A mathematical model of the self-averaging Pitot tube

Flowmeters with self-averaging Pitot tubes are more and more often applied in practice. Their advantages are practically no additional flow losses, usability in the case of high temperature of fluids and simplicity of fitting. A mathematical model of a self-averaging Pitot tube including the influence of the probe shape, selected constructional features and flow conditions on the quantity of differential pressure gained has been given in this paper. The values and ranges of variations of the coefficients established for the model have been assessed on the basis of the numerically computed velocity and pressure fields around and inside the probe. Velocity and pressure fields were calculated by means of solving conservation equation and turbulence models. The characteristics linking values of the flow coefficient with values of the Reynolds number have been presented. The conclusions have been formulated taking flow metrology needs into account.