Influence of bluff body shape on wall pressure distribution in vortex flowmeter

Abstract

To investigate the influence of bluff body shape on wall pressure distribution in a vortex flowmeter, experiments were conducted on a specially designed test section in a closed water rig at Reynolds numbers of 6.2×10⁴-9.3×10⁴. The cross sections of the bluff bodies were semicircular, square, and triangular shaped, and there were totally 21 pressure tappings along the conduit to acquire the wall pressures. It is found that the variation trends of wall pressures are basically identical regardless of the bluff body shapes. The wall pressures begin to diverge from 0.3D (D is the inner diameter of the vortex flowmeter) in front of the bluff body due to the diversity in shape, and all reach the minimum values at 0.3D behind the bluff body. A discrepancy between the triangular or square cylinder and the semicircular cylinder in wall pressure change is observed at 0–0.1D behind the bluff body. It is also found that the wall pressures and irrecoverable pressure loss coefficients increase with flow rates, and the triangular cylinder causes the smallest irrecoverable pressure loss at a fixed flow rate.

Keywords

vortex flowmeter / bluff body shape / wall pressure / irrecoverable pressure loss

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