classic | mobile
 

Search...

 

Nanoscale hydraulics
1st Quarter 2017, This Week's Editor's Pick, Hydraulic systems & components


The properties of hydraulic fluids can have a major impact on the efficiency, performance and life of machines. Mechanical losses at low speed impact the design pressure and displacement requirements of hydraulic machinery. Leakage flow losses at high pressure and temperature impact productivity and cooling requirements. Manufacturers currently use standard chemical laboratory methods to develop new formulations using various polymers, but change is afoot. Now researchers at the University of California, Merced (UC) and the Milwaukee School of Engineering Fluid Power Institute are aiming to understand the interactions of hydraulic fluids at the molecular level through a combination of mechanical testing and molecular modelling. This could lead to the development of more efficient fluid power systems.

Motion Control’s editor caught up with UC Professor of Mechanical Engineering, Ashlie Martini, to find out more about the Simulation, Rheology and Efficiency of Polymer Enhanced Solutions project. “Our goal is to bridge the gap between the fundamental behaviour of polymer-enhanced hydraulic fluids and the performance of complex fluid power systems,” she says. “We aim to understand how polymer structure affects hydraulic power transmission. Specifically, we are trying to connect hydraulic power transmission efficiency to fluid rheology and then rheology to fluid molecular structure in pursuit of formulating more efficient hydraulic fluids.”

Polymer additive structure and chemistry can significantly affect hydraulic efficiency. Increased high temperature viscosity decreases internal pump flow losses under high temperature conditions; reduced traction decreases mechanical losses in pumps at high speeds; and drag reduction reduces pressure drop across valves and through hoses and tubes in the hydraulic circuit.

Two types of mechanical experiments are under way. Firstly, the researchers measure the viscosity of polymer-enhanced hydraulic fluids using a benchtop rheometer. Secondly, they use a dynamometer to measure flow losses (efficiency loss) in a hydraulic system running with these polymer-enhanced fluids. Dynamometer testing assesses the effects of fluid properties on flow and torque losses in an open-loop hydraulic system.

A key element of the research is the use of molecular dynamic simulation (MDS), which can provide insights into the fundamental behaviour of polymers in hydraulic fluids. This is a nanoscale modelling tool that examines the effects of polymer structure on solution viscosity and compressibility at the nano level. It is used to describe how positions, velocities and orientations of molecules change over time and it involves the numerical solution of the classical equations of motion for every atom in a material, giving the position, force and velocity as a function of time. The total force acting on an atom comes from its interaction with other atoms and external fields, and an accurate model to describe atomic interactions is critical in any MDS. It is a computational experiment where a system is defined, allowed to evolve and then observations made based on its evolution. MDS is typically applied in areas like materials science and biochemistry and Martini believes that this is the first time the technique has been used in the fluid power field.

Martini adds that this is the first time a study has attempted to combine molecular scale modelling with hydraulic efficiency measurements in an attempt to quantify the critical connection between the two. The researchers hope to develop a rational basis for the formulation of hydraulic fluids that leads to more efficient hydraulic machinery with reduced friction and leakage flow losses. “We will model the same polymer-enhanced fluids for which we are meas-uring viscosity and flow loss experimentally. However, the simulations will provide molecular scale detail into how those fluids respond to shear and increased temperature. In this way, we hope to be able to explain the experimentally observed trends in terms of the behaviour of the polymers themselves,” she explains.

“Characterising polymer solutions at multiple length scales and using several complementary techniques makes possible a better understanding of the relationship between molecular structure and the behaviour of fluids in hydraulic machines. If we can understand how a polymer additive’s structure and chemistry affect its response to shear and temperature, and then correlate this with hydraulic efficiency, this research can set the foundation for designing polymeric additives that can improve the efficiency of hydraulic components,” she concludes.


