A Novel Gradual Expansion Convergence Hole Flow Conditioner Design to Eliminate Eccentric Jet Flow in an Ultra-High-Pressure Angle Valve

Abstract

Ultra-high-pressure angle valves are critical components in hypersonic wind tunnels for regulating pressure and mass flow, where outlet-flow uniformity directly affects measurement accuracy and service life. Under inlet-to-outlet pressure differences up to 100 MPa, the internal flow becomes strongly inertia dominated, with Reynolds numbers on the order of 107, generating a violent eccentric jet driven by highly non-uniform pressure gradients. This eccentric jet causes severe localized erosion in downstream piping and persistent flow non-uniformity that cannot be effectively mitigated by conventional flow-to-close valve designs. To address this challenge, a novel gradual expansion convergence hole flow conditioner is proposed to suppress the eccentric jet and rapidly restore a uniform outlet flow within a compact downstream length. Parametric analyses show that gradual expansion holes enhance pressure-driven entrainment, redirecting the biased jet toward the orifice center, while the convergent angle promotes cross-stream momentum exchange and suppresses wake formation. The synergistic action of these mechanisms enables efficient jet rectification under strongly inertia-controlled conditions. An orthogonal optimization identifies the optimal configuration. For the optimized design, the velocity-uniformity coefficient Cs exceeds 85% and the flow-direction uniformity Cθ exceeds 90% as early as X=3D downstream. At X=3D, Cs reaches 89.2% and Cθ reaches 93.4%, corresponding to improvements of 18.91% and 14.36% relative to the valve without a flow conditioner, and 6.86% and 5.81% compared with a conventional Laws flow conditioner.