![]() The distribution of local entropy production rate, energy loss, and reverse flow along the streamwise direction shows similar rules, with a local maximum near the leading edge of the impeller due to the impact effect, and a global maximum near the impeller trailing edge resulting from strong flow separation and high vortex strength due to the jet-wake flow. Changing the shape of the impeller trailing edge has a great influence on the reverse flow, shaft power, and energy loss near the impeller trailing edge and diffuser inlet but has little influence on the leading part of the impeller. The results show that different impeller trailing edges can clearly affect the efficiency of the pump, i.e., the thinner the trailing edge, the higher the efficiency, with the thickest model reducing efficiency by 5.71% and the thinnest model increasing efficiency by 0.59% compared to the original one. Finally, a static structural analysis of the impeller with different trailing edges is performed. The entropy production theory and Ω-vortex identification method are used to display the magnitude and location of energy loss and the vortex structure. The reverse flow, shaft power, and energy loss distribution in the impeller and diffuser along the streamwise direction are analyzed by calculating them on each micro control body sliced from the fluid domain. To reveal the mechanism of the effect of different trailing edges on external performance, the internal flow of 16 types of impeller blade trailing edges of a centrifugal pump, consisting of Bezier trailing edges, rounding on the pressure side, cutting on the suction side, and the original trailing edge is studied by numerical simulation. The centrifugal pump is one of the most widely used types of power machinery in the field of ship and ocean engineering, and the shape of the impeller blade trailing edge has an important influence on their performance. First, the RRVP became smooth and large, which reduced the flow loss and increased the flow cross-section second, the eccentrically mounted impeller of the optimal fan enlarged the flow section near the outlet of the volute. Two main factors were found to increase the flow capacity and efficiency of the optimal SCF under strict size constrains. Optimization results show that the maximum volumetric flow rate of the optimal SCF with an RRVP volute increases from 147.1 cubic feet per minute (CFM) to 191.1 CFM, and the fan efficiency also increases from 32.21% to 33.5%, compared with the original SCF with the common logarithmic-spiral volute. Twenty-three control variables were used in the multiobjective optimization process, including the optimization of the blade angles and the impeller position. The multiobjective evolutionary algorithm based on decomposition (MOEA/D) and Kriging model was used to optimize the aerodynamic shape of the compact SCF with an RRVP volute. Then, we proposed a parameterization method for the RRVP with 16 control variables. The CFD simulations indicate that the fan with RRVP volute has the highest flow rate at the maximum flow rate working condition. At first, we used computational fluid dynamics (CFD) to simulate the aerodynamic performances of three SCFs having the same impeller but different volutes, which were the common logarithmic-spiral volute profile, the cutting volute profile, and the RRVP volute at the maximum flow rate working condition. In this study, we proposed a novel rounded rectangle volute profile (RRVP) for the design of compact high-flow SCFs. ![]() Due to the restriction on installation size, the design of high-efficiency SCFs with high flow capacities is an important topic. Squirrel cage fans (SCFs) are widely used in a variety of household appliances. ![]()
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