The source admittance method A new measurement method for hydrostatic pump flow pulsation
2006 (English)In: Proc. of the 4th FPNI - PhD Symposium Sarasota, Vol 1, Sarasota: Coastal Printing , 2006, 297-309 p.Conference paper, Presentation (Refereed)
Two main drawbacks with hydraulic systems are noise and vibrations, mainly created from flow pulsations in positive displacement pumps. The flow ripple can be divided in two parts; kinematic and compressible. Kinematic flow ripple is created due to the limited number of pumping elements. Compressible flow ripple is created due to cornpressibility effects in the pumping chambers and is the dominating effect at high pressures. There are well proven methods to decrease noise in specific operation conditions, but there is an urgent need for new techniques in machines working under varying operation conditions. There is also a need for improved measurement methods to be used in product development and to judge new inventions to decrease noise.
Simulation techniques are useful in the early stages of the development process. There are useful and accurate simulation models capable of predicting source flow ripple in hydrostatic pumps and thereby useful for optimisation purposes. Simulation results are, however, of less practical use before they are experimentally verified . The experimental methods must be simple and straightforward if they are to be accepted in industry.
This paper describes a new method to measure source flow. It is called the source admittance method. Compared to earlier methods such as the two-microphone method, the main benefit is that there is no need for a model of the outlet channel - the source flow is measured through an additional pressure transducer inside the pump. The method works very well with a tested fixed bent-axis pump with a rather simple outlet channel. Experiments have also been performed with a variable in-line pump with added complexity to the out let channel. Although the overall impression is positive, these experiments show that the method needs to be further to be used for such machines. In both cases, the new method is compared with earlier verified simulation models and with measurements based on the two-microphone method. Apart from the mentioned discrepancies in a narrow frequency range, agreement is very good.
Place, publisher, year, edition, pages
Sarasota: Coastal Printing , 2006. 297-309 p.
Flow pulsations, measurement, hydrostatic pump, two-microphone method
Engineering and Technology
IdentifiersURN: urn:nbn:se:liu:diva-36611Local ID: 31745ISBN: 1-4243-0499-7OAI: oai:DiVA.org:liu-36611DiVA: diva2:257460
4th FPNI - PhD Symposium Sarasota. Sarasota, Fl, US, June 2006.