API TR 13M-5-2018 pdf download.Procedure for Testing and Evaluating the Performance of Friction (Drag) Reducers in Aqueous-based Fluid Flowing in Straight, Smooth Circular Conduits.
2.1 base fluid Aqueous liquid media (solvent with or without additives) used to prepare test fluid (see 2.8). 2.2 friction reducer Agent that dissolves in base fluid, thereby reducing frictional resistance to flow. 2.3 straight, smooth circular conduits Metallic-based smooth-walled straight tubing or pipe having a constant diameter. 2.4 drag reduction friction reduction Relative reduction in the change in pressure due to frictional resistance by the addition of friction reducer to the base fluid. 2.5 Reynolds number ( N Re ) The ratio of inertial forces to viscous forces within a fluid (a dimensionless number). 2.6 Fanning friction factor ( f ) For a fluid, the ratio of pipe wall shear stress to the flow kinetic energy (a dimensionless number). 2.7 solvent Aqueous liquid used to prepare the test fluid (water, brine, etc.) and the fluid used to determine the internal diameter of the tubing or pipe (see 5.3). NOTE For the purpose of the document, for determination of internal diameter of the tubing or pipe, the solvent is fresh water. 2.8 test fluid Fluid prepared with the base fluid and the friction reducer.
3 Measurement and Precision Pressure shall be measured to a relative accuracy of 0.5 % of the full-scale reading of the device. Flow rate shall be measured by a device having a relative accuracy of 0.5 % of the full-scale reading. Temperature shall be measured to a precision of ± 1 °C ( ± 2 °F). All other quantitative measurements shall be made to a precision of 2 %, unless specified otherwise. 4 Instrument Calibration The instruments associated with these procedures shall be calibrated according to each manufacturer’s recommended method and frequency. 5 Friction Loop Calibration 5.1 Introduction Fresh water is pumped through the flow conduit at various flow rates in turbulent flow regime in order to gather pressure drop data. These data will be analyzed to determine the internal diameter (ID) of the flow conduit (pipe). 5.2 Flow Loop Schematic Figure 1 represents components of a typical flow loop system.
5.3 Calibration Procedure The purpose of this section is to accurately determine the ID of the tubing. This calibration is performed by comparing the experimental data with theoretical values, using a Fanning friction factor logarithmic plot vs solvent Reynolds number for fresh water. The theoretical values will be calculated using the Drew correlation  . Fresh water is pumped at various flow rates in turbulent flow regime. Turbulent flow regime for this document indicates a solvent Reynolds number greater than 4000. The calculation for solvent Reynolds number is indicated in the Data Analysis section. A minimum of four flow rates in turbulent flow regime shall be measured. A recommended range of flow rate is such that the solvent Reynolds number spans a minimum of two logarithmic cycles or orders of magnitude. The flow rate is set at a desired value, and the steady-state pressure drop data across straight tubing length is recorded. Then, the flow rate is increased to the next desired value, and the corresponding pressure drop is recorded. Between tests, and prior to introducing a new test fluid, the system calibration should be verified by pumping fresh water at two different flow rates within the flow rate range used: one at a low rate and the other at a high rate. The differential pressures at those rates should be compared with previously gathered data. If the data do not match, the pipe test section is not properly cleaned and should be flushed/cleaned further.