Development research of reflection-absorption compound type fluid pulsation attenuator
Based on the disadvantages analysis of the existing fluid pulsation attenuator, two reflection-absorption compound type of fluid pulsation attenuators which are both composed of a chamber and a mass-spring-damping system are developed: in-line reflection-absorption compound type of fluid pulsation attenuators (in-line RAFPA) and side-branch reflection-absorption compound type of fluid pulsation attenuators (side-branch RAFPA). The transfer matrix models of the two attenuators are established as well as expansion chamber attenuator and Helmholtz resonator. Based on the transfer matrix model, the transmission loss of the four attenuators is given out to evaluate their attenuation characteristic. The attenuation characteristic comparisons of in-line RAFPA with expansion chamber attenuator and side-branch RAFPA with Helmholtz resonator are carried out respectively. And the effect of the mass-spring-damping system to in-line RAFPA and side-branch RAFPA is investigated. The simulation reveals the two reflection-absorption compound type of fluid pulsation attenuators have better attenuation characteristic and are more compact than expansion chamber attenuator and Helmholtz resonator.
Investigation of the pulsation-reduction characteristics of an expansion chamber attenuator in a hydraulic system
This paper investigates the expansion chamber attenuator utilized in marine hydraulic systems to determine the pulsation-reduction characteristics in hydraulic deck machinery applications. First, the background is briefly introduced. Next, the advantages and disadvantages of investigation methods borrowed from the aerodynamic field are discussed with regard to hydraulic use. Insertion loss is eventually selected to evaluate the performance of the attenuator. Finally, attenuator prototypes and a test rig that simulates an actual marine hydraulic system in a vessel are manufactured, and the experimental conditions are introduced in detail to calculate and measure the insertion loss. As indicated by the investigation conclusion, mathematic computation generally fits the test results. A better choice of length–diameter ratio ranges and other characteristics are discussed. This paper provides theoretical and experimental evidence regarding design expansion chamber attenuator use in hydraulic systems.
New Method for Experimental Determination of Hydraulic Pump Fliud-borne Vibration Characteristics. 1st Report. Principle of New Method.
All positive displacement pumps generate a flow ripple, which interacts with the characteristics of the circuit connected to produce a fluid-borne vibration. This may be the major source of the overall system noise level as well as the major cause of vibration of the system components. Consequently, to predict accurately the fluid-borne vibration generated in a system during the design stage, and to reduce it and produce quieter systems, it is necessary first to understand and quantify the fluid-borne vibration characteristics of positive displacement pumps as well as the wave propagation characteristics of pressure ripple in system components. In this paper, the measuring procedure referred to as the “2 pressures/2 systems” method has been newly devised for experimental determination of the fluid-borne vibration characteristics of hydraulic pumps. This method has great merit in that the flow ripple and source impedance of the pump can be evaluated just by the analysis of the wave propagation characteristics of pressure ripple in the reference pipe alone, which is just a part of the discharge line adjacent to pump exit, i.e., there is no necessity for evaluating the characteristics of any piping elements other than the reference pipe. Thus, not only the hydraulic test circuit and calculation procedure become very simple compared to the former methods (in which the characteristics of all piping elements have to be evaluated or predicted analytically in advance) but also the tests can be performed very quickly.