Effects of blade lean angle on a hydraulic retarder

Abstract

The rotor and stator blade lean angle of a hydraulic retarder is one of its main geometrical design parameters. The objective of this study is to clarify the effects of blade lean angle on hydraulic retarder performance. In this article, we employ a computational fluid dynamic approach to numerically investigate the fluid flow of a hydraulic retarder for rotor blade lean angles of 35°, 40°, 43°, and 45°in the direction of rotation, where the stator employs an equivalent angle, and all other geometries are held constant. The numerical results of the braking torque were validated against available experimental results. Analyses of torque performance, flow field, and energy loss are conducted in this study. Additionally, the outer loop oil flow rate is used as another indicator of hydraulic retarder heat exchange performance. The results indicate that with increasing blade lean angle, both the braking torque and oil volume flow rate first increase and then decrease, reflecting an optimal value. The lean angle affects secondary vortex flows and separate flows. Relatively large lean angles may enhance the occurrence of separate flow, whereas relatively small lean angles may cause in the oil inlet region. An optimal blade lean angle achieves a smooth oriented inner flow and a maximum braking torque.

Application of Hybrid RANS/LES turbulence models in rotor-stator fluid machinery: a comparative study

“…The inaccuracy of DHRL under each rotating speed was less than 4 per cent, and the minimum error could reach 1.8 per cent. Compared with the reports in literatures (Chen et al , 2016; Liu et al , 2015b; Mu et al , 2016), the performance prediction in this study was remarkably advanced in regard to the HRL method, especially DHRL.…”

“…A hydraulic retarder is a typical rotor-stator fluid machinery, which consists of a pump (rotor) and a turbine (stator). Lately, the reported studies involving hydraulic retarders still indicated that RANS, such as standard k-ε (Chen et al , 2016; Chunbao et al , 2015), realizable k – ε (Chunbao et al , 2015), renormalization-group k – ε (Liu et al , 2015b) and SST(Mu et al , 2016), played an important role in its internal flow calculation. RANS simulations resulted in failures in rotor-stator fluid machinery applications, particularly those that involved strong curvature, rapid compression or expansion and a strong swirl (Argyropoulos and Markatos, 2015).…”

Influence of hydrodynamic retarder blade angle on vortex structure

“…In recent years, scholars have delved into the correlation between the blade of hydrodynamic retarders and the internal flow field characteristics of the cavity. A few examples of this include Chen et al [4] study, which explored the impact of various blade angles on hydrodynamic retarders, and analyzed the cavity flow and secondary vortex flow. Mu et al [5] optimized the blade shape and blade top arc for double-cycle circular hydrodynamic retarders, analyzing the impact of different blades on braking torque and the internal flow field.…”

Multi-objective optimization design for a hydrodynamic retarder based on CFD simulation considering cavitation effect

“…14 Chen et al investigated the optimal design of the forward incline angle and distribution of oil inlet and outlet for the maximum retarding performance of the retarder, after optimization the retarding torque of the optimized retarder was greatly improved. 15,16 In the multi-objective optimization studies Yan's team used the multi-island genetic algorithm and the gradient optimization algorithm to optimize the parameters of the top arc blade of the retarder, the optimized torque was increased by 42.3% and 70.8% respectively. 17 Liu's team analyzed the effects of blade number, circular shape and blade angle on retarding torque and put forward a new optimized model.…”