Question

3. Nitrogen enters a horizontal adiabatic device at 127°C, 1.50 bar with a velocity of 250 m At the exit the conditions are 177°C. 8.00 bar. The outlet is circular in cross-section w diameter of 10 cm. This device is either a nozzle or diffuser. a. Compute the exit velocity of the nitrogen, m/s. (20 points) b. Find the mass flow rate through the device. kg/s (10 points) IF you could not do part a, you may assume the exit velocity to be 300 m/s to do this part.I c. This device is a nozzle because ancies i Veles points) Horizontal - PE=0 adiabatica Q=0

Answer 1

Answer: Given that, Nitrogen enters a horizontal adiabatic device at 1272, 1,5 bar Nelocity = 250 ml At ezit conditions are 177°C, 8.00 bar) (a) diameter = 10 cm Exit Velocity :- For adiabetic porocess Sw= 80 For nozzle dw zo -Hence, La - 0 - 0. consider, but by h2 + vzpon hi che = tur uit Pive = Uz + BV2 + y un (9,- 12) + (Pivi – kve) - v 0 + RVI – Pous = ve - From ideal gas equation wa Rais UR = PATE Pivi = RT, , P2 V2 = RTE where Pio Pz ore presceres R = gas constant Ti,T2 are temperatures RTI — RT2 = { [vm_vi} R[177-127] = { [v – 250"} 2 spo = v - 9s v = 29500 - 350 - 42200 exit velocity 12 = 303. 31 mis

(b) Mass flow rate : Mass flow using relation rate Calculated = PAVZ below where n = 1/2 A2 U2 (P=+) Az e coross sectional area = 75 M M = may flow rate v2 = exit Velocity m = tx(100) * 303 0.167X4 m = 9.5742 0.668 m = 14.24 Kgls c) The devic is a nozzle because increase V2 = 303.31 mis > Vi= 250 m/s in Velocity