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THESE de DOCTORAT - cerfacs

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A<br />

About the π c ′ = 0 assumption<br />

A.1 When is π ′ T<br />

equal to zero?<br />

Let us recall the equation of conservation of the total energy through a compressor. It is <strong>de</strong>fined<br />

as<br />

ρ 1 u 1 h t,1 + W = ρ 2 u 2 h t,2<br />

(A.1)<br />

where W is the work done by the compressor. This equation can be also written as<br />

π T ρ 1 u 1 h t,1 = ρ 2 u 2 h t,2<br />

(A.2)<br />

where π T is the total enthalpy ratio between the upstream and downstream flow. Equation<br />

(A.1) can be re-written as<br />

ρ 1 u 1 h t,1 + ρ 1 u 1 ∆h t = ρ 2 u 2 h t,2<br />

(A.3)<br />

where ∆h t = ∆(Uv θ ) is related to the conservation of the rothalpy (see Fig. A.1)<br />

I = h t,1 − U 1 v θ1 = h t,2 − U 2 v θ2<br />

(A.4)<br />

135

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