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作者： Planko, Urh Svete, Andrej Kutin, Jože Laboratory of Measurements in Process Engineering Faculty of Mechanical Engineering University of Ljubljana Ljubljana Slovenia

This paper experimentally characterizes the aperiodic dynamic pressure generator Spektra DPE-02 for the dynamic calibrations of pressure sensors. In the considered dynamic pressure generator, the pressure pulses in the oil chamber are generated by the piston, which is excited by the projectile. The projectile is propelled vertically upwards through the barrel towards the piston by utilizing the pneumatic potential energy within the compressed air. The amplitude and the width of the generated pressure pulses depend on the propulsion pressure and the initial distance between the projectile and the piston. In this paper the dependence of the generated pressure pulses on both parameters were analyzed in time and frequency domains. © 2024

关键词： Dynamic pressure calibration Dynamic pressure generator Frequency characteristics Time-varying pressure

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Effects of the shock tube diameter on shock wave propagation in a diaphragmless shock tube

Effects of the shock tube diameter on shock wave propagation...

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作者： Novak, Benjamin Svete, Andrej Kutin, Jože Laboratory of Measurements in Process Engineering Faculty of Mechanical Engineering University of Ljubljana Ljubljana Slovenia

This paper experimentally analyses the effects of the inner diameter of the shock tube on the velocity distribution of the generated shock waves along the shock tube. The experiments were conducted in diaphragmless shock tubes with driven sections of different inner diameters, i.e., 40 mm and 80 mm, using different combinations of the driver and driven gases at different initial pressures. The results show that by decreasing the shock tube diameter the generated shock wave velocity increases and therefore increases the generated end-wall pressure step used as the reference input signal for the dynamic calibration of the pressure sensors. © 2024

关键词： Diaphragmless shock tube Dynamic pressure calibration Shock wave velocity Time-varying pressure

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METHOD FOR CORRECTION OF THE SYSTEMATIC ERRORS IN DETECTED SHOCK WAVE PASSAGE TIMES IN THE SHOCK TUBE 6

METHOD FOR CORRECTION OF THE SYSTEMATIC ERRORS IN DETECTED S...

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6th TC16 Conference on Pressure and Vacuum Measurement 2022, Together with the 24th TC3 Conference on the Measurement of Force, Mass and Torque, the 14th TC5 Conference on the Measurement of Hardness, and the 5th TC22 Conference on Vibration Measurement

作者： Castro, Francisco Javier Hernández Svete, Andrej Kutin, Jože Laboratory of Measurements in Process Engineering Faculty of Mechanical Engineering University of Ljubljana Slovenia

ISBN: (纸本)9781713870227

The most important uncertainty component of the pressure step signal determined at the end-wall of the shock tube is associated with the uncertainties of the shock wave velocity and the arrival time of the shock front. Both are determined using a time-of-flight method and are therefore greatly affected by the errors in the detected times of the shock wave passages over the side-wall pressure sensors installed along the shock tube. This paper introduces a method for an automated correction of the systematic errors due to non-ideal dynamic response of the side-wall pressure sensors. © 2022 6th TC16 Conference on Pressure and Vacuum Measurement 2022. All rights reserved.

关键词： Dynamic response

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DYNAMIC CALIBRATION OF PRESSURE SENSORS WITH THE USE OF DIFFERENT GASES IN THE SHOCK TUBE 6

DYNAMIC CALIBRATION OF PRESSURE SENSORS WITH THE USE OF DIFF...

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作者： Planko, Urh Svete, Andrej Kutin, Jože Laboratory of Measurements in Process Engineering Faculty of Mechanical Engineering University of Ljubljana Slovenia

ISBN: (纸本)9781713870227

This paper studies the possibilities of increasing the amplitude range of the generated pressure steps in the developed diaphragmless shock tube by using appropriate combination of gases in the driver and driven sections of the shock tube. The measurement results of the generated pressure steps using different combinations of lower- and higher-molecular-weight gases as driver and driven gas are presented. By comparison of the resulting pressure steps generated in the diaphragmless shock tube, the most appropriate combination of the driver and driven gas for generating the largest pressure step amplitudes is determined and discussed. © 2022 6th TC16 Conference on Pressure and Vacuum Measurement 2022. All rights reserved.

关键词： Shock tubes

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Characterization of Spektra DPE-02 dynamic pressure exciter for the dynamic calibrations of pressure sensors

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Measurement: Sensors 2025年 38卷

作者： Planko, Urh Svete, Andrej Kutin, Jože Laboratory of Measurements in Process Engineering Faculty of Mechanical Engineering University of Ljubljana Ljubljana Slovenia

关键词： Pistons

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Effects of the shock tube diameter on shock wave propagation in a diaphragmless shock tube

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Measurement: Sensors 2025年 38卷

作者： Novak, Benjamin Svete, Andrej Kutin, Jože Laboratory of Measurements in Process Engineering Faculty of Mechanical Engineering University of Ljubljana Ljubljana Slovenia

关键词： Shock tubes

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Experimental study of the blockage effect of a vane anemometer in a small wind tunnel

Experimental study of the blockage effect of a vane anemomet...

