METHOD OF DETERMINING HYDRAULIC CIRCUIT FLOW CHARACTERISTIC FOR TRANSITION AREA FROM TURBULENT TO LAMINAR FLOW CONDITIONS Russian patent published in 2019 - IPC G01M10/00 G01F25/00 

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 [cm³/s]=V_j/t_j, corresponding to pressure H_j, where dose volume V_j [cm³] 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,j²/2g and Reynolds number of flow is Re_j=v_n,jd_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,jd_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,j². 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: ξ₁=f₁(Re), ξ₂=f₂(Re), ξ₃=f₃(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 (ξ₁ and ξ₂) and Re2 (ξ₂ and ξ₃), 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_sv_n,k²/2g, 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,kd_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,k²/2g) 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