Optimized Blade Design of Counter-Rotating-Type Pump-Turbine Unit Operating in Pump and Turbine Modes

Table 3

Results of the multiobjective optimization.

Designs	Design variables (deg.)		Specific objective function		Error (%)	Relative improvement	Efficiency (%)		Relative improvement (%)
	4B_hub	4B_tip	Surrogate	RANS	-	-
Reference design	0	0	-	2.0	-	-	78.78	85.65	-	-
Optimum design	2.64	1.75	2.018	2.017	0.05	0.017	79.79	86.17	1.01	0.52