Pressure Drop Method as a Useful Tool for Detecting Rheological Properties of Non-Newtonian Fluids during Flow

The aim of the research was to develop a pressure drop measuring method dedicated to fluids under real flow through a pipeline. The measurement system is a set of appropriately configured flow meter and pressure sensors installed on the pipeline. The pressure drop values detected on the measuring section are sufficient to clearly determine the rheological properties of the fluid. The measuring system used for the tests consisted of a screw pump, two pressure sensors and an electromagnetic flow meter. The length of the measuring section was 4.12 m, and the internal diameter of the pipeline was 0.026 m. To calibrate of the measuring system a glycerol was used. As a model fluid, a 1% water solution of xanthan gum was used and was subjected to the flow at following shear rate conditions: 5, 11, 17, 23, 29, 35, 41, 47, 53, 59, 65 s−1. The obtained raw experimental data included the pressure drop values and flow rate and they created full information about the fluid behavior during flow. According to the momentum balance equation, the rheological parameters of Ostwald de Waele model were estimated. The estimation procedure was carried out with the help of the Marquardt-Levenberg minimisation method. The same solutions simultaneously were tested with the help of a rotational rheometer. The data obtained from the pressure drop method were consistent with the results obtained from the rotational rheometer. The use of the pressure drop allows to determine the rheological properties of the non-newtonian fluids under the process conditions directly in the pipeline. In addition, it is possible to perform full rheological characteristics based on one flow rate under laminar conditions.

Development of a New Risk Assessment Methodology for Light Goods Vehicles on Two-Lane Road Sections

Increasing mobility directly affects traffic frequency and thus increases the possible risk of traffic accident occurrences. Taking this into account, it is necessary to create models for determining risk and to act preventively based on these models; this is of great importance both to society and science. In this paper, six measuring sections of a road network are considered on the basis of eight geometric-exploitation road parameters, taking into account the data for light goods vehicles. An original methodology is proposed for identifying risk levels of road sections through their evaluation. For identifying risk levels, the Dombi Logarithmic Methodology of Additive Weights (D’LMAW) was used, which was combined with the Measurement Alternatives and Ranking according to the Compromise Solution (MARCOS) method. Statistical indicators were processed using a hybrid methodology based on the application of rough numbers and Dombi–Bonferroni functions. The performance of the presented methodology was verified on a real-world example, processing the statistical parameters of six two-lane road sections, with the sixth measuring section showing the best performance, since it had the minimum risk. Research has shown that measuring sections with increasing longitudinal gradients are safer. The analysis of measuring sections from fall to rise reduces the deviation of speeds from the speed limit on the roads. The effectiveness, rationality, and robustness of the solution of the proposed methodology was confirmed through a sensitivity analysis.

MOTION BASED AUTOMATIC STREETLIGHT SYSTEM WITH VEHICLE SPEED SURVEILLANCE

Extravagance of electrical energy and human efforts is a common context while using manual switching of streetlights. In most of the cases, the streetlights remain ON during evening, night, even daylight the lights manually are switched OFF. This leads to a lot of energy wastage because lights keep glowing even when there is absolutely no necessity of it. This study aims to develop a smart street light system which glows when the vehicle or pedestrian enters the certain point of the road and make the light be in OFF/Dim position when it is not required. An illustration consisting of a transmitter and a receiver are made to accomplish the goal. The proposed system can turn ON the lights while nightfall and OFF the lights detecting the appearance of daylights. Meanwhile, presence as per the requirement. Hence, the street light will ON only when there are road users are present over there. The system is incorporated with a speed measuring section to reduce rash driving while the road has relatively low traffic density. Compared to the conventional street light system, this streetlight can reduce redundant energy consumption as well as reckless driving tendency.

