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熱(re),而降低了(le)空(kong)氣(qi)加熱(re)器(qi)內電(dian)熱(re)元(yuan)件(jian)表面溫(wen)度(du)(du),不(bu)僅有利于(yu)延長(chang)空(kong)氣(qi)加熱(re)器(qi)電(dian)熱(re)元(yuan)件(jian)的使用壽命,而且使得空(kong)氣(qi)電(dian)加熱(re)器(qi)散熱(re)損(sun)失(shi)減小,因而空(kong)氣(qi)換熱(re)器(qi)的效(xiao)率提(ti)高(gao)了(le),但速度(du)(du)如果(guo)過大,使得壓力損(sun)失(shi)陡(dou)增(zeng),這(zhe)將(jiang)不(bu)利于(yu)加熱(re)效(xiao)率的提(ti)高(gao)。
2.若其它條件不變(bian)(bian),改變(bian)(bian)表(biao)(biao)面負(fu)(fu)荷(he)(he),空氣加(jia)熱(re)器(qi)中電(dian)熱(re)元(yuan)件的壁溫(wen)將呈直線變(bian)(bian)化,如果(guo)表(biao)(biao)面負(fu)(fu)荷(he)(he)增大,電(dian)熱(re)元(yuan)件的壁溫(wen)將增大,這將降低空氣加(jia)熱(re)器(qi)中電(dian)熱(re)元(yuan)件的使(shi)用壽命(ming),但是如果(guo)表(biao)(biao)面負(fu)(fu)荷(he)(he)過小(xiao),壁溫(wen)過低,空氣加(jia)熱(re)器(qi)換熱(re)器(qi)的效率又降低了,所以空氣加(jia)熱(re)器(qi)中電(dian)熱(re)元(yuan)件的表(biao)(biao)面負(fu)(fu)荷(he)(he)的選擇比較重(zhong)要。
3.空(kong)(kong)氣(qi)加熱(re)(re)器中空(kong)(kong)氣(qi)終溫T2提高(gao)時(shi),由于(yu)空(kong)(kong)氣(qi)粘性(xing)增(zeng)加,氣(qi)體(ti)雷諾數減小,使(shi)得(de)對流換熱(re)(re)強(qiang)度(du)降低,空(kong)(kong)氣(qi)加熱(re)(re)器中電(dian)熱(re)(re)元件(jian)的(de)(de)(de)表面溫度(du)同(tong)時(shi)上升(sheng),紅外碳硫分析儀(yi)使(shi)得(de)散熱(re)(re)損(sun)失增(zeng)加,從而降低換熱(re)(re)器的(de)(de)(de)效(xiao)率(lv)。當T2提高(gao)過大(da)時(shi),電(dian)熱(re)(re)元件(jian)表面的(de)(de)(de)溫度(du)亦會大(da)大(da)升(sheng)高(gao),致(zhi)使(shi)一般電(dian)熱(re)(re)元件(jian)無(wu)法承受(shou),故T2的(de)(de)(de)增(zeng)加通常(chang)受(shou)到空(kong)(kong)氣(qi)加熱(re)(re)器中電(dian)熱(re)(re)元件(jian)材料耐熱(re)(re)性(xing)能的(de)(de)(de)限制。