An evaluation of the reliability of a widely accepted method for determining pipeline hydraulic resistance is conducted, based on a comparative analysis of theoretical data with the results of laboratory investigations. The research object is a liquid flowing under pressure in a straight pipeline with a circular cross-section. The subject of the study is the pressure losses of the liquid along the length of the pipeline. The aim of the research is to verify the existing method for determining the hydraulic resistance of a straight pipeline. Research methods include the Darcy-Weisbach law for determining pressure losses due to friction in the pipeline and experimentation. The research findings indicate that the air pressure at the inlet and outlet of the pipeline, as determined by experimentation/calculation, were as follows: for a flow capacity of n = 0.33 (1/3) – 4.48 Pa and 2.11 Pa / 4.87 Pa and 1.70 Pa; for n = 0.66 (2/3) – 9.11 Pa and 3.45 Pa / 9.35 Pa and 3.41 Pa; for n = 1 – 15.4 Pa and 5.10 Pa / 15.7 Pa and 5.92 Pa. The absolute and relative errors of indirect technical measurements of linear pressure losses due to friction in the pipeline were approximately ≈1.04 Pa and ≈10.6 %, respectively. Conclusions drawn from the study indicate that the root mean square deviations of calculated air pressure values along the pipeline from experimental data, with a sample volume N = 9, were as follows: for a flow capacity of n = 0.33 (1/3) – σ = 0.40 Pa; for n = 0.67 (2/3) – σ = 0.36 Pa; for n = 1 – σ = 0.61 Pa. Based on the assessment of the error of indirect technical measurements of pressure losses in the pipeline and deviations of calculated air pressure values from instrumental measurement results, it can be concluded that the existing method of hydraulic pipeline calculation is adequate.
