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Modern Engineering Thermodynamics

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650 CHAPTER 15: Chemical <strong>Thermodynamics</strong><br />

99.* Design a combustion chamber for a rocket that will oxidize<br />

liquid hydrazine, N 2 H 4 ðlÞ, with liquid hydrogen peroxide,<br />

H 2 O 2 ðlÞ, at 1.00 MPa and 2000. K as follows:<br />

N 2 H 4 ðlÞ + 2ðH 2 O 2 ðlÞÞ ! 4½H 2 OðgÞŠ + N 2 , and that will supply the<br />

rocket nozzle with 1000. kg/s of exhaust gas. Data:ðh ° f Þ N2H4ðlÞ =<br />

50:417 MJ/kgmole, and ðh ° f Þ H2O2ðlÞ = −187:583 MJ/kgmole:<br />

100. Design a benchtop laboratory-scale facility to produce methanol<br />

from the reaction CO + 2ðH 2 Þ!CH 3 ðOHÞ: Determine all flow<br />

rates, heat transfers, reaction vessel optimum temperature and<br />

pressure, reaction vessel material, and geometry.<br />

Computer Problems<br />

The following open-ended computer problems are designed to be<br />

done on a personal computer using a spreadsheet or equation solver.<br />

101. Develop a spreadsheet to compute the LHV of gaseous octane<br />

and use it to find the adiabatic flame temperature for (a) 100.%<br />

and (b) 200.% theoretical air.<br />

102. Develop a spreadsheet to balance the combustion reaction of<br />

any simple alcohol of the type C n H 2n+1 ðOHÞ with excess or<br />

deficit air or oxygen.<br />

103. Develop a spreadsheet with temperature-dependent specific<br />

heats for a hydrocarbon fuel of your choice listed in Table 15.1<br />

to do one or more of the following:<br />

a. Compute the heat of reaction of the fuel when the reaction<br />

temperature and percent of excess air or oxygen are input by<br />

the user.<br />

b. Compute the adiabatic flame temperature of the fuel for any<br />

excess air or oxygen value.<br />

104. Develop an interactive computer program that outputs the<br />

entropy production rate for any (or a series of) reaction(s) of<br />

your choice. Input from the keyboard is in response to properly<br />

formatted screen prompts for the stoichiometric coefficients, the<br />

heat of reaction, the reaction temperature and pressure, and the<br />

isothermal heat transfer boundary temperature. Use the program<br />

to determine<br />

a. The maximum pressure for a given isothermal boundary<br />

temperature at which the reaction can occur.<br />

b. The maximum isothermal boundary temperature possible for<br />

any given reaction pressure and temperature.<br />

105. Develop an interactive computer program that outputs the<br />

equilibrium constant K e when the stoichiometric coefficients are<br />

input from the keyboard in response to properly formatted<br />

screen prompts. Assume all the components obey the Gibbs-<br />

Dalton ideal gas mixture law.<br />

106. Develop an interactive computer program to replace Table C.17<br />

for the dissociation of H 2 O, CO 2 , and NO. You have to find the<br />

relevant information on H, O, and N in other texts if you wish<br />

to also include the dissociation of H 2 ,O 2 , and N 2 :<br />

107. Develop an interactive computer program that outputs the<br />

<br />

molar specific enthalpy h i , entropy ð si Þ, and Gibbs function<br />

ðg i Þ for any substance of your choice at any user input pressure<br />

and temperature.<br />

108. Develop an interactive computer program that outputs the<br />

power and reaction efficiency of any reaction you desire. Apply<br />

this program to a fuel cell analysis and plot the reaction<br />

efficiency η r vs.<br />

a. The percent of excess oxidizer present.<br />

b. The reaction temperature.<br />

c. The reaction pressure.<br />

d. The entropy production rate.<br />

e. The fuel cell heat transfer rate _Q :<br />

Assume isothermal boundaries and input T b from the<br />

keyboard along with all other necessary information.

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