Patent RU-2709034-C1 (RU)
Title: Method of determining hydraulic circuit flow characteristic for transition area from turbulent to laminar flow conditions
Inventor: BEZMENOV VASILIJ SERAFIMOVICH
IPC: G01M10/00
Filed: 2019-05-24
Granted: 2019-12-13
Abstract: FIELD: measuring equipment. 
     SUBSTANCE: method is characterized by the fact that for the area of transition from turbulent to laminar flow conditions, the path model with design constructs of local resistances and sections of connecting pipelines with length l i ≤L i  with inner diameter d i  with end distribution through locking device with cylindrical drain tip with inner diameter d n  is spilled by tap water through its multiple portion dosing into a measuring container at different values of the acting head H j , stepwise variable from maximum H j,max , corresponding to turbulent flow mode, to minimum H j,min , corresponding to the beginning of the transition from the jet to the drop-jet flow mode, values which during each j-th flow operation are maintained at a given constant level, where j=1, 2 …, n = 31 is the number of spills in each measurement cycle, and quickly, using Microsoft Excel electronic spreadsheets, for each j-th flowing operation volumetric flow rate is successively calculated – Q j  [cm 3 /s]=V j /t j , corresponding to pressure H j , where dose volume V j  [cm 3 ] are recorded by weighing on electronic scales, and dosing time t j [s] is set and measured by an electronic timer; water discharge velocity from the drain nozzle – v n,j [cm/s] = Q j /f n , head loss – h n,j  [cm]=α⋅v n,j   2 /2g and Reynolds number of flow is Re j =v n,j d n /ν w  at its output, where Coriolis coefficient α is assumed equal to 1.05, as in turbulent flow mode, and kinematic viscosity of water ν w  is calculated by its temperature in this cycle of fluences; flow velocity is v i,j [cm/s]=v n,j (d n /d i ) 2 , Reynolds number – Re i,j =v i,j d i /ν w , friction coefficients – λ i,j =64/Re i,j  and frictional pressure loss – h i,j  [cm]=λ i,j (l i /d i )(d n /d i ) 4  on separate sections of pipeline; total pressure losses for friction – h t,j  [cm]=Σ i [h i,j ], at local resistances in path – h m,j [cm]=H j -h n,j -h t,j  and total head loss factors at local resistances – ξ j =2gh m,j /v n,j   2 . Further, the experimental consumption characteristic of the path obtained in a table form Q j =F(H j ) are divided into zones of turbulent, conditionally transient and laminar flow modes; in the "Advanced Grapher" program for each selected zone, graphs of functions are plotted ξ j,s =f(Re j,s ), where indices s=1, 2, 3 refer to turbulent, conditionally transient and laminar zones, accordingly, their regression analysis is carried out and equations for approximating functions are obtained for each of selected zones: ξ 1 =f 1 (Re), ξ 2 =f 2 (Re), ξ 3 =f 3 (Re), wherein for each s power or hyperbolic, by minimum standard deviation value, approximation is selected; constructing graphs of approximating functions and determining points Re1 and Re2 of graphs intersection: Re1 (ξ 1  and ξ 2 ) and Re2 (ξ 2  and ξ 3 ), fixing, accordingly, upper (number Re1) and lower (number Re2) boundary of actual transition zone of predicted flow characteristic of natural liquid with viscosity ν; for latter set of flow rate values Q k =Q j , flow velocities v n,k =v n,j  from drain nozzle and head loss at its outlet is h n,k =h n,j , which coincide with values obtained on water; for each value k=j and for each of the selected zones of natural liquid flow conditions, Reynolds numbers corresponding to these zones are calculated: Re k,s =ξ s v n,k   2 /2g, wherein the numbers Re k,1 >Re1 refer to turbulent flow mode, number Re k,3 <Re2 – to zone of laminar mode, and number Re2<Re k,2 <Re1 – to actual transition zone of predicted flow characteristic; further according to equations obtained earlier ξ s =f s (Re) of approximating functions, calculating total head loss coefficients on local resistances ξ k =f(Re k ), flow velocity is v i,k =v n,k (d n /d i ) 2 , Reynolds number – Re i,,k =v i,k d i /ν, friction coefficients – λ i,k =64/Re i,k  and frictional pressure loss – h i,k =λ i,k (L i /d i )(d n /d i ) 4  on separate sections of pipeline, total head friction losses – h t,k [cm]=Σ i [h i,k ] and at local resistances in path – h m,k =ξ k (v n,k   2 /2g) and, finally, design, for each of selected zones, the value of available head is H pk =h n,k +h t,k +h m,k . 
     EFFECT: invention can be used for calculation of throughput capacity of projected hydraulic ducts of transport and dosing systems in chemical, petrochemical, aviation, textile, varnishing and other industries, in particular, – units for transportation and dosing of glue compositions when assembling small items. 
     4 cl, 1 tbl, 1 dwg