Solved by Expert Tutors
Solved by Expert Tutors
Question

can you solve the problems in the documents attached

1 MAE 320 – Thermodynamics HW 7b Assignment The homework is due Wednesday December 3 rd , 2014. Each problem is worth the points indicated. (1). Multiple choice (18 points ) (1a). (3p) Please circle the valid statement(s) associated with entropy: (A) Entropy is a property. A substance has a fixed entropy at a fixed state; (B) The entropy change between two specified states is the same no matter if the process is reversible or irreversible; (C) On the T-S diagram, the area under the process curve always represents the heat transfer, which has nothing to do with the fact if the process is irreversible or not; (D) Entropy is a path function. The entropy change depends on the path of the process; (E) Entropy generation is a path function, which depends on the path of the process. (1b). (3p) Pease circle the ds equation(s) which is valid for any substance under any process . (A) °± = ²³ ´ + µ²¶ ´ ; (B) °± = · ²´ ´ ; (C) °± = ¸ ²´ ´ + ¹ ²¶ ; (D) °± = ²ℎ ´ ¶²µ ´ . (1c). (3p) Please circle the valid statement(s) associated with an actual steady-operating heat engine cycle: (A) º ̇ »¼½ < 0 ; (B) º ̇ »¼½ = 0 ; (C) º ̇ »¼½ > 0 ; (D) Actual heat engine cycle always involves irreversibility. 1 2 3 4 5 6 18 15 15 15 18 19 100
Background image of page 1
2 (1d). (3p) The Isentropic efficiencies of steady-flow devices can be used only when: (A) There is no work transfer; (B) There is no heat transfer; (C) There are no irreversibility; (D) None of the above. (1e). (3p) Entropy can be transferred from the system to the surroundings by: (A) Mass flow; (B) Boundary work; (C) Heat transfer; (D) Shaft work. (1f). (3p) A piston-cylinder device contains superheated steam. During an actual (irreversible) adiabatic process, the entropy of the steam will: (A) Never increase; (B) Sometimes increase; (C) Always increase; (D) It cannot be determined with the given information. (2). Short answer and brief calculation question: (15 Points) (2a). Using the entropy balance equation (Eqn. 7-68), find the entropy balance relation for a steady-flow, single-stream, adiabatic device. (5 Points). (2b). The inner and outer surfaces of a 5 m by 7 m brick wall with a thickness of 20 cm are maintained at temperatures of 20 °C and 5 °C. If the rate of heat transfer through the wall is 1515 W, what is the rate of entropy generation? (5 points ) (2c). Please find the changes in the specific entropy of helium and nitrogen as its state changes from 2000 kPa and 427 °C to 200 kPa and 27 °C? (5 points )
Background image of page 2
Show entire document
Sign up to view the entire interaction

Step-by-step answer

onec aliquet. Lorem ipsum dolor sit amet, consectetur adipiscing elit. Nam lacinia pulvinar tortor nec facilisis. Pellentesque dapibus effi
ce
, ultrices ac magna. Fusce dui lectus, congue vel laoreet ac, dictum vitae odio. Donec aliquet. Lorem ipsum dolor sit amet, consectetur adipiscing eli

sque dapibus efficitur laor

helpful thermodynamics book.pdf
, dictum vitae odio. Donec itur laoreet. Nam risus ante, dapibus a molestie consequat, ultrices ac magna. Fusce dui lectus, congue vel laoreet ctum vitae odio. Donec aliquet. Lorem ipsum dolor

Subscribe to view the full answer

Why Join Course Hero?

Course Hero has all the homework and study help you need to succeed! We’ve got course-specific notes, study guides, and practice tests along with expert tutors.

  • -

    Study Documents

    Find the best study resources around, tagged to your specific courses. Share your own to gain free Course Hero access.

    Browse Documents
  • -

    Question & Answers

    Get one-on-one homework help from our expert tutors—available online 24/7. Ask your own questions or browse existing Q&A threads. Satisfaction guaranteed!

    Ask a Question
Let our 24/7 Mechanical Engineering tutors help you get unstuck! Ask your first question.
A+ icon
Ask Expert Tutors You can ask You can ask You can ask (will expire )
Answers in as fast as 15 minutes