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Question
In a petrol engine, (internal combustion engine) air at atmospheric pressure and temperature of 20°C is compressed in the cylinder by the piston to `1/8` of its original volume. Calculate the temperature of the compressed air. (For air γ = 1.4)
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Solution
T1 = 20°C = 20 + 273 = 293 K
V1 = 1 m3
V2 = `1/8` V1m3
γ = 1.4
From equation of adiabatic process
TVγ − 1 = constant
`"T"_1"V"_1^(γ - 1) = "T"_2"V"_2^(γ - 1)`
T2 = `("V"_1/"V"_2)^(γ - 1)"T"_1`
T2 = `[1/((1/8))]^(1.4 - 1) xx 293`
= (8)0.4 × 293
= 673.1 K
= 673.1 − 273
T2 ≅ 400°C
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