The aim of the current study is to investigate the effect of inlet blade angles on cavitation performance in a centrifugal pump. In order to reveal this relationship, both hub and shroud blade angles are considered and a two-phase three-dimensional computational fluid dynamics (CFD) study is carried out. Shear stress transport (SST) turbulence and Rayleigh–Plesset cavitation models are used in simulations. Inlet blade angles for both hub and shroud are changed and pump performance (head-discharge) and cavitation (head-inlet pressure) graphs are obtained for eight different designs. Afterward, numerical cavitation tests are conducted, required net positive suction head values of the each design are calculated, and variations are demonstrated. Results show that hub and shroud blade angle variations have no significant effect on the pump characteristic curves excluding for shroud blade angle at high discharge values. However, cavitation performance of the pump is excessively affected for both hub and shroud blade angle alterations. Increasing hub blade angle has slightly negative effect on cavitation performance of the pump. On the other hand, while increasing shroud blade angle from 20 deg to 30 deg have positive effect on cavitation performance, it is negatively affected from 30 deg to 50 deg.

This extensive study is carried out to minimize the pressure drop of a relief valve featuring quick-releasing coupling used in radar systems. The 3D two-phase computational fluid dynamic (CFD) study is verified with the experiments, and Taguchi’s orthogonal method is implemented for pressure drop optimization. Realizable k–ε turbulence model with enhanced wall treatment and the Schnerr and Sauer cavitation model are enforced within the numerical study. Four angles—the collet angle, the inlet angle, the plug angle, and the outlet angle—are considered at five levels of variation for the orthogonal optimization process. According to the statistical analysis, two more designs are suggested, and one of them resulted in further improved pressure drop performance. Moreover, the cavitation behavior of the proposed design is compared with the base design through water vapor volume fractions. While the water vapor volume fraction of the base design is 0.0045, no vapor formation is observed in the optimized designs at 20 l/min. The results of the proposed design are also validated by the experiments. The outcomes of the study showed that the inlet angle has a significant effect on the pressure drop phenomenon.

Turkey is a developing country and its energy requirement is increasing with each passing day. The most important energy sources of Turkey are natural gas, coal, and hydropower. Almost all of the natural gas and one-third of the coal are imported; thus, in order to utilize the national sources, hydropower has vital importance. Moreover, wind energy is also an important factor owing to Turkey’s quite good wind chart. This study discusses the evaluation of the renewable energy potential of Turkey. In detail, the hydropower and windpower potentials, installed capacities, and developments are investigated. The study is extended with the various electricity demand projections existing in the literature. As a result, it is clearly seen that the official electricity demand prediction is much higher than the other prediction values. Moreover, the second-order curve fitting model gives the closest results to the official demand values among all other models.