Question

Question 2 The performance of a nozzle with inlet area of 800 cm? operating at steady state is to be investigated. When steam flows in at 2.5 mº/s, 1200 °C and 5 MPa, the exit velocity was observed to be 100 m/s. To investigate the nozzle's performance, steam will be made to flow in at various rates while maintaining the same inlet temperature and pressure. Select two (2) different values of inlet velocities in the range of 15 to 30 m/s and subsequently plot the exit enthalpy in kJ/kg as a function of exit velocity for these two cases. [10 MARKS]

Answer 1

Criven Exit Velocity = 100m/s Inlet Temprature = 1200c 1200°C & 5 MPa Enthalpy value from Jalet Pressure =5 MPa At Steam tabel is :- h = 5141. 122 ks Ver Now By Energy Equation's h + V² h + 12 - 2000 2000 h₂ = 5141.122 - 10012 + ² 2000 2000 h = 5136.122 + ² 2000 Case I Let v = 15m/s. ha 5136.122 + (15) ² 2000 h = 5136.239 kJ KA

Case II Let Let V, = 28 m/s ha = 5136. 122 + (28) h = 5136.514 us 2000 ka h tz

As we know that Total energy will remain constant at inlet and exit . Thus with increase in exit velocity enthalpy at exit decreases

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