# first law of thermodynamics

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. first law of thermodynamics. 21 . . 22 . (internal energy ) U. - PowerPoint PPT Presentation

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• first law of thermodynamics

• 21

• 22 (internal energy) UUch Unu UemUthUk Up ()Uk+UpUJ , kJ(2-1)J/kg , kJ/kg

• (total energy of thermal system)()0z0cfm.(2-2)(2-3)(2-4)

• 2-3

• () ()

• 2-4 Enthalpy (2-5)(2-5a)2-6(2-6)(2-1)(2-7)(2-8)

• huU h

• 25 - = (2-9)21UWQQWU = U2 - U1(2-10)()+-

• (2-10b)2-12(2-11a)2-15 (2-12a,b)2-162-17(2-12)(2-11)2-14(2-10c)2-13(2-10a)2-11(1-7)1-8

• 2-6 d1-1m1(dV1) 2-2m2(dV2) QWi,(CV)

• (2-13)2-18(2-15)2-20

• (2-15)2-20 m(2-16)(2-17)(2-16a)(2-17a)(2-21)(2-23)(2-22)(2-24)

• 1. 2. (technical work) wt+(2-19)2-26(2-20)2-27(2-21)2-28(2-16)(2-21)(2-25)

• 3.(2-22)2-292-4 + -4.Wt(2-16)(2-23)2-30(2-23b)2-32(2-23d)(2-21)

• a) b) 5. ()w = q um:(2-23a)2-31(2-23c)2-33(2-23e)2-35

• 2-7 (2-16)(2-23)

• --steam turbinegas turbine

• (compressorpump)

• (heat exchanger: boilerheater) q

• 01kgz, z =0q =0 wi =0

• 2-2 (P41)P492-4 (P43) (P51) 2-3P42P50

• ---

• ---p-v12