Fluid Power Teaching and Research, Purdue University, West Lafayette, Indiana, USA

Location West Lafayette, Indiana USA
Contact Person Prof. Gary Krutz
Address Purdue University
Agricultural & Biological Engineering
225 So. University Street
West Lafayette, IN 47907-2065
Telephone number +1 765-494-1179
Fax number +1 765-496-1115
Email krutz@ecn.purdue.edu
Internet Site http://www.purdue.edu/abe

From Editor

International Journal of Fluid Power would like to introduce the fluid power research and education centres with their expertise and particular interests in this column. Jumping from continent to continent we like to offer every research centre the opportunity to present itself.


FLUID POWER RESEARCH CENTRES WORLD-WIDE

General Information

Building on its traditional strengths in engi-neering and agriculture since its founding in 1869, the West Lafayette Campus today offers nearly 6,100 courses in more than 200 specializations through the schools of agriculture, consumer and family sciences, education, engineering, health sciences, liberal arts, management, nursing, pharmacy and pharmacal sciences, science, technology, and veterinary medicine. Programs of graduate study and research leading to advanced degrees are organized through the Graduate School.

Purdue is one of the largest four-year universities in the country, with 38,564 students enrolled in fall 2002 on its West Lafayette Campus. Purdue also offers degrees at four regional campuses and 11 School of Technology sites statewide, bringing its system wide enrollment to 67,548.

When Purdue opened its doors in 1874, five years after its founding, the original faculty of six greeted 39 students. By fall 2000 totals, approximately 2,300 tenured and tenure-track faculty members contribute to Purdue’s excellence in teaching and research throughout the University system. With more than 16,000 faculty and staff, Purdue also is one of the state’s largest employers.

The Purdue University system today is a vital educational, research, and outreach enterprise. More than 38,000 students from all 50 states and about 100 countries study at the West Lafayette Campus, and more than 29,000 are enrolled at other campuses and locations. The University attracts more international students than any other public research university in America. Highly regarded in national surveys, Purdue is ranked among the top public universities in the nation, according to U.S. News & World Report.

More than 320,000 living Purdue alumni have made their marks in a vast range of fields - the first and last men on the moon are alumni; more Forbes 800 CEOs graduated from Purdue than from any other public university; and alumni of note have key roles in business, academia, education, politics, science, industry, media, and the arts.


Computational Fluid Dynamics

Fluid power research in the School of Mechanical Engineering at Purdue has focused on two main activities. First, computational fluid dynamics modelling of three-dimensional valve flow fields have been performed and compared to particle-imaging velocimetry laboratory measure-ments in a transparent valve. Results are being studied to optimize valve flow fields with regard to pressure drop, noise, and cavitation. These simulations have employed the commercial code FLUENT and have used state-of-the-art turbulence and cavitation models.

Second, we have developed a three-dimensional cavitation code based on the large eddy simulation technique for studying vortex cavitation inception in turbulent flows. In particular, we have conducted a series of simulations exploring cavitation incep-tion in submerged jets, as a paradigm for more complex valve flows. Various passive and active control strategies, such as the use of non-circular nozzles, swirl, and acoustic forcing, are being ex-plored to control cavitation. Details of the model and its application to two-dimensional submerged laminar jets can be found in Xing, T., and Frankel, S. H., "Effect of Cavitation on Vortex Dynamics in a Submerged Laminar Jet", AIAA Journal, in press, expected publication date November 2002.

The Maha project is focusing on developing an experimental test stand which can be used to demonstrate cavitation phenomena in hydraulic applications. In particular, we are currently selecting the test geometry and considering the classic example of a backward facing step or sudden expansion flow. A transparent model will be set up in the laboratory and advance laser diagnostics will be used to help characterize the flow field. A companion study will employ computational fluid dynamics models to predict the flow. The effects of expansion geometry and inlet flow conditions will be explored as a means of addressing cavitation control. Development of the facility and application of the models is currently underway.


Non-Metallic Components

The progression of polymer and composite science has brought about many useful engineering polymers and composites. The use of these advanced materials continues to rise. This can be attributed to both cost and performance advantages. These components have the ability to be produced at high rates due to production techniques such as injection molding and filament winding which can minimize or eliminate subsequent machining operations. Superior coefficients of friction, weight, and corrosion resistance coupled with manufacturing advantages makes an overwhelming case for the development of new fluid power components that utilize polymers and composites.

Companies such as Polygon Company have taken the first steps in new composite cylinders that can outperform steel and aluminum cylinders. Applications of non-metallic cylinder where corrosion resistance, weight or system compatibility may have prohibited the use of fluid power, the development of a non-metallic cylinder assembly can overcome these and other limitations to expand the use of fluid power.


Fig. 1: Proposed Purdue University cavitation test bench


Electro hydraulic Valve Design

The Agricultural and Biological Engineering Department at Purdue University is currently working on designing revolutionary new concepts in hydraulic valve design and actuation. These concepts will lead to increased efficiencies in mobile hydraulic systems, as well as decreased energy con-sumption from actuating and controlling the hydraulic valves that comprise much of the hydraulic system. This is being done by considering new designs and ideas relating to the internal workings of hydraulic valves. Some benefits of the designs include fast response times, as well as low internal leakages from the valve. The results of these designs also allow new, more energy conservative actuation methods to be utilized that are alternative methods to the technology of today. The methods proposed are also creating better abilities to accu-rately control the valves, resulting in more accurate flow metering and total system control. The re-search has produced valves that utilize inexpensive actuation devices, while enabling the user to have a high level of control over the valves.


