Determination of the Flow Angle in Hydraulic Components

Authors

  • Lennard Günther Institute of Mechatronic Engineering, Technische Universität Dresden, Helmholtzstrasse 7a, 01069 Dresden
  • Sven Osterland Institute of Mechatronic Engineering, Technische Universität Dresden, Helmholtzstrasse 7a, 01069 Dresden
  • Jürgen Weber Institute of Mechatronic Engineering, Technische Universität Dresden, Helmholtzstrasse 7a, 01069 Dresden

DOI:

https://doi.org/10.13052/ijfp1439-9776.2544

Keywords:

Flow angle, free jet, flow force, hydraulics, design process

Abstract

The paper presents a general analytical equation for the determination of the flow angel in hydraulic components like valves and pumps. Exemplary, the method is applied to two different valve concepts – a cartridge valve and a rotary slide valve.
cos(εavg)=1/2(cos(αl)−cos(αr))

The huge advantage of this equation is the simple expression with no dependencies on operation conditions. Only the geometry is important. The underlying phenomenon is valid for turbulent flows. Thus it is useable for almost all hydraulic applications. It makes it possible to predict the flow force as well as to optimize the flow geometry. It describes the flow angle of the free jet behind a narrow section (e.g. a control edge of a valve). By a suitable choice of the angle of the free jet, the flow force can be reduced by changing the direction of the outgoing impulse. With regard to cavitation, the impact of the free jet can be shifted and thus the cavitation erosion can be shifted or weakened.

This paper deals with the investigation of the flow angle of free jets as well as the prediction of the flow force in valves without CFD. For the illustration a cartridge and a rotary slide valve are used as technical applications. In the first section, geometric factors influencing the flow angle are discussed, as well as the transferability of the results under varying operating conditions (laminar and turbulent). Using a generic minimal model, the behaviour of the flow angle with respect to geometric influence factors and operating conditions is investigated by means of CFD. The results are adapted to real applications in the second section. The direct adjustment of the flow angle results in a significant improvement in the characteristic behaviour of the presented valves (such as flow force and resistance torque). It becomes clear how efficient the adjustment of the flow angle can be if the basis of the formation of the free jet is known. Due to the derivation of the relationship with the help of an abstracted minimal model, the knowledge gained can be used in many ways and can also be transferred to other applications in the field of fluid technology. Optimization processes are more efficiently without using elaborated simulation models e.g. driven by CFD.

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Author Biographies

Lennard Günther, Institute of Mechatronic Engineering, Technische Universität Dresden, Helmholtzstrasse 7a, 01069 Dresden

Lennard Günther received his diploma in Diploma in Mechanical Engineering in the fields of numerical multi-phase flow simulations of cavitation from TU Dresden in 2020. Since 2020 he is working as Research Associate at the Chair of Fluid-Mechatronic Systems (Fluidtronics), Institute of Mechatronic Engineering, Technische Universität Dresden. His research areas include valve development in the field of industrial applications as well as research and numerical investigations of special internal flow phenomena of hydraulic components.

Sven Osterland, Institute of Mechatronic Engineering, Technische Universität Dresden, Helmholtzstrasse 7a, 01069 Dresden

Sven Osterland received his diploma in mechanical engineering in the field of structural durability from TU Dresden in 2014, and completed his Ph.D. thesis on the visualisation and simulation of cavitation and cavitation erosion in hydraulic valves in 2024. Since 2014, he has been working as a research assistant at the Chair of Fluid-Mechatronic Systems (Fluidtronics), Institute of Mechatronic Engineering, Technische Universität Dresden. His research areas include numerical multiphase flow simulations (CFD), experimental flow visualisation of cavitating hydraulic flows and cavitation erosion in hydraulic components.

Jürgen Weber, Institute of Mechatronic Engineering, Technische Universität Dresden, Helmholtzstrasse 7a, 01069 Dresden

Jürgen Weber received his PhD degree in Mechanical Engineering at TU Dresden in 1991. Over 30 years of experience in technology development, research and education followed his graduation.

For 13 years he has worked in executive positions at CNH:

– 4 years Head of Hydraulic Department and Head of Design Department

– 5 years Global Head of Systems Architecture for Construction Equipment in CNH worldwide

– 4 years Global Head of System Integration, Pre-development and Innovation for Construction Equipment in CNH worldwide; for all CNH Construction Machine Platforms: Excavator, Loader, Dozer, Grader, TLB, SSL, TH.

In 2010 Jürgen returned to TU Dresden as appointed university professor and chair of Fluid-Mechatronic Systems “Fluidtronic” and he heads up the Institute of Mechatronic Engineering at TU Dresden hosting the International Fluid Power Conference held every 2 years since 1998, alternating between Aachen and Dresden.

Furthermore, Jürgen has been head of the Consulting Board for HYDAC, Sulzbach/Saar, for 10 years, still being a member, and was also appointed as a member of the Supervisory Board of Musashi Europe GmbH. He is a fellow and now chair of the Global Fluid Power Society. The membership of 5G Lab Germany at TU Dresden is a further indicator for more than 15 years of experience in management and coordination of research alliances as well as the activities as surveyor, PhD supervisor, over 300 publications, technical books and lecture notes. As CEO of the newly founded innovation center Construction Future Lab (CFLab gGmbH, Dresden) Jürgen will keenly continue with applied research and technology transfer.

References

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L. Günther, et al. (2024) Novel streamline model for determining the flow characteristics of hydraulic resistances. 12th JFPS 2024, Hiroshima, JP.

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Published

2024-12-19

How to Cite

Günther, L. ., Osterland, S. ., & Weber, J. . (2024). Determination of the Flow Angle in Hydraulic Components. International Journal of Fluid Power, 25(04), 493–520. https://doi.org/10.13052/ijfp1439-9776.2544

Issue

2024: Vol 25 Iss 4

Section

14th International Fluid Power Conference

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