Research on Unsteady Flow Field of the Pump in Hydraulic Torque Converter

The objective of this investigation is to understand the steady and the unsteady flow field at the exit of an automotive torque converter turbine and inside the stator with a view toward improving its performance. The measurements were conducted in a stationary frame of reference using a high-frequency response five-hole probe, and the data were processed to derive the flow properties in the relative (turbine) frame of reference. The experimental data were processed in the frequency domain by spectrum analysis and in the temporal-spatial domain by ensemble averaging technique. The flow properties (e.g., pressure and velocity) were resolved into mean, periodic, aperiodic, and unresolved components. A velocity profile similar to that of a fully developed flow was observed at all radii. The periodic data in relative reference frame revealed a small separation zone near the suction surface in the core region. The rms values of the unresolved component were found to be significantly higher in this region. The secondary flow vectors show underturning, radially inward flow in the entire passage with a small region of overturning near the separation zone. The overall flow at the turbine exit was nearly two dimensional in nature except in the zone of flow separation. The unsteady flow data show that unresolved and aperiodic components dominate the unsteadiness in the pressure, whereas the periodic components dominate the unsteadiness in velocities and flow angles. Pressure and velocity fluctuations were moderate, whereas the flow angle fluctuations were found to be high. The overall flow at the exit of turbine was found to be highly unsteady.

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Experimental Investigation of Steady and Unsteady Flow Field Downstream of an Automotive Torque Converter Turbine and Stator

International Journal of Rotating Machinery ◽

10.1155/s1023621x95000224 ◽

1995 ◽

Vol 2 (2) ◽

pp. 67-84 ◽

Cited By ~ 7

Author(s):

B. V. Marathe ◽

B. Lakshminarayana

Keyword(s):

Experimental Data ◽

Flow Field ◽

Unsteady Flow ◽

Torque Converter ◽

Mean Value ◽

Frame Of Reference ◽

Secondary Flows ◽

Flow Properties ◽

The Core ◽

Stationary Frame

The objective of this investigation is to understand the steady and the unsteady flow field at the exit of an automotive torque converter turbine and stator with a view towards improving it's performance. A high frequency response five-hole probe was designed and built to measure the three-dimensional steady and unsteady flow fields. The measurements were conducted in a stationary frame of reference and the data were processed to derive the flow properties in the relative (turbine) frame of reference. The experimental data were processed in the frequency domain by spectrum analysis and in temporal-spatial domain by ensemble averaging technique. The data show that the flow field is highly unsteady with high unresolved unsteadiness (approx. 17-21% of mean value) and significant blade-to-blade periodic component approx. 6% of mean value). The unresolved unsteadiness and periodic unsteadiness increase with an increase in the radius from the shell to the core whereas the aperiodic unsteadiness does not show any systematic variation with the radius. The experimental data reveal the presence of a low momentum region near the core due to possible flow separation and reattachment inside the turbine passage. Data also show the presence of strong secondary flow near the core and weak secondary flow near the shell at the exit of the turbine. These secondary flows generate high levels of turbulence. A comparison of the flow properties upstream and downstream of the stator in the stationary frame of reference indicate the presence of high losses near the core due to high turbulence levels and large secondary flows, and high losses near the shell due to possible corner separation near the shell suction surface inside the stator blade passage. The unsteadiness in the flow properties upstream of the stator is high. The rms value of the unsteady total velocity is approx. 20% of the steady state value. Periodic and aperiodic unsteadiness were also found significant.

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Steady and Unsteady Flow Field at Pump and Turbine Exits of a Torque Converter

Journal of Fluids Engineering ◽

10.1115/1.2820696 ◽

1998 ◽

Vol 120 (3) ◽

pp. 538-548 ◽

Cited By ~ 16

Author(s):

Y. Dong ◽

B. Lakshminarayana ◽

D. Maddock

Keyword(s):

Flow Field ◽

Unsteady Flow ◽

Frequency Response ◽

High Frequency ◽

Free Stream ◽

Torque Converter ◽

Flow Data ◽

High Frequency Response ◽

The Core ◽

Measurement Plane

The steady and unsteady flow field at the pump and the turbine exit of a 245 mm diameter automotive torque converter was measured by a miniature high-frequency-response five-hole probe and a high-frequency-response total pressure Pitot probe in the stationary reference frame. The data were decomposed into blade periodic, blade aperiodic, and unresolved unsteady components. The periodic flow data shows that the pump exit flow has four major zones; the free-stream flow, the blade wake flow, the core-suction corner separation flow, and the mixing zone. The unsteady flow data shows that the unsteadiness in the free-stream is uniform, and the unsteadiness in the wake mixing flow zone is very high. The turbine exit flow is almost fully developed at the measurement plane, the flow field is uniform in the tangential direction, and only radial gradients in flow properties exist. A region of separated flow with high unsteadiness and high axial component of vorticity was observed at the measurement plane near the core.

