An experimental investigation of the flow field around a counter-rotating propeller system using a laser doppler velocimeter
Abstract
The flow field and performance characteristics of a two-bladed counter-rotating propeller system were investigated. Investigations were conducted upstream, in between and downstream of the propellers for various relative angular propeller orientations. The number of configurations available for the propeller system was limitless, thus only a small portion of the number of possible cases were examined. A two-component laser doppler velocimeter (LDV) system was used to investigate the flow field. Each LDV scan generated two velocity components and combining a horizontal and vertical scan allowed all three velocity components to be determined. The abundance of data readily available from the LDV system posed a problem of how to effectively present this data. Cascade plots are used to represent specified velocity components over a total range of radial values. Color intensity plots display axial velocity while vector plots, obtained by combining tangential and radial velocities, are used to display the vortices shed from the blades. Complete sets of velocity components at designated radial positions are presented showing the flow variation due to blade passage and the flow reversal across the vortex core. The importance of the phase angle is demonstrated in these plots. Thrust and power coefficients are determined from momentum and energy theory using average velocity values. These coefficients are compared to those determined analytically using a vortex lattice model.
Degree
Ph.D.
Advisors
Sullivan, Purdue University.
Subject Area
Aerospace materials
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