Energy Savings Devices

Energy Savings has become a pressing issue of off-road vehicles as well as more recent interest in the passenger vehicle applications. Industry has realized that energy savings devices will make vehicles more efficient and lead to a higher demand by the consumers purchasing these vehicles.

Many systems that can be used on off-road equipment are too large for most of the applications on passenger cars. Industry is now considering new applications such as everyday passenger vehicles. The major part of the current research in energy savings is how to make these systems more efficient so that we can expand their use and effectiveness. There are many new accumulator and circuit designs that are being considered to create a more efficient systems with more efficient use of the volume that it contains. Results thus far have shown that there is a fine line between costs and true energy savings.


Hydraulic Components Modelling

As an effort to improve the control of hydraulic cylinders, research has been made to study their vibration properties at different operating points. Most of the control strategies available for electro hydraulic control require the rod position as a feedback. The sensors available on the market are not suitable for agricultural applications. External sensors are exposed to potential impacts or damage due to the normal operation of the machines. Internal sensors, although are accurate in measuring they result very expensive and difficult to manufacture. The design of a non-intrusive sensor based on the vibration characteristics of the hydraulic cylinder is being explored at the Agricultural and Biological Engineering Department of Purdue University.

Utilizing Finite Element Analysis, Experimental Modal Analysis and developing mathematical models, the elastic properties of the hydraulic cylinder are being explored. The goal of the project is to create a model of the cylinder that can be used to improve the hydraulic cylinder and seal design. Also it intends to be a base for the design of a non-intrusive position sensor that will be used in the feedback of the control algorithms.

In order to reduce the cost of designing a new product, electronic simulation packages, such as EASY5, can be used to determine the behavior of the system in question prior to construction of the system. One such application of this idea is for hydraulic systems. However, this cannot be done without knowing the behavior of the individual components that will be used in the system. In order to obtain this knowledge, the Agricultural and Bio-logical Engineering Department at Purdue University is developing a hydraulic test bench that is capable of dynamically modeling various hy-draulic components.


Fig. 2: Pro/E model of hydraulic test stand


Three key parameters are involved in the modelling of hydraulic components. In order to model the flow of the hydraulic medium, temperature, flow, and pressure data must be acquired at the inlet and outlet of the component under investigation. Besides these flow parameters, data must be acquired concerning the physical work output of the unit, such as the linear position of a cylinder or the torque output of a motor. Furthermore, accurate modelling of components requires compensation for the viscosity of the fluid as the temperature changes. As the temperature increases, the fluid viscosity decreases and can cause the flow meters to read inaccurately. Thus, viscosity compensation is used when acquiring the flow data. Through the use of pressure transducers from Wika, thermocouples from All-Temp Sensors, and Flow Technology turbine flow meters, this stand will acquire the necessary data to model a wide range of hydraulic components.


Research Topics

Current fluid power research topics include: system simulation, energy savings, component modeling and development, water hydraulics, sensor development, controls - adaptive, fuzzy, and robust, vibration analysis and usage, noise modeling and reduction, and CFD simulation and testing.


Purdue University Faculty


Current Fluid Power Courses

Classes, tours, and short courses have 3,000 contacts in fluid power per year. Agricultural & Biological Engineering teaches an ABET accredited engineering 3-credit course 435 "Hydraulic Control Systems".
Agricultural & Biological Engineering also teaches fluid power to non-engineers in Ag Systems Management 104, 201, and 345. Mechanical Engineering has the basic 4-credit fluid mechanics course (309) and a graduate Computation Fluid Dynamics class (614). Mechanical Engineering Technology teaches Fluid Power (230), Advances Fluid Power (334), Pneumatic Motion Control Systems (435) and Hydraulic Motion Control System (432).
All departments plan new courses in fluid power and offer controls related classes.
See Purdue’s web site for course details.
http://www.purdue.edu, or http://pasture.ecn.purdue./~ehcenter, or http://fluid.power.net.


MAHA DISTANCE EDUCATION CENTER

http://pasture.ecn.purdue.edu/~maha


Distance Learning Courses


Goals


INTELLIGENT AND PRECISION CONTROL LABORATORY

Affiliated with Ray W. Herrick Laboratories - Professor Bin Yao/G. Chio

Research Focus


Applications



Fig. 3: Purdue Programmable Valve (School of Mechanical Engineering, Purdue University photo)



Fig. 4: Motion Control of Hydraulic Arm (School of Mechanical Engineering, Purdue University photo)


Overall Strategies



Fig. 5: Water Hydraulics Test Stand



Fig. 6: Parker Lab in Purdue’s Agricultural & Bio-logical Engineering Department


Water Hydraulics

The use of water hydraulics has many viable opportunities in industrial and mobile hydraulic applications. Current pursuits by water hydraulic manufactures include the food processing and paper production industries, chemical and pharmaceutical producers and agricultural and lawn care equipment. We at Purdue University feel that water hydraulics is a very exciting emerging technology and have recently undertaken several research projects related to the field of water hydraulics, including water hydraulic controls development and water-based power transmission.


Fig. 7: Water Hydraulic Greens Mower Vehicle (2001)

 

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