Design and Research of Large-Scale Reciprocating Clearance Seal Test Rig

With the development of sealing technology, gap sealing is progressing towards high-flow, high-pressure, and low-viscosity. Due to its low friction coefficient and high material limit pv value, it is the preferred sealing solution for high-pressure and high-flow plunger pumps. However, when large-scale annular gap seals are used, issues such as elastic deformation, variations in fluid density and viscosity, and flow state transitions caused by high-pressure fluids become particularly prominent, making leakage prediction challenging. To investigate the leakage characteristics of large-scale dynamic gap seals, a gap sealing test bench with a double plunger pressure balance structure was designed and constructed in this study, which can significantly reduce driving power and experimental costs. The working principle and design specifications of the sealed test bench are described in detail, including the structure and parameter design of the flow testing device, water hydraulic system, hydraulic system, and control system. Through experimentation, the leakage characteristics of annular gaps with different pressure, clearance values, and sealing lengths were thoroughly examined, revealing the relationship between annular gap leakage and pressure, sealing clearance, and sealing length. The results suggest that the critical Reynolds number for the transition from laminar to turbulent flow in a large-scale annular gap falls within the range of 718–899. The findings from this study can serve as a reference for evaluating the performance of gap sealing, thereby establishing a foundation for the theoretical design and product development of high-pressure, large-flow plunger pumps.