Pitot tube designs for compressible and incompressible fluid flow with viscosity and turbulence

摘要

This invention presents a Pitot tube design and methodology for determining the flow characteristics of fluids in subsonic and supersonic flow, including the effects of viscosity and turbulence. A new methodology, the Two-Fluid Theory, is developed which treats a real fluid as being composed of two ideal fluids: an inviscid fluid and a Poiseuille fluid. The resulting expression for flow velocity is applicable to a real fluid of any viscosity and to pipes of any L/D ratios, including entrance effects.;Two designs, comprising annular, smooth-bore tubes, with devices for measuring total and static pressures, are presented: one for incompressible flow; one for compressible, supersonic flow. Allowance is made for the viscous component of the flow to become fully developed, in accordance with the Theory.

主权项

1. this invention provides for two Pitot tube designs: one for incompressible, subsonic fluid flow; the other for compressible, supersonic fluid flow; that the designs are comprised of hollow tubes of length 10 cm and internal diameter 0.5 cm, opened at one end to the flow field; connected to pressure measuring devices at the opposite ends of the devices to measure total pressures; surrounded by annuli of 0.25 cm differential radii, sealed at both ends and connected to pressure measuring device to measure static pressures; small bore holes are positioned around the circumferences of the annuli and 1 cm from the flow entrances in accordance with a new theory, the Two-Fluid Theory, developed for this work, to ensure that the viscous component of the flow is fully established; that the device used for supersonic flow is insulated to fulfill adiabatic conditions, its annulus abbreviated to minimize heat loss; and temperature measuring devices can be added to ensure that adiabatic conditions are met, which are not required for the device used for incompressible fluid flow since isothermal conditions are satisfactory, rendering Pitot tubes for such applications much simpler to fabricate, operate and maintain.