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LUCIAN GAVRILĂ – Fenomene de transfer II - Cadre Didactice

LUCIAN GAVRILĂ – Fenomene de transfer II - Cadre Didactice

LUCIAN GAVRILĂ – Fenomene de transfer II - Cadre Didactice

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3/14/2003<br />

Transfer global <strong>de</strong> căldură la<br />

potenţial termic variabil<br />

ΔT<br />

− ΔT<br />

Q = K ⋅ A⋅<br />

2 1 = K ⋅ A⋅<br />

Δ<br />

ΔT<br />

ln 2<br />

ΔT<br />

Tm<br />

oComparând ecuaţia (236) cu ecuaţia (210):<br />

1<br />

(236)<br />

<strong>–</strong> la <strong>transfer</strong>ul termic staţionar, intre 2 flui<strong>de</strong> in<br />

echicurent <strong>de</strong>spărţite printr-un perete solid, este<br />

valabilă ec. gen. a <strong>transfer</strong>ului termic la potenţial<br />

constant, cu condiţia înlocuirii ∆T cu media logaritmică<br />

a diferenţelor <strong>de</strong> temperatură <strong>de</strong> la extremităţile<br />

schimbătorului <strong>de</strong> căldură, ∆Tm.<br />

<strong>LUCIAN</strong> <strong>GAVRILĂ</strong> <strong>–</strong> <strong>Fenomene</strong> <strong>de</strong> <strong>transfer</strong> <strong>II</strong> 39

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