Analytical and numerical study of fluid flow in propeller-type current-meters

Current-meters are well-known water flowrate measuring instruments in industry, and for many years, they have been used to measure flow velocity in open channels and closed conduits. Despite the extent of their application, there is not much information on basic equations of propeller-type current-meters. This paper is dedicated to present a novel design method for propeller-type current-meters. First of all, the basics of current-meters are theoretically investigated through momentum and airfoil theory approaches. Then, the essential design parameters are discussed to shape the design method. The current-meters are divided into three groups by considering their axial pitch values: low-, medium-, and high-pitch; and for each group, the design procedure is demonstrated thoroughly. In addition, the influence of axial pitch value is numerically studied on performance of current-meters via an experimentally validated CFD model. It is shown that low-pitch current-meters are more sensitive to velocity changes, and high pith meters are more reliable in different flow conditions.