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试解释并比较换热器计算的平均温差法和ε—NTU法?

问答题
2022-01-06 01:57
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从平均温压法和ε—NTU法的原理、特点上加以阐述。两种方式都可以用于换热器的设计计算和校核计算,平均温差法是利用平均温差来进行换热器的计算,而ε—NTU法是利用换热器效能ε与传热单元数NTU来进行换热器计算。平均温压法要计算对数平均温压,而ε—NTU法则要计算热容量比、传热单元数或换热器效能。设计计算时,用平均温差法比用ε—NTU法方便,而在校核计算时,用ε—NTU法比用平均温差方便。


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试解释并比较换热器计算的平均温差法和ε—NTU法?
计算题:某换热器平均温差为5℃,传热系数为50W/(m·℃),换热面积为100m2,求该换热器的热负荷。
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