Experimental and numerical investigations of overlapping function in enhancing flow continuity for reciprocating-switcher energy recovery device

Abstract

For reciprocating-switcher energy recovery device(RS-ERD), there still exists a significant flow discontinuity during the periodical stroke switching of the device, which causes broad fluid pulsations and additional energy dissipation. To enhance the continuity, overlapping function was structurally built in the switcher of RS-ERD, and was experimentally and numerically investigated under three overlapping distances(0 mm, 6 mm and 12 mm). The experimental results showed that, compared to 0 mm overlapping distance, the pulsations in pressure loss and flowrate of high pressure fluid decreased by 62.82% and 26.92% respectively for 6 mm overlapping distance at the operating condition of 6.0 MPa and 30 m3/h. For 12 mm overlapping distance, the corresponding pulsations were further reduced by 98.72% and 90.77%. Thanks to the overlapping function, the power dissipation for each stroke switching unit decreased by 65.23%(in 6 mm) and 99.00%(in 12 mm) in comparison to 0 mm overlapping distance, which significantly declined the self-energy consumption of RS-ERD. The decreases in the pulsation amplitudes and energy dissipation can be attributed to the overlapping of opening degree in valve plates, which achieves the reduction of the local flow velocity and flowrate variation rate in switching. The research results provide a new approach to strengthen the operational stability of RS-ERD.