Flow averaging tube geometry improvement for K-factor stability increase

Fluid flow around two-profile averaging differential pressure sensor was investigated in this paper. Research concentrated particularly on fluid movement direction and velocity over the investigated flow sensor. Analysis was conducted experimentally in low velocity wind tunnel. Because of large number of measuring points placed very close to each other, it was decided that velocity profile measurement will be performed by means of fully automated test stand. Due to a recirculation of the stream in the vicinity of the probe tested in the wind tunnel, an original two-direction probe was used. A linear module with a stepper motor formed an integral part of the measurement system. The location of the measuring probe, the possibility of adjusting stream mean velocities and data acquisition was undertaken by means of a dedicated program. The above mentioned investigation method helped to improve the metrological properties of the flowmeter applying non symmetrical probe cross-section forced air stream to be redirected in the desired direction. This modification significantly increased K-factor value and stability of air flow through the contraction of the flowmeter.