Thermodynamic Properties 2

The flashcards below were created by user RJVan on FreezingBlue Flashcards.

What is the equation for the speed of sound?
How can a new speed of sound be calculated when the temperature changes?

$chart?chf=bg,s,00000000&cht=tx&chl=%5Cfrac%7Ba_1%7D%7Ba_2%7D%3D%5Csqrt%7B%5Cfrac%7BT_1%7D%7BT_2%7D%7D&chs=156x94$
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?

$chart?chf=bg,s,00000000&cht=tx&chl=%5Ceta_%7Bth%7D%3D%5Cfrac%7BW_%7Bout%7D-W_%7Bin%7D%7D%7BQ_%7Bin%7D%7D&chs=246x82$ $chart?chf=bg,s,00000000&cht=tx&chl=%3D%5Cfrac%7BW_%7Bnet%7D%7D%7BQ_%7Bin%7D%7D&chs=106x82$

First Law:

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

Q_in = 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.
What is the equation for thermal efficiency?

$chart?chf=bg,s,00000000&cht=tx&chl=%5Ceta_%7Bth%7D%3D%20%5Cfrac%7BW_%7Bnet%7D%7D%7BQ_%7Bin%7D&chs=160x82$
What is the Second Law of thermodynamics?

Entropy must always increase in a real process or cycle.
Identify lines of constant pressure.
Identify lines of constant superheat.
Identify lines of constant moisture.
What equation calculates the quality of a vapor-liquid mixture?

$chart?chf=bg,s,00000000&cht=tx&chl=x%3D%5Cfrac%7Bm_%7Bvapor%7D%7D%7Bm_%7Bvapor%7D%2Bm_%7Bliquid%7D%7D&chs=274x70$
What equation gives the enthalpy of a liquid-vapor mixture?

Similar equations apply for internal energy (u) and entropy (s).
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.
In the steady flow energy equation, break apart the enthalpy component and make note of the units.

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
In the steady flow energy equation, break apart the potential energy component and make note of the units.

$chart?chf=bg,s,00000000&cht=tx&chl=%5CDelta%20e_p%3D%5Cfrac%7B(z_2-z_1)g%7D%7Bg_cJ%7D&chs=230x88$

units are BTU/lbm, and J=778.17 ft-lbf/BTU
In the steady flow energy equation, break apart the kinetic energy component and make note of the units.

$chart?chf=bg,s,00000000&cht=tx&chl=%5CDelta%20e_k%3D%5Cfrac%7B(v_2%5E%5E2-v_1%5E%5E2)%7D%7B2g_cJ%7D&chs=236x88$

units are BTU/lbm, and J=778.17 ft-lbf/BTU
In the steady flow energy equation, break apart the shaft work component and make note of the units.

$chart?chf=bg,s,00000000&cht=tx&chl=%5Cfrac%7Bw_%7Bshaft%7D(ft-lbf%2Flbm)%7D%7BJ(ft-lbf%2FBTU)%7D&chs=282x90$

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

P/P_c and T/T_{c are calculated using critical temperature and pressure listed in a chapter table.}
What is the relationship between power, mass flow and change in internal energy?
What is the relationship between power, force and speed?

P=Fv
How do you calculate a thermodynamic property (such as c_p) 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
What is the relationship between power, torque and rotational speed?

P=Tω

Author

ID

307733

Card Set

Thermodynamic Properties 2

Description

Mechanical Professional Engineering Exam Review

Updated

2016-01-16T18:26:13Z

Show Answers