Question

(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 (k-14, R 287 Jg K) enters the nozzle with pressure and temperature of 10 bar and 600 Krespectively 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 yarg malar pada heluaran Diameter saluran adalah sama dengan diameter keluar nazel Luas keratan rentas nozel adalah tiga kalt kepada leher nazel tersebut. Gar (1.4, R -287 Jg K) memanuki nazel dengan tekanan dan suhu masing-masing adalah 10 bar dan 600 K dengan halaju diabaikan Jika kejuaar normal berlaku di bahaglan mencapah nozel di mana nisbah luas NA-2.0 i. Calculate the stagnation pressure in the duct [Kirakan tekanan statik dalam salwan.] (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 onedimensional 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 adiabarik 2 am diameter dengan keadacn subsonik Aliran ini diangg arkan sebogai aliran Farno satu dimensi. Purata faktor geseran boleh diambil wntuk sama kepada 0.024. Andaikank = J.4] . Calculate the length of duct to accelerate the flow from Ma, - 0.4 to Ma2 0.8 [Kirakan panjang saluaran untuk memecutkan aliran dari Ma, - 0.4 ke Mo;- 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 Ma=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;- s (5 Marks/Markah)

Answer 1

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A2 A* Mach No at a so ct Subsonie Mech No evreponding b &ubsonic / Af Fable 0.2 Mach Nufnber at enit GIveo M P 600 kPa = 0.8 D c 0.024 - L 4fL M, qet Valu Can M M2, We Conespo ndling fanno tabl d 4L 0.07229 2. 308493 Langthduet 46.59 Cm) LL

M-0.8 P. P. we Can ak t. Valu P/f fRow ano ablo, 236-95 kPa T T M 0.8 Mo.4 qet Vo T br Can Panno ablet, We M, M .OG 383 1.t6 2191 Paemuae and ompuatas at M 0.8