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An air-standard, steady-flow brayton cycle has a pressure ratio of 15. the minimum and maximum temperatures within the cycle are 300 k and 1000 k. the pressure at the inlet to the compressor is 100 kpa. assume the adiabatic compressor has a 90% isentropic efficiency, and the turbine is 85% efficient compared to an isentropic one

determine the pressure and temperature of the air at the beginning of the four processes that make up the cycle

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Final answer:

The Brayton cycle is an air-standard, steady-flow cycle used in gas turbine engines. It consists of four processes: intake, compression, combustion, and exhaust. By applying the given values and the adiabatic efficiency of the compressor and turbine, we can calculate the temperature and pressure at the beginning and end of each process.

Step-by-step explanation:

The Brayton cycle is an air-standard, steady-flow cycle used in gas turbine engines. It consists of four processes: intake, compression, combustion, and exhaust. In this case, the pressure ratio is 15, the minimum temperature is 300 K, and the maximum temperature is 1000 K.



Intake process: The air at the beginning of this process has a pressure of 100 kPa and a temperature of 300 K.

Compression process: The air is compressed adiabatically and its temperature and pressure increase. To find the temperature and pressure at the end of this process, you can use the adiabatic compression equation: T2 = T1 * (P2 / P1)(k-1)/k and P2 = P1 * (T2 / T1)k/(k-1), where k is the specific heat ratio.

Combustion process: The air is mixed with fuel and ignited, resulting in a temperature and pressure increase. The temperature and pressure at the end of this process can be calculated using the adiabatic combustion equation: T3 = T2 * (P3 / P2)(k-1)/k and P3 = P2 * (T3 / T2)k/(k-1).

Exhaust process: The air expands adiabatically and its temperature and pressure decrease. To find the temperature and pressure at the end of this process, you can use the adiabatic expansion equation: T4 = T3 * (P4 / P3)(k-1)/k and P4 = P3 * (T4 / T3)k/(k-1).

By applying the given values and the adiabatic efficiency of the compressor and turbine, you can calculate the temperature and pressure at the beginning and end of each process in the Brayton cycle.

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