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Flashcards in L_1 Deck (18):
1

Hypersonic flight, usual definition

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2

Are real gas effects important for hypersonic flight?

Yes

3

Thermally perfect gas equation

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4

calorically perfect gas meaning

constant specific heats cp and cv

5

Can a gas be thermally perfect but calorically imperfect?

Yes

Air in many aerothermodynamic problems is treated as thermally perfect but calorically imperfect

6

"Real gas" effects in aerothermodynamics are usually .....

high temperature real-gas effects

7

Classical real gas

van der Waals gas

molecular spacing comparable to range of intermolecular forces (e.g. low temperatures and high pressures)

8

real gas factor Z definition

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9

virial coefficients equation

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10

air real gas factor maximum value above room temperature for 100 atm

about 1.04

11

specific heat ratio of air for all pressures and temperature of 1500 K

 

approximate specific heat ratio of air for 100 atm and room temperature

about 1.30

 

 

about 1.55

12

For a hypersonic free stream, are these parameters small or large?

velocity

pressure

density

temperature

van der Waals effects

large velocity

small pressure

small density

small temperature

small van der Waals effects (due to small temperatures and small pressures/density)

(neglect van der Waals effects in hypersonic flight)

13

For a hypersonic stagnation area, are these parameters large or small?

velocity

pressure

density

temperature

van der Walls effects

small velocity

large pressure

large density

large temperature

small van der Waals effects (due to large temperatures and large pressures/density)

(neglect van der Waals effects in hypersonic flight)

14

Neglect van der Waals effects in ground test facilities?

Not always, due to high reservoir pressures/enthalpy

15

Internal energy of a molecule

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16

characteristic rotational temperatures of N2, O2, and NO

Rotational energy is fully present at very low temperatures.

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17

For lower hypersonic flight speeds, how is eelectronic treated?

eelectronic is treated as unchanging (neglected)

18

high temperature real gas effects of interest

vibrational excitation

dissociation/recombination