Velocity and Flow Rate Measuring Instruments used in Pipes Essay

Velocity and Flow Rate Measuring Instruments used in Pipes - Essay Example Some relevant principles of fluid mechanics that are underlying principles of various flow velocity and flow rate measuring types of equipment are – â€Å"Pascal’s Law†, â€Å"Equation of Continuity† and Bernoulli's Equation†. These are briefly discussed below. The law states that pressure applied to any region of a liquid is transmitted to the entire liquid without any drop in the magnitude. This is the underlying principle for pressure measurement using the manometer. This law has several interesting applications like hydraulic lift and other hydraulic devices. This law can be mathematically stated as Where P1 and P2 are pressures at points 1 and 2 respectively, ‘ï  ²Ã¢â‚¬â„¢ is a density of the liquid, ‘g’ is the acceleration due to gravity and ‘h’ is the elevation of point 2 with respect to point 1.This is essentially a statement of the law of conservation of matter as applied in fluid mechanics. This law states that for an incompressible fluid the flow rate remains the same at any cross-section along the flow direction. This equation is essentially a statement of the law of conservation of energy as applied in fluid mechanics. This law states that for an incompressible and non-viscous fluid the total mechanical energy remains conserved along the flow line. This law can be mathematically expressed as This equation forms the backbone of most of the flow velocity and flow rate measuring instruments. Some of the important instruments measuring flow rate and flow velocity in a pipe are briefly discussed in the subsequent sections.While both the instruments work on the principle of Bernoulli’s equation and introduce in variation in the cross-sectional area of the flow path, there is the small difference in the two instruments. Venturi meter is much longer than an orifice plate, which is essentially a plate. Normally the reduction in cross-section is much larger in case of the orifice meter than that in case of Venturi Meter. Hence, measurements are more accurate in case of orifice plate than in case of venture meter.