Answer Happy

98-Mar-B5 December 2016 Page 3 of 20 QUESTION 2 COMPRESSOR BLADE ANGLES TUDO Rolls-Royce/SNECMA Olympus 593 Mark 610 Afterburning Turbojet The diagram above (for illustrative purposes only) shows a cross section of the engine of the Concorde supersonic aircraft (without the variable geometry intake and variable area nozzle). Basic specifications and assumed operational conditions are as follows: 3 6500 rev/min LP compressor stages LP compressor pressure ratio LP compressor speed HP compressor stages HP compressor pressure ratio HP compressor speed HP and LP isentropic efficiency LP first stage moving blade tip diameter LP first stage moving blade hub diameter Inlet air temperature to first stage Inlet air velocity to first stage Air mass flow rate 8500 rev/min 0.9 1.12 m 0.38 m 80°C 184 m/s 116 m/s Consider the first stage moving blade conditions and assume no prewhirl at the inlet (air enters in a purely axial direction to give maximum flow). Refer to the Examination Paper Attachments Page 11 Compressor Velocity Diagram and Page 12 Compressor Inlet Blades for guidance and reference. This question is continued on the next page
98-Mar-B5 December 2016 Page 4 of 20 Question 2 Continued (a) Calculate the blade velocity at the tip and hub of the first stage moving blade, (b) (2) Calculate the temperature at the exit of the first stage. (c) Calculate the work done (J/kg) by the first stage and hence determine the values of the components in the direction of blade motion) of the absolute air velocities (Cy1 and Cyz). (2) (d) Draw to scale the velocity (vector) diagrams for the first stage moving blades at both the tip and hub and determine the inlet and outlet blade angles for these blades. A scale of 1mm = 5 m/s is suggested. (4) Refer to the photograph of the first stage inlet blades on Page 12 and assess whether the blade angles determined in (d) above are reasonably correct. Justify your answer. (1) (e) (10 marks ]
98-Mar-B5 December 2016 Page 11 of 20 EXAMINATION PAPER ATTACHMENTS QUESTION 2 COMPRESSOR VELOCITY DIAGRAM B1 01 w C1 CX1 U Wy1 Cyn U Rotor Blade Row B2 (122 W, C2 1 Cx2 Wy2 • Cyz U ! Stator Blade Row 03 U Blade velocity C Rotor blade absolute inlet velocity W Rotor blade relative inlet velocity C. Rotor blade absolute outlet velocity W, Rotor blade relative outlet velocity CStator blade absolute outlet velocity CX3 C3
98-Mar-B5 December 2016 Page 12 of 20 EXAMINATION PAPER ATTACHMENTS QUESTION 2 & QUESTION 6 COMPRESSOR INLET BLADES *** ST Rolls-Royce Olympus 593-610 first stage low pressure compressor blades Microsoft Word File