Flow meter accuracy vs viscosity to balance flow range

Flow meter accuracy vs viscosity means when the flow rate of a turbine flow meter is minimum. When the product viscosity increases, minimum turbine flow rate is required to balance a specific degree of accuracy growth. There is a close relation between accuracy and viscosity, if the liquid is provided correctly in the turbine meter; it produces high accuracy through a small engineering process. Generally accuracy of a turbine flow meter is counted in percentage of actual reading (C), percentage of full scale (FS), Percentage of calibrated span (CS) units. And the percentages of AC, FS and CS must be separately mentioned at normal, minimum and maximum flow rates. Viscosity of liquid or fluid means thickness of the fluid. Through this we can understand the quality of the liquid. Low viscosity of a liquid means low thickness and high viscosity means high thickness. When the fluid or liquid is passed at the turbine flow meter, it moves faster close to the axis and near the walls of turbine where some stress is required to overcome the friction between the fluid moving and layers. The viscosity of liquid also depends on the attractions between the particles and size and shape of them and also influenced by temperature of a turbine flow meter. The accuracy of a turbine flow meter highly depends on viscosity calibration. And fluid viscosity is a must to consider I order to select the type of turbine (Helical or conventional)

Flow meter accuracy vs viscosity is designed requirement of turbine flow meter to balance the flow rate by viscosity increases and the flow rate decreases causing pressure drop across the turbine flow meter. It highly affects turbine flow meters performance. Accuracy is highly dependent on several items like linearity, repeatability, specific gravity of liquid, viscosity. Viscosity of a turbine meter means the measurement of the liquid resistance to flow. It has two diverse effects on the turbine flow meter rotor; First, the profile of the rotor causes thickness to increase to determine the k-factor as viscosity increases the fixed flow volume. Second, one of viscous change of shear force on the rotor causes increased viscous drag within the bearing. Such effect results in slow the rotor while the immediate rotation of rotor blade due to profile effect results in speed the rotor. The relative magnitude of both of these forces changes the Reynolds number. A measure of the laminar or turbulent nature of flow is the Reynolds Number (Re).


Flow meter viscosity vs accuracy is widely known as flow range matter in the field of flow meter. The features of flow meter viscosity vs accuracy are given below:

  • The viscosity of the liquid or fluid to be metered.
  • The amount of accuracy required.
  • The high amount of pressure drop allowed through the flow meter.
  • If a diagram can be designed with an individual turbine flow meter (According to its size), viscosity accuracy factors, and pressure drop across the flow meter, easily maximum and minimum flow rates can be determined.
  • Operation of flow meter within such balanced flow rates meets the super operation requirements.
  • The viscosity of a liquid or fluid is highly dependant on temperature, an increase temperature will cause decrease viscosity. So, flow range can be balance3d through temperature controlling.
  • When viscosity of the flowing flow increase, the flow from constant pressure source will decrease.

Technical Specifications of Flow meter viscosity vs accuracy:

  • The Universal Viscosity Curve is designed by stating for every calibration data point.
  • Generally, there are thirty points, each ten for different fluids
  • The thirty points are placed on a graph to design a smooth curve.
  • After doing that, K- factor may be decide for any flow rate in liquid of any viscosity until the ration HZ/v is in range of values.
  • A more usable form for the calibration data is called a universal viscosity curve. This is a semi log plot of the sensitivity of the meter as a function of the ratio of the output frequency to the kinematic viscosity. An example is shown in Figure 9. The sensitivity of the meter is commonly known as the K factor wich results the output frequency .It is derived from the calibration data as follows: K = HZ x 60 / GPM.