Influence of the Flatness Ratio of an Automotive Torque Converter on Hydrodynamic Performance

1999 ◽  
Vol 121 (3) ◽  
pp. 614-620 ◽  
Author(s):  
E. Ejiri ◽  
M. Kubo
Keyword(s):  
Flow Characteristics ◽  
Internal Flow ◽  
Torque Converter ◽  
Hydrodynamic Performance ◽  
Pump Efficiency ◽  
Torque Transmission ◽  
Performance Deterioration ◽  
Overall Performance ◽  
Torque Converters ◽  
Shock Loss

Automotive torque converters have recently been designed with an increasingly narrower profile for the purpose of achieving a smaller axial size, which also translates into weight savings. Four torque converters with different flatness ratios were manufactured and tested in order to evaluate the change in their overall performance, including efficiency, stall torque ratio and torque transmission capacity. The experimental results show that the overall performance deteriorates when the flatness ratio is reduced to less than about 0.2. The internal flow characteristics of the torque converters were also investigated by numerical analysis using a CFD code. The computational results indicate that the main cause of this performance deterioration is a reduction in pump efficiency, which is attributed to increases in shock loss in the inlet region, separation loss in the fore half region, and friction loss in the exit region.

scholarly journals Mathematical Model for Elliptic Torus of Automotive Torque Converter and Fundamental Analysis of Its Effect on Performance

2015 ◽  
Vol 2015 ◽  
pp. 1-13
Author(s):  
Chunbao Liu ◽  
Changsuo Liu ◽  
Wenxing Ma
Keyword(s):  
Design Method ◽  
Flow Characteristics ◽  
Internal Flow ◽  
Torque Converter ◽  
Hydrodynamic Performance ◽  
Elliptic Type ◽  
Flat Torus ◽  
Type Method ◽  
Compact Size ◽  
Torque Converters

Passenger car torque converters have been designed with an increasingly flatter profile in recent years for the purpose of achieving a weight saving and more compact size. However, a flatter design tends to result in the reduced hydrodynamic performance. To improve its performance, a new flat torus of elliptic type method concentrating on the solution to flat TC was put forward, and four torque converters of different flatness ratios were designed to judge the superiority of the flat torus design method. The internal flow characteristics were numerically investigated using CFD codes and resulted in good agreement with experimental data. The results indicate that the main cause of this performance degradation can be attributed to deterioration of the velocity fields of the pump, and a case of flatness ratio 0.8 illustrates the reason that the performance designed by the flat torus design method based on the elliptic shape is more excellent than that of the traditional one. Furthermore, this study proposed a structure of removal of inner ring to improve the performance of torque converter.

Improvement of Hydrodynamic Performance of a Multiphase Pump Using Design of Experiment Techniques

2015 ◽  
Vol 137 (8) ◽  
Author(s):  
Joon-Hyung Kim ◽  
Him-Chan Lee ◽  
Jin-Hyuk Kim ◽  
Young-Seok Choi ◽  
Joon-Yong Yoon ◽  
...  
Keyword(s):  
Design Optimization ◽  
Design Of Experiment ◽  
Deep Sea ◽  
Internal Flow ◽  
Fractional Factorial ◽  
Hydrodynamic Performance ◽  
Pump Efficiency ◽  
Design Variables ◽  
Optimized Model ◽  
Offshore Plants

Multiphase pumps for offshore plants must perform at high pressure because they are installed on deep-sea floors to pressurize and transfer crude oil in oil wells. As the power for operating pumps should be supplied to deep sea floors using umbilicals, risers, and flow lines (URF), which involve a higher cost to operate pumps, the improvement of pump efficiency is strongly emphasized. In this study, a design optimization to improve the hydrodynamic performance of multiphase pumps for offshore plants was implemented. The design of experiment (DOE) techniques was used for organized design optimization. When DOE was performed, the performance of each test set was evaluated using the verified numerical analysis. In this way, the efficiency of the optimization was improved to save time and cost. The degree to which each design variable affects pump performance was evaluated using fractional factorial design, so that the design variables having a strong effect were selected based on the result. Finally, the optimized model indicating a higher performance level than the base model was generated by design optimization using the response surface method (RSM). How the performance was improved was also analyzed by comparing the internal flow fields of the base model with the optimized model. It was found that the nonuniform flow components observed on the base model were sharply suppressed in the optimized model. In addition, due to the increase of the pressure performance of the optimized model, the volume of air was reduced; therefore, the optimized model showed less energy loss than the base model.

