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98-Mar-B5 May 2016 Page 5 of 22 Question 3 Continued PART II TURBINE SETTING Refer to the Examination Paper Attachments
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- 98 Mar B5 May 2016 Page 5 Of 22 Question 3 Continued Part Ii Turbine Setting Refer To The Examination Paper Attachments 1 (62.56 KiB) Viewed 40 times
98-Mar-B5 May 2016 Page 5 of 22 Question 3 Continued PART II TURBINE SETTING Refer to the Examination Paper Attachments Page 14 Critical Cavitation Parameter. Vanderkloof Hydro Power Station has the following technical parameters: 120 MW 11 kV 125 rev/min Francis Electrical generator design output Electrical generator voltage Speed of turbine-generator Type of hydro turbine Design head on turbine Maximum water consumption (at lower head) Inlet diameter to spiral casing Turbine runner diameter Turbine runner material 65 m 217 m/s 7 m 5462 mm Stainless cast steel (a) Calculate the specific speed of the turbine. (b) From the graph determine the Thoma cavitation parameter o. (c) Calculate the setting (maximum elevation of the turbine runner relative to the tailrace water level based on the critical cavitation parameter (Thoma coefficient) Show on the attached diagram on Page 14 where data has been obtained and retum this page with your answer booklet. (5 marks) [ 10 marks ]
98-Mar-B5 May 2016 Page 15 of 22 QUESTION 4 & QUESTION 7 PART II STEAM TURBINE VELOCITY DIAGRAM Nomenclature for velocity vectors and angles 0 VS1 VR1 al 0 VB 8 VR2 Vs2 Ve Vst VR1 Absolute steam velocity entering moving blades Relative steam velocity entering moving blades VB Moving blade velocity VRZ Vsz Relative steam velocity leaving moving blades Absolute steam velocity leaving moving blades