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Required information

Helium is used as the working fluid in a Brayton cycle with regeneration. The pressure ratio of the cycle is $8,$ the compressor inlet temperature is $300$ K $,$ and the turbine inlet temperature is $1800$ K $.$ The effectiveness of the regenerator is $75$ percent. The net power output is $62$ MW $.$ The properties of helium are $\backslash (\backslash$mathrm$\{$c$\}\_\{\backslash$mathrm$\{$p$\}\}=5\mathrm{.}1926\backslash$mathrm$\{$~kJ$\}/\backslash$mathrm$\{$kg$\}\backslash$cdot $\backslash$mathrm$\{$K$\}\backslash )$ and $\backslash ($ k$=1\mathrm{.}667\backslash ).$

Determine the thermal efficiency and the required mass flow rate of helium assuming both the compressor and the turbine have an isentropic efficiency of $100$ percent.

The required mass flow rate of helium is

$\backslash (\backslash$mid $\backslash$mathrm$\{$kg$\}/\backslash$mathrm$\{$s$\}\backslash ).$

The thermal efficiency is