CFD Analysis of Pressure Pulsation and Internal Flow for a Positive Displacement Hydraulic Turbine

To understand the effect of internal leakage on the torque field and characteristics of a torque converter (TC), a transient analysis was performed on the internal flow of a TC and the pressure pulsation characteristics of monitoring points in the convection channel. It was found that dividing the leakage area of the TC into a separate watershed improved simulation accuracy by 4%. When there was a leakage area, there were distinct collision, mixing, and assimilation stages between the leakage flow and the main flow. These phenomena caused energy loss that was highest at low speed ratios. However, the leakage flow always accounted for 12% of the main flow regardless of the speed ratio. At the same time, the leakage flow had a larger influence on pressure pulsation inside the TC and especially the low frequency band was more substantial. This shows that the leakage area has a large influence on the TC performance, energy loss, and flow state. Analysis of the leakage area showed that reducing the leakage area helps to improve powertrain performance and fuel economy.

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Study of the internal flow structure of an ultra-small axial flow hydraulic turbine

Renewable Energy ◽

10.1016/j.renene.2019.03.004 ◽

2019 ◽

Vol 139 ◽

pp. 1000-1011 ◽

Cited By ~ 3

Author(s):

Yasuyuki Nishi ◽

Tomoyuki Kobori ◽

Nozomi Mori ◽

Terumi Inagaki ◽

Norio Kikuchi

Keyword(s):

Flow Structure ◽

Axial Flow ◽

Internal Flow ◽

Hydraulic Turbine

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The Design Method of Axial Flow Runners Focusing on Axial Flow Velocity Uniformization and Its Application to an Ultra-Small Axial Flow Hydraulic Turbine

International Journal of Rotating Machinery ◽

10.1155/2016/5390360 ◽

2016 ◽

Vol 2016 ◽

pp. 1-13 ◽

Cited By ~ 4

Author(s):

Yasuyuki Nishi ◽

Yutaka Kobayashi ◽

Terumi Inagaki ◽

Norio Kikuchi

Keyword(s):

Flow Velocity ◽

Performance Test ◽

Design Method ◽

Axial Flow ◽

Internal Flow ◽

Hydraulic Turbine ◽

Small Rivers ◽

Axial Component ◽

Turbine Efficiency ◽

Piv Measurement

We proposed a portable and ultra-small axial flow hydraulic turbine that can generate electric power comparatively easily using the low head of open channels such as existing pipe conduits or small rivers. In addition, we proposed a simple design method for axial flow runners in combination with the conventional one-dimensional design method and the design method of axial flow velocity uniformization, with the support of three-dimensional flow analysis. Applying our design method to the runner of an ultra-small axial flow hydraulic turbine, the performance and internal flow of the designed runner were investigated using CFD analysis and experiment (performance test and PIV measurement). As a result, the runners designed with our design method were significantly improved in turbine efficiency compared to the original runner. Specifically, in the experiment, a new design of the runner achieved a turbine efficiency of 0.768. This reason was that the axial component of absolute velocity of the new design of the runner was relatively uniform at the runner outlet in comparison with that of the original runner, and as a result, the negative rotational flow was improved. Thus, the validity of our design method has been verified.

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Measurement of Positive Displacement Pump Flow Ripple and Impedance

Proceedings of the Institution of Mechanical Engineers Part I Journal of Systems and Control Engineering ◽

10.1243/pime_proc_1996_210_437_02 ◽

1996 ◽

Vol 210 (1) ◽

pp. 65-74 ◽

Cited By ~ 10

Author(s):

D N Johnston ◽

J E Drew

Keyword(s):

Internal Flow ◽

Linear Interpolation ◽

Secondary Source ◽

Test Rig ◽

Impedance Measurements ◽

British Standard ◽

Flow Ripple ◽

Positive Displacement ◽

Source Impedance ◽

Displacement Pump

The secondary source method forms the British Standard for pump fluid-borne noise testing. This is a powerful technique but requires care in order to produce accurate results. This paper describes practical aspects for implementing the method. The requirements for the test rig, data acquisition system and analysis are detailed. The British Standard specifies that either mathematical modelling or linear interpolation is used on the source impedance measurements. A method for smoothing the impedance results is described in this paper, which is shown to give more repeatable results than linear interpolation. Some physically realistic mathematical models of pump impedance are described, and their use in determining the internal flow ripple discussed.

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Advances in Design Methods and Characteristics of Internal Flow for Centrifugal Pumps

ASME 2010 3rd Joint US-European Fluids Engineering Summer Meeting: Volume 1, Symposia – Parts A, B, and C ◽

10.1115/fedsm-icnmm2010-30288 ◽

2010 ◽

Author(s):

Shouqi Yuan ◽

Jianping Yuan ◽

Houlin Liu ◽

Yue Tang ◽

Jinfeng Zhang ◽

...

Keyword(s):

Unsteady Flow ◽

Pressure Pulsation ◽

Design Method ◽

Internal Flow ◽

Design Methods ◽

Centrifugal Pumps ◽

Flow Induced Vibration ◽

Hydraulic Design ◽

Piv Measurement ◽

Engineering And Technology

Centrifugal pump is widely used in various fields of the national economy. Pumps, of which 70% are centrifugal pumps, consume 20.9% of the total electricity generation nationwide in China in 2009, according to the statistics. In this paper, the research advances in design methods and characteristics of internal flow fields for centrifugal pumps, carried out by the Research Center of Fluid Machinery Engineering and Technology of Jiangsu University, is introduced. First of all, the Greater Flow Design method, Non-Overload Design method and Splitter Blade Offset Design method are fully discussed through systematically studies. In addition, three methods of performance prediction for centrifugal pumps are adopted, and a CAD/CFD software for hydraulic design and analysis is initially developed. Secondly, to deepen the understanding of characteristics of internal flow in centrifugal pumps, the numerical simulation and PIV measurement investigation have been done. Then the unsteady flow induced vibration and noise are studied considering fluid-structure interaction and fluid-sound interaction. The control of the unsteady flow in centrifugal pumps is also attempted to optimize the design method for centrifugal pumps. In addition, the pressure pulsation and vibration behaviors under both cavitation and non-cavitation conditions are obtained and analyzed. Finally, some detecting methods and criterion for cavitation incipiency and development are put forward.

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