Question

Could someone help with the following problem???

Helium enters a constant flow heat exchanger at 100 kPa, 100 C, and 90 m / s, and receives heat in the amount of 120 kJ / kg as it flows through it. Helium leaves the heat exchanger at 80 kPa with a speed of 150 0 m / s. Determine the pressure and temperature of nitrogen stagnation in the input and output states.

Helium enters a constant flow heat exchanger at 100 kPa, 100 C, and 90 m / s, and receives heat in the amount of 120 kJ / kg as it flows through it. Helium leaves the heat exchanger at 80 kPa with a speed of 150 0 m / s. Determine the pressure and temperature of helium stagnation in the input and output states.

Answer 1

Isteb: Guiven Inlet Conditions temperature, T, 2 100°C Pressure, Pi 2 100 kPa 90 m/s 2 Velocity _< From thermodynamic tables, For Helium Heat capacity, p= 5.2 KJ / kg. K constant volume Heat Capacity, w z 3.2 constant pressure KJ / kg .k Heat capacity Ratio, kg 3.2 Kalib

Stagnation temperature and pressure is the temperature and pressure at the stagnation point where the fluid Velocity is Zero. Stagnation temperature, To ²T + v² ) 26 At Inlet To - Ti + Vi 24 2 2 100°C + (90 mls) 9+5.9 kJ/ hy.k * 1000 5/KI To 2 100.78c

Stagnation measure *1 k-1 To @ A As at At Inlet, 1.6/1.6-1 100.78 + 273 100 kPa [" 100 + 273 Po 2 100 kPa * 1.005 Po 2 100.56 kPa Outlet Conditions Pressure, P 80 kPa 2 Velocity Vaga Vol 2 150 m/s Heat transferred, 120 KI I hig

Energy Balance for an open System m[ AH + AV? + Ag+] - $ + W 8. m = Mass flow rate AH = change in Enthalpy AV? change in kinectic Energy ee AgZ = change in potential Energy Rate Heat transferred W Bate of Work / Power transferred

Here, Wro [No Work Done Agz -o [ Negligible change hij P.E) AH » G [ 12-T) So Eq 2 G (1-1) + و 2 5.2 KJ (Tz - 100 + (150) – (70) 120 KI 2 5.9T2 - 520 + 7.92 190 5.2 Tog 2 63918 12. » 122°

On Ego To's Tq + V2 २५ To's (150) (miles) 2 199°C + (150) 9* 5.2 + 18 Il lagok To 2 124 -16°C stagnation temperature at outlet RIK-1 on Eq @ Po To 2 A Tz 16/1.6-1 Po'z 80 kPa 124.16+973 123 + 273 Pol 80 kPa * 1.0146 2 Po 2 81.18 kPa Stagnation pressure at outlet