Effect of the blade shaped by Joukowsky airfoil transformation on the characteristics of the torque converter

Pan, Xiong; Chen, Xinyuan; Sun, Hongjun; Jiping, Zhong; Lin, Wen‐Wei; Gao, Huichao

doi:10.1177/09544070211014291

Cited by 14 publications

(6 citation statements)

References 26 publications

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“…It can be found from Figure 9 that the velocity in the turbine and stator is greater than that in the pump. Moreover, reverse flows were observed in these impellers [26], which were located on the suction side of the stator blade near the inlet, in the middle of the turbine flow passages and on the pressure side of the pump blade near the inlet [27]. These reverse flows were located near the cavitation site, which would induce cavity breakoff and hence cause vibration and noise.…”

Section: Cavitating Flow Fieldmentioning

confidence: 99%

The Effect of Rotating Speeds on the Cavitation Characteristics in Hydraulic Torque Converter

et al. 2022

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Hydraulic torque converter is a kind of high speed rotating machine using viscosity hydraulic oil as working medium, and its internal flow field is very complex. Thereby cavitation can occur easily in the working process, resulting in severe degradation of torque converter performance, noise, vibration and even failure. In order to reveal the effect of rotating speeds on the cavitation characteristics, a full flow passage geometry and a computational fluid dynamics (CFD) model with cavitation were developed to analyze the flow behavior in the torque converter. The results show that cavitation occurs when the speed difference between pump and turbine exceeds 1400 rpm for the basic model torque converter, which could be used as a useful indicator for the occurrence and degree of severity of flow cavitation. The increase of pump rotating speed or the decrease of speed ratio will intensify cavitation, which reduces the hydraulic transmission capacity and efficiency by over 20%, and seriously alters the shape, size, vapor volume fraction and region of cavitation bubbles. In extreme cases, more than 80% of the area on the suction side of the stator blade could be covered by cavitation bubbles. Moreover, the increase of pump rotating speed also changes the critical cavitation number and extends the cavitation range towards high speed ratio conditions not previously affected. These findings can provide guidance on how to choose the operating conditions of the hydraulic torque converter and how to improve its hydrodynamic performance and stability.

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Section: Cavitating Flow Fieldmentioning

confidence: 99%

The Effect of Rotating Speeds on the Cavitation Characteristics in Hydraulic Torque Converter

et al. 2022

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“…They optimized the curvature change rate of the stator to ensure that its flow line is consistent with the hydrodynamic characteristics, which reduces the probability of cavitation. The study is cited in reference [14].…”

Section: Introductionmentioning

confidence: 99%

Identification and Optimization Study of Cavitation in High Power Torque Converter

Wang,

Xu,

Zhao

et al. 2024

Applied Sciences

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Aiming at the phenomenon that a high-power torque converter is susceptible to cavitation, which leads to performance degradation, first, a transient flow field model of the torque converter is established, and CFD simulation and experimental research on the torque converter are carried out to find out the speed ratio region where cavitation occurs in the torque converter as well as the rule of occurrence of cavitation, and then the cavitation identification method based on the difference between the inlet and outlet flow of the torque converter is proposed. Then, the transient flow process inside the torque converter is analyzed, and it is pointed out that the angle between the inlet angle of the stator and the outlet angle of the turbine of the torque converter, i.e., the fluid inflow injection deviation angle is an important factor affecting the cavitation phenomenon. By adjusting the key parameters of the stator blade bone line, the fluid inflow deviation angle of the torque converter stator is optimized, so that the speed ratio range of cavitation under large load conditions is greatly reduced from the original 0–0.5 (50%) to 0–0.15 (15%). Meanwhile, in terms of test performance, the nominal torque of the torque converter is greatly improved under the premise of ensuring that the performance is basically unchanged, in which the nominal torque of the test zero speed is increased by 28.7%, and the cavitation of the torque converter has been greatly improved.

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“…Guo Meng et al developed a full flow passage geometry and a computational fluid dynamics (CFD) model with cavitation to analyze the flow behavior in the torque converter (Guo et al, 2022a). Xiong Pan et al optimized the Joukowsky airfoil used in the design of stator blades, which greatly reduced the probability of cavitation and improved the performance and service life of the torque converter (Pan et al, 2021).…”

Section: Introductionmentioning

confidence: 99%

“…Guo et al (Guo et al, 2021;Guo et al, 2022b) proposed full-flow CFD models with and without cavitation for torque converters, and studied the effects of different pump impeller speeds, pump turbine speed differences and cavitation parameters on the internal flow field of the torque converter. Xiong et al (Xiong et al, 2021) modified the torque converter stator blades through Joukowsky airfoil transformation, which greatly reduced the probability of cavitation.…”

Section: Introductionmentioning

confidence: 99%

Numerical simulation of transient cavitation characteristics of valve-controlled liquid-filled hydrodynamic coupling

Cui,

Zhang,

et al. 2023

Front. Energy Res.

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In high-power impeller industries, valve-controlled liquid-filled hydrodynamic couplings are widely used in the soft startup of heavy-duty scraper conveyors for mining. However, the water circulation speed in internal flow fields is higher at lower speed ratios, making the hydrodynamic couplings prone to severe cavitation, which further results in severe performance degradation, noise, vibration, or even erosion failure. Meanwhile, because a hydrodynamic coupling is a piece of closed-loop multicomponent turbomachinery, internal transient cavitation flow behavior cannot be easily controlled. To reasonably predict the characteristics of cavitation and its influence on the working performance of the hydrodynamic coupling, a high-quality structured mesh model of the internal flow field for an impeller was established. Considering the periodic structural characteristics of the impeller, a scale-resolving simulation turbulence model was combined with a Rayleigh–Plesset cavitation model to establish a single-cycle hydrodynamic coupling calculation model. The cavitation distribution characteristics and torque transmission of the flow field under different working conditions were obtained, and the effect of cavitation on the soft startup performance was analyzed. The results demonstrated that cavitation in the hydrodynamic coupling mainly occurred under low speed ratios. The degree of cavitation decreased as speed ratio increased. The worst-case scenario for cavitation occurred when the speed ratio was zero. Most of the cavitation bubbles were generated at the tip of the blades, resulting in unstable variation in torque characteristics and deterioration of the working performance of the hydrodynamic coupling. The analysis reveals that the cavitation process in the impeller is highly unstable and periodic, and the cavitation development near the tip of the blades occurs in four stages: birth, growth, separation, and disintegration. The generated steam accumulates in the inner ring of the impeller. Therefore, a method for accurately predicting the cavitation characteristics of hydrodynamic couplings based on high-precision technology is proposed, and a theoretical basis for coupling design and cavitation suppression technology is provided.

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Effect of the blade shaped by Joukowsky airfoil transformation on the characteristics of the torque converter

Cited by 14 publications

References 26 publications

The Effect of Rotating Speeds on the Cavitation Characteristics in Hydraulic Torque Converter

The Effect of Rotating Speeds on the Cavitation Characteristics in Hydraulic Torque Converter

Identification and Optimization Study of Cavitation in High Power Torque Converter

Numerical simulation of transient cavitation characteristics of valve-controlled liquid-filled hydrodynamic coupling

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