Towards Optimum Swirl Recovery Vanes for Propeller Propulsion Systems

Abstract

Swirl Recovery Vanes (SRVs) are a row of stationary vanes located downstream of a single-rotating propeller to recover swirl losses and thereby enhance propulsive efficiency. This paper presents the development, application, and experimental validation of a low-order SRVs design tool. The design procedure consists of three steps: first the inflow velocities can be obtained either from the simulation of isolated propeller or from experimental measurements, after which the loading distribution is defined using lifting-line theory, and lastly an airfoil design routine is performed. The design method features both a short computation time useful in the preliminary design phase and parameter investigation, and a detailed vane-shape representation, such that the final overall blade shape can be determined. In this study the model is presented together with a test example, consisting of a set of SRVs designed for a six-bladed propeller operating at high disk-loading condition. Results from the computations are subsequently experimentally validated in a wind-tunnel test of the designed model. The additional thrust generated by the SRVs was measured at different propeller loading conditions. At the design point a 2.6% increase of thrust was reported, together with a similar amount of improvement in the propeller propulsive efficiency. Velocity profiles obtained with PIV fields in the propeller slipstream were used as validation of the numerical simulation, together with quantification of the swirl recovery by SRVs.

Aerodynamic and Aeroacoustic Performance of a Propeller Propulsion System with Swirl-Recovery Vanes

“…A symmetrical airfoil was selected for the entire vane; manufacturing constraints on the minimum thickness led to the selection of a NACA 0009 profile. Later studies [8,9], performed after the work discussed in the current paper had been completed, showed that cambered airfoils typically provide better performance.…”

“…However, in the same study, it was found that the total system efficiency was reduced, stressing the importance of proper SRV design and integration. This was addressed by a follow-up work of the same research group [8], focusing on the development, application, and experimental validation of a low-fidelity tool for SRV design. In this work, a measured 2.6% increase in thrust was reported at the design condition for high propeller thrust at low flight velocity and low Reynolds number.…”

Aerodynamic Performance and Interaction Effects of Circular and Square Ducted Propellers

“…In order to improve the convergence of the simulations, the corners of the square duct were slightly rounded, so that the minimum corner radius (at the airfoils' thickest point) would be 1% of the propeller radius, R p . The minimum gap between the propeller tips and duct surface (or tip clearance) was maintained at 0.3% of the propeller radius, leading to a duct chord of approximately 0.217 m. The propeller geometry was based on an existing design, denoted "XPROP", that has been characterized previously in both experimental and numerical studies [15][16][17][18]. The six-bladed wind-tunnel model has a radius of R p = 0.2032 m. Details regarding the propeller geometry, such as chord and twist distributions, can be found in Ref.…”

“…The six-bladed wind-tunnel model has a radius of R p = 0.2032 m. Details regarding the propeller geometry, such as chord and twist distributions, can be found in Ref. [15]. In this study, the blade pitch for the radial location r/R p = 0.7, β 0.7 , was kept at 30°.…”

“…The only data available for validation of the propeller CFD results consist of experimental data obtained at the Open-Jet Facility (OJF) at Delft University of Technology. These data were provided via internal communication by Sinnige [35], who acquired the data using the same experimental setup as Li [15]. The data consists of thrust and torque measurements, performed with a rotating shaft balance at the same free-stream velocity and advance ratios as the ones tested in the CFD simulations.…”