روح اله فاتحی

Pitot tubes are one of the systems for measuring the velocity of fluid flow that measure the flow velocity by measuring the difference of pressure between two points of flow and using a Bernoulli equation. This device generally requires a correction factor while using the Bernoulli equation, and this factor for each pitot tube and also depend on flow conditions can be varied. Therefore, each constructor or user will have to Calibrate Pitot tubes according to its operational conditions and obtains the corresponding correction factor. In this thesis, the purpose is to obtain a correction factor of a pitot tube numerically which used by the industry ,which the information and correction factors are available in three operating modes, and due to changing the conditions of using the pitot tube, obtaining the Correction factor is essential for new working conditions According to the cylindrical geometry of the pitot tube, the free stream is examined on the cylinder in two dimensions firstly. By comparing the characteristics of this flow like the drag coefficient and the pressure coefficient obtained from simulation with other numerical results or empirical results published, suitable tools and methods for solving this flow were selected. Then for numerical validation, the simulation was performed according to the operating conditions of the pitot tube and its results were compared with the experimental results, which showed a difference of about 5% of the simulation results and the experimental results. In the next step, the accuracy of the two-dimensional assumption of the flow with the three-dimensional solution of the flow around the pitot tubes in a particular state is checked, this resulted in a difference of less than 4% with two-dimensional results and the correctness of this assumption. Finally, after selecting and validating the used simulation, concentrate on modeling the flow in new working conditions, and it is possible to obtain the correction factor as a fun