27.03.2014 Views

Tehnička termodinamika - Kemijsko-tehnološki fakultet

Tehnička termodinamika - Kemijsko-tehnološki fakultet

Tehnička termodinamika - Kemijsko-tehnološki fakultet

SHOW MORE
SHOW LESS

You also want an ePaper? Increase the reach of your titles

YUMPU automatically turns print PDFs into web optimized ePapers that Google loves.

TEHNIČKA TERMODINAMIKA__________________________________________<br />

za 10 kg vode → 22660 kJ<br />

−1<br />

qpregr.<br />

= h4<br />

− h3<br />

= hpregr.<br />

− h0.883<br />

′′ = 2835 − 2670 = 165 kJ kg<br />

za 10 kg vode → 1650 kJ<br />

ukupno 28004 kJ<br />

Primjer 5.2.<br />

3<br />

Koliko je topline potrebno da se 50 dm H2O temperature 25 °C ugrije<br />

do vrelišta, zatim potpuno ispari i pregrije na 250 °C ako je tlak 1.372 bar?<br />

Skica u T, s – dijagramu!<br />

Rješenje<br />

Slika P5.2.<br />

Q = Q +<br />

1 + Q2<br />

Q3<br />

−1<br />

q1 = h2<br />

− h1<br />

= 456.0 − 104.5 = 351.5 kJ kg<br />

−1<br />

q2 = h3<br />

− h2<br />

= h′′<br />

− h′<br />

= r = 2233 kJ kg<br />

240

Hooray! Your file is uploaded and ready to be published.

Saved successfully!

Ooh no, something went wrong!