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Experimental Investigation of Steady and Unsteady Flow Field Downstream of an Automotive Torque Converter Turbine and Inside the Stator: Part I — Flow at the Exit of Turbine

Volume 1: Turbomachinery ◽

10.1115/95-gt-231 ◽

1995 ◽

Cited By ~ 3

Author(s):

B. V. Marathe ◽

B. Lakshminarayana ◽

Donald G. Maddock

Keyword(s):

Flow Field ◽

Unsteady Flow ◽

Separation Zone ◽

Torque Converter ◽

Frame Of Reference ◽

Flow Properties ◽

Ensemble Averaging ◽

Suction Surface ◽

Flow Angle ◽

Periodic Components

The objective of this investigation is to understand the steady and the unsteady flow field at the exit of an automotive torque converter turbine and inside the stator with a view towards improving its performance. The measurements were conducted in a stationary frame of reference using a high frequency response five-hole probe and the data were processed to derive the flow properties in the relative (turbine) frame of reference. The experimental data were processed in the frequency domain by spectrum analysis and in temporal-spatial domain by ensemble averaging technique. The flow properties (e.g. pressure and velocity) were resolved into mean, periodic, aperiodic and unresolved components. A velocity profile similar to that of a fully developed flow was observed at all radii. The periodic data in relative reference frame revealed a small separation zone near the suction surface in the core region. The rms values of the unresolved component were found to be significantly higher in this region. The secondary flow vectors show underturning, radially inward flow in the entire passage with a small region of overturning near the separation zone. The overall flow at the turbine exit was nearly two dimensional in nature except in the zone of flow separation. The unsteady flow data shows that unresolved and aperiodic components dominate the unsteadiness in the pressure whereas the periodic components dominate the unsteadiness in velocities and flow angles. Pressure and velocity fluctuations were moderate whereas the flow angle fluctuations were found to be high. The overall flow at the exit of turbine was found to be highly unsteady.

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Experimental Investigation of Steady and Unsteady Flow Field Upstream and Downstream of an Automotive Torque Converter Pump

International Journal of Rotating Machinery ◽

10.1155/s1023621x99000093 ◽

1999 ◽

Vol 5 (2) ◽

pp. 99-116 ◽

Cited By ~ 3

Author(s):

B. V. Marathe ◽

B. Lakshminarayana

Keyword(s):

Flow Field ◽

Unsteady Flow ◽

Torque Converter ◽

Frame Of Reference ◽

Operating Conditions ◽

Maximum Efficiency ◽

Speed Ratio ◽

Secondary Vortex ◽

Flow Properties ◽

Periodic Components

The objective of this investigation is to understand the steady and the unsteady flow field at the exit of an automotive torque converter pump with a view towards improving its performance. The measurements were conducted in a stationary frame of reference using a high frequency response five-hole probe and the data were processed to derive the flow properties in the relative (pump) frame of reference. The experimental data were processed at three different operating conditions: maximum efficiency point, design point and near-stall point. The unsteady values of flow properties (pressure, velocity and flow angles) were divided into five components: mean, periodic, blade aperiodic, revolution aperiodic and unresolved components.The velocity profiles indicate zones of separation near the core region at speed ratio (SR) 0.8. This zone is transported to the shell region at SR 0.065 due to the presence of a strong secondary vortex. The secondary vortex (weak) for the SR 0.8 rotates anti-clockwise, and is located only near core-wake region. The secondary vortex (strong) at SR 0.065 rotates clockwise, and encompasses the entire passage. The unsteady flow data show that unresolved and periodic components dominate the unsteadiness at the pump exit. The overall aperiodicity is negligible and is dominated by the blade aperiodic component.

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Modal characteristics and fluid–structure interaction vibration response of submerged impeller

Journal of Vibration and Control ◽

10.1177/10775463211003695 ◽

2021 ◽

pp. 107754632110036

Author(s):

Shihui Huo ◽

Hong Huang ◽

Daoqiong Huang ◽

Zhanyi Liu ◽

Hui Chen

Keyword(s):

Flow Field ◽

Unsteady Flow ◽

Damping Ratio ◽

Pure Water ◽

Vibration Response ◽

Modal Identification ◽

Liquid Oxygen ◽

Modal Characteristics ◽

Oxygen Pump ◽

Turbo Pump

Turbo pump is one of the elements with the most complex flow of liquid rocket engine, and as an important component of turbo pump, an impeller is the weak point affecting its reliability. In this study, a noncontact modal characteristic identification technique was proposed for the liquid oxygen pump impeller. Modal characteristics of the impeller under three different submerged media, air, pure water, and brine with same density as liquid oxygen, were tested based on the noncontact modal identification technology. Submersion state directly affects the modal frequencies and damping ratio. The transient vibration response characteristics of the impeller excited by the unsteady flow field was achieved combining with unsteady flow field analysis and transient dynamic analysis in the whole flow passage of the liquid oxygen pump. Vibration responses at different positions of the impeller show 10X and 20X frequencies, and the amplitude at the root of short blade is significant, which needs to be paid more attention in structural design and fatigue evaluation.

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