- 98 Mar B5 May 2016 Page 4 Of 22 Question 3 Hydro Turbines Parti Pelton Wheel Refer To The Examination Paper Attachments 1 (49.32 KiB) Viewed 36 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 13 of 22 QUESTION 3 PARTI BRIDGE RIVER PLANT 484 15 Impulse Turbines Figure 15.2 Vertical-shaft impulse turbine with six nozzles at Bridge River plant in British Columbia Gross head 1,226 ft. net head - 1.118 ft, 62,000 hp. 300 rpm, pitch diameter = 95 in.
98-Mar-B5 May 2016 Page 14 of 22 NAME QUESTION 3 PART II CRITICAL CAVITATION PARAMETER 4.0 2.0 turbines Kaplan 1.0 0.4 Cavitation coefficient, No cavitation region 0.2 0.1 Francis turbines Severe cavitation region 0.04 0.02 0.1 0.2 4.0 6 8 10 0.4 0.6 1.0 2.0 Power specific speed, asp (rad) Variation of critical cavitation parameter with non-dimensional specific speed for Fran and Kaplan turbines