UNIFORMITY AND STATIONARITY OF INFORMATION ON THE RIVER FROW IN NOVOSIBIRSK REGION

The series of mean annual and maximum water discharges of the rivers of the Novosibirsk region are considered from the point of view of compliance with the necessary conditions for the use of statistical processing methods in their analysis. Hydraulic calculations necessary for the design of hydraulic engineering and other structures associated with water bodies require for uniformity and stationarity of observations forming the hydrologic series. Uniformity is related to the compliance with the condition that all values should be taken from the same distribution of “general population”. Stationarity means there were no statistically significant changes in the estimates of flow characteristics in the analyzed period (the average values and dispersions do not depend much on the number of sample members). The article presents tables with calculated criteria for the uniformity of the observation series (Dixon and Smirnov-Grubbs) and stationarity (Fischer and Student) for mean and maximum water discharges, for 33 hydrologic measuring section for water run-off observations in rivers of Novosibirsk region.

Analysis of the Behavior in the Wind Tunnel of an Experimental Model of Savonius with Interlocking Cups with the Classic Ones with 2, 3 and 4 Semi-Cylindrical Cups

The paper is based on experiments conducted on the wind tunnel at low wind speeds (<9.5 m/s), on an experimental model of S-rotor wind turbine type with four blades and a D/H ratio of 1. Semi-cylindrical cups opposite 180 degrees are aerodynamically coupled by overlap and with an air passage gap to equalize the pressures. The formed channel is shaped to allow the same for pairs of blades at 90 degrees. The experimental model has an area of 0.025 m2 which represents 10% of the surface of the measuring section of the wind tunnel (0.25 m2). The behavior of the experimental model was compared with the experimental models of S-rotor with 2, 3 and 4 semi-cylindrical cups, with the same interception surface. The results confirm the better start of the experimental model by reducing dead zones and operating more evenly and stably over a longer range of wind speeds. The results confirm the validity of the proposed concept of interwoven aerodynamic coupling of semi-cylindrical cups.

The structure of turbulent flow behind the NACA 0012 airfoil at high angles of attack and low Reynolds number

This paper shows the results of a study of the turbulent structure behind the NACA 0012 airfoil. During the experiment, the flow velocity was 20 m·s−1. That corresponds the Reynolds number 1.3·105. The point behind the trailing edge was chosen for experimental studies. Measurements were performed at six angles of attack α = 0°, 15°, 30°, 45°, 60°, 75° and various cases of positioning the measuring section. Namely at a constant crosssection and a constant distance behind the airfoil. The NetScanner pressure system and hot-wire technique were used for experimental studies. The obtained data allowed us to investigate the wake topology. The average velocity and standard deviation distributions are clearly grouped depending on the angle of attack. Thus, flowing around the airfoil is better up to α ≤15°. Distributions by power density and dissipation spectra also have a similar grouping tendency. Finally, we investigated the turbulent structure according to the research program. We found that at α ≥45°, depending on the measurement case, there is a clear difference in the distribution of standard deviation, Eulerian length scale, Taylor micro-scale, and Reynolds number based on the Taylor micro-scale. The obtained values at the constant distance, in contrast to the constant cross-section, are reduced.

Применение индукционных датчиков в исследованиях быстропротекающих процессов

When testing on a rocket track, one of the most difficult problems is the system for controlling and launching pyrotechnic devices at a given coordinate. The way of start-up and device for its implementation, is intended to provide actuation of pyrotechnic means during acceleration of the rocket trains on the rails rocket catapult track to hypersonic speeds with ejection test subject in free flight. The method is based on the principle of generating current pulses for triggering pyrotechnic devices of moving stages of a rocket train using induction sensors. The same principle makes it possible to implement a non-contact method for starting recording systems and a device for measuring the average speed of a thrown object in continuous media. The method is based on the principle of generating triggering signals (rectangular pulses of positive polarity) for starting the recording equipment with synchronization of the launch along the path in a given coordinate and measuring the speed of the object being thrown at the time of its passage through the measuring section. The methods of starting recording systems and the results obtained as a result of hydrodynamic and terradynamic experiments are presented.