关键词: |
HELICOPTERS, GROUND EFFECT MACHINES, VELOCITY, COMPUTATIONS, PRODUCTION, NOZZLES, VEHICLES, VALUE, FRICTION, STATIC TESTS, COANDA EFFECT, GROUND EFFECT, PROPELLERS, TORQUE, FLUID DYNAMICS, GAS BEARINGS, TABLES(DATA), THESES, DEGREES OF FREEDOM, FLOW RATE. |
摘要: |
This experimental study investigated the feasibility of applying the concept of a skirtless hovercraft into the production of an operational vehicle. A 0.255 m diameter prototype was designed, built and tested. An air bearing table was used as a testing platform, virtually eliminating the influence of friction and providing one degree of freedom for the experiments. Static tests were performed at various heights and craft configurations, providing a wide range of data for comparison. Lift, torque and efficiency were measured and calculated for each setting. Pressure and velocity information was also collected at specific points around the craft when operating at different heights above ground. The results indicate a significant increase in total lift and efficiency when operating the model at close to the ground heights, in ground effect, compared to the lift produced by the propeller and motor alone. Even more significant changes were found when comparing the in ground effect results with the out of ground effect values of lift and efficiency. The study also investigated the use of Coanda nozzles on the peripheral region of the craft, and found them to be less efficient than straight nozzles with similar size and flow rates. Comparisons between the experimental results and previous computational fluid dynamic analysis are also made and presented in this study. |