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作者： Bobovnik, G. Sambol, P. Geršl, J. Kutin, J. University of Ljubljana Faculty of Mechanical Engineering Laboratory of Measurements in Process Engineering Ljubljana 1000 Slovenia Czech Metrology Institute Okružní 31 Brno 63800 Czech Republic

This study investigates the blockage effect of a vane anemometer in a small, closed test section of an open circuit wind tunnel. The experimental analysis examines the axial and cross-sectional positions of the vane anemometer in the test section. The results show that the changes in the calibration results due to different vane anemometer positions are within 1 %. The observed relative differences are compared with the existing guidelines for estimation of the blockage effect. Furthermore, a comparison with a larger wind tunnel facility demonstrates good agreement between the results, suggesting minimal systematic errors due to the blockage effect. The study underscores the potential using the variation in calibration results around the primary calibration point as a possible method to estimate blockage effect contribution to uncertainty in small wind tunnels. © 2024

关键词： air velocity Blockage effect Intercomparison Vane anemometer Wind tunnel

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Synthesis of methanol via CO_(2) hydrogenation catalyzed by La_(2)O_(2)CO_(3)/Cu catalysts

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Nano Research 2025年第2期18卷 153-163页

作者： Jun He Chenglong Yu Zhijuan Zhao Bo Guan Bin Zhang Yanru Zhang Longbo Zhang Yanyan Wang Ying Wang Yahui Wu Jia Guo Yang Li Tianbin Wu Qingli Qian Hongxing Wang Buxing Han Beijing National Laboratory for Molecular Sciences Key Laboratory of Colloid and Interface and ThermodynamicsCenter for Carbon Neutral ChemistryInstitute of ChemistryChinese Academy of SciencesBeijing 100190China College of Chemical Engineering and Materials Science Tianjin University of Science and TechnologyTianjin 300457China School of Chemical Sciences University of Chinese Academy of SciencesBeijing 100049China Center for Physicochemical Analysis Measurements Institute of ChemistryChinese Academy of SciencesBeijing 100190China Shanghai Key Laboratory of Green Chemistry and Chemical Processes State Key Laboratory of Petroleum Molecular and Process EngineeringSchool of Chemistry and Molecular EngineeringEast China Normal UniversityShanghai 200062China

The development of efficient Cu-based heterogeneous catalysts for CO_(2) hydrogenation to methanol has been an appealing *** by the concept of inverse catalysts,a series of La_(2)O_(2)CO_(3)/Cu nanorod composites with varying Cu contents(denoted as LOC/Cu-x,where x stands for the mass ratio of La and Cu in the catalysts)were prepared by combining coprecipitation and calcination *** composition-dependence of catalytic activity and selectivity were observed when different LOC/Cu-x(x=0.1,0.2,0.5,1,3 and 5)were used to catalyze the CO_(2) *** predominant product shifted from methane to methanol with the increasing Cu *** highest reaction rate(13.3 mmol·gCu^(-1)·h^(-1))and methanol selectivity(85.5%)were achieved when LOC/Cu-1 was tested at 200℃.The LOC was not active for the reaction,while the Cu itself displayed poor catalytic *** Cu–LOC interactions significantly affected the nature of the catalysts,including mutual electron transfer,crystal structure,morphology,porosity,surface Cu valence and capability of adsorbing the reactant gases,etc.,which account for the outstanding behavior of the LOC/Cu-1 *** work provides a new strategy for the design and optimization of Cu-based catalysts.

关键词： CO_(2)hydrogenation methanol heterogeneous catalysts Cu-La_(2)O_(2)CO_(3)(LOC)interaction

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Bilateral comparison of gas microflow primary standards in the range between 0.12 mg/min and 2.4 mg/min

Bilateral comparison of gas microflow primary standards in t...

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作者： Žibret, P. Spazzini, P.G. Bobovnik, G. Kutin, J. University of Ljubljana Faculty of Mechanical Engineering Laboratory of Measurements in Process Engineering (LMPS) Aškerčeva 6 Ljubljana Slovenia INRiM Gas Flow & Volume Laboratory Strada delle Cacce 91 Torino Italy

A bilateral comparison of small gas flow rates in the range between 0.12 mg/min and 2.4 mg/min was performed between INRiM (Italy) and LMPS (Slovenia). The primary standard at INRiM is a type of a motor driven piston prover. The primary standard at LMPS is a pVTt method with a static mass determination and flying start-stop. The transfer standard main part are two capillary leaks, with measuring ranges up to 0.25 mg/min and 2.5 mg/min respectively. A Hagen-Poiseuille equation with a constant geometric factor is used to calculate the mass flow rate. The comparison was carried out at five measurement points with the large capillary leak and at two points with the small capillary leak. The results show that there are statistically significant differences between the measurements of the two laboratories. The estimated uncertainties are also too large to confirm the target CMCs, as the repeatability of the measurements was too weak. © 2024

关键词： Bilateral comparison Capillary transfer standard Gas flow measurement Microflow Normalized error

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Implementation of the dynamic flying start-stop method in the pVTt gas flow standard 19

Implementation of the dynamic flying start-stop method in th...

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19th International Flow Measurement Conference 2022, FLOMEKO 2022

作者： Žibret, P. Bobovnik, G. Kutin, J. University of Ljubljana Faculty of Mechanical Engineering Laboratory of Measurements in Process Engineering Aškerčeva 6 LjubljanaSI-1000 Slovenia

ISBN: (纸本)9781713871989

The gas flow standards using the volumetric method with a constant volume (pVTt) determine the flow rate based on the rate of mass change determined by measuring the density of the gas inside a constant volume. These standards normally use the static method of mass determination and rarely the dynamic one, due to dynamic changes of the gas temperature during mass collection. We have developed the analytical model that predicts the change of temperature in the pVTt system for gas flow rates up to 12 mg/min. Both measurement methods, the static and the dynamic, were implemented in the measuring system, with the dynamic method being corrected using the analytical model. The analytical correction model was validated by a comparison between the flow-rate measurements using the static and the dynamic methods. Based on successful validation of the analytical model we believe the corrected dynamic method is a viable alternative to the static one for the considered flow range. © FLOMEKO *** rights reserved

关键词： Analytical models

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