An axial compressor operates such that it has an inlet and an exit total temperature of $300 \mathrm{~K}$ and $430 \mathrm{~K}$, respectively. The isentropic efficiency of the compressor is $85 \% .$ If the ratio of specific heats is 1.4 , then the total pressure ratio across the compressor is____________

An axial compressor operates such that it has an inlet and an exit total temperature of $300 \mathrm{~K}$ and $430 \mathrm{~K}$, respectively. The isentropic efficiency of the compressor is $85 \% .$ If the ratio of specific heats is 1.4 , then the total pressure ratio across the compressor is____________

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