Patent RU-2765801-C1 (RU)
Title: Method for determining the flow characteristics of a hydraulic tract in the transition outflow area
Inventor: BEZMENOV VASILIJ SERAFIMOVICH
IPC: G01M10/00
Filed: 2020-09-08
Granted: 2022-02-03
Abstract: 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 =H 31 =4 cm. Consecutively calculated therein by means of Microsoft Excel spreadsheets are: volumetric flow rates Q  j  [cm 3 /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 H   2 /4), head losses h Hj [cm]=α·ν Hj   2 /2g and the Reynolds numbers of the flow - Re j =ν Hj d 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 ij d 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 Hj   2 . 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