Influence of Stator Blade Geometry on Torque Converter Cavitation

2017 ◽  
Vol 140 (4) ◽  
Author(s):  
Cheng Liu ◽  
Wei Wei ◽  
Qingdong Yan ◽  
Brian K. Weaver ◽  
Houston G. Wood
Keyword(s):  
High Speed ◽  
Torque Converter ◽  
Operating Conditions ◽  
Hydrodynamic Performance ◽  
Speed Ratio ◽  
Capacity Loss ◽  
Wide Range ◽  
Stator Blade ◽  
Torque Converters ◽  
Blade Geometry

Cavitation in torque converters may cause degradation in hydrodynamic performance, severe noise, or even blade damage. Researches have highlighted that the stator is most susceptible to the occurrence of cavitation due to the combination of high flow velocities and high incidence angles. The objective of this study is to therefore investigate the effects of cavitation on hydrodynamic performance as well as the influence of stator blade geometry on cavitation. A steady-state homogeneous computational fluid dynamics (CFD) model was developed and validated against test data. It was found that cavitation brought severe capacity constant degradation under low-speed ratio (SR) operating conditions and vanished in high-speed ratio operating conditions. A design of experiments (DOE) study was performed to investigate the influence of stator design variables on cavitation over various operating conditions, and it was found that stator blade geometry had a significant effect on cavitation behavior. The results show that stator blade count and leaning angle are important variables in terms of capacity constant loss, torque ratio (TR) variance, and duration of cavitation. Large leaning angles are recommended due to their ability to increase the cavitation number in torque converters over a wide range of SRs, leading to less stall capacity loss as well as a shorter duration of cavitation. A reduced stator blade count is also suggested due to a reduced TR loss and capacity loss at stall.

Parametric Analysis and Optimization of Leaning Angle in Torque Converters

2020 ◽  
Vol 142 (10) ◽  
Author(s):  
Cheng Liu ◽  
Meng Guo ◽  
Qingdong Yan ◽  
Wei Wei ◽  
Houston G. Wood
Keyword(s):  
Angular Position ◽  
Three Dimensional ◽  
Torque Converter ◽  
Hydrodynamic Performance ◽  
Parameter Study ◽  
Cfd Models ◽  
Multi Objective Genetic Algorithm ◽  
Mass Flowrate ◽  
Cubic Model ◽  
Torque Converters

Abstract Torque converters are durable fluid couplings that can provide output torque multiplication. Blade leaning angle represents the angular position of a blade chord with respect to its radial reference line, and it is an important blade variable regarding both hydrodynamic performance and manufacturability of a torque converter. In traditional design processes, blade leaning angles are often determined based on experiences of engineers; hence, this study proposed a design approach using the combination of computational fluid dynamics (CFD) and optimization. Two CFD models were developed to design blade leaning angles. A steady-state periodic CFD model was employed for the parameter study and the optimization, and a transient full three-dimensional (3D) model was performed to study the flow mechanism and evaluate the performance with higher accuracy. Design of experiment (DOE) technique was employed to investigate the relationship between blade leaning angles and hydrodynamic performance, and a reduced cubic model was derived from the results. It was found that blade leaning angles had profound effects on torque converter performance; a large blade leaning angle intensified the flow blockage effect, thus resulting in a lower mass flowrate and torque capacity. Seven torque converters with different blade leaning angles were tested to validate the obtained numerical results, and the test data were found to be in good agreement with the CFD predictions. Finally, the hydrodynamic performance of the base model torque converter was optimized by a multi-objective genetic algorithm.

