جستجوی مقالات مرتبط با کلیدواژه « differential pressure sensor » در نشریات گروه « مکانیک »

In this paper, the behavior of a non-Newtonian polymer through fluid hammer phenomenon in the pipe investigates. Special properties of this fluid such as nonlinear relation between stress and strain, having relaxation time make the pressure wave resulting from this phenomenon to behave differently from a Newtonian fluid. The system under investigation is reservoir-pipe-valve system and the equations representing the conservation of mass and momentum govern the transitional flow in the pipes. In the modeling of the equations finite difference numerical method is used. After defining non-dimensional numbers of governing equations, the effect of Deborah and Reynolds numbers on pressure historic at critical points such as at valve and midpoint investigate. The modeling results show that about investigating sensitivity to the Reynolds number, the pressure wave produced by non-Newtonian polymer shows a sensitivity similar to that of Newtonian fluids. It was also found that an increase in the Deborah number, indicating the elasticity of the polymer, affects the reduction of tensions and increases the oscillation height and consequently attenuation time of the created transient flow to be longer. It has been observed that in similar conditions, the phenomenon of line packing in viscoelastic fluid is slightly higher than in Newtonian fluid. The reason for this is definitely related to the constant characteristic of the relaxation time, which is strongly inclined to maintain the incoming potential energy and resists the damping of the transfer flow, which causes a long damping time compared to the Newtonian fluid have more.

One of the important parameters in the navigation of an intelligent subsurface vehicle is to estimate the speed with appropriate accuracy. One of the available methods for measuring the speed under the surface is the use of differential pressure sensors. In this study, in order to achieve the lowest sensitivity to the azimuth angle of the water flow in the subsurface, the optimal place of installing pressure gauge sensors on the forehead of a cylindrical geometry has been considered. In this study, experimentally and numerically, nine positioning angles of the sensors with respect to the top of the cylinder have been investigated as an effective parameter in six specific speeds and five flow attack angles. The results of these investigations have shown that the best estimation of the speed in the subsurface can be achieved with the positioning angle of the sensors in the range of 35 degrees and with the lowest sensitivity to the azimuth angle (5% difference with the reference speed).