Series "Mechanical engineering industry"

The article presents the results of numerical and experimental studies, which are aimed at improving the accuracy of non-intrusive measurements of the temperature of a liquid flow in pipelines, which are elements of hydraulic systems of machines and mechanisms. The auxiliary problem of estimating the fluid flow rate by measuring the intensity of noise on the surface of the pipeline is being solved. The noise source in the pipeline is the fluid velocity fluctuations in the turbulent flow, which we perceive as pressure and sound fluctuations, while for high flow velocities the distribution of the average velocity in the pipe cross section is quite uniform and has a logarithmic character, and the total flow temperature is close to the center of the pipe. However, at low and moderate flow rates, the temperature distribution is uneven and the error from the un-evenness can make a significant contribution to the overall measurement error, especially with measurement using relatively accurate resistance thermometers. Therefore, it is necessary to introduce a correction function of the average flow rate and compensate the measurement error due to not-enough flow uniformity, to increase the accuracy of non-intrusive temperature measurements.

A reasonable choice is made of a numerical simulation environment suitable for the requirements of this problem: the turbulence energy density in a pipeline with two bends (temperature compensator), the turbulence energy dissipation, the distribution of turbulence energy in the flow cross section at one of the bends were calculated. This allows us to say that the maximum values of the energy density of turbulence arise on the side walls of the pipeline bend in the boundary layer of the flow, and the dependence of energy on speed is described by a polynomial of the third degree, that is consistent with the results of other authors. In addition, the insertion of a logarithmic scale for the dependence of turbulence energy on speed allows to linearize this dependence and, thus, construct a linear measurement function for the moderate and large Reynolds numbers range.

An experimental study was conducted on a flowstand in a flow range of up to 0.1 kg/s with DN50 pipeline and temperatures of 20 and 80 °С. The spectral characteristics of the signals on the pipeline surface were determined. Was revealed that for surface noise, as well as for noise in the center of the pipeline, there are three characteristic spectral zones are characteristic, and the first zone (energy-bearing) is informational and should be the object of measurements.
The width of this zone is proportional to the flow rate and can be determined by frequency detection methods. A quadratic amplitude detector can be used to determine the energy intensity of
the noise signal in the energy-carrying band of the spectrum.

non-intrusive measurements; pipeline; temperature; flowrate velocity; temperature measurement error; flow modeling; boundary layer; temperature distribution; piezo-film sensor; spectral density; quadratic detector

Nekrasov, S.G. The Problems of Non-intrusive Measurements of Fluid Flow Parameters in Pipelines / S.G. Nekrasov, S.A. Fomchenko, A.M. Sukharev // 2nd International Ural Conference on Measurements (UralCon). – Chelyabinsk, 2017. – P. 428–437.

Patent US 2017/0212065A1. Non-intrusive process temperature calculation system / J.H. Rud, Y.N. Kuznetsov, S.S. Garipov, A.A. Krivonogov, S.A. Fomchenko, V.V. Repyevsky, M.V. Palkin. – Заявл. 25.03.2016; опубл. 27.07.2017.

Ландау, Л.Д. Теоретическая физика. Гидродинамика: учеб. пособ. / Л.Д. Ландау, Е.М. Лифшиц. – М.: Наука, 1986. – Т. 6. – 736 с.

Дорофеева, А.А. Изучение зависимости уровня шума турбулентного потока от параметров течения / А.А. Дорофеева, Т.В. Жариков // Ученые записки физич. факультета Моск.

ун-та. – 2017. – № 5. – C. 1750601-1– 1750601-5.

Филиппов, А.С. Турбулентность и ее моделирование / А.С. Филиппов. – http://:www.ibrae. ac.ru/docs/Kafedra/Филиппов%20МТТ%20март16.pdf (дата обращения: 15.09.2019).

Turbulence Modeling Effects on the CFD Predictions of Flow over a Detailed Full-Scale Sedan Vehicle / C. Zhang, C.P. Bounds, L. Foster, M. Uddin // Fluids. – 2019. – Vol. 4. – P. 148–156. DOI: 10.3390/fluids4030148

Huang, J. Assessment of Turbulence Models in a Hypersonic Cold-Wall Turbulent Boun-dary Layer / J. Huang, J.-V. Bretzke, L. Duan // Fluids. – 2019. – Vol. 4. – P. 37–43. DOI: 10.3390/fluids4010037

He, X. Stability Analysis on Nonequilibrium Supersonic Boundary Layer Flow with Velocity-Slip Boundary Conditions / X. He, K. Zhang, C. Cai // Fluids 2019. – Vol. 4. – P. 142–150. DOI: 10.3390/fluids4030142

Колмогоров, А.Н. Уравнения турбулентного движения несжимаемой жидкости / А.Н. Колмогоров // Известия АН СССР. Физика. – 1942. – Т. 6. – № 2. – С. 56–58.

Гарбарук, А.В. Моделирование турбулентности в расчетах сложных течений / А.В. Гарбарук, М.Х. Стрелец, М.Л. Шур. – СПб.: Изд-во Политехн. ун-та, 2012. – 88 с.

Wilcox, D.C. Turbulence Modeling for CFD / D.C. Wilcox. – DCW Industries, La Canada,

California, 1998. – 477 p.

Wang, S. Modeling and Analysis of the Effects of Noise Barrier Shape and Inflow Conditions on Highway Automobiles Emission Dispersion / S. Wang, X. Wang // Fluids. – 2019. – Vol. 4. – P. 151–157. DOI: 10.3390/fluids4030151

Gong, L. Numerical Study of Noise Barriers’ Side Edge Effects on Pollutant Dispersion near Roadside under Various Thermal Stability Conditions / L. Gong, X. Wang // Fluids. – 2018. – Vol. 3. – P. 105–112. DOI: 10.3390/fluids3040105

Wind noise spectra in small Reynolds number turbulent flows / S. Zhao, E. Cheng, X. Qiu, I. Burnett, J.C.-C. Liu // J. Acoust. Soc. Am. – 2016. – Vol. 140. – P. 4178–4182. DOI: 10.1121/1.5012740

Manhard B. Numerical Simulation of Turbulent Flows and Noise Generation / B. Manhard, J. Munz // J. Acoust. Soc. Am. – 2014. – Vol. 104. – P. 3117–3122. DOI: 10.1121/1.2012532

Xu, J. Numerical Simulation of In-Pipe Turbulent Noise / J. Xu, Z.R. Hao, Z.H. Zhou // Applied Mechanics and Materials. – 2014. – Vol. 607. – P. 565–568. DOI: 10.4028/AMM.607.565

Радиотехнические цепи и сигналы: учеб.-метод. комплекс / сост.: С.И. Малинин, В.С. Токарев. – СПб.: Изд-во CЗТУ, 2010. – 224 с.

Радиотехнические цепи и сигналы: учеб. для вузов. Стандарт третьего поколения / под ред. В.Н. Ушакова. – СПб.: Питер, 2014. – 336 с.

Нефедов, В.И. Радиотехнические цепи и сигналы: учеб. для СПО / В.И. Нефедов, А.С. Сигов. – М.: Изд-во Юрайт, 2019. – 266 с.

Savaux, Louet. MMSE-Based Algorithm for Joint Signal Detection, Channel and Noise Variance Estimation for OFDM Systems / Louet Savaux. – USA, ISTE Ltd, 2014. – 129 p.

ГОСТ Р ИСО 15665-2007. Шум. Руководство по акустической изоляции труб и арматуры трубопроводов. – М.: Стандартинформ, 2008. – 39 с.