the work done by this compressed air during adiabatic expansion is (p2V2 - p1V1) / ( 1 - gamma )
i deleted a previous solution and updated my notes linked in bio
the new volume after expansion is V2 = V1 ( p1/p2 ) ^ (1/gamma) and gamma for air is 1.4 until very high temperatures so V2 = 8 gallons * 3.8 L/g ( 90/14.7 ) ^ (1/1.4) = 111 L
pV compressed is 90 psi * 6.9 kPa/psi * 8 gallons * 3.8 L/g * 0.001 m^3/L = 19 kJ
pV uncompressed is 14.7 psi * 6.9 kPa/psi * 111 L * 0.001 m^3/L = 11 kJ
David /
npub1a8…zd8rx
2024-11-09 01:33:16
in reply to nevent1q…kggv
Author Public Key
npub1a8kpyw5429mc4vyc2t6r20mvgn39wfdpcewhz5s0mhcpuk64rs8qdzd8rxPublished at
2024-11-09 01:33:16Event JSON
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"content": "the work done by this compressed air during adiabatic expansion is (p2V2 - p1V1) / ( 1 - gamma )\n\ni deleted a previous solution and updated my notes linked in bio\n\nthe new volume after expansion is V2 = V1 ( p1/p2 ) ^ (1/gamma) and gamma for air is 1.4 until very high temperatures so V2 = 8 gallons * 3.8 L/g ( 90/14.7 ) ^ (1/1.4) = 111 L\n\npV compressed is 90 psi * 6.9 kPa/psi * 8 gallons * 3.8 L/g * 0.001 m^3/L = 19 kJ\npV uncompressed is 14.7 psi * 6.9 kPa/psi * 111 L * 0.001 m^3/L = 11 kJ",
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