Energy Characteristics of a Bidirectional Axial-Flow Pump with Two Impeller Airfoils Based on Entropy Production Analysis

Abstract

This research sought to determine the spatial distribution of hydraulic losses for a bidirectional axial-flow pump with arc- and S-shaped impellers. The unsteady Reynolds time-averaged Stokes (URANS) approach with the SST k-omega model was used to predict the internal flow field. The total entropy production (TEP) and total entropy production rate (TEPR) were used to evaluate the overall and local hydraulic losses. The results show that the distribution of TEP and TEPR was similar for both impeller cases. Under a forward condition, TEP mainly comes from the impeller and elbow pipe. The high TEPR inside the impeller can be found near the shroud, and it shifts from the leading edge to the trailing edge with an increase in the flow rate due to the decline in the attack angle. The high TEPR inside the elbow pipe can be seen near the inlet, and the area shrinks with an increase in the flow rate caused by a reduction in the velocity circulation. Under the reverse condition, TEP mainly comes from the impeller and the straight pipe. The TEPR of the region near the shroud is obviously higher than for other regions, and the area of high TEPR near the suction side shrinks with an increase in the flow rate. The high TEPR of the straight pipe can be found near the inlet, and declines in the flow direction. These results provide a theoretical reference for future work to optimize the design of the bidirectional axial-flow pump.

Study on the Energy Loss Characteristics of Shaft Tubular Pump Device under Stall Conditions Based on the Entropy Production Method

“…According to Refs. [35,[43][44][45], the Yplus values of each part are in the range of 20~100. Hence, scheme 4 is a reasonable choice.…”

Study of Energy Loss Characteristics of a Shaft Tubular Pump Device Based on the Entropy Production Method

“…According to the Yplus values in the numerical simulations in refs. [15,31], the mesh scheme in this study can be used.…”

“…Herwig et al [14] completed a correlation table between the actual roughness and the equivalent roughness. This method not only provides the loss value but also allows observation of where the loss occurs, making it a useful tool for optimizing the design of hydraulic machinery [15,16] and investigating energy loss in complex flow [17][18][19]. Gong et al [20] applied entropy production theory in the study of a large Francis turbine firstly, and the results showed that the entropy production method can effectively locate high-loss areas.…”

Entropy Production Analysis of a Vertical Mixed-Flow Pump Device with Different Guide Vane Meridians

“…The time step was 4.1 × 10 −4 s, that is, the time for the impeller to rotate by 3°, and the total time was 4.92287 × 10 −1 s, that is, the time required for the impeller to rotate 10 turns. Since the shape of all walls remains unchanged during the simulation, no slip is set for all solid walls [ 27 ].…”