TABLE OF CONTENTS The accurate measurement of fluid flow is very important in many industrial applications. Optimum performance of many processes requires specific flow rates. The cost of many liquids and gases are based on the measured flow through a pipeline, making it necessary for accounting purposes to accurately measure and control the rate of flow. This chapter discusses the basic terms, formulas, and techniques used in flow measurements and flow instrumentation. Highly accurate and rugged flow devices have now been developed and are commercially available. Developments in technology are continually improving measurement devices [1] , [2]. However, one single flow device is not suitable for all applications, and careful selection is required.
[1]Boillat, M. A., et al., "A Differential Pressure Liquid Flow Sensor For Flow Regulation and Dosing Systems," Proc. IEEE Micro Electro Mechanical Systems, 1995, pp. 350 352.
[2]Konrad, B., P. Arquint, and B. van der Shoot, "A Minature Flow Sensor with Temperature Compensation," Sensors Magazine, Vol. 20, No. 4, April 2003.
At low flow rates, fluids have a laminar flow characteristic. As the flow rate increases, the laminar flow starts to break up and becomes turbulent. The speed of the liquid in a fluid flow varies across the flow. Where the fluid is in contact with the constraining walls (the boundary layer), the velocity of the liquid particles is virtually zero, while in the center of the flow, the liquid particles have the maximum velocity. Thus, the average rate of flow...