Share via email     Print this page  

Further reading:

  • A revolution in automation
    3rd Quarter 2017, Festo, This Week's Editor's Pick, Pneumatic systems & components
    All this is made possible by the latest developments in piezo technology and associated software. Just as the smartphone turned the mobile communication market on its head a decade ago, so too Festo’s ...
  • Siemens software for high performance bikes
    3rd Quarter 2017, Siemens Digital Factory & Process Ind. & Drives, This Week's Editor's Pick, Electrical switching & drive systems & components
    Bike manufacturer develops high performance bikes with Solid Edge from Siemens PLM Software.
  • Thirty years of innovation
    3rd Quarter 2017, The Hydraulic Centre, Hydraulic systems & components
    With the introduction of the third tier Dynamische range of hydraulic products, THC can also offer reasonably priced products with exceptional quality and performance – the best value in the industry. ...
  • Drives and motors in automotive test rigs
    3rd Quarter 2017, Nidec Industrial Automation Southern Africa, This Week's Editor's Pick, Electrical switching & drive systems & components
    Regenerative drives are also often used, so that the drive is able to regenerate electric power when the motor is absorbing energy or providing a load, returning this energy to the supply and reducing ...
  • NASA relies on maxon technology
    3rd Quarter 2017, DNH Tradeserve, This Week's Editor's Pick, Electrical switching & drive systems & components, Robotics & Mechatronics
    Swiss drive specialist, maxon motor will supply several drives specifically developed for the task to the Jet Propulsion Laboratory, which is building the Mars 2020 rover for NASA. The maxon drives are ...
  • Innovation goes hand in hand
    3rd Quarter 2017, Horne Technologies, This Week's Editor's Pick, Robotics & Mechatronics
    To make daily life easier, the British company Steeper has developed the bebionic myoelectric hand prosthesis. This is controlled by myoelectric signals generated from muscle contractions in the arm, ...
  • Easy plant automation with Contactless Energy Transfer
    3rd Quarter 2017, SEW-Eurodrive, This Week's Editor's Pick, Electrical switching & drive systems & components
    SEW-Eurodrive’s Movitrans Contactless Energy Transfer system is based on inductive energy transfer, whereby electrical energy is transferred without contact from a fixed conductor. The electromagnetic ...
  • Mobility of the future
    3rd Quarter 2017, Horne Technologies, This Week's Editor's Pick, Electrical switching & drive systems & components
    In celebration of its 100th anniversary, the BMW Group commissioned the development of the Iconic Impulses exhibition, which looks ahead to the future: ‘What will mobility look like in the next 100 years? ...
  • XTS drives toothbrush packaging line
    3rd Quarter 2017, Beckhoff Automation, This Week's Editor's Pick, Electrical switching & drive systems & components
    Koch Pac-Systeme in Pfalzgrafenweiler, Germany, is a specialist in customer-specific blister packaging machines and systems and has again proven its expertise with an innovative and complex new packaging ...
  • From the President’s desk: SAFPA reaches out with new qualifications
    2nd Quarter 2017, SA Fluid Power Association (SAFPA), This Week's Editor's Pick, SAFPA
    SAFPA’s training initiative to develop properly accredited fluid power qualifications for the industry has made significant progress. Motion Control’s editor recently paid a visit to the training service ...
  • Innovation for mechanical engineering
    2nd Quarter 2017, Beckhoff Automation, This Week's Editor's Pick
    Beckhoff’s eXtended Transport System (XTS) has found its way into numerous new machines supporting the development of innovative automation concepts in a diversity of forms, from simple to highly complex.
  • A new chapter for hydraulics
    2nd Quarter 2017, This Week's Editor's Pick, Hydraulic systems & components
    A new groundbreaking technology could change the face of hydraulics – digital displacement technology (DDT).

 
 
         
Contact:
Technews Publishing (Pty) Ltd
1st Floor, Stabilitas House
265 Kent Ave, Randburg, 2194
South Africa
Publications by Technews
Dataweek Electronics & Communications Technology
Electronic Buyers Guide (EBG)

Hi-Tech Security Solutions
Hi-Tech Security Business Directory

Motion Control in Southern Africa
Motion Control Buyers’ Guide (MCBG)

South African Instrumentation & Control
South African Instrumentation & Control Buyers’ Guide (IBG)
Other
Terms & conditions of use, including privacy policy
PAIA Manual





 

         
    classic | mobile

Copyright © Technews Publishing (Pty) Ltd. All rights reserved.