Experimental and Numerical Study on the Performance Change of a Simple Propeller Shape Using the Coanda Effect

Abstract

In this study, a jet injection propeller was designed to increase its efficiency, and the results were compared by open water tests and numerical computations. Also, the change in shape of the slit and injection volume conditions, which are difficult to perform experiments with, were analyzed through computations. The jet injected from the blade surface generates additional thrust due to the Coanda effect, and the jet injection generates a moment in the direction of propeller rotation, resulting in a decrease in the total torque. Computations were performed for three slit heights. When the height of the slit is high, the efficiency of the propeller increases, even if the power of the pump required for jet injection is considered. The result was found to increase the efficiency by about 8.7%, even when the efficiency was compared under the condition of generating the same thrust by controlling the injection volume of the jet by designing a normal propeller that does not inject a jet.

Numerical investigation of the effect of dust shields on accumulation of dust over PV panels

“…At the air gap, there is a pressure loss, so increasing the size of the air gap minimizes the pressure losses, consequently, increases the exit air velocity from the air gap. The air passing out of the nozzle keeps intact with the PV panel’s surface and does not divert from the panel’s surface, which is known as the Coanda effect (Lee et al 2021 ; Ahmed 2020 ; Shakouchi and Fukushima 2022 ), and such a performance assists in removing the deposited dust particles. Increasing the air gap size between the shield and the panel to a certain extent induces more kinetic air drafts; thus, more area of the panel’s surface is swept by the air draft as can be seen by comparing Fig.…”