METHOD FOR DETERMINING THE ESTIMATED FLOW CHARACTERISTICS OF A HYDRAULIC CIRCUIT DURING A TURBULENT FLOW MODE Russian patent published in 2019 - IPC G01F25/00 G01M9/06 

FIELD: measurement technology.

SUBSTANCE: invention relates to methods and devices used for calculation of capacity of designed hydraulic circuits of transport and dosing systems in chemical, petrochemical, aviation, textile, paint and other industries, particularly to transportation units of adhesive compositions in assembly plants with adhesive joints. Proposed method is implemented by pouring a model circuit with the design constructions of local resistances and sections of connecting pipelines of length l_i≤L_i with the internal diameters d_i tap water by means of its repeated portion dosing in a measured container and weighing doses on electronic scales at various values of the current head H_i, that are stepwise variable from the maximum (H_j,max) to minimum (H_j,min) values and supported during each j-th pouring operation (j=1, 2 … n, n≈20 – the number of spills in a given measurement cycle) at a given constant level, and on-line sequential computation for each j-th pouring operation (using the Microsoft Excel spreadsheets) of the following flow parameters: volume flow – Q_j [cm³/s] = V_j/t_j, corresponding to the head H_j (where v_j [cm³] is a dose volume recorded by electronic weighing, t_j[s] is a dosing time); water flow rates from the drain tip – v_{n, j} [cm/s] = Q_j/f_n, head loss – h_n,j [cm] = v_n,j²/2g and Reynolds Stream numbers – Re_j=v_n,_jd_j/ν_v on its way out; flow rates – V_i,j [cm/s] = v_n,j (d_n/d_i)², Reynolds number – Re_i,j=V_i,jd_i/ν_v, friction coefficients – λ_i,j=0.3164/Re_i,j^0.25 and head friction losses – h_i,j [cm] =λ_i,j,(L_i/d_i) (d_n/d_i)⁴ on separate sections of the pipeline; total pressure loss on friction – h_t,j [cm] = Σ_i[h_i,j] and on local resistances in the circuit – h_m,j [cm] = H_j-h_n,j-h_t,j; total pressure loss rates for local resistances – ξ_i=2gh_m,j/v_n,j². Further, in the program "Advanced Grapher" a graph of the function ξ_i=f(Re_i) is built, its regression analysis is conducted, as a result of which an equation is determined by approximating the following decreasing power function: ξ=a⋅Re^b (where a and b are the coefficients of approximation), series of values of the flow rate of full-scale fluid with viscosity v – Q=Q_k (k=1, 2 _... m) is set from the minimum – Q₁=Q_min to the maximum – Q_m=Q_max from the specified range of its change and is calculated successively for each value of k the following parameters included in the Bernoulli equation: fluid flow rates from the drain tip – v_n,k [cm/s]=Q_k/f_n; head loss – h_n,k [cm] = v_n,k²/2g and Reynolds Stream numbers – Re_k=v_n,kd_n/ν on its way out; flow rates – v_i,k [cm/s]=v_n,k(d_n/d_i)², Reynolds numbers – Re_i,k=v_i,kd_i/ν, friction coefficients – λ_i,k= 0.3164/Re_i,k^0.25 (for the turbulent flow of natural fluid) or λ_i,k=64/Re_i,k (for laminar mode) and friction head loss – h_i,k [cm]=λ_{i k}(L_i/d_i)(d_n/d_i)⁴ on separate sections of the pipeline; total friction head loss – h_t,k [cm] = Σ_i[h_i,k] and local resistances in the circuit – h_m,k =ξ(v_n,k²/2g), where ξ_k=a⋅Re_k^b, and the calculated (predicted) values of disposable head – H_p,k=h_n,k+h_t,k+h_m,_k.

EFFECT: higher accuracy and reliability of determining the estimated flow characteristics of a hydraulic circuit during transportation of liquid products of different viscosity through it and the possibility of its prediction by varying the specified range of flow variation and length of pipeline sections forming the circuit.

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