This paper deals with the attenuation characteristics of expansion chamber-type hydraulic pulsation absorbers, especially taking into consideration the pulsation of the delivery flow of pumps.
In carrying out experiments, a rotary spool-type hydraulic vibration machine capable of producing a sinusoidal pulsating flow of large amplitude up to about 800 Hz was recently developed, which enables accurate experiments covering a wide frequency range from the 1st to the 3rd pulsation components of common pumps.
After dividing the components of the absorber into circular pipe elements, the transfer matrix method is used to predict the attenuation characteristics.
The following results were obtained:
(1) The calculated values, obtained by applying the wave equation of two-dimensional viscous flow to all divided circular pipe elements and inlet and outlet conduits, agree well with the experimental values, except for some in the frequency range for which mechanical vibration cannot be disregarded.
(2) It is possible to treat fluid motion in an absorber as a lumped parameter system, since the lengths of the expansion chamber and connecting conduit in the absorber are, in general, fairly short compared with the corresponding wave length of the pulsation frequency of the pump.
(3) The approximate equation, which represents effects of the inlet conduit, the outlet conduit and the absorber independeals, . is accurate enough for practical use in the case of high loads.