METHOD FOR DETERMINING THE FLOW CHARACTERISTICS OF A HYDRAULIC TRACT IN THE TRANSITION OUTFLOW AREA Russian patent published in 2022 - IPC G01M10/00 

FIELD: measuring equipment.

SUBSTANCE: invention relates to measuring equipment and can be used to calculate the throughput capacity of the designed hydraulic paths of transport and dosing systems in the chemical, petrochemical, aviation, textile, paint and varnish, and other branches of industry, in particular, for determining (predicting) the flow characteristics of systems for automated batch dosing of test liquids maintaining a constant pressure drop on the loading line, metering the dose over time. The proposed method is characterised by the fact that the model of the path with the designed constructs of local resistances and sections of connecting pipelines with the inner diameter d_i with endwise distribution via a shutoff apparatus with a cylindrical drainage tip with the inner diameter d_H is flushed with tap water by multiple batch dosing thereof into a metering container at different values of the actual head H_j, maintained at a predetermined constant level, (wherein j = 1, 2 …, n=31 is the number of flushes in each flushing cycle), reduced stepwise at a pitch of 10 cm from the maximum H_jmax=H_j=1=184 cm to the intermediate value H_j=H_j=18=34 cm - and further at a pitch of 2 cm to the lower boundary of the measurement range - H_jmin=H₃₁=4 cm. Consecutively calculated therein by means of Microsoft Excel spreadsheets are: volumetric flow rates Q _j [cm³/s]=V_j/t_j corresponding to the heads H_j, where the volume of the dose V_j is recorded by weighing on an electronic balance, and the time of dosing t_j is set and metered by means of an electronic timer; the outflow rates ν_Hj[cm/s]=Q_j/ƒ_H from the drainage tip (wherein ƒn=πd_H²/4), head losses h_Hj[cm]=α·ν_Hj²/2g and the Reynolds numbers of the flow - Re_j=ν_Hjd_H/ν_B at the output, where the Coriolis coefficient α is initially taken as 1.05 as in the turbulent outflow mode, and the kinematic viscosity of water ν_V is calculated based on the temperature thereof in the current flushing cycle; the flow rates ν_ij[cm/s]=ν_Hj(d_H/d_i)², the Reynolds numbers Re_ij=ν_ijd_i/ν_B, the friction coefficients λ_ij=64/Re_ij, and the head losses for friction at separate sections of the pipeline; the total head losses for friction h_Tj[cm]=Σ_i[h_ij], for the local path resistances h_Mj[cm]=H_j-h_Hj-h_Tj, and the total coefficients of head losses for local resistances - ξ_j=2gh_Mj/ν_Hj². The resulting tabular experimental flow characteristic of the path Q_j=F(H_j) is divided into zones of turbulent, conditionally transitional, and conditionally laminar outflow modes by means of consistent comparative analysis of the numerical values of the standard deviation of points thereof and selection of the amounts of points Q_j=1,2,…p (p≥6 in the upper area of the measuring range) and Q_j=34,33,…q (q≥6 in the lower area of the range) with minimum values of the standard deviation from the graph of the approximating power function corresponding to said points.

EFFECT: increase in the accuracy and reliability of determining the calculated flow characteristic of a hydraulic tract in the transition area during transportation of liquid products of various viscosities through the path and possibility of predicting said characteristic when varying the preset range of changes in the flow and length of the pipeline sections forming the path.

2 cl, 1 dwg, 1 tbl