Question

Question 4 Soalan 4] (a) A supersonic nozzle is attached to a constant diameter circular duct at its exit The duct diameter is the same as the nozzle exit diameter. Nozzle exit cross- section area is three times that of its throat. The gas (k1.4, R = 287 J/kg-K ) enters the nozzle with pressure and temperature of 10 bar and 600 K respectively with negligible velocity. If a normal shock occurs at a section in the diverging part of the nozzle where the area ratio A/A-2.0 [Satu nozel supersonik dipasangkan kepada saluran berdiameter bulat yang malar pada keluaran. Diameter saluran adalah sama dengan diameter keluar nozel. Luas keratan rentas nozel adalah tiga kali kepada leher nozel tersebut. Gas (k-1.4, R -287 Jkg K) memasuki nozel dengan tekanan dan suhu masing-masing adalah 10 bar dan 600 K dengan halaju diabaikan. Jika kejutan normal berlaku di bahagian mencapah nozel di mana nisbah luas A/A= 20. i. Calculate the stagnation pressure in the duct [Kirakan tekanan statik dalam saluran] (5 Marks /Markah) i. Predict Mach number at exit of the nozzle [Ramalkan nombor Mach pada nozel keluar.] (5 Marks/ Markah) (b) Air flows in an adiabatic 2 cm diameter duct in subsonic condition. This flow is approximated as one-dimensional Fanno flow. The average friction factor may be taken to be equal to 0.024. Assume k= 1.4. [Udara mengalir dalam saluran dalam keadaan adiabatik 2 cm diameter dengan keadaan subsonik. Aliran ini dianggarkan sebagai aliran Fanno satu dimensi. Purata faktor geseran boleh diambil untuk sama kepada 0.024. Andaikan k= 1.4] i. Calculate the length of duct to accelerate the flow from Ma 0.4 to Maz 0.8. [Kirakan panjang saluran untuk memecutkan aliran dari Ma,- 0.4 ke Ma;-0.8 (5 Marks/Markah) i. If the pressure and temperature at location where Ma, 0.4 are given as 600 kPa and 450 K respectively, predict the pressure and temperature at location where Maz= 0.8. [Jika tekanan dan suhu pada lokasi dimana Ma,- 0.4 adalah masing-masing diberi 600 kPa dan 450 K, ramalkan tekanan dan suhu pada lokasi dimana Ma-0.8 (5 Marks /Markah)

Answer 1

Given A, 3A (or) A 3 A R 287 P1o bar10'a T600k Threat () Entry Exitto) Mzi caei Rfer enthopic foo tahe for 2-44 M2 0.417 0.0417

0.417 x 7 250.2 k 2-2-1) 0.04 7/ x A-4- 0.0471 x10 x0 we knowr C, Mxa, M xRT 2.64 x(14x247X 250.2) 2 cord shock Ey MJ Ma1 er : 3 A* AZ enkigpic tkle Ma2.64 and -1y

Th 0.417 o.0417 0.417 x60D2S0.2k 0.0417x o.0417x 10 X10-0.417 XR Refer Nov mal Shock table fo M2-6y 1 My 0.5 7,965 2.279 4- X1D N 7.695 x aLihoxst 2.75 tlho 2.279 1 2.279 x 25o.2 S70.2K GMyxaMy X VI4 x28 7X5F0.2 s0.5 x

Cy23932 ml Caseln) Aea satio A 2 -2 pfer entopic Ho tabl 2/ At MA Refor Nomal hoks table jor M2-2 2.2 My 0.S47 0.628 Rey 0.628 x1ox1D 0.628 x 6.28 x I0 Nm Throat (*) DMp A, M Ety M, >Exit M2 Ayo houk Wawe

Pifer Jntapic Hoo tate for 0.547 -1 Hy Aty 1-255 Ay 3 X0 Jx 1.25s o) &25 ty* Rfe entopic table for t 8825 -14 M2 0.33 0.927 By eetty ie - 0.978 -0-9子{x 6o S86.8k 0.927 x 0.927x 6-28x ID M2Xa, 1 MNRE 160-23 mls