Question

(4 Marks/Markah) b) A supersonic wind tunnel nozzle is to be designed for Mach number, Ma = 2.5 with a test section I m' in area as shown in Figure 2. The supply pressure and the temperature at the nozzle inlet, where the velocity is negeligible, are 8 x 10° Pa and 27Crespectively. The preliminary design is to be based on the assumptions that the flow is isentropic, with k =1.4, R = 287 Jkg.K, and that the flow is one- dimensional throughout. For the above given data pa Nozel terowong angin supersonit direkabentuk untuk nombor Mach, Ma = 2.5 dengan bahagian jian 1 m' di kawasan seperti yang dinsnjukton dalam Gambarajah 2. Tekanan dan suhu bekalan i salr masuk noel, di mana halaju boleh diabaikan, masing-masing odalah 8x 10' Pa dan suhu 27 C Rekabertut awal berdasarkan andaian bahawa separjang aliran adalah seentropi dengan k I.4, R-287 JK dan aliran adalah satu dimensi. Begi data yang diberikan di atas:] Throat Test Section Ma-25 Figure 2 Gambarajah 2) i. Determine the throat area [Tentukan luas leher. (3 Marks/Markah) i. Calculate the temperature at the throat [Kirakan suhu pada leker.] (3 Marks/Markah) iii. Estimate the flow veiocity in the test section, Tentukan halaju aliran dalam bahagian jian. -6 iv. Evaluate if there any change in the flow yelocity in the test section, if the velocity of gas at entry to the nozzle is taken to be 300 m/s? Calculate percentage change in velocity will be in comparison to that obtained in b(iii}? [Nilaikan sebarang perubahan dalam halaju aliran dalam bahagian ujian, jika halaju gas pada marukan ke nozel diambil 300 m/s? Kirakan peratus perubahan dalam halaju dibandingkan dengan halaju yang diperolehi dalam b(iüi)?] (7 Marks/Markah)

Answer 1

gived stagnatioo tempurature Toafc Test atnoak Inlet TA To t23 Ta To,300k no33 mlet Po,e Sx\05 Pa stagnafuon pressur at propurties stangnation are Cons tant -thoughout the ow To1 To2 since isentmphic Alous Po-Po Arta c the Test section design mach number of -tect seetion m= aSs k4 From Tsentophie table at mach mumber m,- 5 the Tatios T7 4yuu: A To 2636 AA Po pressure in the test secton PL= 46824 kPa Tempera lu In th test section T q444xTor 133-32 K. A ) throat anua A Thoat aswa A A o31 D 3192 m - 6367 At throat mach number is i so from Isen trphic tabls at mach number 1 T 0 & 333 To T= d44.99 k T-temperatu at threat vehely n the test ecton V Js 4 xa8x 133.32. Scanned with CS CamScanner

to the no3al is V>300 m3e at Eny h louy T 300 k mach numbcy m* KRTI 300 hgg,9 Deentrop hic tablus at m, 0'86y From T T tampuratur Toy To stagnation TTo 347 18 k Tsentophic tabus at m-a5, 0 4444 To2 3418 X4444 То хо"чччу Ta - n the test secion Vi- M2KRT velouty 2 25u x2 87X1S4*29 v2622.46 m)sec velocity is increayed to The percentage change 62246-518'4 x loo uelopty 518 6 veloity is incrcaed in 'Compasisn tothat obtalhed in ( Scanned with CamScanner.gae e'