Unit 3 - Engi2800(Section I Engineering Thermodynamics I...

Info icon This preview shows pages 1–8. Sign up to view the full content.

View Full Document Right Arrow Icon
09/28/09 http://jjl.me.dal.ca/Engi2800 1 J.M. Chuang Dalhousie University Dept. of Mechanical Engineering Last Modified: September 28, 2009 Unit #3 ( Textbook Reference: Ch.3 ) Properties of a Pure Substance Engi2800 (Section I) Engineering Thermodynamics I
Image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
09/28/09 http://jjl.me.dal.ca/Engi2800 2 Contents Introduction The Pure Substance Three Principal Phases Solid Phase Liquid & Gas Phases Vapor-Liquid-Solid Phase Equilibrium Saturation Temperature and Pressure Vapor-Pressure Curve The and Diagrams The Diagram for Different Pressure Quality ( Two-Phase Liquid-Vapor Region ) The Diagram The Diagram Water Phase Diagram Thermodynamic Surface Thermodynamic Tables Water Tables Other Tables State Equation of Ideal Gas Compressibility Factor P - v T - v T - v P - v P - T
Image of page 2
09/28/09 http://jjl.me.dal.ca/Engi2800 3 Introduction Three properties of substance: specific volume, pressure and temperature. Pure Substance Phases of substance The number of independent properties Methods of presenting thermodynamic properties Steam Power Plant (Using water as the working substance) High pressure (boiled in steam generator) Low pressure (expansion in turbine) Cooling (in the condenser) High pressure (return to boiler by pump) Refrigerator Substance: boil from liquid to vapor at a low temperature, , absorbing energy from the cold space, keeping it cold. Hot substance is cooled by air flowing around the grille Gas turbine (jet engine) (working substance: gas, no phase change) ¡ 20 o C Thermodynamic Surface: P-v-T
Image of page 3

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
09/28/09 http://jjl.me.dal.ca/Engi2800 4 Thermodynamic Surfaces The Diagram (Fig. 3.18 & 3.19, Textbook) Substance that expands on freezing Substance that contracts on freezing No distinction Between liquid and vapor P - T - v
Image of page 4
09/28/09 http://jjl.me.dal.ca/Engi2800 5 Steam Power Plant Cycle Devices: Stream drum: absorb heat from heat reservoir Turbine: Extract energy from substance Condenser: extract heat from substance Pump: increase pressure to substance Physical Laws: Conservation of mass (Continuity Eqn.) Conservation of energy (1 st Law) Entropy equation (2 nd Law) State of substance Specific volume, Internal energy, Enthalpy, Entropy, Condenser Steam drum Turbine Pump P hi ; T hi P lo ; T hi P lo ; T lo P hi ; T lo W out W in ( P; T ) Reservoir Reservoir T H T L v (m 3 = kg) u (kJ = kg) h (kJ = kg) s (kJ = kg K) Stream table Q H Q L
Image of page 5

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
09/28/09 http://jjl.me.dal.ca/Engi2800 6 Substance: Refrigerant R-134a, R-410a For R-134a (Table B.5, p. 810) -20 133.7 60 1681.8 30 771.0 -25 107.0 For a give temperature, : If , compressed liquid If , vapor (superheated) Note: heat transfer from to Evaporator Condenser Compressor Expansion valve Reservoir Refrigerated space W in Cold Vapor Warm Vapor Warm Liquid Cold Liquid +Vapor T L Q L Q H T H P > P sat P < P sat T T low T high T ( o C) P sat (kPa) (120 kPa ; ¡ 20 o C) (800 kPa ; 60 o C) (800 kPa ; 30 o C) (120 kPa ; ¡ 25 o C) Vapor-Compression Refrigeration Cycle Desired output Required input COP R = Desired Output Required Input
Image of page 6
09/28/09 http://jjl.me.dal.ca/Engi2800 7
Image of page 7

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
Image of page 8
This is the end of the preview. Sign up to access the rest of the document.

{[ snackBarMessage ]}

What students are saying

  • Left Quote Icon

    As a current student on this bumpy collegiate pathway, I stumbled upon Course Hero, where I can find study resources for nearly all my courses, get online help from tutors 24/7, and even share my old projects, papers, and lecture notes with other students.

    Student Picture

    Kiran Temple University Fox School of Business ‘17, Course Hero Intern

  • Left Quote Icon

    I cannot even describe how much Course Hero helped me this summer. It’s truly become something I can always rely on and help me. In the end, I was not only able to survive summer classes, but I was able to thrive thanks to Course Hero.

    Student Picture

    Dana University of Pennsylvania ‘17, Course Hero Intern

  • Left Quote Icon

    The ability to access any university’s resources through Course Hero proved invaluable in my case. I was behind on Tulane coursework and actually used UCLA’s materials to help me move forward and get everything together on time.

    Student Picture

    Jill Tulane University ‘16, Course Hero Intern