• Friday, March 17, 2017 - 01:00
  • University of Trieste, Aula A (Giorgieri) Edificio C7 (ex-Macchine)

Seminar "Key aspects in design and modeling of positive displacement machines"

ESTECO Academy proudly presents the seminar "Key aspects in design and modeling of positive displacement machines", organized by the University of Trieste, Faculty of Engineering and Architecture, to be held in Trieste on Friday, March 17th.

Andrea Vacca, associate professor at Purdue University specialized in fluid power technology, will introduce the participants into the most popular design for positive displacement machines for high-pressure applications.

The seminar will illustrate the following:

  • The flow non-uniformity as the main source of noise emissions.
  • The lubricating gaps as the main source of power loss due to leakage and fluid shear.
  • The thermal-fluid-structure interaction modeling approach developed at Purdue University for the internal lubricating gaps.
  • Several simple examples of virtual prototyping through software optimization.

The seminar is open both to students and researchers of University of Trieste, as well as to external visitors with free admission upon registration.



This seminar will first introduce the most popular designs for positive displacement machines for high-pressure applications. The most important aspects that determine the efficiency, the reliability and the level of noise emissions of each design solution will be illustrated. In particular, the non-uniformity of the port flow constitutes the main source of fluid borne noise, while the internal lubricating gaps present in all these units represent the most important source of power loss due to leakage and fluid shear. Pumps and motors for high-pressure applications often utilize pressure compensation techniques to achieve minimum gaps thicknesses while also avoiding contacts between internal parts. 
The modeling of such internal lubricating interfaces involves the use of proper thermal-fluid-structure interaction modeling techniques to account for the effect of the material deformation and the viscous dissipation of the working fluid. The seminar will illustrate the main features of the simulation approach formulated by Dr. Vacca’ team at Purdue University (Fig. 1), along with validation against experimental results.

The last part of the seminar will present some significant examples of virtual prototyping, in which the simulation models previously introduced are used within properly designed optimization schemes to achieve the best desired performance. 

Aula A (Giorgieri) Edificio C7 (ex-Macchine)

09:15 - 09:30 AM Introduction to the seminar by prof. Carlo Poloni 
09:30 - 10:15 AM Andrea Vacca: "Key aspects in design and modeling of positive displacement machines"


Admission is free and open to all.


Associate Professor, Purdue University
In 1999 Andrea Vacca earned his Master's degree - with honors - in Mechanical Engineering from the University of Parma (Italy) and his doctorate in Energy Systems from the University of Florence (Italy) in 2005. For both degrees he presented theses in the field of Heat Transfer and Gas Turbine Blade Cooling Technology. Before joining Purdue University as Assistant Professor in 2010, Prof. Vacca was Assistant Professor of Fluid Machinery at the University of Parma (Italy).
In 2014, he was promoted to the role of Associate Professor, with joint appointment between Purdue Agricultural and Biological Engineering and Purdue Mechanical Engineering.
Prior to his arrival to Purdue, Prof. Vacca participated in various research activities related to the fields of internal combustion engines, food technology, and hydraulic systems.
Fluid power technology has been Prof. Vacca's major research interest since 2002. Particular goals of his research are the improvement of energy efficiency and controllability of fluid power systems and the reduction of noise emissions of fluid power components. To accomplish the goals of his research, his research team has developed original numerical and experimental techniques to simulate fluid power systems and components, especially for gear machines and hydraulic control valves. Prof. Vacca's interests also include the modeling of the properties of hydraulic fluids, with particular focus on the effects of aeration and cavitation, as well as the use of low viscous fluids (such as water) in fluid power systems.
Prof. Vacca is the author of more than 80 papers, most of them published in international journals or conferences. He is also active in the fluid power research community. He is a faculty member of the Center for Compact and Efficient Fluid Power (CCEFP), and he is currently chair of the SAE Fluid Power division. Prof. Vacca is also Treasurer and Secretary of the Board of the Fluid Power Net International (FPNI). Furthermore, he is an Executive member of the Fluid Power Systems and Technology Division (FPST) of ASME. He is also Associate Editor of the International Journal of Fluid Power.