(jian)的(de)使用壽命,但是如果(guo)表(biao)面負(fu)(fu)荷(he)過(guo)(guo)小,壁溫(wen)(wen)過(guo)(guo)低,空氣(qi)加(jia)(jia)熱(re)器(qi)換熱(re)器(qi)的(de)效(xiao)率又(you)降低了,所以(yi)空氣(qi)加(jia)(jia)熱(re)器(qi)中電熱(re)元件(jian)(jian)的(de)表(biao)面負(fu)(fu)荷(he)的(de)選擇比較重要。
3.空(kong)(kong)(kong)氣加熱器中(zhong)空(kong)(kong)(kong)氣終溫(wen)(wen)T2提高(gao)(gao)時(shi),由于空(kong)(kong)(kong)氣粘(zhan)性(xing)增(zeng)加,氣體雷諾數(shu)減(jian)小(xiao),使得對流(liu)換熱強度降(jiang)低,空(kong)(kong)(kong)氣加熱器中(zhong)電熱元件(jian)(jian)的表面(mian)溫(wen)(wen)度同(tong)時(shi)上升(sheng),紅外碳硫分析儀使得散(san)熱損失增(zeng)加,從而降(jiang)低換熱器的效率。當T2提高(gao)(gao)過大時(shi),電熱元件(jian)(jian)表面(mian)的溫(wen)(wen)度亦會(hui)大大升(sheng)高(gao)(gao),致使一(yi)般電熱元件(jian)(jian)無法承受(shou),故T2的增(zeng)加通(tong)常受(shou)到空(kong)(kong)(kong)氣加熱器中(zhong)電熱元件(jian)(jian)材料耐熱性(xing)能的限制。