Actuation moments for hydrofoil flaps
Master thesis
Date
2018Metadata
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- Institutt for marin teknikk [3469]
Abstract
The following thesis investigates how the computer software STAR-CCM+ andXfoil are used to determine the hydrodynamic loads on the two foil profiles EP-PLER E817 and NASA/LANGLEY LS(1)-0417 (GA(W)-1) with trailing edgeflaps. The foils are analysed with flap lengths of 0.1c, 0.25c and 0.4c, at a Reynoldsnumber of 20·10^6 , where c is the total foil chord length. STAR-CCM+ uses steadyanalysis performed with steady and unsteady solvers depending on when flow sep-aration occurs for the different cases. The flap is deflected to increase lift, withinthe interval 0◦ to 20◦ or 22◦ with interval of 2◦. The main objective is to de-termine the design parameters for a hydraulic actuator. Hence, the focus is todetermine the hinge moment generated by the hydrofoil. The thesis suggests onerecommended actuator for each of the two foil profiles. From the CFD analysis acritical hinge moment of 225kNm is found for the EPPLER E817 profile with aflap length of 0.25c and a span of 4meter, at a Reynolds number of 20·10^6 . Forthe NASA/LANGLEY LS(1)-0417 profile with a flap length of 0.1c and a span of4meter, the critical hinge moment was found to be 5732Nm at a Reynolds numberof 20·10^6. For the EPPLER E18 profile an actuator with piston diameter of 160mmand rod diameter of 80mm with a design pressure of 250 bar is recommended. Forthe NASA/LANGLEY LS(1)-0417 (GA(W)-1) an actuator with a piston diameterof 80mm and a rod diameter of 40mm with a design pressure of 250 bar is foundto be sufficient.