A schematic representation of a jet engine is presented in Figure. Flow of air at 50 kPa and -16 °C enters compressor (state 1 in figure) and then it leaves from compressor at 2850 kPa and 560 °C (state 2 in figure). After combustion, air flow enters the turbine at 1250 °C and 2750 kPa (state 3 in figure) and then it leaves from the turbine at 325 kPa and 650 °C (state 4 in figure). Finally, air flow leaves from the nozzle at 50 kPa and 420 °C (state 5 in figure). Assume there is no heat transfer and neglect kinetic energy except out of the nozzle. determine; a-) The compressor specific work (work per unit mass) b-) The turbine specific work (work per unit mass) c-) The velocity of air leaving the nozzle. Compressor Combustors Turbine Air Product gases out a 3 5 Diffuser Nozzle 2. in

2. Electrical components often failure due to thermal overload. It follows that thermal analysis of electrical components is critical to their longevity. Consider a silicon chip which is sitting atop a ceramic substrate with 35 mm2 of exposed surface area. Operating at steady state, the chip can pull up to 120 mW of power. The chip surface is cooled by convection from flowing air at 20°C. The heat transfer from the chip to the air is given by Q = hA(T, – T) where h is the thermal convection coefficient, A is the exposed surface area, and Tb and Tr are absolute temperatures of the body and coolant fluid, respectively. h of the flowing air is found to be 250 W/(m2-K). Assuming heat transfer to the substrate is negligible compared to convection, determine: the heat transfer occurring at steady state (W) the temperature at the outer surface of the chip ("C) a. b.

This question requires the use of the extracts from the tables of thermodynamic properties supplied. Ammonia, NH3, was once a commonly used refrigerant. In a particular (very old) refrigeration plant, ammonia has a pressure of 2.9 bar and a temperature of 40 °C. What would be the specific enthalpy of the ammonia under these conditions. 1433 kJ/kg a. b. 1552 kJ/kg 135 kJ/kg O d. 1622 kJ/kg O e. 1665 kJ/kg

For a closed system undergoing a thermodynamic cycle, what statement from the list below is correct when comparing the system's initial and final states? Temperature may change. O Pressure may change Volume may change Mass may change Internal energy may change Potential energy may change No system property may change