Numerical Simulation of Torque Converter With Different Pump Blade Camber

2019 ◽  
Author(s):  
Zhifang Ke ◽  
Cheng Liu ◽  
Wei Wei ◽  
Qingdong Yan ◽  
Xianglu Meng
Keyword(s):  
Internal Flow ◽  
Torque Converter ◽  
Flow Fields ◽  
Hydrodynamic Performance ◽  
Maximum Efficiency ◽  
Speed Ratio ◽  
Main Function ◽  
Flow Mechanism ◽  
Entrance Angle ◽  
The Difference

Abstract The main function of the torque converter pump is to transfer mechanical power into fluid dynamic energy. It has been proved that the pump blade shape, especially pump blade camber peak, is crucial to torque converter hydrodynamic performance. However, it remains unclear how this parameter affects internal flow characteristics, and how it leads to the difference in performance. Thus, the relationship between the pump blade camber and the performance of torque converter and the flow mechanism were explored in this study. Torque converters with different pump blade camber were tested. Meanwhile, the corresponding numerical models were also established and their internal flow fields were investigated through steady-state simulations. The influence of the pump blade camber on the hydrodynamic performance was studied using both numerical and experimental methods, and the flow mechanism was also revealed and elaborated by exploring the numerical flow fields. The results from both experiments and simulations showed that larger pump blade camber peak led to higher pump capacity, higher maximum efficiency and lower stall torque ratio. The flow field simulation revealed that larger pump camber peak would lead to higher total pressure in pump channel. And the pressure distribution between the suction and pressure surface showed a similar pattern; however, their difference, especially near the leading and tailing edge, depends on the camber peak. Besides, higher camber peak blade absorbed more power, also induced more complex vortex, but there always existed the most efficient speed ratio when pump efficiency can reach to peak, at this moment, the difference between angle of attack and entrance angle reach the zero, which can be used to guide the design of pump blade.

Numerical study on the effects of installing an inducer on a pump in a turbopump

2021 ◽  
pp. 095765092110149
Author(s):  
Changhyun Kim ◽  
Chang-Ho Choi ◽  
Semi Kim ◽  
Jehyun Baek
Keyword(s):  
Numerical Study ◽  
Flow Characteristics ◽  
Internal Flow ◽  
High Flow ◽  
Stable Operation ◽  
Ansys Cfx ◽  
Performance Deterioration ◽  
Suction Performance ◽  
High Thrust

In a projectile, a turbopump is widely used to pressurize oxidizer and fuel to gain high thrust instead of using high pressure tank which has a disadvantage in total weight. Pumps in a turbopump employ an inducer upstream to prevent performance degradation by increasing pressure at the impeller inlet. However, cavitation and related instabilities take place frequently, so numerous analysis have been conducted for turbopumps. In this study, the pumps with and without an inducer were numerically studied using ANSYS CFX 13.0 to analyze the effects of installing an inducer, which was rarely treated before. By comparing these two pumps, the merits and demerits of installing an inducer can be analyzed in the aspects of hydraulic/suction performances and internal flow characteristics. Also, the role of an inducer can be understood in both of non-cavitating and cavitating conditions. As a result, head rise and efficiency of the pump were degraded by installing an inducer in non-cavitating conditions. The inducer could not play a role at high flow rate, and efficiency of the inducer was steeply declined in the off-design conditions. However, suction performance of the pump was greatly improved by adopting the inducer. Head of the pump with an inducer abruptly decreased at the low cavitation numbers, while head of the pump without an inducer started to decline gradually at the high cavitation numbers. In spite of high cavitation number, severe cavitation appeared in the case without an inducer, so it can be said that installing an inducer can prevent performance deterioration from the cavitation and satisfies stable operation which is more important for pumps rather than obtaining high hydraulic performance.

scholarly journals Performance Prediction Based on Effects of Wrapping Angle of a Side Channel Pump

Energies ◽  
2019 ◽  
Vol 12 (1) ◽  
pp. 139 ◽  
Author(s):  
Ji Pei ◽  
Fan Zhang ◽  
Desmond Appiah ◽  
Bo Hu ◽  
Shouqi Yuan ◽  
...  
Keyword(s):  
Performance Prediction ◽  
Flow Characteristics ◽  
Internal Flow ◽  
Operating Conditions ◽  
Physical Parameters ◽  
Side Channel ◽  
Pump Efficiency ◽  
Coefficient Increase ◽  
Pump Head ◽  
Flow Pressure

