Reed valves are a type of check valve commonly found in a wide range of applications including air compressors, internal combustion engines, and even the human heart. While reed valves have been studied extensively in these applications, published research on the modeling and application of reed valves in hydraulic systems is severely lacking. Because the spring and mass components of a reed valve are contained in a single element, it is light and compact compared to traditional disc, poppet, or ball style check valves. These advantages make reed valves promising for use in high frequency applications such as piston pumps, switch-mode hydraulics, and digital hydraulics. Furthermore, the small size and fast response of reed valves provide an opportunity to design pumps capable of operating at higher speeds and with lower dead volumes, thus increasing efficiency and power density. In this paper, a modeling technique for reed valves is presented and validated in a hydraulic piston pump test bed. Excellent agreement between modeled and experimentally measured reed valve opening is demonstrated. Across the range of experimental conditions, the model predicts the pump delivery with an error typically less than 1% with a maximum error of 2.2%.
Reed valves are a type of check valve commonly found in a wide range of applications including air compressors, internal combustion engines, musical instruments, and even the human heart. While reed valves have been studied extensively in these applications, published research on the modeling and application of reed valves in hydraulic systems is sparse. Because the spring and mass components of a reed valve are contained in a single element, it is light and compact compared to traditional disk, poppet, or ball style check valves. These advantages make reed valves promising for use in high-frequency applications such as piston pumps, switch-mode hydraulics, and digital hydraulics. Furthermore, the small size and fast response of reed valves provide an opportunity to design pumps capable of operating at higher speeds and with lower dead volumes, thus increasing efficiency and power density. In this paper, a modeling technique for reed valves is presented and validated in a hydraulic piston pump test bed. Excellent agreement between modeled and experimentally measured reed valve opening is demonstrated. Across the range of experimental conditions, the model predicts the pump delivery with an error typically less than 1% with a maximum error of 2.2%.
Boundary-layer instabilities for a finned cone at Mach = 6, Re = 8.4 × 10 6 [ −1 ], and zero incidence angle are examined using linear stability methods of varying fidelity and maturity, following earlier analysis presented in [1]. The geometry and laminar flow conditions correspond to experiments conducted at the Boeing Air Force Mach 6 Quiet Tunnel (BAM6QT) at Purdue University. Where possible, a common mean flow is utilized among the stability computations, and comparisons are made along the acreage of the cone where transition is first observed in the experiment. Stability results utilizing Linear Stability Theory (LST), planar Parabolized Stability Equations (planar-PSE), One-Way Navier Stokes (OWNS), forced direct numerical simulation (DNS), and Adaptive Mesh Refinement Wavepacket Tracking (AMR-WPT) are presented. A dominant three-dimensional vortex instability occurring at ≈ 250 kHz is identified that correlates well with experimental measurements of transition onset. With the exception of LST, all of the higher-fidelity linear methods considered in this work were consistent in predicting the initial growth and general structure of the vortex instability as it evolved downstream. Some of the challenges, opportunities, and development needs of the stability methods considered are discussed.
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