Thermodynamic Properties 2

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  1. What is the equation for the speed of sound?
    chart?chf=bg,s,00000000&cht=tx&chl=a%3D%5Csqrt%7Bkg_c%20RT&chs=196x60
  2. How can a new speed of sound be calculated when the temperature changes?
    chart?chf=bg,s,00000000&cht=tx&chl=%5Cfrac%7Ba_1%7D%7Ba_2%7D%3D%5Csqrt%7B%5Cfrac%7BT_1%7D%7BT_2%7D%7D&chs=156x94
  3. Thermal efficiency is the ratio of useful work output to energy input. What equation results from combining this definition with the First Law of thermodynamics?
    chart?chf=bg,s,00000000&cht=tx&chl=%5Ceta_%7Bth%7D%3D%5Cfrac%7BW_%7Bout%7D-W_%7Bin%7D%7D%7BQ_%7Bin%7D%7D&chs=246x82chart?chf=bg,s,00000000&cht=tx&chl=%3D%5Cfrac%7BW_%7Bnet%7D%7D%7BQ_%7Bin%7D%7D&chs=106x82

    First Law: chart?chf=bg,s,00000000&cht=tx&chl=W_%7Bnet%7D%3DQ_%7Bin%7D-Q_%7Bout%7D&chs=270x42

    So:  chart?chf=bg,s,00000000&cht=tx&chl=%5Ceta_%7Bth%7D%3D%5Cfrac%7BQ_%7Bin%7D-Q_%7Bout%7D%7D%7BQ_%7Bin%7D%7D&chs=230x90
  4. What equation describes the First Law of thermodynamics for closed systems, and what does the equation mean?
    Qin = ΔU+W

    Any heat entering a closed system can either increase the energy of the system (U) or be used to perform work on the surroundings.
  5. What is the equation for thermal efficiency?
    chart?chf=bg,s,00000000&cht=tx&chl=%5Ceta_%7Bth%7D%3D%20%5Cfrac%7BW_%7Bnet%7D%7D%7BQ_%7Bin%7D&chs=160x82
  6. What is the Second Law of thermodynamics?
    Entropy must always increase in a real process or cycle.
  7. Identify lines of constant pressure.
    Image Upload
    Image Upload
  8. Identify lines of constant superheat.
    Image Upload
    Image Upload
  9. Identify lines of constant moisture.
    Image Upload
    Image Upload
  10. What equation calculates the quality of a vapor-liquid mixture?
    chart?chf=bg,s,00000000&cht=tx&chl=x%3D%5Cfrac%7Bm_%7Bvapor%7D%7D%7Bm_%7Bvapor%7D%2Bm_%7Bliquid%7D%7D&chs=274x70
  11. What equation gives the enthalpy of a liquid-vapor mixture?
    chart?chf=bg,s,00000000&cht=tx&chl=h%3Dh_f%2Bxh_%7Bfg%7D&chs=214x36

    Similar equations apply for internal energy (u) and entropy (s).
  12. What can be said of the kinetic and potential energies of a closed system?
    The kinetic and potential energies of a closed system are negligible.
  13. In the steady flow energy equation, break apart the enthalpy component and make note of the units.

    chart?chf=bg,s,00000000&cht=tx&chl=q%3D%5CDelta%20h%2B%5CDelta%20e_p&chs=206x38chart?chf=bg,s,00000000&cht=tx&chl=%2B%5CDelta%20e_k%2Bw_%7Bshaft%7D&chs=228x46
    chart?chf=bg,s,00000000&cht=tx&chl=%5CDelta%20h%3D%5CDelta%20u%20%2B%20w_%7Bflow%7D&chs=262x46

    and 

    chart?chf=bg,s,00000000&cht=tx&chl=w_%7Bflow%7D%3D%5Cfrac%7Bp_2v_2-p_1v_1%7D%7BJ&chs=274x70

    units are BTU/lbm, and J=778.17 ft-lbf/BTU
  14. In the steady flow energy equation, break apart the potential energy component and make note of the units.
    chart?chf=bg,s,00000000&cht=tx&chl=q%3D%5CDelta%20h%2B%5CDelta%20e_p&chs=206x38chart?chf=bg,s,00000000&cht=tx&chl=%2B%5CDelta%20e_k%2Bw_%7Bshaft%7D&chs=228x46
    chart?chf=bg,s,00000000&cht=tx&chl=%5CDelta%20e_p%3D%5Cfrac%7B(z_2-z_1)g%7D%7Bg_cJ%7D&chs=230x88

    units are BTU/lbm, and J=778.17 ft-lbf/BTU
  15. In the steady flow energy equation, break apart the kinetic energy component and make note of the units.
    chart?chf=bg,s,00000000&cht=tx&chl=q%3D%5CDelta%20h%2B%5CDelta%20e_p&chs=206x38chart?chf=bg,s,00000000&cht=tx&chl=%2B%5CDelta%20e_k%2Bw_%7Bshaft%7D&chs=228x46
    chart?chf=bg,s,00000000&cht=tx&chl=%5CDelta%20e_k%3D%5Cfrac%7B(v_2%5E%5E2-v_1%5E%5E2)%7D%7B2g_cJ%7D&chs=236x88

    units are BTU/lbm, and J=778.17 ft-lbf/BTU
  16. In the steady flow energy equation, break apart the shaft work component and make note of the units.
    chart?chf=bg,s,00000000&cht=tx&chl=q%3D%5CDelta%20h%2B%5CDelta%20e_p&chs=206x38chart?chf=bg,s,00000000&cht=tx&chl=%2B%5CDelta%20e_k%2Bw_%7Bshaft%7D&chs=228x46
    chart?chf=bg,s,00000000&cht=tx&chl=%5Cfrac%7Bw_%7Bshaft%7D(ft-lbf%2Flbm)%7D%7BJ(ft-lbf%2FBTU)%7D&chs=282x90

    units are BTU/lbm, and J=778.17 ft-lbf/BTU
  17. Identify the lines of constant temperature ratio on this graph of compressibility factors, and define the ratios for temperature and pressure.
    Image Upload
    Image Upload

    P/Pc and T/Tc are calculated using critical temperature and pressure listed in a chapter table.
  18. What is the relationship between power, mass flow and change in internal energy?
    chart?chf=bg,s,00000000&cht=tx&chl=P%3D%5Cdot%20m%20%5CDelta%20u&chs=150x30
  19. What is the relationship between power, force and speed?
    P=Fv
  20. How do you calculate a thermodynamic property (such as cp) of a non-reacting mixture?
    • Calculate the gravimatric fraction of each constituent chart?chf=bg,s,00000000&cht=tx&chl=G_i%3D%5Cfrac%7Bm_i%7D%7B%5Csum_i%7Bm_i%7D%7D&chs=160x78
    • and use this relationship chart?chf=bg,s,00000000&cht=tx&chl=c_p%3D%5Csum_i%7BG_i%20c_%7Bp%2Ci%7D&chs=220x80
  21. What is the relationship between power, torque and rotational speed?
    P=Tω

Card Set Information

Author:
RJVan
ID:
307733
Filename:
Thermodynamic Properties 2
Updated:
2016-01-16 18:26:13
Tags:
thermo Thermodynamics Mollier
Folders:
Mechanical Engineering
Description:
Mechanical Professional Engineering Exam Review
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