This paper seeks to predict the performance of the side channel pump by considering the influences of different wrapping angles. Firstly, three pump cases 1, 2 and 3 are modeled with wrapping angles 15°, 30° and 45°, respectively. Secondly, different physical parameters comprising exchanged mass flow, pressure and velocity distributions are plotted at the best efficiency point (QBEP) to analyze the internal flow characteristics. Since the flow exchange times depend on the size of the wrapping angle, the size of the wrapping angle has significant effects on the pump head performance. Case 1 with the smallest wrapping angle recorded the largest head improvement at all operating conditions compared to case 2 and case 3. Case 1 at QBEP attained a head coefficient increase of about 9.8% and 38.6% compared to that of case 2 and case 3, respectively. However, the size of the wrapping angle had a slight effect on the pump efficiency; thus, case 1 still predicted a marginal increase in efficiency compared to case 2 and case 3 at all operating conditions. Lastly, the numerical simulations were validated with experimental data after manufacturing pump case 2.

Design of experiments to investigate blade geometric effects on the hydrodynamic performance of torque converters

2017 ◽  
Vol 233 (2) ◽  
pp. 276-291 ◽  
Author(s):  
Cheng Liu ◽  
Wei Wei ◽  
Qingdong Yan ◽  
Neal R Morgan
Keyword(s):  
Design Of Experiments ◽  
Factorial Design ◽  
Reaction Force ◽  
Three Dimensional ◽  
Torque Converter ◽  
Fractional Factorial ◽  
Hydrodynamic Performance ◽  
Design Parameters ◽  
Design Variables ◽  
Torque Converters

Torque converters are key components in automatic and hydrodynamic transmissions. Power is transmitted through the reaction force of fluid on cascades; thus, the geometry of the blade is essential to torque converter performance. The traditional one-dimensional blade design approach becomes inefficient for modern torque converter design because torque converters are highly coupled turbomachines and the flow is three-dimensional. In the present research, a novel six-parameter blade camberline design was developed to describe the overall shape of the blade. A full two-level factorial design was conducted with computational fluid dynamics (CFD) simulations on each component to determine the sensitivity of design variables and investigate the relationship between design parameters and hydrodynamic performance. The design variables were reduced from 18 to nine after the screening design. A quarter-fractional factorial design was performed on the selected primary design variables to explore the first-order interaction effects between different wheels. Then a response surface was generated for each component to provide a substitution model for further optimization. A series of torque converters with various design parameters were fabricated and tested to validate the important effects determined in the design of experiments (DOE) process. It is found that CFD in combination with DOE is able to precisely capture the correlation between design variables and hydrodynamic performance. A base torque converter was optimized based on the DOE studies and the result was tested. Pronounced improvement in powertrain performance and fuel economy were observed.

Flow Characteristics of Tip Clearance in Axial Compressor

2015 ◽  
Vol 741 ◽  
pp. 504-508
Author(s):  
Yong Lei Qu ◽  
Bo Wan ◽  
Xiao Meng Pei
Keyword(s):  
Flow Characteristics ◽  
Axial Compressor ◽  
Axial Flow ◽  
Internal Flow ◽  
Tip Clearance ◽  
Leakage Flow ◽  
Compressor Rotor ◽  
Overall Performance ◽  
Flow Compressor ◽  
The Impact

Tip clearance of compressor rotor blade is introduced for avoiding friction collision between the moving blade and the casing. Because of the existence of the pressure difference between pressure surfaces and the suction surfaces of the blade, the blending of the leakage flow with the mainstream causes losses, which affects internal flow field and overall performance of the compressor. In this article, numerical analysis software is used to study the multi-condition performance of a six and a half axial flow compressor, for analyzing the impact of leakage flow patterns on compressor.

TORQUE CONVERTER INTERNAL FLOW: VISUALIZATION AND IMAGE PROCESSING

2017 ◽  
Vol 24 (1-4) ◽  
pp. 209-222
Author(s):  
Fujio Yamamoto ◽  
Ari-isa Wada ◽  
Manabu Iguchi ◽  
Masa-aki Ishikawa
Keyword(s):  
Image Processing ◽  
Flow Visualization ◽  
Internal Flow ◽  
Torque Converter
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