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|Title: ||Performance Analysis Based on The Characteristics of Hydraulic Cylinders of Flap Type Wave Energy Converters|
|Authors: ||Jiun-Chyi Wang;Chen-Chou Lin|
|Keywords: ||Wave Energy Converters (WEC);Bottom-hinged;Flap-type;Hydraulic cylinder;Damping coefficient;Conversion efficiency;Power Take-Off (PTO)|
|Issue Date: ||2017-04-28T01:06:17Z
|Abstract: ||abstract:The thesis aims to explore the conversion efficiency of flap-type wave energy converters (WEC) by regulating the damping coefficient of hydraulic cylinders of the WEC, and then determining the proper damping coefficient of the bottom-hinged WEC. Based on the experiments on damping coefficient of hydraulic cylinders of various sizes, the variation relations of damping coefficient versus different cylinder’s inner diameter sizes can be obtained. Thus we may use the relations to design the cylinder bore size of the bottom hinge WEC.
From the previous literature, the efficiency of converters could be improved by using an active damping controller in the hydraulic cylinders, showing that the cylinder damping coefficient had influences on the efficiency of the WEC. In our experiments, we first explored the correlations between the cylinder bore sizes and the damping coefficients of hydraulic cylinders, and then combined the measured force of piston rod and piston displacement of the hydraulic cylinders to derive the output power of the WEC; finally, we could obtain the overall efficiency of the WEC. In addition, based on the analyzed data, the optimal damping coefficient of the WEC could be determined, and the available mechanical work could be calculated and expressed in elevation head, thereby serving as the reference position of the generator.
For the wave condition of the experiments, the 1/20 scale of the mean wave height at Keelung offshore area was adopted, that is, a wave height of 7.5 cm, and a wave period of 1.56 seconds. We conducted experiments with 8 sets of damping coefficients and 4 sets of cylinder bore sizes. According to the experiment results, the conversion efficiency of the flap was up to 20.51% when the damping coefficient was 323.8 (N-s/m). Based on the established relations, the cylinder’s inner diameter size meeting the damping coefficient was found to be 31.62 mm. When the height of the water outlet was 1 meter, the flow rate of the WEC would reach 55.13 liters per hour.
|Appears in Collections:||[機械與機電工程學系] 博碩士論文|
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