OpenProp v2.3 theory document

OpenProp is an open-source code suite that can be used for the design, analysis, and fabrication of optimized propellers and horizontal-axis turbines. The numerical model is based on propeller lifting line theory, which is used in parametric design codes employed by the U.S. Navy as well as commercial designers. OpenProp is written in Matlab M-code, which is widely used in academia and industry. OpenProp is designed to be a user-friendly tool that can be used by both propeller design professionals as well as novices to propeller design. A team of researchers at MIT and Maine Maritime Academy have contributed to the currentOpenProp code. OpenProp began in 2001 with the propeller code PVL developed by Kerwin (2007) as part of his MIT propeller design course notes. The first Matlab version of this code, MPVL, incorporated graphical user interfaces for parametric design and preliminary bladerow design (Chung, 2007). Geometry routines were later added which interfaced with the CAD program Rhino to generate a 3D printable propeller (D’Epagnier et al, 2007). These early codes were capable of designing propellers using a simple Lerb’s criteria optimizer routine (Lerbs, 1952). Epps et al (2009b) implemented Coney’s generalized propeller optimizer (Coney, 1989) and also created a turbine optimization routine. Epps et al (2009a) created an off-design analysis routine to predict the performance curve for a given propeller or turbine design. Onand off-design cavitation analysis capabilities were implemented by Flood (2009). Stubblefield (2008) extended the numerical model to handle the design of ducted propellers. Epps (2010) presented experimental data validating the off-design performance analysis feature for the propeller case, but his data showed that further development is required to accurately predict the off-design performance in the turbine case. What follows is the theoretical foundation and numerical implementation of the OpenProp propeller/turbine design code suite. This text is taken from (Epps, 2010, ch. 7), and it draws from the theory presented in (Coney, 1989), (Kerwin, 2007), (Kerwin and Hadler, 2010), (Abbott and von Doenhoff, 1959), and (Carlton, 1994). In this document, all equations are given in dimensional terms, and their non-dimensionalized forms are given in table 1.