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(er)(er)降(jiang)低了空氣(qi)加熱(re)器(qi)內電(dian)(dian)熱(re)元件表面溫度(du),不(bu)僅有利(li)于(yu)延長(chang)空氣(qi)加熱(re)器(qi)電(dian)(dian)熱(re)元件的(de)使(shi)用(yong)壽命,而(er)(er)且使(shi)得(de)空氣(qi)電(dian)(dian)加熱(re)器(qi)散熱(re)損失減小,因(yin)而(er)(er)空氣(qi)換熱(re)器(qi)的(de)效率提高了,但(dan)速(su)度(du)如果過大,使(shi)得(de)壓力損失陡增,這將不(bu)利(li)于(yu)加熱(re)效率的(de)提高。
2.若其(qi)它條件不變,改變表面(mian)負(fu)荷,空(kong)氣(qi)加熱器(qi)(qi)中電(dian)熱元(yuan)件的壁溫將(jiang)(jiang)呈(cheng)直線變化,如(ru)果(guo)表面(mian)負(fu)荷增大(da),電(dian)熱元(yuan)件的壁溫將(jiang)(jiang)增大(da),這(zhe)將(jiang)(jiang)降(jiang)低(di)空(kong)氣(qi)加熱器(qi)(qi)中電(dian)熱元(yuan)件的使用壽(shou)命(ming),但是如(ru)果(guo)表面(mian)負(fu)荷過小(xiao),壁溫過低(di),空(kong)氣(qi)加熱器(qi)(qi)換熱器(qi)(qi)的效(xiao)率(lv)又降(jiang)低(di)了,所以空(kong)氣(qi)加熱器(qi)(qi)中電(dian)熱元(yuan)件的表面(mian)負(fu)荷的選擇比較(jiao)重(zhong)要。
3.空(kong)氣(qi)(qi)加(jia)熱(re)(re)器中(zhong)(zhong)(zhong)空(kong)氣(qi)(qi)終(zhong)溫(wen)T2提高(gao)時,由于空(kong)氣(qi)(qi)粘性增(zeng)(zeng)加(jia),氣(qi)(qi)體雷諾數減小,使得對(dui)流換熱(re)(re)強度降(jiang)低(di),空(kong)氣(qi)(qi)加(jia)熱(re)(re)器中(zhong)(zhong)(zhong)電(dian)熱(re)(re)元(yuan)件(jian)(jian)的(de)表(biao)(biao)面溫(wen)度同時上升(sheng),紅(hong)外碳硫分析儀使得散熱(re)(re)損失(shi)增(zeng)(zeng)加(jia),從而降(jiang)低(di)換熱(re)(re)器的(de)效(xiao)率。當(dang)T2提高(gao)過大(da)時,電(dian)熱(re)(re)元(yuan)件(jian)(jian)表(biao)(biao)面的(de)溫(wen)度亦會(hui)大(da)大(da)升(sheng)高(gao),致使一般電(dian)熱(re)(re)元(yuan)件(jian)(jian)無法承受(shou),故T2的(de)增(zeng)(zeng)加(jia)通常受(shou)到空(kong)氣(qi)(qi)加(jia)熱(re)(re)器中(zhong)(zhong)(zhong)電(dian)熱(re)(re)元(yuan)件(jian)(jian)材料耐(nai)熱(re)(re)性能的(de)限(xian)制。