Regenerative pumps can supply relatively high heads at low flow rates. On the other hand, regenerative pump impellers can be manufactured at a low cost due to their specific design. Although regenerative pumps perform with high heads at low flow rates, they have low nominal efficiency. This study aims to design and optimize a new S-shaped impeller. A conventional radial impeller was replaced with a new impeller to improve head and efficiency. The new S-shaped optimized impeller and the conventional radial impeller have been investigated numerically and experimentally. The design variables for the optimization process are blade number, thickness, and curvature. The Design of Experiments (DOE), the response surface methodology, and the Box Behnken design (BBD) have been utilized for optimization. The pump efficiency increased by 2.85% in single-objective optimization with efficiency as the objective. In addition, the efficiency increased by 1.67% in dual-objective optimization with head and efficiency as objectives. The casing pressure value was the same for dual-objective optimization and radial geometries. Single-objective optimization increased the pressure on the casing and ultimately raised the head amount.
