Experimental Investigation of Steady and UnsteadyFlow Field Upstream and Downstream of anAutomotive Torque Converter Pump

Marathe, B. V.; Lakshminarayana, B.

doi:10.1155/s1023621x99000093

Cited by 8 publications

(5 citation statements)

References 5 publications

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“…A research team led by Lakshminalayana from Pennsylvania State University has conducted a large number of tests to measure the internal flow field of torque converters by using a high-frequency response 5-hole probe [1][2][3][4][5] . Another team that has been engaged in this field for a long time is led by Flack from the University of Virginia, which uses laser velocimetry [6][7][8][9] .…”

Section: Introduction *mentioning

confidence: 99%

Numerical Analysis of the flow field in the torque converter

WANG

2023

Preprint

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Computational fluid dynamics (CFD) based on the finite volume method (FVM) is used to simulate the three-dimensional viscous flow in a torque converter. The simulation result is in good coincidence with the test value and is analyzed theoretically. First, rotor enthalpy is applied to evaluate the hydraulic performance of the torque converter. It is effective to locate and classify hydraulic losses according to the drop in rotor enthalpy. Then, the mechanisms of the jet-wake and secondary flow are analyzed. There is strong coupling between the jet-wake and the secondary flow. The jet-wake flow begins with low-speed flow at the suction-core corner, which is transported to the suction side of the pump blade by the secondary flow. Finally, a prediction model of mainstream vorticity charging with pitch-wise and span-wise components is deduced from the momentum equation. The prediction model reveals that there is a positive mainstream vorticity in the first half of the pump flow channel and a negative value in the second half, which is consistent with the CFD result.

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Section: Introduction *mentioning

confidence: 99%

Numerical Analysis of the flow field in the torque converter

WANG

2023

Preprint

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“…Flow visualization and a three-dimensional flow analysis were used to investigate the cause of the losses in the pump. Marathe and Lakshminarayana [5] also obtained average and unsteady pressure and velocity data upstream and downstream of a torque converter pump using the high frequency response five-hole probe. Separation zones were found near the core at the 0.800 speed ratio and at the shell at the 0.065 speed ratio.…”

Section: Introductionmentioning

confidence: 99%

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

Liu

Changsuo

2015

Mathematical Problems in Engineering

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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.

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“…A torque converter, however, can be operated at high positive speed ratios beyond the cruise point. Therefore, positive speed ratios greater than 1.0 indicate that the turbine is overrunning, or exceeding the speed of the pump's impeller.Others have performed studies of the flow fields in torque converters, including Browarzik (1994), Ejiri and Kubo (1998), Marathe and Lakshminarayana (1997), and Watanabe and colleagues (1997). Efforts at the University of Virginia have used nonintrusive laser velocimetry to map out the detailed flow fields discussed by, for example, Brun and Flack (1994) and Whitehead (1995).…”

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confidence: 99%

Flow Characteristics at the Pump‐Turbine Interface of a Torque Converter at Extreme Speed Ratios

Habsieger

Flack

2003

International Journal of Rotating Machinery

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The average velocity field at the pump-turbine interface in a scaled version of a truck torque converter was studied. Seven different turbine-to-pump rotational-speed ratios were examined, ranging from near stall (0.065) to overspeed (1.050) so as to determine the effect of the speed ratio on the flow field and on the mass flow rate. Laser velocimetry was used to measure the flow velocity through the pump's exit and the turbine's inlet plane. At the pump's exit, as the speed ratio increases, the high velocities move to the pressure-shell corner and then to both the core-suction and the pressureshell corners. Concentrated velocity gradients are largest at the lowest speed ratio, but areas of velocity gradients are largest near the coupling point. Near the coupling point, the flow field is most nonuniform, which yields a highly periodic flow into the turbine inlet. Above the coupling point, the high velocity remains in the pressure-shell corner but separation is seen to develop at the highest speed ratio. At the turbine's inlet, reverse flow is seen at low speed ratios and is an indicator of flow leakage through the core. Velocity gradients are very large at low speed ratios. As the speed ratio increases to the coupling point, the high velocities remain on the shell side. Above the coupling point, the high-velocity flow migrates from the shell side to the core side. The mass flow rate decreases significantly and nonlinearly with the increase of the speed ratio, but for speed ratios greater than 1.000, the negative slope decreases. Torque converters are commonly used in cars, buses, locomotives, and construction equipment as a mean of smooth torque transmission between the engine and the automatic transmission and to provide torque amplification during start-up conditions. The typical torque converter is a recirculating hydrodynamic, mixed-flow turbomachine (containing both radial and axial flow) with three independent blade cascade elements that govern the internal flow field. These three elements are the pump, which energizes the working fluid and which is connected to the engine; the turbine, which extracts the energy from the flow and translates it into output torque; and the stator which, ideally, redirects the turbine's exit flow back into the pump with a zero flow incidence at a specific design speed ratio. The pump and turbine are rotating at different angular speeds while the stator is either locked or allowed to float freely. Because of the significant curvature of the flow path and the high interaction among these three elements, the internal flow field is highly three-dimensional.The flow field, the torque, and the efficiency curves are normally determined only from the zero speed ratio (turbine has stopped) to the coupling point (turbine torque and pump torque are equal), which typically occurs at a speed ratio of 0.85 to 0.90. Performance characteristics are normally required only in the range from stall to cruise. A torque converter, however, can be operated at high positive speed ratios beyond the c...

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Experimental Investigation of Steady and UnsteadyFlow Field Upstream and Downstream of anAutomotive Torque Converter Pump

Cited by 8 publications

References 5 publications

Numerical Analysis of the flow field in the torque converter

Numerical Analysis of the flow field in the torque converter

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

Flow Characteristics at the Pump‐Turbine Interface of a Torque Converter at Extreme Speed Ratios

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